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feeding value and nutritive properties of citrus by-products

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feeding value and nutritive properties of citrus by-products
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Bulletin - University of Florida Agricultural Experiment Station ; 275
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Arnold, P. T. Dix.
Neal, W. M.
Becker, R. B.
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Gainesville, Fla.
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University of Florida Agricultural Experiment Station
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English

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Bulletin 275


January, 1935


AGRICULTURAL EXPERIMENT STATION
UNIVERSITY OF FLORIDA
GAINESVILLE, FLORIDA WILMON NEWELL, Director




THE FEEDING VALUE

AND NUTRITIVE PROPERTIES OF

CITRUS BY-PRODUCTS

1. The Digestible Nutrients of Dried Grapefruit and
Orange Cannery Refuses, and the Feeding Value of
the Grapefruit Refuse for Growing Heifers.

W. M. NEAL, R. B. BECKER and P. T. Dix ARNOLD


Figure I.-These heifers show the good condition and gloss of the hair produced by 120 days on a ration of sugarcane or sorghum silage, dried grapefruit refuse, and cottonseed meal.


Bulletins will be sent free to Florida residents upon application to
AGRICULTURAL EXPERIMENT STATION
GAINESVILLE, FLORIDA








EXECUTIVE STAFF

John J. Tigert, M.A., LL.D., President of the University
Wilmon Newell, D.Sc., Director H. Harold Hume, M.S., Asst. Dir., Research Harol:i Mowry, M.S.A., Asst. Dir., Adm. J. Francis Cooper, M.S.A., Editor R. M. Fulghum, B.S.A., Assistant Editor Jefferson Thomas, Assistant Editor Ida Keeling Cresap, Librarian Ruby Newhall, Administrative Manager K. H. Graham, Business Manager Rachel McQuarrie, Accountant

MAIN STATION, GAINESVILLE

AGRONOMY
W. E. Stokes, M.S., Agronomist" W. A. Leukel, Ph.D., Agronomist G. E. Ritchey, M.S.A. Associate* Fred H. Hull, Ph.D., Associate W. A. Carver, Ph.D., Associate John P. Camp, M.S., Assistant

ANIMAL HUSBANDRY
A. L. Shealy, D.V.M., Animal HusbandmanR. B. Becker, Ph.D., Dairy Husbandman W. M. Neal, Ph.D., Associate in Animal Nutrition
D. A. Sanders, D.V.M., Veterinarian M. W. Emmel, D.V.M., Asst. Veterinarian W. W. Henley, B.S.A., Asst. Animal Husbandman
P. T. Dix Arnold, B.S.A., Assistant Dairy Husbandman

CHEMISTRY AND SOILS
R. W. Ruprecht, Ph.D., Chemist" R. M. Barnette, Ph.D., Chemist C. E. Bell, Ph.D., Associate R. B. French, Ph.D., Associate H. W. Winsor, B.S.A., Assistant H. W. Jones, M.S., Assistant

ECONOMICS, AGRICULTURAL
C. V. Noble, Ph.D., Agricultural EconomistBruce McKinley, A.B., B.S.A., Associate Zach Savage, M.S.A., Associate A. H. Spurlock, M.S.A., Assistant

ECONOMICS, HOME
Ouida Davis Abbott, Ph.D., Specialist** L. W. Gaddum, Ph.D., Biochemist C. F. Ahmann, Ph.D., Physiologist J. T. Hall, Jr., B.S.Ch.E., Asst. Physiologist

ENTOMOLOGY
J. R. Watson, A.M., Entomologist** A. N. Tissot, Ph.D., Associate H. E. Bratley, M.S.A., Assistant J. W. Kea, B.S.A., Assistant
HORTICULTURE
A. F. Camp, Ph.D., Horticulturist** G. H, Blackmon, M.S.A., Horticulturist A. L. Stahl, Ph.D., Associate F. S. Jamison, Ph.D., Truck Horticulturist R. J. Wilmot, M.S.A., Specialist, Fumigation Research
R. D. Dickey, B.S.A., Assistant Horticulturist
PLANT PATHOLOGY
W. B. Tis0ale, Ph.D., Plant Pathologist-5 George F. Weber, Ph.D., Plant Pathologist R. K. Voorhees, M.S., Assistant Erdman West, M.S., Mycologist Lillian E. Arnold, M.S., Assistant Botanist
* In cooperation with U.S.D.A.
* Head of Department


BOARD OF CONTROL

Geo. H. Baldwin, Chairman, Jacksonville A. H. Landing, Bartow A. H. Wagg, West Palm Beach Oliver J. Semmes, Pensacola Harry C. Duncan, Tavares J, T. Diamond, Secretary, Tallahassee

BRANCH STATIONS

NORTH FLORIDA STATION, QUINCY
L. 0. Gratz, Ph.D., Plant Pathologist in Charge
R, R, Kincaid, Ph.D., Asso. Plant Pathologist J. D, Warner, M.S., Agronomist R. M. Crown, B.S.A., Asst. Agronomist Jesse Reeves, Farm Superintendent

CITRUS STATION. LAKE ALFRED
John H. Jefferies, Superintendent Geo. D. Ruehle, Ph.D., Associate Plant Pathologist
W. A. Kuntz, A.M., Assoc. Plant Pathologist B. R. Fudge, Ph.D., Associate Chemist W. L. Thompson, B.S., Asst. Entomologist

EVERGLADES STATION, BELLE GLADE
A. Daane, Ph.D., Agronomist in Charge R. N. Lobdell, M.S., Entomologist F. D. Stevens, B.S., Sugarcane Agronomist G. R. Townsend, Ph.D., Asst. Plant Pathologist
J. R. Neller, Ph.D., Biochemist R. W. Kidder, B.S., Asst. Animal Husbandman
Ross E. Robertson, E.S., Assistant Chemist

SUB-TROPICAL STATION, HOMESTEAD
IT. S. Wolfe, Ph.D., Horticulturist in Charge W. M. Fifield, M.S., Asst. Horticulturist Stacy 0. Hawkins, M.A., Assistant Plant Pathologist

WEST CENTRAL FLORIDA STATION, BROOKSVILLE
E. W. Sheets, D.Agri., Animal Husbandman in Charge*
W. F. Ward, M.S.A., Asst. An. Husbandman*


FIELD STATIONS

LeesLurg
M. N. Walker, Ph.D., Plant Pathologist in Charge
W. B. Shippy, Ph.D., Asso. Plant Pathologist K. W. Loucks, M.S., Asst. Plant Pathologist J. W. Wilson, Ph.D., Associate Entomologist C C_ Goff, M.S., Assisttt Entomologist
Plant ( ity
A. N. Brooks, Ph.D., Plant Pathologist R. E. Nolen, M.S.A., Asst. Plant Pathologist
Cocoa
A, S. Rhoads, Ph.D., Plant Pathologist
Hastings
A. H. Eddins. PhD., Plant Pathologist
Monticello
G. B. Fairchild, M.S., Assistant Entomologist
Bradenton
David G. Kelbert, Asst. Plant Pathologist
Sanford
E. R. Purvis, Ph.D., Assistant Chemist, Celery Investigations

























CONTENTS

Introduction . . . . . . . . . . . . . .
Statement of the Problem . . . .
R eview of L iterature . . . . . . . .
Experimental Methods . . . . .
Presents tion and Discu-ion of the Data.
Palatability of Dried Grapefruit Cannery Refuse . .
" ige8tibility of Dried Grapefruit Cannery Refuse . .
" ige8tibility of Dried Orange Peel. . -------Discussion of Digestion Trials. .
Feeding Trial wih Growing Heifers- . .
G eneral D iscussion . . . . . . . Summary anl Conclusions.,. , . - . .
A cknow ledgm ents . . . . . . . . . . .
L iterature C ited. . . . ----- . .
Appendix __ . . . . . .


Page
3
4
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10 10
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. . . . . - --- ----- 17

- -- --------------- 10
. . . . . 20
21


The use of dried citrus fruit by-products for livestock feeding was suggested by F. A. McDermott, holder of a Florida Citrus Exchange fellowship at the Mellon Institute, in 1916. Since that time the matter has received attention in California, and more recently in Florida. At the present time there is a limited amount of dried grapefruit cannery refuse reaching the market.

The citrus industry is one of the principal sources of income to the state through the marketing of fresh and canned fruit. However, there is a proportion of the crop that drops in the grove, is not fit to pick, is culled out in the packinghouse, or remains as refuse at the canning plant. Much of this part of the crop has not been utilized in any manner, except as fertilizer. Some outlet is needed f or this part of the crop that will return more than fertilizer value to the grower, especially when it is remembered that a large part of the groves in the state have not reached their mature yields, and the crop is increasing year by year.

A method of utilization of citrus cannery refuse that would change this material from a liability to an asset to the cannery, and also provide an outlet for cull fruit, would be of inestimable value to the citrus industry. If, at the same time, a valuable


THE FEEDING VALUE AND NUTRITIVE PROPERTIES

OF CITRUS BY-PRODUCTS


1. The Digestible Nutrients of Dried Grapefruit and Orange

Cannery Refuses, and the Feeding Value of the Grapefruit

Refuse for Growing Heifers.


W. M. NEAL, R. B. BECKER and P. T. Dix ARNOLD





Florida Agricultural Experiment Station


feed for livestock were produced, less feed material from other sections of this country and from foreign countries would be needed. The fact that a valuable feed could be produced from citrus cannery refuse should stimulate investigations on the mechanical problems of drying these products. Much work remains on this phase of the problem.
This report presents the composition, coefficients of digestibility, and the digestible nutrients of dried grapefruit cannery refuse, and of dried orange peel, and the results of a short feeding trial with growing heifers in which dried grapefruit cannery refuse was the principal source of digestible nutrients.
STATEMENT OF THE PROBLEM
At the present time the peel, rag and seed of the fruit which constitute cannery refuse are a liability to the cannery, due to the necessity for their disposal. A very small amount is fed to livestock in the fresh state; some is returned to the groves as fertilizer, and a considerable amount is dumped in the woods to decay. There is some evidence that the citrus peel oil in the fresh refuse will flavor milk when fed to cows in production, so that the feeding of this fresh product to dairy cows, except dry cows, cannot be advised.
The amount of this refuse from the canneries in this state is indicated from the data in Table 1, compiled from data by the Bureau of Foreign and Domestic Commerce, U. S. Department of Commerce.
Almost one-fifth of the grapefruit crop is canned as either juice or hearts each season. Two-thirds of this part of the crop constitutes the refuse of which the canneries must make some disposition. This grapefruit refuse together with the small amount of orange refuse amounts to about 65,000 tons in an average season. This quantity will increase as the demand for canned fruit is developed.
Dr. C. V. Noble, Agricultural Economist of the Florida Agricultural Experiment Station, has supplied the authors with data for the 1931-32 season, which was considered normal. Based on nine estimates for oranges, 10 for grapefruit, and four for tangerines, there were 8.0 percent, 13.7 percent, and 10.0 percent, respectively, of these fruits left in the groves. Based on 37 estimates for oranges and 36 estimates for grapefruit and tangerines, it was estimated that 2.75 percent of the oranges, 3.37 percent of the grapefruit, and 4.01 percent of the tangerines taken to the packinghouses found their way to the cull pile.






The Feeding Value of Citrus BV-Products


TABLE I.-CITRUS CANNERY REFUSE AVAILABLE IN FLORIDA DURING THE FIVE SEASONS or 1929-34.*
Jrotal Amount of
Season Field Boxes Percent of Fresh Cannery Refuse"
to Canneries Fruit as Refuse poundsGRAPEFRUIT

1929-80 - ------------------------ 1,639,923 74.2 109,580,934
1930-31 . 1-1 ---------- 2,892,705 69.4 180,667,298
1931-32 . ------------------- 932,864 64.9 54,505,898
1932-33 ------------------- 2,525,992 67.6 153,696,759
---------------- 66.6 141,950,574
1933-34 ----- 2,369,058

A verage ----------- . --------------------------------------------- ----------------------- 64,040 tons

ORANGES

1929-30 ------------------------ 36,514 70.9 2,328,684
1930-31 ---------------------- 61,351 71.8 3,963,285
1931-32 . 36,362 71.7 2,345,349
1932-33 -------------------------- 60 ' 720 70.0 3,824,666
1933-34 ----------------------- 55848 70.7 3,555,531

A verage ------- . ----------- . 1,602 tons
T otal per season ----- ---------------------------------------------------------------------------------- 65,642 tons

*Cornputed by Dr. C. V. Noble, Agricultural Economist of the Florida Agricultural Experiment Station from data compiled by the Bureau of Foreign and Domestic Commerce, U. S. Department of Commerce.
*This represents the difference between the weight of the field boxes received, and the net weights of the canned products.

Leading fruit men estimate that 10 percent of the fruit now marketed is of such low grade that it does not pay the marketing expenses. The market for fruit of higher quality is injured by this competition of low grade fruit. Considering (a) the amount of fruit that drops or is lef t in grove, (b) the amount that reaches the cull pile, (c) the refuse from the canneries, and (d) the low grade fruit that reaches the market, there is from one-fifth to one-fourth of the citrus crop that would be available f or the production of livestock f eeds. The cannery refuse and the cull pile at the packinghouse are the parts of this supply that first merit attention, due to the problem of their disposal.
The method of drying cannery refuse remains near the experimental stage. The product now on the market in Florida is passed through corrugated rollers that tend to disintegrate the fibrous structure of the peel and express a part of the water.





Florida Agricultural Experiment Station


Also, a part of the citrus peel oil is expressed in this operation. From the rollers the refuse is conveyed to a five-compartment drier which is heated by a fuel oil furnace. Circulation of the heated air is assured by means of pressure and suction fans. In the first compartment the material is heated to near the boiling point as it is agitated by rotary paddles. It is passed from compartment to compartment with continuous agitation until discharged at the outlet with a moisture content of 10 percent or less. The dried product takes up atmospheric moisture slowly.
The physical condition of this feed is determined by the processing method. The fresh refuse is cut into narrow strips as it passes through the corrugated rollers. The length of these strips varies due to the size of the pieces of peel, and the amount of breaking as they pass through the drier. The final product consists of flakes and shreds of the dried refuse, somewhat coarser than beet pulp. The pieces are hard and slightly brittle; however, dairymen state that when soaked like beet pulp, the fresh texture is recovered. In the dry state it can be ground into a meal with a hammer mill, although there is nothing to indicate that such is desirable for cattle feeding.
In color, the dried grapefruit refuse varies from a golden brown to a bright gold. The dried orange peel has a more reddish tint. The brightest product is secured by the use of lower drying temperatures.
The characteristics of this material that set it aside from the usual stock feeds are: high content of citric acid, pectin, 'and soluble sugars, and the presence of --lucosides, pigments, and essential oils. The physiological effects of these constituents on large animals remain to be investigated. The first concern of the stock feeder is the palatability of a product and the amount of digestible nutrients that it contains.
In addition to knowing the palatability and digestible nutrient content, it is necessary when making the final evaluation of a feed, to compare the value of the nutrients in actual feeding practice with those of the most similar known feed, and to study the effects of long continued feeding of the product to determine any special beneficial or harmful effects on the animal. Further, it is desirable to study the effects that specific constituents might have on the animal. None of this information was available for dried grapefruit cannery refuse, and very little for any of the dried citrus by-products.








