Bulletin 262 Jun=, 1933
UNIVERSITY OF FLORIDA
AGRICULTURAL EXPERIMENT STATION
Wilmon Newell, Director
UPON MILK PRODUCTION AND
WELFARE OF DAIRY COWS
R. B. BECKER
W. M. NEAL
A. L. SHEALY
Fig. 1.-Cow No. 120 showing that both hips had been "knocked down"
(broken) while receiving low-calcium rations.
Bulletins will be sent free upon application to the
AGRICULTURAL EXPERIMENT STATION
EXECUTIVE STAFF BOARD OF CONTROL
John J. Tigert, M.A., LL.D., President of the Raymer F. Maguire, Chairman, Orlando
University A. H. Blanding, Bartow
Wilmon Newell, D.Sc., Director A. H. Wagg, West Palm Beach
H. Harold Hume, M.S., Asst. Dir., Research Geo. H. Baldwin, Jacksonville
Harold Mowry, B.S.A., Asst. Dir., Adm. J. T. Diamond, Secretary, Tallahassee
J. Francis Cooper, M.S.A., Editor
R. M. Fulghum, B.S.A., Assistant Editor
Ida Keeling Cresap, Librarian BRANCH STATIONS
Ruby Newhall, Administrative Manager
K. H. Graham, Business Manager
Rachel McQuarrie, Accountant NORTH FLORIDA STATION, QUINCY
L. O. Gratz, Ph.D., Plant Pathologist in Charge
R. R. Kincaid, M.S., Asst. Plant Pathologist
MAIN STATW GAN VI. A. Carver, Ph.D., Associate Agronomist
MAIN STATION, GAINESVILLE R. M. Crown, B.S.A., Assistant Agronomist
Jesse Reeves, Farm Superintendent
W. E. Stokes, M.S., Agronomist** CITRUS STATION, LAKE ALFRED
G. A. Leukel, Ph.D., Agronomist John H. Jefferies, Superintendent
Fred H. Hull, M.S., Associate Geo. D. Ruehle, Ph.D., Associate Plant Pathol-
J. D. Warner, M.S., Associate ogist
John P.Ca MS, Assistant W. A. Kuntz, A.M., Associate Plant Pathologist
John P. Camp, B. R. Fudge Ph.D., Associate Chemist
ANIMAL HUSBANDRY W. L. Thompson, B.S., Assistant Entomologist
A. L. Shealy, D.V.M., Animal Husbandman**
R. B. Becker, Ph.D., Specialist in Dairy Hus- EVERGLADES STATION, BELLE GLADE
bandry V. Allison, Ph.D., Soils Specialist in Charge
W. M. Neal, Ph.D., Associate in Animal Nutri- R. N. Lobdell, M.S., Entomologist
tion F. D. Stevens, B.S., Sugarcane Agronomist
E. F. Thomas, D.V.M., Assistant Veterinarian G. R. Townsend, Ph.D., Asst. Plant Pathologist
W. W. Henley, B.S.A., Assistant Animal Hus- B. A. Bourne, M.S., Sugarcane Physiologist
bandman J. R. Neller, Ph.D., Biochemist
P. T. Dix Arnold, B.S.A., Assistant in Dairy In- A. Daane, Ph.D., Agronomist
vestigations R. W. Kidder, B.S., Asst. Animal Husbandman
CHEMISTRY AND SOILS Ross E. Robertson, B.S., Assistant Chemist
R. W. Ruprecht, Ph.D., Cherhist** SUB-TROPICAL STATION, HOMESTEAD
R. M. Barnette, Ph.D., Chemist
C. E. Bell, Ph.D., Associate H. S. Wolfe, Ph.D., Horticulturist in Charge
J. M. Coleman, M.S., Assistant W. M. Fifield, M.S., Assistant Horticulturist
H. W. Winsor, B.S.A., Assistant Stacy O. Hawkins, M.A., Assistant Plant
H. W. Jones, M.S., Assistant Pathologist
C. V. Noble, Ph.D., Agricultural Economist**
Bruce McKinley, A.B., B.S.A., Associate FI TTI
M. A. Brooker, Ph.D., Associate FIELD STATIONS
Zach Savage, M.S.A., Assistant
ECONOMICS, HOME M. N. Walker, Ph.D., Plant Pathologist in
Ouida Davis Abbott, Ph.D., Specialist** Charge
L. W. Gaddum, Ph.D., Biochemist W. B. Shippy, Ph.D., Associate Plant Pathol-
C. F. Ahmann, Ph.D., Physiologist ogist
K. W. Loucks, M.S., Asst. Plant Pathologist
ENTOMOLOGY J. W. Wilson, Ph.D., Associate Entomologist
J. R. Watson, A.M., Entomologist** C. C. Goff, M.S., Assistant Entomologist
A. N. Tissot, Ph.D., Associate P t
H. E. Bratley, M.S.A, Assistant Plant City
P. W. Calhoun, Assistant, Cotton Insects A. N. Brooks. Ph.D., Plant Pathologist
R. E. Nolen, M.S.A.. Asst. Plant Pathologist
A. F. Camp, Ph.D., Horticulturist**
M. Ensign, M.S., Associate A. S. Rhoads, Ph.D., Plant Pathologist
A. L. Stahl, Ph.D., Associate H
G. H. Blackmon, M.S.A., Pecan Culturist Hastings
C. B. Van Cleef, M.S.A., Greenhouse Foreman A. H. Eddins, Ph.D., Asso. Plant Pathologist
PLANT PATHOLOGY West Palm Beach
W. B. Tisdale, Ph.D., Plant Pathologist** D. A. Sanders, D.V.M., Veterinarian
George F. Weber, Ph.D., Plant Pathologist Monticello
R. K. Voorhees, M.S., Assistant
Erdman West, M.S., Mycologist Fred W. Walker, Assistant Entomologist
*In cooperation with U.S.D.A. Bradenton
"*Head of Department. David G. Kelbert, Asst. Plant Pathologist