REVIEW OF LITERATURE

McDermott (7)1, holder of a Florida Citrus Exchange fellowship with the Mellon Institute, suggested in 1916 that the dried by-product from the manufacture of various products from cull fruits might have a place as livestock feed.
The only feeding trial reported with cattle using dried grapefruit cannery refuse was conducted by Scott (14) at this station in 1925-26. He used a product, furnished by the Florida Citrus Exchange, that analyzed 18.00 percent moisture, 5.25 percent fat, 5.31 percent crude protein, 61.69 percent nitrogen-free extract and ash, and 9.75 percent crude fiber. The six Jersey cows to which this product was fed gave increased milk yields as a result of additions of the dried grapefruit refuse to their rations.
Studies concerning the composition, coefficients of digestibility, and digestible nutrients of dried fruit by-products have been conducted at the California (8, 9) and Virginia (5) stations. The data from these studies are summarized in Table 2.

TABLE 2-THE COMPOSITION, COEFFICIENTS OF DIGESTIBILITY, AND DIGESTIBLE NUTRIENTS OF CIT.iUS AND OTHER FRUIT BY-PRODUCTS.
Dry ' Crude I Crude I N-Free Crude Dried Fruit By-Product Matter Protein I Fiber Extract Fat I-Ash I percent percent I percent percent percent I percent
COMPOSITION OF THE PRODUCT
Orange pulp (8) --_--_-- 87.50 1 7.70 7.81 66.96 1.68 1 3.35
Lemon pulp (9) . - --- 92.90 1 6.39 15.00 65.24 1.23 5,04 Raisin pulp (8) ------------ 88.68 9.58 19.32 45:9547 10.54 3.67
Pineapple pulp (9) ------ 83.60 3.81 13.88 61 0.71 3.26
Olive pulp (9) . 92.02 5.91 36.45 31.54 15.63 2.49 Olive pulp* (9) - ------ 95.11 13.99 19.27 31.04 27.39 3.43
Apple pomace (5) . 86.68 4.31 17.03 69.76 5.13 3.77 COEFFICIENTS OF DIGESTIBILITY
Orange pulp --- . 89.33 78.54 83.73 95.40 48.89 Lemon pulp __. --------------- 81.43 46.18 60.33 92.01 27.44
Raisin pul 44.78 24.13 18.54 52.01 90.16
Pineapple pu i 74.56 20.75 69.62 79.75 neg.
Olive pulp . . . 19.09 neg. neg. 20.27 86.02 App'e pomace . . 67. 37. 54. 80. 32.
DIGESTIBLE NUTRIENTS T.D.N.


The Feeding Value of Citrus By-Products


Orange pulp . - 6 15 6.54 63.88 0.82 78.3
Lemon pulp . . 2 95 9.05 60.03 0.34 72.8
Raisin pulp . --------------------_-_- 2.31 3.58 23.70 9.50 50.9
Pineapple pulp --------- . J 0.79 9.66 49.40' 0.00 59.8
Olive pulp . __ ---------------------- --- Ili 0.00 0.00 6.39 13.44 36.6
Apple pomace . ----------------------- . _ 1 1.59 5.79 55.81 1.64 66.8
Prepared from pitted olives.
Figures in parentheses (Italic) refer to "Literature Cited", page 20.


I
0
8
5
3
8





Florida Agricultural Experiment Station


The orange pulp referred to in Table 2 was the dried residue from the manufacture of orange juice, orange oil, or other orange extracts. Dried lemon pulp was the rind, pulp, and seeds after the extraction of citric acid. Dried raisin pulp consisted of the various wastes with most of the sugar extracted. Pineapple pulp contained the outer skin, trimmings, and cores after juice extraction. The first analysis of olive pulp represented a sample from the commercial preparation of olive oil. This pulp contained the pits, and was used in the digestion trials. The second sample represented a pit-free pulp and hence was lower in fiber. Dried apple pomace was the dried residue from cider manufacture.
Digestion trials at the California station were conducted with five wethers, using a basal ration of alfalfa hay. Preliminary periods were 10 days in length and experimental periods 15 days. A basal ration of mixed grain and corn silage was used with cows at the Virginia station in the studies with dried apple pomace.
These citrus and apple by-products are seen to be low in protein and fiber, and high in nitrogen-free extract. They are essentially carbohydrate feeds and are highly digestible. One trial at the California station (13) with dried orange pulp showed it to be equivalent to beet pulp for milk production. Fresh pulp was not found to have any effect on percent of fat in the milk. Nothing was mentioned of any flavor being imparted to the milk when as much as 20 pounds of the fresh pulp was f ed daily, nor was mention made of the particular extracts from which this pulp was a residue. The citrus peel oils may have been removed in the process of manufacture.
EXPERIMENTAL METHODS
The palatability of the dried grapefruit refuse was tested in the dairy herd of the Florida Agricultural Experiment Station by offering small portions to the individual cows of the dairy herd after they had received the usual offering of corn silage and grain feed.
The methods used in conducting the digestion trials were essentially as recommended by Forbes and Grindley (3). The basal ration per day consisted of one pound of prime cottonseed meal and enough No. I federal grade alfalfa hay to supply slightly more than the requirement of total digestible nutrients for maintenance. In the trials with the feeds to be tested, onehalf of the alfalfa hay was replaced by the particular feed. In





The Feeding Value of Citrus By-Products


every case the requirement for digestible crude protein was exceeded by the total ration. Preliminary periods were 10 days in length, and the experimental periods consisted of four successive five-day periods.
Four steers, three Jerseys and one grade Hereford, ranging in weight from 450 to 700 pounds, were used in all the trials. The individual feeds for an entire trial were weighed into separate bags on a solution balance before the beginning of a trial. Samples were taken at that time. The feed was given in two equal portions at 6:00 a.m. and 6:00 p.m. The steers were held in a dry lot for the first nine days of the preliminary periods and then stanchioned in a barn. Water was provided in buckets. Salt was offered in small boxes. Each animal was brushed vigorously for one hour daily as a substitute for exercise.
Feces collections were manual. The daily collections of feces were weighed and sampled separately at 9:00 a.m. each day. Triplicate five to 10 gram samples were taken in weighing bottles for the determination of nitrogen, thus avoiding volatilization of any ammonia. A twentieth aliquot was taken in pyrex dishes, dried, and used in the preparation of five-day composite samples, for the determination of the other constituents.
Proximate analyses were made by the methods of the Association of Official Agricultural Chemists (1). Calcium, magnesium, and phosphorus were determined by the method of Morris, Nelson, and Pamer (10).
Indirect calculations were made of the digestibility of the nutrients. The coefficients of digestibility for cottonseed meal, as compiled by Henry and Morrison (4), were used for that feed. Coefficients for the alfalfa hay were calculated from the trial on the basal ration of cottonseed meal and alfalfa hay, and were used in the calculations 117 ith the dried grapefruit cannery refuse, and with the dried orange peel. The crude protein as determined in the fresh feces was used in all calculations to avoid any error due to the volatilization of ammonia.
To secure some information as to the general feeding qualities and effect of the dried grapefruit refuse on the animal, a feeding trial was conducted with eight native and grade Hereford heifers. The ration used was 30 pounds of sugarcane silage, 15 pounds of dried grapefruit refuse, and 5 pounds of prime cottonseed meal daily per thousand pounds liveweight. The cottonseed meal supplied the requirement for digestible crude protein. Sorghum silage was substituted for the sugarcane silage at the end of 80 days. These feeds were mixed and fed to the lots in equal off er-





Florida Agricultural Experiment Station


ings, morning and evening. Water and salt were available at all times. Finely ground feeding bonemeal was offered to Lot 1.
Blood samples were taken at the beginning of the trial and at the end of the first, second, and fourth 30-day periods. These samples were analyzed for calcium and inorganic phosphorus in the blood plasma by the methods of Kramer and Tisdal (6), and Fiske and Subbarow (2), respectively. Hemoglobin determinations were made by the Newcomer method (12).
The heifers were weighed on three successive days at each 30-day interval. Feed records were kept, and feed samples taken and analyzed for the ca'culation of the efficiency of the ration. General observations were made on the condition of the animals.

PRESENTATION AND DISCUSSION OF THE DATA*
Palatability of Dried Grapefruit Cannery Refuse.-One pound of dried grapefruit ref use was offered to each of 31 cows in the dairy herd after they had eaten their regular evening offering of corn silage and mixed grain. The refusal was weighed. Only one individual ref used the product on all six occasions. Fourteen cows tasted it when first offered, their appetites for this product increasing progressively. The refusal decreased from 29.8 pounds to 6.0 pounds out of the 31 pound daily offering over the six-day test.
Four steers used in the digestion trials refused a small part of their feed at the first offering when it was used to replace a part of the alfalfa hay in the ration of alfalfa hay and cottonseed meal. At no other time during the 30-day period was there any refusal.
Eight heifers, just off grass pasture, were used in the feeding trial. A 10-day preliminary period was allowed in which to determine their appetites for a ration of sugarcane silage, grapefruit refuse and cottonseed meal. When the bulk of their rations was reduced to the quantities fed in the actual trial, they refused only 60 pounds of feed in the entire trial. This refusal consisted almost totally of coarse pieces of silage.
Digestibility of Dried Grapefruit Cannery Refuse.-The four steers used in the digestion studies refused no feed after the first offering of the preliminary period. They maintained their weight or made slight gains. The composition of the grapefruit refuse, digestibility of the nutrients by each of the four steers, and the digestible nutrient content of the product are given in
* A preliminary report appeared in a recent press bulletin (11).








Table 3. Feed intakes per day, digestibility of the nutrients by 5-day periods, weight and composition of the feces, and composition of the feeds are given in Appendix Tables A, C, E and F.
TABLE 3-THE COMPOSITION, COEFFICIENTS OF DIGESTIBILITY, AND DIGESTIBLE NUTRIENTS OF DRIED GRAPEFRUIT REFUSE,


The Feeding Value of Citrus By-Products


The composition of the dried grapefruit refuse was: 91.77 percent dry matter, 4.94 percent crude protein, 11.94 percent crude fiber, 69.60 percent nitrogen-free extract, 1.06 percent crude fat, and 4.23 percent ash. The digestibility of the crude protein as shown by the individual steers varied from 19.32 percent to 33.07 percent, crude fiber from 63.72 percent to 81.04 percent, nitrogen-free extract from 92.04 percent to 93.19 percent, and of crude fat from 74.01 percent to 88.78 percent. Respective averages were: 24.83 percent (protein), 71.52 percent (fiber), 92.4' percent (N-free extract), and 79.37 percent (fat).
As determined from the above composition and digestibility, the dried grapefruit refuse contained 1.23 percent digestible crude protein, 72.87 percent digestible carbohydrates, 0.84 percent digestible crude fat, or a total of 75.99 percent digestible nutrients. The total digestible nutrients per hundredweight of dry matter were 82.80 pounds.
Digestibility of Dried Orange Peel.-The same amounts of dried orange peel were fed as of the dried grapefruit refuse. Live weights of the steers were maintained and no feed was refused after the initial offering. The composition of the dried orange peel, digestibility of the nutrients by each of the four steers, and the digestible nutrient content of the product are given in Table 4. Feed intakes per day, coefficients of digestiility by five-day periods, weight and composition of the feces, and composition of the feeds are given in Appendix Tables A, D, E and F.


Dry Crude Crude N-Free Crude Matter Protein Fiber Extract ' Fat I Ash percent percent percenill pe ree n 0 per ce n tj pe r-c ent
Composition _ . 91.77 4.9 4 11.94 69.60 1.06 4.23 Steer
Coefficients of E-49 24.46 67.51 92.11 74.01
digestibility E-50 19.32 73.81 92.39 88.78
E-51 33.07 81.04 93.19 79.31 E-52 22.48 63.72 92.04 75.38 Ave. 24.83 71.52 92.43 79.37
Digestible nutrients . -------------- _1 1.23. 8.54 64.33 0.84 __ 75.99








TABLE 4.-THE COMPOSITION, COEFFICIENTS OF DIGESTIBILITY, AND DIGESTIDLE NUTRIENTS OF DRIED ORANGE REFUSE.
Dry Crude I Crude N-Free Crude Matter -Protein i Fiber Atractl I Fati-Ashpercent percent percent percent percent pere ent
Composition . . . 1 86.05 5.84 10.64 64.74 0.69 4.13 Steer
Coefficients of E-49 44.30 90.18 89.35 -20.45
digestibility E-50 26.41 84.92 86.64 11.80
E-51 31.21 89.36 86.38 11.84 E-52 44.36 111.16 91.65 33.15 Ave. 36.57 93.91 88.51 __ 6.59
Digestible nutrients . 1 2.14 9.99 57.30 0.05 69.55

The composition of the dried orange peel was: 86.05 percent dry matter, 5.84 percent crude protein, 10.64 percent crude fiber, 64.74 percent nitrogen-free extract, 0.69 percent crude fat, and 4.13 percent ash. The dry matter, nitrogen-free extract, and crude fat were lower than in the dried grapefruit refuse, the ash nearly the same, and the crude protein slightly higher. The digestibility of the crude protein varied with the individual steers from 26.41 percent to 44.36 percent, the crude fiber from 84.92 percent to 111.16 percent, the nitrogen-free extract from 86.38 percent to 91.65 percent, and crude fat from -30.45 percent to 33.15 percent. The apparent high digestibility of the fiber with one steer and the negative coefficient for crude fat with one of the others were not surprising when the small proportion of crude fiber and crude fat in the total ration derived from the dried orange peel are considered. Averages were: 36.57 percent of crude protein, 93.1 percent for crude fiber, 88.51 percent for nitrogen-free extract, and 6.59 percent for crude fat.
The nutrients in the dried orange peel as calculated from the above composition and digestibility were: 2.14 percent digestible crude protein, 67.29 percent digestible carbohydrates, and 0.05 percent digestible crude fat, or a total of 69.55 percent digestible nutrients. This latter amount is equivalent to 80.82 pounds of digestible nutrients per hundredweight of dry matter.
Discussion of Digestion Trials.-Coefficients of digestibility varied most for the crude fiber and crude protein in both sets of trials, and for crude fat in the dried orange peel trials. Variations in these cases can be explained by the small proportion of the total intake of these constituents in the ration that were derived from the citrus by-products. The apparent low digestibility of the crude protein may be due to several factors, namely:


Florida Agricultural Experiment Station





The Feeding Value of Citrus By-Products


(a) the heating of the protein during the drying process which tends to make it less digestible, (b) the presence of non-protein nitrogen compounds in the citrus fruit that are not digestible, or (c) an apparent depression of digestibility as observed at the Virginia station (5) when a high carbohydrate feed such as apple pomace was added to a basal ration low in protein. This last factor should not be of importance in these trials, since the intake of digestible crude protein was more than adequate in all cases.
The coefficients of digestibility as determined for the nitrogenfree extract were remarkably consistent. As this constituent made up 75 percent of the dry matter in both citrus by-products, the variations observed in the digestibility of the other constituents had but a small effect on the measure of the total digestible nutrient content of these feeds. The low content of digestible crude protein precludes either dried grapefruit refuse or dried orange peel from being an important source of this nutrient.
Feeding Trial With Growing Heifers.-Eight native and grade Hereford heifers ranging in weight from 207 to 520 pounds were available for this trial. They were divided into two lots, the three larger in Lot 1 and five smaller in Lot 2. They were fed 30 pounds of sugarcane silage, 15 pounds of dried grapefruit refuse, and 5 pounds of prime cottonseed meal per day per thousand pounds liveweight. Sorghum silage was substituted for the sugarcane silage at the end of 80 days. Lot 1 was continued on feed for 60 days and Lot 2 for 120 days. Live weights of the individual animals and feed and nutrient intakes for the lots are given in Tab'e 5.
The ration was very palatable, as only 60 pounds of feed were refused during the entire trial. This refusal consisted of coarse pieces of silage. Lot I took 14 pounds of salt in 60 days; Lot 2, IS pounds in the first 60 days, and 22 pounds in the second 60 days, or'an average of 2.08 pounds per head each 30 days. Lot 1, allowed bonemeal, consumed 18 pounds in 60 days, or three pounds per head per month.
Rate of gain varied from 0.98 to 2.40 pounds per day, except for No. 26. Fecal examination showed that this animal was infested heavily with stomach worms. Her gain in weight for the 120-day period was only 21 pounds. Since such an infestation interferes with the utilizatioii of feed, her -,veight and one-fifth of the nutrient intake were deducted from Lot 2, before calculating the economy of gains on this ration.
Digestible crude protein and total digestible nutrient intakes











TABLE 5.--THE LIVEWEIGHT, AND FEED AND DIGESTIBLE NUTRIENT INTAKES OF HEIFERS FED SILAGE, DRIED GRAPEFRUIT CANNERY REFUSE, AND COTTONSEED MEAL.