EFFECT OF CALCIUM-DEFICIENT ROUGHAGES UPON
MILK PRODUCTION AND WELFARE OF DAIRY COWS
By R. B. BECKER, W. M. NEAL AND A. L. SHEALY
Introduction ............................ ......... ........... 3
Review of literature ................................................... 4
Statement of problem .................................................. 7
Plan of work .......................................................... 9
P presentation of data ................................................... 11
Typical rations used ........................: ................... 11
Chemical analyses of feeds used.................................. 12
Bone strengths before and during use of bonemeal................. 16
Milk production before and during the inclusion of bonemeal in the
rations ....................................... ................ 20
Mineral demands for reproduction................................ 22
Discussion of results ........................................ 25
Summary and conclusions .............................................. 26
Acknowledgements ........................... ......................... 27
Literature cited ....................................................... 27
Cattle require a wide variety of nutrients in their feed in order
to supply all the requirements of the body. Proteins, starches,
sugars and fats provide organic compounds for maintenance,
energy, growth and certain constituents of milk. A supply of
vitamins is necessary for the performance of the normal func-
tions of life, and to impart these nutritive entities to milk. The
mineral elements provide for the body framework, for the vital
processes of the blood and body tissues, and for the ash of milk.
Reproduction also calls for a small but definite amount of nutri-
ents to form the calf.
On the open range, cattle depend entirely upon the native for-
ages for their feed. Dairy cows, with larger milk yields, require
more nutrients, a part of which must be supplied in more con-
centrated form. These concentrates usually provide for the ad-
ditional amount of organic compounds-the proteins, carbohy-
drates and fats-but often leave the ration inadequate in some
of the mineral nutrients. Calcium and phosphorus are two of the
major mineral nutrients that most often are found deficient.
Dairy cows depend chiefly upon roughages as sources of cal-
cium, and upon grains and milling by-products as the principal
natural sources of phosphorus. The mineral content of the rough-
ages is affected directly by the character of the soils upon which
they are grown, and upon the rainfall of the locality(9). When
4 Florida Agricultural Experiment Station
the calcium content in roughages is low, as is characteristic of
those grown on low-calcium soils, cattle dependent upon them may
be affected by a deficiency of this element in the feeds.
REVIEW OF LITERATURE
The literature here reviewed is grouped in relation to effect of
mineral matter upon the skeleton, its utilization for milk pro-
duction, the amount required for reproduction, and mineral feed-
Chossat(5) was one of the earliest investigators to demon-
strate that lack of calcium caused malnutrition in bones. Two
lots of adult pigeons were fed for 10 months on wheat and water.
One lot, receiving calcium carbonate in addition, remained in nor-
mal health, while the other lot without calcium developed porous,
softened and fragile femur and sternum bones-so-called "bone
softening." Roloff(24), Voit(29), Aron and Sebauer(1) observed
that the skeletons of dogs, pigeons and rabbits became weakened
and porous on rations deficient in calcium. Nessler(22) found
that the bones of a cow affected with Knochenbruchigkeit (bone-
fragility) contained less calcium and phosphorus, were lighter
in weight, and had thinner shaft walls than had those of a healthy
cow. Greater differences were observed in the spongy bones
such as the vertebrae, joints and pelvis than in the shaft bones
of the legs. This depletion of calcium and phosphorus in the
skeleton occurred when the cattle received feeds that contained
inadequate amounts of the bone-forming mineral elements.