30-Day
Period Lot
Number Number


Animal Number


I 1 19
20 22




II 1 19
20 22




I 2 23
24 25
26 27


Initial Final Weight Weight pounds pounds

520 581
350 395
432 459

1,302 1,435


581 665
395 437
459 530

1,435 1,632


207 270 277
274 320

1,348


217 309 305 304 363

1,498


Feed Intake Nutrient Intake
Cotton- Digestiblej Total
Grape- seed Crude Diges-ible Silage fruit Meal Protein Nutrients pounds i pounds pounds -pounds j pounds





1,188 594 197 71.4 753.6





1,544 772 232 85.0 954.9







1,188 594 197 71.4 753.6


T. D. N. Per 100 Pounds Gain Total Net* pounds pounds




565.9 321.9





484.7 299.7







502.4 277.8





TABLE 5.-THE LIVEWEIGHT, AND FEED AND DIGESTIBLE NUTRIENT INTAKES OF HEIFERS FED SILAGE, DRIED GRAPEFRUIT CANNERY REFUSE, AND COTTONSEED MEAL continuedd).


30-Day
Period Lot
Number Number


II 2


Animal Number


23 24 25 26 27



23 24 25 26 27



23 24 25 26 27


Initial Weight pounds

217 309 305 '304 363

1,498

237 347 317 289 399

1,589

279 387 347 312 424

1,749


Final Weight pounds

237 347 317 289 399

1,589

279 387 347 312 424

1,749

337 418 395 295 505

1,950


Feed Intake


Silage pounds






1,526 1,652 1,800


CottonGrape- seed fruit Meal pounds pounds


Nutrient Intake Digestiblej Total Crude Digesti Protein Nutrier pounds I pound






84.9 945.8






102.2 1,048.1






117.2 1,162.,


Average 488.0


374.7


257.9 298.1


* Net total digestible nutrients per hundred weight of gain were calculated by deducting maintenance at the rate of 7.925 pounds daily per thousand pounds liveweight from the total nutrient intake. The weight of No. 26 and one-fifth of the nutrient intake were deducted before making this calculation for Lot 2.


T. D. N. Per 100 ble Pounds Gain its Total Net* s pounds pounds455.8 281.4


612.0 426.5





Florida Agricultural Experiment Station


were calculated from actual analyses of the feeds by applying the coefficients of digestibility for the silage and cottonseed meal as given by Henry and Morrison (4), and for the grapefruit refuse as given in Table 3. Fif ty-f our percent of the dry matter, and 60 percent of the total digestible nutrients were provided by the dried grapefruit refuse. The digestible nutrient intake per hundredweight gain varied from 426 to 612 pounds, or an average of 488 pounds. The extremes were for periods 3 and 4 with Lot 2, and variations in fill may account f or a part of the difference, especially since the periods were successive. When a maintenance requirement (of 7.925 pounds of digestible -nutrients daily per thousand pounds liveweight) was deducted from the total nutrient intake, the average net requirement per hundredweight of gain 'became 298 pounds, with a range from 258 to 375 pounds. This is an economy of gain comparable with that secured with rather heavy grain feeding.
Blood samples were taken on three successive days at the beginning of the trial and at the end of the first, second, and fourth 30-day periods. Calcium and inorganic phosphorus were determined on the composite citrated blood plasma samples, and hemoglobin on the daily samples. Detailed results are given in Table 6.
No significant variations were observed in any of these constituents. Even though Lot 1 consumed bonemeal at the rate of 3.0 pounds per head per month, the inorganic phosphorus was no higher than in Lot 2. Also, the inorganic phosphorus in the blood plasma of Lot 2 did not decrease during the entire trial. However, a decrease would not be expected, since all the heifers had free access to bonemeal on pasture previously. Cottonseed meal also is one of the high phosphorus feeds.
The effect of the total ration was markedly laxative. A soft jelly-like consistency of the feces was observed during the entire trial. Sugarcane silage used in these rations is considered to be moderately laxative, and cottonseed meal relatively constipating. It was presumed that pectin was the constituent having this laxative effect, although the high citric acid content of the feed may have contributed.
All of the animals had a sleek, thrifty appearance, were alert, and had bright eyes. The sleek, oily appearance of the coat of hair was similar to that secured by feeding bran, oats, and linseed meal. Even No. 26 did not seem to be "out of condition", and failure to make gains was the only casual symptom of the parasitic infestation. Every animal except No. 26 improved in






The Feeding Value of Citrus By-Products


thickness of flesh while on the ration. Figure 1 shows Lot 2 at the end of 120 days on the ration of silage, grapefruit refuse and cottonseed meal.

TABLE 6.-THE CALCIUM AND INOGRANIC PHOSPHORUS CONTENT OF THE
BLOOD PLASMA, AND THE HEMOGLOBIN CONTENT OF THE BLOOD OF HEIFERS FED SILAGE, DRIED GRAPEFRUIT CANNERY REFUSE AND COTTONSEED MEAL.
Animal D A T E
Number 7/16-18 I 8/15-17 9/14-16 I 11/13-15

CALCIUM PER 100 ML. OF CITRATED BLOOD PLASMA
ags. mgs. rags. mgs.

19 11.66 12.29 10.65 .
20 11.11 10.59 .
22 11.88 11.47 10.06
23 11.66 11.35 10.24 11.23
24 12.21 10.76 9.83 11.35
25 11.88 11.00 9.65 11.00
26 11.66 11.35 10.24 10.82
27 11.66 11.12 9.42 11.88

PHOSPHORUS PER 100 ML. OF CITRATED BLOOD PLASMA

19 7.09 8.13 6.85 .
20 6.54 7.60 6.02 .
22 5.56 10.87 6.85
23 5.38 7.78 6.80 7.81
24 5.36 7.49 6.01 6.45
25 6.43 7.14 7.66 8.03
26 5.08 6.76 6.85 7.09
27 5.19 6.76 6.29 5.83

HEMOGLOBIN PER 100 ML. OF BLOOD

gs. - gs. gs. gs.

19 11.10 9.68 11.35 .
20 13.37 11.65 12.94 .
22 10.80 9.68 9.82
23 11.66 8.48 9.01 12.02
24 12.48 11.29 12.49 17.29
25 11.74 9.82 9.52 12.70
26 15 25 11.44 10.20 11.87
27 11.84 12.98 13.29 19.29


GENERAL DISCUSSION

The bitter taste of the grapefruit caused by its narangin (glucoside) content, or the sourness caused by the citric acid, did not seem to detract from the palatability of the product. The effect of the drying process is not known. The grapefruit refuse was consumed with relish by almost all the animals having access to it. Dried orange peel seemed to be equally palatable. This





Florida Agricultural Experiment Station


is contrary to the results of the California station (8, 9, is) where orange pulp ground into a meal, and lemon pulp from citric acid manufacture, had to be fed in combination with other feeds in order to insure consumption.
Both the grapefruit refuse and orange peel were similar in chemical composition to the orange and lemon pulps studied at the California station (8, 9). They have slightly less fiber and crude fat than the dried apple pomace investigated at the Virginia station (5). The low fiber content and high proportion of nitrogen-free extract place these feeds in the group of concentrates. Their high degree of digestibility was evidenced both by the actual results of the digestion trials, and by the lesser quantity of feces voided by the steers when these feeds were substituted for one-half of the alfalfa hay of the basal ration. There was no indication of a deficiency of roughage when 3.0 pounds of silage and 1.5 pounds of grapefruit refuse were fed per each hundred pounds of liveweight. This is less than the "Rule of Thumb" recommendations for roughage in feeding practice.
It would seem that these feeds could be substituted for such a feed as beet pulp and for at least a part of the carbohydrate feeds like corn.
So far as could be determined from a 120-day feeding trial the general effects of the grapefruit refuse on the animal were favorable. It was fed at a much higher level than would be followed in general feeding practice. The glossy, oily appearance of the coat of hair and the thrift of the animals receiving the grapefruit refuse make it appear that this feed belongs in that group of feeds prized by stockmen for their beneficial effect on the animal. The particular constituent, or constituents, producing this effect is not known.
Even though the results of the digestion trials and the feeding trial indicate that dried grapefruit refuse and dried orange peel are good sources of digestible carbohydrates, longer continued feeding trials and actual comparisons with some of the standard feeds for fattening and for milk production are necessary for a final evaluation. Further studies of the physiological effects on the animal are desirable. Too little is known of the effect of fruit by-products upon animal welfare.






The Feeding Value of Citrus By-Products


SUMMARY AND CONCLUSIONS
Dried grapefruit cannery refuse and dried orange peel were palatable to cattle, contrary to the findings elsewhere with or ange and lemon pulp.
The citrus by-products were low in crude protein, fiber, and fat. They were high in nitrogen-free extract, which was 88-92 percent digestible. Total digestible nutrients per hundred pounds of dry matter were 82.80 and 80.82 pounds for grapefruit and orange refuse, respectively. The results of the digestion trials placed these feeds in the class of high carbohydrate concentrates.
Dried grapefruit and orange cannery refuses have a laxative action when fed as a large proportion of the ration. General effects of the dried grapefruit refuse were favorable as indicated by thrifty appearance, gloss of the coat of hair, and improvement in thickness of flesh.

ACKNOWLEDGMENTS
Acknowledgments are made to Herbert Henley who cared for the steers on digestion trials; to Arlington Henley, J. H. Warrington, S. L. Mimms, and T. J. Davis for manual collection of the feces; and to W. T. Dunn, L. L. Rusoff, and 1. 1. Rusoff for aid in analyses of the feed and feces samples. Three Jersey steers were loaned to the experiment station by J. L. Taylor for use in the digestion trials. A part of the experimental feeds were donated by R. B. Webster. Dr. M. W. Emmel made microscopic examinations of fecal samples for the determination of parasitic infestations.






Florida Agrciultural Experiment Station


LITERATURE CITED
1. Association of Official Agricultural Chemists. Official and tentative methods of analysis. Ed. 2, 535p. illus. Washington, D. C. 1925. 2. FIsKE, C. H. and Y. SUBBARoW. The colorimetric determination of phosphorus. Jour. Biol. Chem. 66; 375-400. 1925.
3. FORBES, E. B. and H. S. GRINDLEY. On the formulation of methods of experimentation in animal production. Bul. Natl. Research Council,
Vol. 6, Part 2, No. 33; 17-27. 1923.
4. HENRY, W. A. and F. B. MORRISON. Feeds and Feeding. 18th ed. illus.
Henry-Morrison Company, Madison, Wis. Pages 723 and 726. 1923. 5. HOLDAWAY, C. W., W. B. ELLETT, J. F. EHEART, and M. P. MILLER.
The importance of properly balanced rations in trials to determine digestibility as shown in experiments with dried apple pomace. Va.
Agr. Exp. Sta. Tech. Bul. 32; 3-18. 1927.
6. KRAMER, BENJAMIN and F. S. TISDAL. A simple technique for the determination of calcium and magnesium in small amounts of
serum. Jour. Biol. Chem. 47; 475-481. 1921.
7. MCDERMOTT, F. A., as summarized by S. S. WALKER. The utilization of cull ciLrus fruits in Florida. Fla. Agr. Exp. Sta. Bul. 135; 2-16.
1917.
8. MEAD, S. W. and H. R. GUILBERT. The digestibility of certain fruit
by-products as determined for ruminants. Part 1. Dried orange pulp and raisin pulp. Calif. Agr. Exp. Sta. Bul. 409; 3-11. 1926. 9. MEAD, S. W. and H. R. GUILBERT. The digestibility of certain fruit
by-products as determined for ruminants. Part 2. Dried pineapple pulp, dried lemon pulp, and dried olive pulp. Calif. Agr. Exp. Sta.
Bul. 439; 3-11. 1927.
10. MORRIS, H. P., J. W. NELSON, and L. S. PALMER. A quantitative determination of calcium, magnesium, and phosphorus in feedstuffs and cattle excreta. Indus. and Engin. Chem., Anal. Ed. 3; 164-167.
1931.
11. NEAL, W. M., R. B. BECKER, and P. T. Dix ARNOLD. Dried grapefruit
refuse-a valuable feed. Fla. Agr. Exp. Sta. Press Bul. 466; 1-2.
1934.
12. NEWCOMER, H. S. A new optical instrument for the determination of
hemoglobin in blood. Jour. Biol. Chem. 55; 569-574. 1923.
13. REGAN, W. M. and S. W. MEAD. The value of orange pulp for milk
production. Calif. Agr. Exp. Sta. Bul. 427; 3-16. 1927.
14. SCOTT, J. M. Grapefruit refuse as a dairy feed. Fla. Agr. Exp. Sta.
Ann. Rpt. 25R-26R. 1926.






APPENDIX

TABLE A.-FEED INTAKE PER DAY OF STEERS USED IN DETERMINING THE DIGESTIBILITY OF THE BASAL RATION, OF DRIED GRAPEFRUIT CANNERY REFUSE, AND OF DRIED ORANGE PEEL.