Eckles(9) observed bones similarly depleted, though seldom
broken, with cows under conditions of extreme phosphorus defi-
ciency in the feeds.
Reid and Aston(23) studied osseus cachexia of sheep in New
Zealand, and found that the bones of affected animals fractured
easily. Chemical analyses revealed a subnormal percentage of
total ash in the fresh bones. Aston(2) made a similar observa-
tion with sheep on a low-lime soil, in which the bones showed un-
usual weakness. He stated further that a ration deficient in cal-
cium also may result in phosphorus starvation even when suffi-
cient amounts of phosphorus are in the feed.
Fraser(12) stated that some high producing cows come through
a lactation period in a state of mineral starvation without show-
ing it outwardly, their failure in health, production, or reproduc-
tion being attributed to other causes. In one case a high pro-
Bulletin 262, Effect of Calcium Deficient Roughages 5
during cow sank to the ground because her pelvic arch had
broken, being so depleted in substance that it could not support
her body. Another cow, found in her stall with a broken leg, was
discovered on post-mortem examination to have bones so brittle
that they could be broken with the hands. Kellner(18) men-
tioned that dairy rations are deficient in calcium more frequently
than in phosphorus, this being more noticeable in dry years. This
condition is conducive to bone ailments, especially with lactating
cows that even withdraw calcium from their skeletons in order
to maintain milk production. When the bones become too im-
poverished through continued withdrawal, the milk yield is di-
Mineral deficiency in calcium or phosphorus affects yield of
milk rather than its composition. Eckles and associates(3, 9)
found that even in extreme shortage of phosphorus, the calcium
and phosphorus contents of the milk were maintained normal in
concentration and proportion. Hart and associates(13) calcu-
lated that a cow with insufficient mineral matter in the feed dur-
ing a 110-day feeding trial, withdrew as much as 25 percent of
the lime content of her skeleton in order to maintain the usual
proportion of mineral matter in the milk. Ellenberger, New-
lander and Jones(10) were the first to prove conclusively that
cows in heavy milk production normally withdraw mineral ele-
ments from the body reserves, and replace them toward the close
of lactation or during the dry period. This had been suggested
from the earlier work of Forbes(11), Huffman(17), Meigs(14,
20, 21) and others. The fact that cows in heavy production, or
on inadequate rations, utilize minerals in the feeds more efficient-
ly also had been shown(17).
When cows have been fed a ration inadequate in mineral matter
over a period sufficient to deplete the available body reserves of
the essential elements, their restoration to the ration has re-
sulted in material response in milk yield, as observedby Eckles(8),
Theiler(27), Meigs(21) and Tuff(28). No benefits were derived,
however, from additions of mineral matter to rations already
Reproduction is a slight but positive drain upon mineral matter
in the cow's body. Five Jersey calves weighing an average of
51.7 pounds (30 to 70.4) were found to contain 4.257 percent of
ash on the live weight basis. Of this ash, 42.05 percent was cal-
cium oxide, 38.83 percent phosphorus pentoxide and 1.89 percent
6 Florida Agricultural Experiment Station
magnesium oxide(16). On this basis, these five calves contained
about 2.2 pounds of ash. The foetal membranes and amniotic fluid
accompanying one of them, contained an additional 0.37 pounds
Calcium and phosphorus are eliminated from the body in both
urine and feces, interfering with attempts to determine their co-
efficients of digestibility in feeds. This, together with the facts
that the daily requirements of the animal affect the proportions
utilized from the feeds(17), have retarded development of min-
eral feeding standards for dairy cows.
Stohmann, Nautenberg and Henneberg(26) stated that the
maintenance requirements with oxen, per 1,000 pounds live
weight, would be covered when the feeds provided daily about
71/2 pounds of nitrogen-free and one pound of nitrogen-containing
nutrients, besides 1/4 pound alkalies, 1/20 pound phosphoric acid
and 1/10 pound of lime.