Alfalfa Hay .t (Sample nds number

8.0 855

0.0) 855

0.0 855

6.0 855


Anirral Number


E-49 ----E-50 ----E S

E-52 -----E-49.

E-50 -.

E-51.

E-52 -.


E-49 .-----E-50 .E-51 .E-52 ._


Cottonseed Meal


Number


21


Amii~
1)01


Grapefruit Refuse IDried Orange


Amount Sample
pounds number


Amount
-pounds

1.0 1.0 1.0 1.0


1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0


Amount ISa pounds nus


j Sample number

856 856 856 856 1013 1013 1013 1013 1213 1213 1213 1213


Peelm~ple
Tiber




















212


1212 1212


1014 1014 1014 1014


I


855 855 855 855


1211 1211 1211 1211






Florida Agricultural Experiment Station


TABLE B.-THE DIGESTIBILITY OF THE NUTRIENTS OF THE ALFALFA HAY


USED IN THE BASAL RATION As DETERMINED WITH FOUR SUCCESSIVE FIVE-DAY PERIODS.


Animal Trial
Number Number


E-49 21




E-50 22


E-51




E-52






Average Average Average Average


24


Coefficients of


5-Day Period Number


IV II

IVI
Average

I

IV
Aveag Iv


III IVI
Average


"I" periods --. . "I1" periods .---"III" periods .---"IV" periods. .----


Grand average.----.


Crude Protein percent

63.19
63.44 64.09 64.80 63.88

59.11 62.86
61.12
59.45 60.64

62.90 63.67 63.83
62.45 63.21

62.34 58.69 59.32 55.29 58.91


61.88 62.16
62.09 60.50


61.66


Crude Fiber percent

46.58 39.53 33.03
24.98 36.03

45.71 40.00 24.78 18.90 32.35

47.77
49.09 50.93
42.73 47.63

43.63 36.15
28.45 15.72 30.99


45.92 41.19
34.30 25.58


36.75


FOUR STEERS IN


Di gestibility N-Free ICrude Extract IFat Percent percent

72.45 0.37
69.06 -4.99 79.63 -1.95 68.83 -12.70 69.11 -4.82

72.28 0.23
69.51 2.01
61.43 -20.62 65.86 -10.57 67.27 -7.24

73.91 -12.58
72.49 12.80 73.05 7.10
69.95 1.94
72.35 2.31

77.57 6.82
68.18 -0.52 69.78 -3.94 63.67 -12.00 69.80 -2.41


74.05 69.81 70.97 67.08


69.63


-1.29
2.32
-4.85
-8.33


-3.04






The Feeding Value of Citrus By-Products


TABLE C.-THE DIGESTIBILITY OF THE NUTRIENTS OF DRIED GRAPEFRUJIT
CANNERY REFUSE As DETERMINED WITH FOUR STEERS IN FOUR SucCESSIVE FIVE-DAY PERIODS.


Animal Number E-49 E-50 E-51 E-52


Trial Number


25 26 27




28


5-Day Period Number



IV



IVI
Average

I
II III IV
Average


IV

Average


Average "I" periods._. Average "II" periods . . Average "III" periods -- --------Average "IV" periods . ----Grand average .


I Coefficients of


Crude Protein percent

-11.01
17.43 61.80 29.62
24.46

20.69
4.37 36.47 15.76 19.32

26.86
34.13 37.54 33.74 33.07

22.81
21.57 21.27
24.26 22.48


14.84 19.38


24.83


Crude Fiber percent


71.52


Digestibility
N-Free Crude Extract Fat percent percent

91.07 36.22 90.90 57.87 95.67 108.46 90.79 93.49 92.11 74.01

92.13 85.52 90.32 81.27 93.49 101.75 93.62 86.59 92.39 88.78

94.85 68.27 91.52 61.29
93.14 93.5bs 93.23 94.13 93.19 79.31

94.11 90.80 91.64 54.44 90.58 75.91 91.81 80.36 92.04 75.38


45.09 20.26 108.06
96.64 67.51

76.53
55.94 66.47 96.31 73.81

88.53 60.32
74.68 100.60
81.04

95.91
42.19 29.16 87.63 63.72


76.52
44.68 69.*59 95.30


70.20 63.72
94.91 88.64


79.37


93.04 91.10 93.22 92.36


92.43






Florida Agricultural Experiment Station


TABLE D.-THEm DIGESTIBILITY OF THE NUTRIENTS OF DRIED ORANGE PEEL
As DETERMINED WITH FOUR STEERS IN FOUR SUCCESSIVE FIVE-DAY
PERIODS.


Trial Number


- -Coefficients of Digestibility 5-Day Crude ICrude N-Free Crude
Period Protein Fiber Extractl Fat
Number percent Ipercent Ipercent Ipercent


Animal Number E-49 E-50 E-51 E-52


Average "I" periods --Average "II" periods ---------- - .
Average "III" periods ------. -----.
Average "IV" periods . .


Grand average.


49.40 60.43 33.24 34.13 44.30

18.85
27.14 29.19
30.47 26.41

30.16 30.83 29.99 33.86 31.21

40.04 55.75 51.01
30.64 44.36


34.61
43.54 35.86 32.28


36.57


107.98 102.92
48.82 82.99 90.18

90.57 73.63 87.81 87.65
84.92

91.60 85.74 101.26 78.82 89.36

108.51
114.32 116.25 105.55 111.16


99.67 98.65 88.54 88.75


93.91


90.60 92.98
84.43 89.40 89.35

84.72 87.29 86.35 88.21 86.64

88.25 82.65 86.55 88.09 86.38

90.84 91.50
93.45 90.81 91.65


88.60 88.61 87.70 89.13


88.51


-92.42
-75.91
-5.12
51.65
-30.45

60.41
-12.01
1.56
-2.77
11.80

30.22 17.25
-4.14
4.00 11.84

33.99 21.71 48.80 28.09 33.15


8.05
-25.72 10.28
20.24


33 1

IV

Average

34 1
II III IV
Average
35 I
II III IV
Average

36 I

IV

Average


I






The Feeding Value of Citrus By-Products


TABLE E.-THE WEIGHT AND COMPOSITION OF FECES FROM STEERS DURING DIGESTION TRIALS.


I
Anima Trial
Number Number


5-Day Period Number


I I Composition of Dry Matter
Total -- - -
Fresh Crude Dry Crude Crude N-Free ICrude
Excreta Protein I Matter I Ash Protein Fiber 1Extract Fat grams percent I percent percent I percent percent I percent I percent


BASAL RATION


I 36,365
II 36,785
III 1 37,655 IV 39,363
I 47,644
II 48,141
III 51,947 IV 57,406
I 42.602
II 43,284
III 42,923 IV 47,077
1 31,016
II 34,917
III 36,588 IV 44.219
BASAL RATION


31,805 30,636 21,523 24,342 35,857
42,433 30,921 35,292 32,451 36,441 36,196 33,783 22,428 23,211 23,378
20,978


2.766 2.739 2.634 2.477 2.838 2.758 2.488 2.337
2.910 2.812 2.824 2.662 2.613 2.507 2.362 2.116


22.59 23.25 23.27 22.99 23.62 21.11 21.30 20.62
23.86 21.32
20.56 20.66 21.83 19.13 18.20 17.71


20.93 15.30 11.20 10.42 26.26 12.48 10.57 8.78 20.63 14.19 12.80 11.73 26.94 13.75 10.28 10.84


10.47 10.59 9.90 10.09 10.76 11.40 10.65
10.14 12.06 12.31 12.14 11.12 10.55 11.09 10.68 10.57


38.12 41.50
44.60 48.22 35.22 42.93 44.39 49.33 37.571 40.38 40.77 42.89 37.94 42.59 47.58 47.28


PLUS DRIED GRAPEFRUIT REFUSE


3.460 3.175 3.595 3.772 3.237 2.951 3.467 3.367 3.470 2.978 2.945 3.219 3.338 3.243 3.224 3.545


20.91 21.14 22.30 22.69 20.28 18.43 22.64 19.00 21.12 19.96 19.16 18.98 23.16 i 20.17 21.34 20.54


16.44? 11.75 12.74 13.65 16.21 15.59 13.57 15.03 16.55 12.37 13.51 12.81 20.77 11.43 13.01 12.92


14.70 13.54 13.57 14.23 13.95 14.01 13.75 15.01 14.56 13.73 14.19 14.60 14.75 13.91 14.11 15.15


37.38 42.54 37.57
34.89 36.46 37.47 39.82 35.54 36.31 39.47 38.59 36.26 32.76 40.97 40.57 35.94


BASAL RATION PLUS DRIED ORANGE PEEL


IV
II IVI Iv

II III
IV
I
If III
IV


27,570 23,944 30,621 29,823 39,322 38,845 38,629 37,720 36,400 37,883
35,533 35,418 23,876 19,741 19,700 22,628


3.266 3.593 3.221 3.292 3.289 3.188 3.170 3.225 3.347 3.204 3.432 3.371 3.133
3.472
3.575 3.470


20.51 22.40 20.99 18.44 21.60
19.80 19.22 18.79 20.92 20.78 20.31 20.27 20.25 20.82 19.94 18.36


16.99 16.44 11.25 11.63 22.70 15.58 14.02 12.81 19.47 15.38 14.14 12.31 25.09
14.46 13.67 12.77


15.01 15.59 15.25 14.42 14.75 15.22 15.82 15.54 14.85 14.83 16.07 15.42 15.16 16.85 17.32 17.08


33.62 33.82 38.47 38.96 30.01 35.80 34.78 36.46 33.31 33.12 33.53 37.48 30.19 34.49 35.73 35.65


E-49 E-50


E-50


E-52 E-49


E-52


26.27 28.73 30.56 27.34 24.27 29.39 30.52 28.08 25.39 29.39 30.14 30.29 21.22 28.97 27.73 27.90


28.06 28.98 32.83 34.11 30.31 30.01
29.95 31.11 29.02 30.96 30.63 33.01 28.78 30.29 29.43 32.73


3.81 3.88 3.68 3.93 3.49 3.80 3.87 3.67 4.35 3.73 4.15 3.97 3.35 3.60 3.73
3.41



3.42 3.19 3.29 3.12 3.07 2.92 2.91 3.31 3.56 3.47 3.08 3.32 2.94 3.40 2.88 3.26


29.73 29.34 31.79 31.85 29.36 29.97 31.97 31.57 29.34 33.61 32.69 31.29 26.67 30.66 29.90 31.07


BASAL RATION













TABLE F.-THE COMPOSITION OF FEEDS USED IN DIGESTION AND FEEDING TRIALS.

composition of Dry Matter
Sample Dry Crude- C-rude N-Free Crude
Kind of Feed Number IMatter Protein Fiber Extract Fat IAsh I Ca Mg P
Percent percent [percent percent p erc-ent I percent I-percent Ipercent -perc-ent

Alfalfa Hay, No. 1 __ ---- 855 92.93 14.03 33.18 43.73 1.83 I 7.23 1.317 0.126 0.396
1211 90.41 15.59 35.20 39.10 1.59 8.52 1.290 .118 .225
Sugarcane Silage _. 1373 23.93 3.34 39.39 50.78 1.76 4.73 1 .343 .195 .181
1374 23.32 3.27 36.98 50.68 2.46 6.61 .365 .242 1 .167
Sorghum Silage.1377 24.17 3.12 29.30 59.40 3.13 5.05 21 .254 .175

Cottonseed Meal . 856 93.55 41.69 12.24 32.78 7.27 6.02 .230 I .172 I1.097
1014 93.44 43.74 9.00 34.27 6.60 6.39 .241 .184 1.121
1213 89.74 43.11 11.74 30.93 7.53 6.69 .2-36 .187 1.208
1375 89.62 43.22 13.33 30.03 6,81 6.61 .241 I .161 1.175
1378 91.12 41.93 14.94 29.43 7.08 6.62 .225 .147 1.149

Grapefruit Refuse . 1013 91.77 5.38 13.01 75.84 I 1.16 4.61 .787 .288 .100
1376 90.54 5.49 12.28 76.25 1.89 4.09 1 .689 .352 .097
1379 89.86 5.64 11.93 75.67 1.77 4.99 .746 . 378 .107

Dried Orange Peel . 1212 86.05 6.79 12.37 75.24 0.80 4.80 .725 .252 .107
























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Full Text

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Bulletin 275 January, 1935 AGRICULTURAL EXPERIMENT STATION UNIVERSITY OF FLORIDA GAINESVILLE, FLORIDA WILM ON NEWELL, Director THE FEEDING VALUE AND NUTRITIVE PROPERTIES OF CITRUS BY-PRODUCTS I. The Digestible Nutrients of Dried Grapefruit and Orange Cannery Refuses, and the Feeding Value of the Grapefruit Refuse for Growing Heifers. w. M. NEAL, R. B. BECKER and P. T. DIX ARNOLD Figure 1.-The se heifers s how the good co ndition and gloss of the hair produced by 120 days on a ration of s ugarcan e or sorghum silage, dried grapefruit refuse, and cottonseed meal. Bulletins will be sent free to Florida residents upon application to AGRICULTURAL EXPERIMENT STATION GAINESVILLE , FLORIDA

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EXECUTIVE STAFF John J. Tigert, M.A., LL.D., President of the University Wilmon Newell, D.Sc., Director H. Harold Hume, M.S., Asst. Dir., Research Haro!:\ Mowry, M.S.A .. Asst. Dir., Adm. J. Francis Cooper, M.S.A., Editor R. M. Fulghum, B.S.A., Assistant Editor Jefferson Thomas, Assistant Editor Ida Keeling Cresap, Librarian Ruby Newhall, Administrative Manager K. H. Graham, Business Manager Rachel McQuarrie, Accountant MAIN STATION, GAINESVILLE AGRONOMY W. E. Stokes, M.S., Agronomist** W. A. Leukel, Ph.D., Agronomist G. E. Ritchey, M.S.A .. Associate• Fred H. Hull, Ph.D., Associate W. A. Carver, Ph.D., Associate John P. Camp, M.S., Assistant ANIMAL HUSBANDRY A. L. Shealy, D.V.M., Animal Husbandman .. R. B. Becker, Ph.D., Dairy Husbandman W. M. Neal, Ph.D., Associate in Animal Nutrition D. A. Sanders, D.V.M., Veterinarian M. W. Emmel, D.V.M., Asst. Veterinarian W. W. Henley, B.S.A., Asst. Animal Husbandman P. T. Dix Arnold, B.S.A., Assistant Dairy Husbandman CHEMISTRY AND SOILS R. W. Ruprecht, Ph.D., Chemist•• R. M. Barnette, Ph.D., Chemist C. E. Bell, Ph.D., Associate R. B. French, Ph.D., Associate H. W. Winsor, B.S.A., Assistant H. W. Jones, M.S., Assistant ECONOMICS, AGRICULTURAL C. V. Noble, Ph.D., Agricultural Economist•• Bruce McKinley, A.B., B.S.A., Associate Zach Savage, M.S.A., Associate A. H. Spurlock, M.S.A., Assistant ECONOMICS, HOME Ouida Davis Abbott, Ph.D., Specialist•• L. W. Gaddum, Ph.D., Biochemist C. F. Ahmann, Ph.D., Physiologist J. T. Hall, Jr., B.S.Ch.E., Asst. Physiologist ENTOMOLOGY J. R. Watson, A.M., Entomologist** A. N. Tissot, Ph.D., Associate H. E. Bratley, M.S.A., Assistant J. W. Kea, B.S.A., Assistant HORTICULTURE A. F. Camp, Ph.D., Horticulturist** G. H. Blnckmon, M.S.A., Horticulturi!3t A. L. Stahl, Ph.D., Associate F. S. Jamison, Ph.D., Truck Horticulturist R. J. Wilmot, M.S.A., Specialist, Fumigation Research R. D. Dickey, B.S.A., Assistant Horticulturist PLANT PATHOLOGY W. B. Tisdale, Ph.D., Plant Pathologist•• George F'. Weber, Ph.D., Plant Pathologist R. K. Voorhees, M.S., Assistant Erdman West, M.S., Mycologist Lillian E. Arnold, M.S., Assistant Botanist In cooperation with U .S.D.A. "'* Head of Department. BOARD OF CONTROL Geo. H. Baldwin, Chairman, Jacksonville A. H. Blanding, Bartow A. H. Wagg, West Palm Beach Oliver J. Semmes, Pensacola Harry C. Duncan, Tavares J _ T. Diamond, Secretary, Tallahassee BRANCH STATIONS NORTH FLORIDA STATION, QUINCY L. 0. Gratz, Ph.D., Plant Pathologist in Charge R. R. Kincaid, Ph.D., Asso. Plant Pathologist J. D. Warner, M.S., Agronomist R. M. Crown, B.S.A., Asst. Agronomist Jesse Reeves, Farm Superintendent CITRUS STATION, LAKE ALFRED John H. Jefferies, Superintendent Geo. D. Ruehle, Ph.D., Associate Plant Pathologist W. A. Kuntz, A.M., Assoc. Plant Pathologist B. R. Fudge, Ph.D., Associate Chemist W. L. Thompson, B.S., Asst. Entomologist EVERGLADES STATION, BELLE GLADE A. Daane, Ph.D., Agronomist in Charge R. N. Lobdell, M.S., Entomologist F. D. Stevens, B.S .• Sugarcane Agronomist G. R. Townsend, Ph.D., Asst. Plant Patholo gist J. R. Neller, Ph.D., Biochemist R. W. Kidder, B.S., Asst. Animal Husband man Ross E. Robertson, B.S., Assistant Chemist SUB-TROPICAL STATION, HOMESTEAD IL S. Wolfe, Ph.D., Horticulturist in Charge W. M. Fifield, M.S., Asst. Horticulturist Stacy 0. Hawkins, M.A., Assistant Plant Pathologist WEST CENTRAL FLORIDA STATION, BROOKSVILLE E. W. Sheets, D.Agri., Animal Husbancjman in Charge* W. F. Wa1d, M.S.A., Asst. An. Husbandman• FIELD STATIONS Leeslurg M. N. Walker, Ph.D., Plant Pathologist in Charge W. B. Shippy, Ph.D., Asso. Plant Pathologist K. W. Loucks, M.S., Asst. Plant Pathologist J. W. Wilson, Ph.D., Associate Entomologist C. C. Goff, M.S., Assist:: nt Entomologist Plant City A. N. Brooks, Ph.D., Plant Patholo:ist R. E. Nolen, M.S.A., Asst. Plant Pathologist Cocoa A. S. Rhoads, Ph.D., Plant Pathologist Hastings A. H. Eddins, Ph.D., Plant Pathologist Monticello G. B. Fairchild, 1\1.S., Assistant Entomologist Bradenton David G. Kelbert, Asst. Plant Patho)oglat Sanford E. R. Purvis, Ph.D., Assistant Chemist. Celery Investigations

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THE FEEDING VALUE AND NUTRITIVE PROPERTIES OF CITRUS BY-PRODUCTS I. The Digestible Nutrients of Dried Grapefruit and Orange Cannery Refuses, and the Feeding Value of the Grapefruit Refuse for Growing Heifers. w. M. NEAL, R. B. BECKER and P. T. DIX ARNOLD Introdue.tion --Statement of the Probl em. Revie:w of Literatu re .... . .. . . Experimental M ethod s .. CONTENTS Present a tion and Discus sion of th e Data ... . ... . ... .. . Palatability of Dried G r apefru :t Cannery Re fu se .. . . Di gestib ility of Dr ied Grape fr u it Can nery Re f u se . . . . . Di gest ibility of Dried Orange Peel.. Di scuss ion of Digesti o n Trlal s ... ...... F eeding Tri al wi~h Gr o wing H e ifers . . Gener a l Di sc u s sion ... . .... .......... . Summ a ry anJ C o nclu s i ons .. . Acknowl ed a::ments ...... .. . Literat u re Cittd . .......... . Appendix. Paa-e 3 4 7 . 8 . ... 10 . ... -10 10 . .. 11 12 13 . . . .. ... . .. .. 17 19 19 20 . .. ....... ... 2 1 The use of dried citrus fruit by-products for liv es tock feeding was suggested by F. A. McDermott , holder of a Florida Citrus Exchange fellowship at the Mellon Institute, in 1916. Since that time the matter has received attention in California, and more recently in Florida. At the present time there is a limited amount of dried grapefruit cannery refuse reaching the market. The citrus industry is one of the principal sources of income to the state through the marketing of fresh and canned fruit. However, there is a proportion of the crop that drops in the grove, is not fit to pick, is culled out in the packinghouse, or remains as refuse at the canning plant. Much of this part of the crop has not been utilized in any manner, except as fertilizer. Some outlet is needed for this part of the crop that will return more than fertilizer value to the grower, especially when it is remembered that a large part of the groves in the state have not reached their mature yields, and the crop is increasing year by year. A method of utilization of citrus cannery refuse that would change this material from a liability to an asset to the cannery, and also provide an outlet for cull fruit, would be of inestimable value to the citrus industry. If, at the same time, a valuable

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4 Florida Agricultural Experiment Station feed for livestock were produced, less feed material from other sections of this country and from foreign countries would be needed. The fact that a valuable feed could be produced from citrus cannery refuse should stimulate investigations on the mechanical problems of drying these products. Much work re mains on this phase of the problem. This report presents the composition, coefficients of digestibil ity, and the digestible nutrients of dried grapefruit cannery refuse, and of dried orange peel, and the results of a short feed ing trial with growing heifers in which dried grapefruit cannery refuse was the principal source of digestible nutrients. STATEMENT OF THE PROBLEM At the present time the peel, rag and seed of the fruit which constitute cannery refuse are a liability to the cannery, due to the necessity for their disposal. A very small amount is fed to livestock in the fresh state; some is returned to the groves as fertilizer, and a considerable amount is dumped in the woods to decay. There is some evidence that the citrus peel oil in the fresh refuse will flavor milk when fed to cows in production, so that the feeding of this fresh product to dairy cows, except dry cows, cannot be advised. The amount of this refuse from the canneries in this state is indicated from the data in Table 1, compiled from data by the Bureau of Foreign and Domestic Commerce, U. S. Department of Commerce. Almost one-fifth of the grapefruit crop is canned as either juice or hearts each season. Two-thirds of this part of the crop constitutes the refuse of which the canneries must make some disposition. This grapefruit refuse together with the small amount of orange refuse amounts to about 65,000 tons in an average season. This quantity will increase as the demand for canned fruit is developed. Dr. C. V. Noble, Agricultural Economist of the Florida Agri cultural Experiment Station, has supplied the authors with data for the 1931-32 season, which was considered normal. Based on nine estimates for oranges, 10 for grapefruit, and four for tangerines, there were 8.0 percent, 13.7 percent, and 10.0 per cent, respectively, of these fruits left in the groves. Based on 37 estimates for oranges and 36 estimates for grapefruit and tangerines, it was estimated that 2.75 percent of the oranges, 3.37 percent of the grapefruit, and 4.01 percent of the tangerines taken to the packinghouses found their way to the cull pile.

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The Peeding Value of Citrus By-Products 5 TABLE 1.-CITRUS CANNERY REFUSE AVAILABLE IN FLORIDA DURING THE FIVE SEASONS OF 1929-34.''' Season \ I \Total Amount of Field Boxes Percent of Fresh Cannery Refuse** to Canneries Fruit as Refuse pounds ~1929-30 ..... 1930-31 ................... ( 1931-32 ::::::::::: : ::::::::::::::1 I GRAPEFRUIT 1,639,923 2,892,705 932,864 2,525,992 2,369,058 74.2 69.4 64.9 67.6 66.6 109,580,934 180,667,298 54,505,898 153,696,759 141,950,574 Average ........................................................................................................ 64,040 tons 1929-30 .......................... \ 1930-31 ......................... . 1931-32 .......................... 1 1932-33 .................. . ...... . 1933-34 ......................... I I ORANGES 36,514 61,351 36,362 60,720 55,848 70.9 71.8 71.7 70.0 70.7 2,328,684 3,963,285 2,345,349 3,824,666 3,555,531 Average.......................................... . ............................................................. 1,602 tons Total per season ...................................................................................... 65,642 tons *Computed by Dr. C. V. Noble, Agricultural Economist of the Florida Agricultural Experiment Station from data compiled by the Bureau of Foreign and Domestic Commerce, U. S. Department of Commerce. '''*This represents the difference between the weight of the field boxes received, and the net weights of the canned products. Leading fruit men estimate that 10 percent of the fruit now marketed is of such low grade that it does not pay the market ing expenses. The market for fruit of higher quality is injured by this competition of low grade fruit. Considering (a) the amount of fruit that drops or is left in grove, (b) the amount that reaches the cull pile, (c) the refuse from the canneries, and (d) the low grade fruit that reaches the market, there is from one-fifth to one-fourth of the citrus crop that would be available for the production of livestock feeds. The cannery refuse and the cull pile at the packinghouse are the parts of this supply that first merit attention, due to the problem of their disposal. The method of drying cannery refuse remains near the experi mental stage. The product now on the market in Florida is passed through corrugated rollers that tend to disintegrate the fibrous structure of the peel and express a part of the water.

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6 Florida Agricultural Experiment Station Also, a part of the citrus peel oil is expressed in this operation. From the rollers the refuse is conveyed to a five-compartment drier which is heated by a fuel oil furnace. Circulation of the heated air is assured by means of pressure and suction fans. In the first compartment the material is heated to near the boil ing point as it is agitated by rotary paddles. It is passed from compartment to compartment with continuous agitation until discharged at the outlet with a moisture content of 10 percent or less. The dried product takes up atmospheric moisture slowly. The physical condition of this feed is determined by the processing method. The fresh refuse is cut into narrow strips as it passes through the corrugated rollers. The length of these strips varies due to the size of the pieces of peel, and the amount of breaking as they pass through the drier. The final product consists of flakes and shreds of the dried refuse, somewhat coarser than beet pulp. The pieces are hard and slightly brittle; however, dairymen state that when soaked like beet pulp, the fresh texture is recovered. In the dry state it can be ground into a meal with a hammer mill, although there is nothing to indicate that such is desirable for cattle feeding. In color, the dried grapefruit refuse varies from a golden brown to a bright gold. The dried orange peel has a more red dish tint. The brightest product is secured by the use of lower drying temperatures. The characteristics of this material that set it aside from the usual stock feeds are: high content of citric acid, pectin, 'and soluble sugars, and the presence of glucosides, pigments, and essential oils. The physiological effects of these constituents on large animals remain to be investigated. The first concern of the stock feeder is the palatability of a product and the amount of digestible nutrients that it contains. In addition to knowing the palatability and digestible nutrient content, it is necessary when making the final evaluation of a feed, to compare the value of the nutrients in actual feeding practice with those of the most similar known feed, and to study the effects of long continued feeding of the product to determine any special beneficial or harmful effects on the animal. Further, it is desirable to study the effects that specific constituents might have on the animal. None of this information was avail able for dried grapefruit cannery refuse, and very little for any of the dried citrus by-products.

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The Feeding Value of Citrus By-Products 7 REVIEW OF LITERATURE McDermott (7) 1, holder of a Florida Citrus Exchange fellow ship with the Mellon Institute, suggested in 1916 that the dried by-product from the manufacture of various products from cull fruits might have a place as livestock feed. The only feeding trial reported with cattle using dried grape fruit cannery refuse was conducted by Scott (14) at this station in 1925-26. He used a product, furnished by the Florida Citrus Exchange, that ana ly zed 18.00 percent moisture, 5.25 percent fat, 5.31 percent crude protein, 61.69 percent nitrogen-free ex tract and ash, and 9.75 percent crude fiber. The six Jersey cows to which this product was fed gave increased milk yields as a result of additions of the dried grapefruit refuse to their rations. Studies concerning the composition, coefficients of digestibility, and digestible nutrients of dried fruit by-products have been conducted at the California (8, 9) and Virginia (5) stations. The data from these studies are summarized in Table 2. TABLE 2.-THE COMPOSITION, COEFFICIENTS OF DIGESTIBILITY, AND DIGEST IBLE NUTRIENTS OF CIT:ius AND OTHER FRUIT BY-PRODUCTS. I Dry ' [ Crud~ I C~ude I N-Free\ Crude I Dried Fruit By-Product / Matter Pro tern [ Fiber _ [ Extract Fat _ Ash _ percent I nercent I percent I percent I percent I percent COMPO S ITION OF THE PRODUCT Orange pulp (8) [ 87.50 I 7 . 70 7.81 66.96 1.68 I 3.35 Lemon pulp (9) 1 92 .9 0 , 6.39 15.00 65.24 1.23 5.04 Raisin pulp (8) .. .. ........ , 88 . 68 9.58 19.32 45.57 10.54 3.67 Pineapple pulp (9) ...... 1 83.60 3.81 13.88 61.94 0.71 3.26 Olive pulp (9) .............. ! 92.02 5.91 36.45 31.54 15.63 2.49 Olive pulp* (9) / 95.11 13.99 19.27 31.04 27.39 3.43 Apple pomace (5) . .. ..... 86 . 68 4.31 17.0 3 69.76 5.13 3.77 COEFFICIENTS OF DIGESTIBILITY Orange pulp . .... . .. .. ...... . . , 89.33 '78.54 83.73 95.40 48.89 Lemon pulp --81.43 46.18 60. 33 92.01 27.44 Raisin pulp 44.78 24.13 18.54 52.01 90.16 Pineapple pulp 74.5(3 20.75 69.62 79.75 neg. Olive pulp ... .. ... ... .. . ........ 19 . 09 neg. neg. 20.27 86.02 App'e pomace . ... . . .. . . ...... 67. 37. 54. 80. 32. DIGESTIBLE NUTRIENTS T.D.N. Orange pulp 6.05 6 . 54 63.88 0.82 78.31 Lemon pulp ...... ...... ...... . .. . ......... . .... 2.95 9.05 60.03 0.34 72.80 Raisin pulp ........ . ... .. ........... . .. . . . . .. . 2.31 3.58 23.70 9.50 50.98 Pineapple pulp . . .... . .... . ............ . ... .. / 0.79 9.66 49.40 0.00 59.85 ~~;ie ~~I:ia~~ :::::::::::::::: :::::::::: :::::i 0.00 0 . 00 6.39 13.44 36.63 1.59 5.79 55.81 1.64 66.88 * Prepared from pitted olives. 1 Figures in parentheses (Italic) refer to "Literature Cited", page 20.

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8 Florida Agricultural Experiment Station The orange pulp referred to in Table 2 was the dried residue from the manufacture of orange juice, orange oil, or other orange extracts. Dried lemon pulp was the rind, pulp, and seeds after the extraction of citric acid. Dried raisin pulp consisted of the various wastes with most of the sugar extracted. Pineapple pulp contained the outer skin, trimmings, and cores after juice extraction. The first analysis of olive pulp represented a sample from the commercial preparation of olive oil. This pulp con tained the pits, and was used in the digestion trials. The second sample represented a pit-free pulp and hence was lower in fiber. Dried apple pomace was the dried residue from cider manu facture. Digestion trials at the California station were conducted with five wethers, using a basal ration of alfalfa hay. Preliminary periods were 10 days in length and experimental periods 15 days. A basal ration of mixed grain and corn silage was used with cows at the Virginia station in the studies with dried apple pomace. These citrus and apple by-products are seen to be low in protein and fiber, and high in nitrogen-free extract. They are essentially carbohydrate feeds and are highly digestible. One trial at the California station (13) with dried orange pulp showed it to be equivalent to beet pulp for milk production. Fresh pulp was not found to have any effect on percent of fat in the milk. Nothing was mentioned of any flavor being imparted to the milk when as much as 20 pounds of the fresh pulp was fed daily, nor was mention made of the particular extracts from which this pulp was a residue. The citrus peel oils may have been removed in the process of manufacture. EXPERIMENTAL METHODS The palatability of the dried grapefruit refuse was tested in the dairy herd of the Florida Agricultural Experiment Station by offering small portions to the individual cows of the dairy herd after they had received the usual offering of corn silage and grain feed. The methods used in conducting the digestion trials were essentially as recommended by Forbes and Grindley (3). The basal ration per day consisted of one pound of prime cottonseed meal and enough No. 1 federal grade alfalfa hay to supply slightly more than the requirement of total digestible nutrients for maintenance. In the trials with the feeds to be tested, one half of the alfalfa hay was replaced by the particular feed. In

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The Fe e ding Value of Citrus By-Products 9 every case the requirement for digestible crude protein was exceeded by the total ration. Preliminary periods were 10 days in length, and the experimental periods consisted of four suc cessive five-day periods. Four steers, three Jerseys and one grade Hereford, ranging in weight from 450 to 700 pounds, were used in all the trials. The individual feeds for an entire trial were weighed into sepa rate bags on a solution balance before the beginning of a trial. Samples were taken at that time. The feed was given in two equal portions at 6 :00 a . m. and 6 :00 p.m. The steers were held in a dry lot for the first nine days of the preliminary periods and then stanchioned in a barn. Water was provided in buckets. Salt was offered in small boxes. Each animal was brushed vigorously for one hour daily as a substitute for exercise. Feces collections were manual. The daily collections of feces were weighed and sampled separately at 9 :00 a.m. each day. Triplicate five to 10 gram samples were taken in weighing bottles for the determination of nitrogen, thus avoiding volatilization of any ammonia. A twentieth aliquot was taken in pyrex dishes, dried, and used in the preparation of five-day composite samples, for the determination of the other constituents. Proximate analy ses were made by the methods of the Associa tion of Official Agricultural Chemists (1). Calcium, magnesium, and phosphorus were determined by the method of Morris, Nel son, and Palmer (10). Indirect calculations were made of the digestibility of the nutrients. The coefficients of digestibility for cottonseed meal, as compiled by Henry and Morrison ( 4), were used for that feed. Coefficients for the alfalfa hay were calculated from the trial on the basal ration of cottonseed meal and alfalfa hay, and were used in the calculations with the dried grapefruit cannery refuse, and with the dried orange peel. The crude protein as determined in the fresh feces was used in all calculations to avoid any error due to the volatilization of ammonia. To secure some information as to the general feeding qualities and effect of the dried grapefruit refuse on the animal, a feeding trial was conducted with eight native and grade Hereford heifers. The ration used was 30 pounds of sugarcane silage, 15 pounds of dried grapefruit refuse, and 5 pounds of prime cottonseed meal daily per thousand pounds liveweight. The cottonseed meal supplied the requirement for digestible crude protein. Sorghum silage was substituted for the sugarcane silage at the end of 80 days. These feeds were mixed and fed to the lots in equal offer

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10 Flo r ida Ag ri c u lt u ral E x p e r i ment Station ings, morning and evening. Water and salt were available at all times. Finely ground feeding bonemeal was offered to Lot 1. Blood samples were taken at the beginning of the trial and at the end of the first , second, and fourth 30-day periods. These samples were analyzed for calcium and inorganic phosphorus in the blood plasma by the methods of Kramer and Tisdal ( 6), and Fiske and Subbarow ( 2 ), respectively. Hemoglobin determina tions were made by th e Newcomer method (1 2 ). The heifers were weighed on three succe s sive days at each 30-day interval. Feed records w e re kept, and feed s amples taken and analyzed for the ca'.culation of the efficiency of the ration. General ob se rvations w e re made on the condition of the animals. PRESENTATION AND DISCUSSION OF THE DATA * Palatability of Dried Grapefruit Cannery Refuse.-One pound of dried grapefruit refu s e was offered to each of 31 cows in the dairy herd after they had eaten their regular evening offering of corn silage and mixed grain. The refusal wa s weighed. Only one individual refus e d the product on all six occasions. Four teen cows tasted it when first offered, their appetites for this product increasing progressively. The refusal decreased from 29.8 pounds to 6.0 pounds out of the 31 pound daily offering over the six-day test. Four steers used in the digestion trials refused a small part of their feed at the first offering when it was used to replace a part of the alfalfa hay in the ration of alfalfa hay and cottonseed meal. At no other time during the 30-day period was there any refusal. Eight heifers, just off grass pasture, were used in the feeding trial. A 10-day preliminary period was allowed in which to determine their appetites for a ration of sugarcane silage, grape fruit refuse and cottonseed meal. When the bulk of their rations was reduced to the quantities fed in the actual trial, they refused only 60 pounds of feed in the entire trial. This refusal consisted almost totally of coarse pieces of silage. Digestibility of Dried Grapefruit Cannery Refuse.-The four steers used in the digestion studies refused no feed after the first offering of the pre : iminary period. They maintained their weight or made slight gains. The composition of the grapefruit refuse, digestibility of the nutrients by each of the four steers, and the digestible nutrient content of the product are given in * A preliminary report appeared in a recent press bull e tin (11).

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The Feeding Va,lue of Citrus By-Products 11 Table 3. Feed intakes per day, digestibility of the nutrients by 5-day periods, weight and composition of the feces, and compo sition of the feeds are given in Appendix Tables A, C, E and F. TABLE 3.-THE COMPOSITION, COEFFICIENTS OF DIGESTIBILITY, AND DIGESTIBLE NUTRIENTS OF DRIED GRAPEFRUIT REFUSE. I Dry I C rude \ Crude I N-Free ! Crude I Matter Protein Fiber Extract ) Fat . Ash -I percent I percen t I percent I percent I percent I percent" Composition .................. / 91.77 / 4.94 I 11.94 I 69.;0 I 1.06 \ ~4.23 Steer ---Coefficients of E-49 24.46 67.51 92.11 74.01 digestibility E-50 19.32 73.81 92.39 88.78 E-51 33.07 81.04 93.19 7 9.31 E-52 22.48 63 . 72 92.04 75. 3 8 Ave. 24.83 71.52 92.43 79.37 ~~;~~:-=~r~:n~s ~ ~ -~---~ -I 1.23 I 8.54 I 64,;3 , ~-;4 r T7~. 9r The composition of th e dried grap e fruit refuse was: 91.77 percent dry m atter, 4.94 percent crude protein, 11.94 percent crude fiber, 69.60 percent nitrogen-free extract, 1.06 percent crude fat, and 4.23 percent ash. The digestibility of the crude protein as shown by th e individual steers varied from 19.32 percent to 33.07 percent, crude fiber from 63.72 percent to 81.04 percent, nitrog e n-free extract from 92.04 percent to 93.19 per cent, and of crude fat from 74.01 percent to 88.78 percent. Re spect ive average s were: 24.83 percent (protein), 71 . 52 percent (fiber), 92.43 percent (N-free extract), and 79.37 percent (fat). As determined from the above compo s ition and dig es tibility, the dried grapefruit refuse contained 1.23 percent digestible crude protein, 72.87 percent digestible carbohydrates, 0.84 per cent digestible crude fat, or a total of 75.99 percent digestible nutrients. The total digestible nutrients per hundredweight of dry matter were 82.80 pounds. Digestibility of Dried Orange Peel.-The same amounts of dried orange peel were fed as of the dried grapefruit refuse. Live weights of the steers were maintained and no feed was refused after the initial offering. The composition of the dried orange peel, digestibility of the nutrients by each of the four steers, and the digestible nutrient content of the product are given in Table 4. Feed intakes per day, coefficients Of digesti ~ility by five-day periods, weight and composition of the feces, and composition of the feeds are given in Appendix Tables A, D, E and F.

PAGE 12

12 Florida Agricultural Experiment Station TABLE 4.-THE COMPOSITION, COEFFICIENTS OF DIGESTIBILITY, AND DIGEST IBLE NUTRIENTS OF DRIED ORANGE REFUSE. I Dry I Crude I Crude / N-Free I Crude I I Matter I Protein I Fiber Extract Fat Ash I percent I percent fpe rcent !percent I pe rcent I percent _ _ _ ___ _ __ ---'.; ~ Composition 86.05 I ;~-:-1 10.6~\ 64.741 0.691 4.13 Steer Coefficients of E-49 digestibility E-50 E-51 E-52 Ave. 44.30 26.41 31.21 44. 36 36.57 90.18 89.35 -~0.45 84.!l2 86.64 11.80 8!).36 86.38 11.84 111.16 91.65 33.15 93.91 88.51 6.59 Digestible nutrients 2.14 I 9.99 -, 57.30 I 0.05 I T6~ . 5~ The composition of the dried orange peel was: 86.05 percent dry matter, 5.84 percent crude protein, 10.64 percent crude fiber, 64.74 percent nitrogen-free extract, 0.69 percent crude fat, and 4.13 percent ash. The dry matter, nitrogen-free extract, and crude fat were lower than in the dried grapefruit refuse, the ash nearly the same, and the crude protein slightly higher. The digestibility of the crude protein varied with the individual steers from 26.41 per ce nt to 44.36 percent, the crude fiber from 84.92 percent to 111.16 percent, the nitrogen-free extract from 86.38 perc en t to 91.65 percent, and crude fat from -30.45 per cent to 33.15 percent. The apparent high dige s tibility of the fiber with one s teer and the negative coefficient for crude fat with one of the others were not surprising when the small pro portion of crude fiber and crude fat in the total ration derived from the dried orange peel are considered. Averages were: 36.57 percent of crud e protein, 93.1 percent for crude fiber, 88.51 percent for nitrogen-free extract, and 6.59 percent for crude fat. The nutrients in the dried oran ge peel as calculated from the above compo s ition and digestibility were: 2.14 percent digestible crude prot ein, 67.29 percent dig est ible carbohydrates, and 0.05 percent di ges tible crude fat, or a total of 69.55 percent dig es tible nutri e nt s. Thi s latt er amount is equivalent to 80.82 pounds of digestible nutrients per hundredw e i gh t of dry matter. Discussion of Digestion Trials.-Coefficients of digestibility varied mo st for the c rude fiber and crude protein in both se ts of trials, and for crude fat in the dried orange peel trials. Varia tion s in these cases can be explained by the s mall proportion of the total intake of these constituents in the ration that were derived from the citrus by-products. The apparent low dige s ti bility of the crude protein may be due to several factors, namely:

PAGE 13

The Feeding Valu e of Citrus By-Products 13 (a) the heating of the protein during the drying proces s which tends to make it less digestible, (b) the presence of non-protein nitrogen compounds in the citrus fruit that are not digestible, or (c) an apparent depression of digestibility as observ e d at the Virginia station (5) when a high carbohydrate feed such as apple pomace was added to a basal ration low in protein. Thi s last factor should not be of importance in these trials, since the in take of digestible crude protein w as more than adequate in all cases. The coefficients of digestibility as d e termined for the nitrogen free extract were remarkably consistent. As this con s tituent made up 75 percent of the dry matt er in both citrus by-products, the variations ob se rved in the digestibility of the other constit uents had but a small effect on th e me as ure of the total digestible nutri e nt content of these feeds. The low content of digestible crud e protein precludes either dried grapefruit refuse or dried orange peel from being an import a nt source of this nutrient. Feeding Trial With Growing Heifers.-Eight native and grade Hereford heifers ranging in weight from 207 to 520 pounds were available for this trial. Th ey were divided into two lots, the thre e larg e r in Lot 1 and five s maller in Lot 2. They were fed 30 pounds of sugarcane s ila ge, 15 pounds of dried grapefruit refu se, a nd 5 p o unds of prime cottonseed meal per day p e r thou sand pounds liveweight. Sorghum s ilage was substituted for th e sugarcane s ilage at the end of 80 days. Lot 1 was continued on feed for 60 days and Lot 2 for 120 days. Live weights of the individual animals and feed and nutrient intakes for the lots are given in Tab:e 5. Th e r a ti o n was very palatabl e, as on ly 60 pounds of feed were r e fused during the entire tri a l. Thi s refusal consisted of coar s e pi eces of s ila ge . L ot 1 took 14 pounds of sa lt in 60 da ys ; Lot 2, 1 8 pounds in th e fir s t 60 day s, and 22 pounds in the seco nd 60 da ys, or a n ave ra ge o f 2.08 pounds per h ead eac h 30 days. Lot 1, allow ed bonemeal, consumed 1 8 pounds in 60 da ys , or thr ee pound s per h ead per month. Rate of gain varied from 0.9 8 to 2.40 pounds per day, except for No. 26. Fecal examination s h owe d that this animal w as in fest e d h eav ily with stomach w or m s. Her gain in weight for the 120-cl ay period was only 21 pounds. Since such an inf esta tion in terfe r es with the utilization of feed, her weight and on e-fifth of the nutri e nt intake wer e deducted from Lot 2, before calc lating th e econo m y of gains on th i s ration. Di gest ible crude protein a nd t ota l dig est ible nutrient intakes

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TABLE 5.-THE LIVEWEIGHT, AND FEED AND DIGESTIBLE NUTRIENT INTAKES OF HEIFERS FED SILAGE, DRIED GRAPEFRUIT CANNERY REFUSE, AND COTTONSEED MEAL. I II 1 19 1 20 22 19 20 22 520 350 432 581 395 459 1,435 581 395 459 665 437 530 1,632 I 1,544 :---~--207 270 277 274 320 1,348 217 309 305 304 363 1,498 1,188 232 I ~-----'----~----~---772 85.0 954.9 484.7 299.7 594 197 71.4 753.6 502.4 277.8 I

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TABLE 5.-THE LIVEWEIGHT, AND FEED AND DIGESTIBLE NUTRIENT INTAKES OF HEIFERS FED SILAGE, DRIED GRAPEFRUIT CANNERY REFUSE, AND COTTONSEED MEAL (continued), 30-Day I Period ! Number II III IV Lot Number ---2 2 2 Animal Number 23 24 25 26 27 23 24 25 26 27 23 24 25 26 27 Initial Weight pounds 217 309 305 304 363 1,498 237 347 317 289 399 1,589 279 387 347 312 424 1,749 I I Final I Weight 1rnunds11 237 347 317 280 3UO 1,589 279 387 347 312 424 1,749_ _ 337 418 395 295 505 1,950 Feed Intake ---------I I CottonGrapeseed Silage I fruit Meal pounds I pounds I pounds 1,52G 2:i2 11 1,652 826 286 1,800 900 :mo 1 Nutrient Intake I . . -~ T. D. N. Per 100 Digestible I . Tot11:l Pounds Gain Crude D1gest1ble _ _ _ __ _ Protein Nutrients I Total I_ Net* pounds I pounds pounds I pounds 102.2 117.2 D45.8 1,048.1 1,162.3 Average 455.8 612.0 426.5 488.0 281.4 374.7 257.9 --298.i* Net total digestible nutrients per hundred weight of gain were calculated by deducting maintenance at the rate of 7.925 pounds daily per thousand pounds liveweight from the total nutrient intake. The weight of No. 26 and one-fifth of the nutrient intake were deducted before making this calculation for Lot 2.

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16 Florida Agricultural Experiment Station were calculated from actual analyses of the feeds by applying the coefficients of digestibility for the silage and cottonseed meal as given by Henry and Morrison (4), and for the grapefruit refuse as given in Table 3. Fifty-four percent of the dry matter, and 60 percent of the total digestible nutrients were provi _ ded by the dried grapefruit refuse. The digestible nutrient intake per hundredweight gain varied from 426 to 612 pounds, or an average of 488 pounds. The extremes were for periods 3 and 4 with Lot 2, and variations in fill may account for a part of the difference, especially since the periods were successive. When a maintenance requirement ( of 7 .925 pounds of digestible nutri ents daily per thousand pounds liveweight) was deducted from the total nutrient intake , the average net requirement per hun dredweight of gain became 298 pounds, with a range from 258 to 375 pounds. This is an economy of gain comparable with that secured with rather heavy grain feeding. Blood samples were taken on three successive days at the beginning of the trial and at the end of the first, second, and fourth 30-day periods. Calcium and inorganic phosphorus were d e termined on the composite citrated blood plasma samples, and hemoglobin on the daily samples. Detailed results are given in Table 6. No significant variations were observed in any of these con stituents. Even though Lot 1 consumed bonemeal at the rate of 3.0 pounds per head per month, the inorganic phosphorus was no higher than in Lot 2. Also, the inorganic phosphorus in the blood plasma of Lot 2 did not decrease during the entire trial. However, a decrease would not be expected, since all the heifers had fr ee access to bonemeal on pasture previously. Cottonseed meal al s o is one of the high phosphorus feeds. The eff e ct of the total ration was markedly laxative. A soft j e ll y -like consistency of the f ece s was observed during the entire trial. S u g arcane silage u s ed in the s e rations is considered to be moderately l a xative, and cotton se ed meal relatively constipating. It w as pr es umed that pectin wa s the constituent having this laxa tive e ff ect, although the high citric acid content of th e feed may hav e c ontributed. All of the animals had a sleek, thrifty appearance, were alert, and had bright eyes. The sl ee k, oily appearance of the coat of hair w as similar to that secured by feeding bran, oats, and lin s eed m ea l. Even No. 26 did not seem to be "out of condition", and failure to make gain s was the only casual symptom of the para s itic infestation. Every animal except No. 26 improved in

PAGE 17

The Feeding Value of Citrus By-Products 17 thickness of flesh while on the ration. Figure 1 shows Lot 2 at the end of 120 days on the ration of silage, grapefruit refuse and cottonseed meal. TABLE 6.-THE CALCIUM AND !NOGRANIC PHOSPHORUS CONTENT OF THE BLOOD PLASMA, AND THE HEMOGLOBIN CONTENT OF THE BLOOD OF HEIFERS FED SILAGE, DRIED GRAPEFRUIT CANNERY REFUSE AND COTTON SEED MEAL, Animal 1 7l16-18 D A T E Number 8 / 15-17 I 9/14-16 11/13-15 CALCIUM PER 100 ML. OF CITRATED BLOOD PLASMA _ mg s. __ _ _I _ __ mgs. __ _ __ _ mgs. _ _ -' ~ mgs. _ _ ___ 19 11.66 12.29 10.65 20 11.11 10 . 59 22 11. 88 11.47 10 . 06 23 11.66 11.35 10.24 11.23 24 12.21 10.76 9 . 83 11. 3 5 25 11.8 8 11.00 9.65 11.00 26 11.66 IJ.35 10 . 24 10.82 27 11.66 11.12 9.42 11.88 PHOSPHOR U S PER 100 ML. OF CITRATED BLOOD PLASMA 19 7.09 8.13 6.85 ------20 6. 54 7 . 60 6 . 02 .............. 22 5.56 10.87 6 .8 5 23 5.38 7.78 6.80 7.81 24 5 . 36 7.49 6 . 01 6.45 25 6. 43 7.14 7.(l6 8.03 26 5.0 8 6.76 6.85 7.09 27 5.1 9 6.76 6.29 5.83 HEMOGLOBIN PER 100 ML. OF BLOOD _ __ -,-_ _ gs. I gs. g~ -1 ~i:~ gs. _ ____ I ___ gs . .. _ _ 19 20 22 23 2 4 25 2 6 27 10.80 9.68 11.66 8.4 8 12.4 8 ll. 29 11.74 9 .82 15 25 11.44 1.'l.84 12 .08 11. 3 5 1 2.94 9 . 8 2 9 . 01 1 2 . 4 9 9.52 10 . 20 1 3. 29 GENERAL DISCUSSION 12 . 02 1 7.29 12 . 70 11. 8 7 19 .29 The bitter taste of the grapefruit caused by its narangin (glucoside) content, or the sourness caus e d by the citric acid, did not seem to detract from the palatabilit y of the product. The effect of the dryin g process is not known. The grapefruit r e fuse wa s consumed with relish by a lm ost all the animals having access to it. Dried oran g e pe e l seemed to be equally palatable. This

PAGE 18

18 Florida Agricultural Experiment Station is contrary to the results of the California station (8, 9, 13) r where orange pulp ground into a meal, and lemon pulp from citric acid manufacture, had to be fed in combination with other feeds in order to insure consumption. Both the grapefruit refuse and orange peel were similar in chemical composition to the orange and lemon pulps studied at the California station (8, 9). They have slightly less fiber and crude fat than the dried apple pomace investigated at the Vir ginia station (5). The low fiber content and high proportion of nitrogen-free extract place these feeds in the group of con centrates. Their high degree of digestibility was evidenced both by the actual results of the digestion trials, and by the lesser quantity of feces voided by the steers when these feeds were substituted for one-half of the alfalfa hay of the basal ration. There was no indication of a deficiency of roughage when 3.0 pounds of silage and 1.5 pounds of grapefruit refuse were fed per each hundred pounds of liveweight. This is less than the "Rule of Thumb" recommendations for roughage in feeding practice. It would seem that these feeds could be substituted for such a feed as beet pulp and for at least a part of the carbohydrate feeds like corn. So far as could be determined from a 120-day feeding trial the general effects of the grapefruit refuse on the animal were favorable. It was fed at a much higher level than would be followed in general feeding practice. The glossy, oily appear ance of the coat of hair and the thrift of the animals receiving the grapefruit refuse make it appear that this feed belongs in that group of feeds prized by stockmen for their beneficial effect on the animal. The particular constituent, or constituents, producing this effect is not known. Even though the results of the digestion trials and the feeding trial indicate that dried grapefruit refuse and dried orange peel are good sources of digestible carbohydrates, longer con tinued feeding trials and actual comparisons with some of the standard feeds for fattening and for milk production are neces sary for a final evaluation. Further studies of the physiological effects on the animal are desirable. Too little is known of the effect of fruit by-products upon animal welfare.

PAGE 19

The Feeding Value of Citrus By-Products 19 SUMMARY AND CONCLUSIONS Dried grapefruit cannery refuse and dried orange peel were palatable to cattle, contrary to the findings elsewhere with or ange and lemon pulp. The citrus by-products were low in crude protein, fiber, and fat. They were high in nitrogen-free extract, which was 88-92 percent digestible. Total digestible nutrients per hundred pounds of dry matter were 82.80 and 80.82 pounds for grape fruit and orange refuse, respectively. The results of the diges tion trials placed these feeds in the class of high carbohydrate concentrates. Dried grapefruit and orange cannery refuses have a laxative action when fed as a large proportion of the ration. General effects of the dried grapefrut refuse were favorable as indicated by thrifty appearance, gloss of the coat of hair, and improve ment in thickness of flesh. ACKNOWLEDGMENTS Acknowledgments are made to Herbert Henley who cared for the steers on digestion trials; to Arlington Henley, J. H. Warrington, S. L. Mimms, and T. J. Davis for manual collec tion of the feces; and to W. T. Dunn, L. L. Rusoff, and I. I. Rusoff for aid in analyses of the feed and feces samples. Three Jersey steers were loaned to the experiment station by J. L. Taylor for use in the digestion trials. A part of the experimental feeds were donated by R. B. Webster. Dr. M. W. Emmel made micro scopic examinations of fecal samples for the determination of parasitic infestations.

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20 Florida Agrciultural Experiment Station LITERATURE CITED 1. Association of Official Agricultural Chemists. Official and tentative methods of analysis. Ed. 2, 535p. illus. Washington, D. C. 1925. 2. FISKE, C. H. and Y. SUBBAROW. The colorimetric determination of phosphorus. Jour. Biol. Chem. 66; 375-400. 1925. 3. FORBES, E. B. and H. S. GRINDLEY. On the formulation of methods of experimentation in animal production. Bul. Natl. Research Council, Vol. 6, Part 2, No. 33; 17-27. 1923. 4. HENRY, W. A. and F. B. MORRISON. Feeds and Feeding. 18th ed. illus. Henry-Morrison Company, Madison, Wis. Pages 723 and 726. 1923. 5. HOLDAWAY, C. w., w. B. ELLETT, J. F. EHEART, and M. P. MILLER. The importance of properly balanced rations in trials to determine digestibility as shown in experiments with dried apple pomace. Va. Agr. Exp. Sta. Tech. Bul. 32; 3-18. 1927. 6. KRAMER, BENJAMIN and F. s. TISDAL. A simple technique for the determination of calcium and magnesiudi in small amounts of serum. Jour. Biol. Chem. 47; 475-481. 1921. 7. McDERMOTT, F. A., as summarized by S. S. WALKER. The utilization of cull citrus fruits in Florida. Fla. Agr. Exp. Sta. Bul. 135; 2-16. 1917. 8. MEAD, S. W. and H. R. GUILBERT. The digestibility of certain fruit by-products as determined for ruminants. Part 1. Dried orange pulp and raisin pulp. Calif. Agr. Exp. Sta. Bul. 409; 3-11. 1926. 9. MEAD, S. W. and H. R. GUILBERT, The digestibility of certain fruit by-products as determined for ruminants. Part 2. Dried pineapple pulp, dried lemon pulp, and dried olive pulp. Calif. Agr. Exp. Sta. Bui. 439; 3-11. 1927. 10. MORRIS, H. P., J. w. NELSON, and L. s. PALMER. A quantitative de termination of calcium, magnesium, and phosphorus in feedstuffs and cattle excreta. Indus. and Engin. Chem., Anal. Ed. 3; 164-167. 1931. 11. NEAL, W. M., R. B. BECKER, and P. T. Dix ARNOLD. Dried grapefruit refuse-a valuable feed. Fla. Agr. Exp. Sta. Press Bul. 466; 1-2. 1934. 12. NEWCOMER, H. S. A new optical instrument for the determination of hemoglobin in blood. Jour. Biol. Chem. 55; 569-574. 1923. 13. REGAN, W. M. and S. W. MEAD. The value of orange pulp for milk production. Calif. Agr. Exp. Sta. Bui. 427; 3-16. 1927. 14. SCOTT, J. M. Grapefruit refuse as a dairy feed. Fla. Agr. Exp. Sta. Ann. Rpt. 25R-26R. 1926.

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APPENDIX TABLE A . -FEED INTAKE PER DAY OF STEERS USED IN DETERMINING THE DIGESTIBILITY OF THE BASAL RATION, OF DRIED GRAPEFRUIT CANNERY REFUSE, AND OF DRIED ORANGE PEEL. Animal I Trial Number Number E-4!1 E50 E5 1 E-4!) ......... .. . E50 ... ..... .. . . E-51 ........ .. . E-52 ...... . E:-4~ .... . E-50 ........... . E-51 .. ..... .. . E-52 ......... .. . 21 22 23 24 25 26 27 28 33 34 35 36 Alfalfa Hay Amo unt i Sample pounds .. 1 :number 8.0 10.0 10.0 G.O 4.0 5.0 5.0 3.0 4.0 5.0 5.0 3.0 855 855 855 855 855 855 855 855 1211 1211 1211 1211 Cottonseed M ea l ~ -~ ---Amount I Sample pound s I number 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 856 856 856 856 1013 1013 1013 1013 1213 1213 1213 1213 Grap e fruit R e fuse Amount I Sample poun d s .. I number 4.0 5 . 0 5 . 0 3.0 1014 1014 1014 1014 Dri ed Oran ge Peel Amount 1 Sample _ _ _ J)Ol lnds , numbe r 4.0 5 .0 5. 0 3 .0 1212 1212 1212 1212

PAGE 22

22 Florida Agricultural Experiment Station TABLE B.-THE DIGESTIBILITY OF THE NUTRIENTS OF THE ALFALFA HAY USED IN THE BASAL RATION AS DETERMINED WITH FOUR STEERS IN FOUR SUCCESSIVE FIVE-DAY PERIODS, Animal Trial 5-Day Number Number Period Number E-49 I 21 I II III IV Average E-50 22 I II III IV Average E-51 23 I II III IV Average E-52 24 I II III IV Average A "I" ' d~-----\ verage per10 s ........ _., .. _ ................. . Average "II" periods... ......... _ .. ........... . Average "III" periods .......... ............... .. Average "IV" periods .......................... .. Grand average ............ ............................. 1 Coefficients of Digestibility Crude I Crude I N-Free I Crude Protein Fiber Extract Fat percent lpercentl percent I percent 63.19 63.44 64.09 64.80 63.88 59.11 62.86 61.12 59.45 60.64 62.90 63.67 63.83 62.45 63.21 62.34 58.69 59.32 55.29 58.91 61.88 62.16 62.09 60.50 61.66 46.58 39.53 33.03 24.98 36.03 45.71 40.00 24.78 18.90 32.35 47.77 49.09 50.93 42.73 47.63 43.63 36.15 28.45 15.72 30.99 45.92 41.19 34.30 25.58 36.751 72.45 0.37 69.06 -4.99 79.63 -1.95 68.83 -12.70 69.11 -4.82 72.28 0.23 69.51 2.01 61.43 -20.62 65.86 -10.57 67.27 -7.24 73.91 -12.58 72.49 12.80 73.05 7.10 69.95 1.94 72.35 2.31 77.57 6.82 68.18 -0.52 69.78 -3.94 63.67 -12.00 69.80 -2.41 74.05 -1.29 69.81 2.32 70.97 -4.85 67.08 -8.33 69.63 ! -3.04

PAGE 23

The Feeding Value of Citrus By-Products 23 TABLE C.-THE DIGESTIBILITY OF THE NUTRIENTS OF DRIED GRAPEFRUIT CANNERY REFUSE AS DETERMINED WITH FOUR STEERS IN FOUR SUC CESSIVE FIVE-DAY PERIODS. Animal Trial Number Number I E-49 I 25 I E-50 26 E-51 27 E-52 28 Coefficients of Dig es tibility 5-Day Crude I Crude I N-Free I Crude Period Protein Fiber Extract Fat Number -pe rcent-1 percent_ I _ perce nt l percent h -~i~:i~-~ ~ g~ r -i6~ii tt~~ III 61.80 108.06 95.67 108.46 IV 29.62 96.64 90.79 93.49 Average 24.46 67.51 92.11 74.01 I II III IV Average I II III IV Average I II III IV Average 20.69 4 .37 36.47 15.76 19.32 26.86 34 .13 37.54 33.74 33.07 22.81 21.57 21.27 24.26 22.48 76.53 55.94 66 .47 96.3 1 73.81 88.53 60.32 74.68 100.60 81.04 95 .91 42.19 29.16 87.63 63.72 92.13 90.32 93.49 93.62 92. 39 94.85 91.52 93.14 93. 23 93.19 9 4.11 91.64 90. 58 91.81 92.04 85.52 81.27 101.75 86.59 88.78 68.27 61.29 93 .5,:1 94.13 79.31 90 .80 54.44 75.91 80.36 75.38 Average "I" periods .. ------------------14.84 76.52 9 3 .04 70.20 Average "II" periods ------------19.38 44.68 91.10 63.72 Average "III" periods _____ ___ _ _ ___ _ _ ___ ___ _______ 39.27 69.59 93.22 94.91 Average "IV" period s. 25.85 95.30 92.36 88.64 --. . -.., Grand average _______ __ --•-------------24 . 83 71.52 92.43 79.37

PAGE 24

24 Florida Agricultural E:cperiment Station TABLE D.-THE DIGESTIBILITY OF THE NUTRIENTS OF DRIED ORANGE PEEL AS DETERMINED WITH FOUR STEERS IN FOUR SUCCESSIVE FIVE-DAY PERIODS. Animal Number E-49 E-50 E-51 E-52 Trial Number 33 34 35 36 5-Day Period Number I II III IV Average I II III IV Average I II III IV Average I II III IV Average I I ' !~:~::: ::};,,P;~~i~ds_ _ _ _:_ : ____ : ___ ::~:::! Average "Ill" periods _______ _ __ _ -----------i Average "IV" periods __________ _ _________ _ ______ _ I Grand average ___ _ . --------1 Coefficients of Digestibility Crude ICrude I N-Free,-Crude Protein I Fiber Extract Fat _percent I percent I percent Iier_cent 49.40 60.43 33.24 34.13 44.30 18.85 27.14 29.19 30.47 26.41 30.16 30.83 29.99 33.86 31.21 40.04 55.75 51.01 30.64 44.36 34.61 43.54 35.86 32.28 -736.57 I 107.98 102.92 48.82 82.99 90.18 90.57 73.63 87.81 87.65 84.92 91.60 85.74 101.26 78.82 89.36 108.51 114.32 116.25 105.55 111.16 99.67 98.65 88.54 88.75 I 93.91 I 90.60 92.98 84.43 89.40 89.35 84.72 87.29 86.35 88.21 86.64 88.25 82.65 86.55 88.09 86.38 90.84 91.50 93.45 90.81 91.65 88.60 88.61 87.70 89.13 -92.42 -75.91 -5.12 51.65 -30.45 60.41 -12.01 1.56 -2.77 11.80 30.22 17.25 -4.14 4.00 11.84 33.99 21.71 48.80 28.09 33.15 8.05 -25.72 10.28 20.24

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Th e Feedinr1 Value of Citrus B11-Prnducts 25 TABLE E.-TH E WEIGHT AND COMP OSITION OF FECES FROM STEERS DURING DI GEST ION TRIAL S. aDay I j Tota l j 1 J _____ Com!)Osition ~f ~ry Ma~e::_ __ _ Animal Trial Pe ri od Fresh 'I C rud e , Dr y j I Crude ; C ru de \ N-Free j Crud e Number N umber Number _ Excret _ ~ _ _ !:' _ rotei n _ l ,',latter _ As h j Protein I Fiber 1 Ext ra c~ _ !'~ . E-4 9 21 E50 22 E-51 23 E-52 24 E-4 9 25 E-50 26 E-51 27 E-52 28 E-4 9 33 E 50 34 E-51 35 E-52 36 I grams I percent I percent I percent I percent I percent I perce nt I pe rcent I II III IV I II III IV I II III IV I II III IV BASAL RATION I I 36,365 2.766 I 22.59 1: 20.93 10.47 ; i~.lit 2. 739 , 23.25 1 s.30 10.59 2.634 ' 23 . 27 : 11.20 9.90 I 39,363 2.477 22 .9 9 10.42 10.09 47,644 2.838 23.62 i 26.26 10 .76 48,141 2.758 i 21.11 ' 1 2.48 11.40 51,947 2.488 . 21.30 10.57 10.65 57,406 2.33 7 20.62 8.78 10.14 42.602 2 . 910 . 23.86 i 20.63 12 . 06 I 43,284 : 2.8 1 2 ' 21. 32 ! 1 4. 1 9 12 .3 1 I I 42,923 j 2.824 i 20.56 ! 1 2.8 0 12.14 47,077 , 2 . 662 ! 20.66 J 11.73 11.1 2 / 3 1,016 I 2 . 613 . 21.83 1 26.94 . 10.5 5 : 34,917 i 2.50 7 : 19.1 3 ! 1 3. 75 I 11.09 I 36,588 I 2 .86 2118.20 i 10.2 81 10.68 44.219 I 2. 116 17. n I 1 0 . 84 10.57 38. 12 26.27 4 1. 50 28.73 44.6 0 30.56 48.22 27.34 35.22 24.27 42.93 29.39 44.39 30.52 49 . 33 28.08 37.57 25.39 40.38 29 .39 40.77 30. 14 42.89 30 . 29 37 . 94 21.22 42.591 28.97 4 7 .58 27.73 47.28 27.90 BASAL RATION PLU S DRIED GRAPEFRUIT REF USE I II III IV I II III IV I II III IV I II III IV I 31,805 i 3..J.6o 1 20.91 I 16 .44 I 3 0,636 1 3 . 175 ; 21.14' 11.75 21,52 3 3 . 595 I_ 22.30 I 1 2.74 I 24,342 ' 3.77 2 1 22.69 1 3 . 65 35,857 I 3 . 237 20.28 rn.21 42,433 I 2.951 1 8.43 15.59 30,921 I 3 .467 22.64 1 3.57 35,292 3 . 367 19 .00 1 5.03 32,451 3.470 21.12 16.55 36,441 2.978 19.96 12.37 36,196 2.945 19.16 1 3.5 1 33,783 3 . 219 18.98 12.81 22,428 3.338 23.16 20.77 23,211 3 . 243 20.17 11.4 3 23,378 3.22 4 2 1. 34 1 3.01 20,978 3.545 20.54 1 2.92 14. 7 0 13.54 13.57 14.23 13.95 14.01 13. 75 1 5.0 1 14.56 13.73 14.19 14.60 14.75 13.91 14.11 15.15 BASAL RATION PLUS DRIED OR AN GE PEEL 37.38 42 . 54 3 7. 5 7 34 .8 9 36.46 37.47 39.82 35 . 54 36.3 1 39.47 38.59 36.26 32.76 40.97 40.57 35.94 28.06 28.98 32.83 34.11 30.31 3 0.01 29.95 3 1.11 I 29.02 . 30.96 30.63 33.01 28.78 30.29 29.43 32.73 3.81 3 .8 8 3 .68 3.93 3.49 3.8 0 3.8 7 3.67 4.35 3 .7 3 4. 1 5 3.9 7 3 . 35 3.6 0 3. 73 3 .41 3.42 3 .1 9 3.29 3 .12 3.07 2. 92 2.91 3.3 1 3.56 3.47 3 .08 3.32 2.94 3.4 0 2.88 3.26 I [ 27,570 I 3 .266 20.51 1 6.99 15.01 33 . 62 29.73 4.65 II 23,944 ' 3.593 22.40 16.44 15.59 33.82 29.34 4 . 8 1 III 3 0 , 621 3.22 1 20.99 11.25 15.25 38.47 3 1.79 3. 24 IV 29,823 3.292 18.44 11.6 3 14.4 2 38.96 3 1.85 3. 14 I 39,322 3.289 2 1.60 22. 70 14. 75 30 .01 29 .36 3. 18 II 38,845 3. 188 19. 8 0 15.58 15.22 35.80 29.97 3.43 III 38,629 3.17 0 19.22 14.02 15.82 34 .78 31.97 3.4 1 IV 37,720 3.225 18.79 12 .81 15.54 36 .46 31.57 3.62 I 36,400 3.34 7 20.92 1 9.47 14.85 33 . 3 1 29.34 3. 0 3 II 37,883 3.204 20.78 1 5 . 38 14. 83 33 .12 33 .61 3.06 III 35,533 3 .4 32 20.31 1 4.14 1 6 .0 7 33.53 32 .6 9 3 . 5 7 IV 35,4 1 8 3.37 1 20.27 1 2 . 3 1 15.42 37.48 3 1.2 9 3.50 I 28,876 : U33 20.25 ! 25 .0 9 15.1 6 30. 19 26.67 2.8 9 II ' 19,741 3.4 72 : 20. 82 14.4G 16.8 5 34.49 3 0.66 3.54 III 19,700 3.5 75 1 lD.\)4 [ 1 3.6 7 17.:32 35 .7 3 29.90 3.38 IV 22,G28 3.4 70 18.86 12 .77 17.08 35.65 31.07 3.43

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TABLE F.-THE COMPOSITION OF FEEDS USED IN DIGESTION AND FEEDING TRIALS. Kind of Feed \ I Composition of Dry Matter ~~fer iH:~: Tt~fr:~~ / CF~~e 1 Ash .. I Ca Mg -, P -~--,-percent 1 percent I percent ,percent i percent rpercent7 percent percent_ I percent -------------~--. ----------------T-----, -------------------------Alfalfa Hay, No. 1 .855 92.93 14.03 33.18 43.73 I 1.83 I 7.23 1.317 0.126 0.396 --.. . .. I 1211 90.41 15.59 35.20 39.10 I 1.59 8.52 1.290 .118 .225 I Sugarcane Silage .... 1373 23.93 3.34 39.39 50.78 I 1.76 4.73 .343 I .195 .181 1374 23.32 3.27 36.98 I 50.68 I 2.46 6.61 .365 .242 .167 Sorghum Silage ............ ! 1377 24.17 3.12 29.30 I 59.40 3.13 5.05 .211 .254 .175 i Cottonseed Meal 856 93.55 41.69 12.24 32.78 I 7.27 6.02 I .230 .172 1.097 ----I I 1014 93.44 43.74 9.00 34.27 I 6.60 6.39 .241 .184 1.121 ! I 1213 89.74 43.11 11.74 30.93 7.53 6.69 ! .236 .187 1.208 1375 89.62 43.22 13.33 30.03 6.81 6.61 I .241 .161 1.175 1378 91.12 41.93 14.94 29.43 I 7.08 6.62 I .225 .147 1.149 I Grapefruit Refuse . 1013 91.77 5.38 13.01 75.84 1.16 4.61 .787 .288 .100 1376 90.54 5.49 12.28 76.25 1.89 4.09 I .689 .352 .097 1379 89.86 5.64 11.93 75.67 1.77 4.99 .746 .378 .107 Dried Orange Peel .............. 1212 86.05 6.79 12.37 75.24 0.80 4.80 I .725 .252 .107 Cl) .,..._ f::) .,..._ "" 0 ;:l

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If information of a relat ed character, additional to that contained in the foregoing bulletin, would be of service, you are cordially invited to write for it. List of bulletins on the sundry phases of Florida agriculture also will be furnished on requ e st. Criticisms of the contents, and suggestions for makin g the se bulletins more helpful to farmers and growers, will be received with appreciation. Address STATE AGRICULTURAL EXPERIMENT STATIONS UNIVER S ITY OF FLORIDA, GAINESVILLE Wilmon Newell, Director

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BULLETINS FURNISHED FREE FROM FLORIDA FARM SERVICE AGENCIES Results of the investigations and research carried on at the Florida Agricultural Experiment Stations are recited in the bulletins pub lished by this farm service agency. During the period of approaching 50 years that have elapsed since the work was begun, in 1887, more than 270 of these bulletins have been issued. In print at the present and available for distribution are some 95 of them, covering nearly as many subjects vitally important to farmers, fruit growers, live stock raisers and truck crop producers. Any of these bulletins will be furnished free on application, as will a list giving the titles, from which selections may be made. Application in practical agriculture of research findings, according to methods of demonstrated merit, is described in bulletins which the Florida Agricultural Extension Service publishes. Dealing primarily with the "how" of doing the things that research endeavor has shown to be feasible, these bulletins bring together science and practice. Titles of the 25 issues now in stock will be supplied free on receipt of request. Bulletins desired then may be obtained through the offices of county farm and home demonstration agents or from the office of publication. Communications for either the Agricultural Experiment Stations or the Agricultural Ex tension Service-both cooperative agencies of state and federal governments-should be ad dressed to Gainesville, Florida, where they are operated under the College of Agriculture in the University of Florida, which also has a division of resident teaching.