Kellner(18) accepted Stohmann's maintenance requirements
for calcium and phosphorus, and made allowance as follows for
the requirements of lactation (translated) :
"Milk always contains a known amount of mineral matter, on
the average 7.4 grams per liter, of which 1.8 grams is CaO and
1.5 grams P20*. If the body is not to be depleted by this output,
then the feed must provide it. If 20 kg. of milk are produced per
1,000 kg. live weight daily, then the requirements will be covered
with 36 grams CaO and 30 grams P205. One adds to this, the
requirements for maintenance of the animal (100 grams of CaO
and 50 grams of P20O), then there are provided under the indi-
cated hypothesis per 1,000 kg. live weight daily around 150 grams
of CaO and 100 grams of P205. With increased milk yields, cor-
respondingly more must be included."
Thus, Kellner makes a greater allowance than just the calcium
and phosphorus content of the milk, in that he adds 50 grams each
of CaO and P20s, rather than 36 and 30 grams, respectively, of
Wellman(30) has given mineral requirements for maintenance,
growth and milk production, as follows (translated):
"Per 100 kg. live weight, we calculate daily for the maintenance
requirement 5 to 10 grams of calcium oxide and 3 to 5 grams of
phosphorus pentoxide. Besides these, with the growing animal
for production of 100 grams of gain, 3.5 grams of calcium oxide
and 2.8 grams of P205; with cows for production of one kilogram
of milk, 5 grams of calcium oxide and 4.5 grams of phosphorus
*CaO and P205, are the symbols for calcium oxide (lime) and phosphorus
Bulletin 262, Effect of Calcium Deficient Roughages 7
pentoxide are necessary, since in plant food three times as much
calcium and twice as much phosphorus must be taken in as is
necessary for production of body substance and milk."
In terms of English units, the calcium and phosphorus require-
ments as set forth above by Kellner and Wellman are as shown in
TABLE I.-MINERAL FEEDING STANDARDS COMPARED.
Kellner's standard Wellman's standard
Calcium Phosphorus Calcium Phosphorus
(Ca) (P) (Ca) (P)
pounds pounds pounds pounds
1,000 lb. cow, maintenance 0.0716* 0.0218* 0.0358-.0716 0.0130-.0218
1 lb. gain in body wt... .... ..... .0250 .0122
1 lb. milk ......... .0018 .0011 .0036 .0020
In summation, it may be stated that, after maintenance, lacta-
tion creates a major demand upon available mineral supplies, espe-
cially calcium and phosphorus. Reproduction adds slightly to these
requirements. Rations low in these essential mineral elements
cause a cow to draw upon those stored within the body in order to
maintain the normal composition of milk. These withdrawals
fall most heavily upon the skeletal tissues, weakening them to
the point that they are softened, fragile, and broken easily.
STATEMENT OF PROBLEM
Sandy soils, low in available lime, occur in areas of the Gulf
coast and Coastal Plain regions. Roughages fed to cattle in these
regions are largely home-grown. Consequently, rations low in
calcium are used frequently. Pastures and silages used in feed-
ing dairy cattle at the Florida Agricultural Experiment Station
were grown on acid sandy soils, and serve as an illustration of
the effects of such roughages upon cattle. The feeding practices
formerly employed in the Station herd are outlined best by quot-
ing from an early Florida publication(25) written before the
mineral problem was understood:
"Hay is not a necessity . Good corn silage can be substi-
tuted for hay, and at a big saving in cost . When cows are
fed a rich nitrogenous ration . it will be found more eco-
nomical to supply roughage in a cheaper form-silage, pasture or
soiling crop. In Florida, cows can have the run of pasture at all
seasons. During the winter they may not get much in the way
of feed, but they get a good deal of dry matter The author
*This maintenance requirement is the same as the one given by Stohmann,
Nautenberg and Henneberg(26).
8 Florida Agricultural Experiment Station
believes that when cows are fed a rich concentrated feed such
roughage as alfalfa, clover hay, or even crab grass hay, is not
necessary; and that a cheaper form of roughage will give us
satisfactory results at much less cost."
Fig. 2.-Cow No. 225, showing the right side with four ribs broken.
For at least 20 years prior to 1929, dairy cattle in the Florida
Station herd received grass pasture and silages as the principal
roughages, except that alfalfa meal was fed to one cow on Register
of Merit test. Since December, 1920, alfalfa meal comprised
Fig. 3.-Fatness of the cows was one indication of adequacy of the total
digestible nutrient intake while the cows received the low-calcium rations.
Bulletin 262, Effect of Calcium Deficient Roughages 9
one-ninth to one-eighth of the regular concentrated mixtures.
Little or no attention was given to use of mineral supplements
other than common salt.
Up to January 1, 1929, five of the 34 cows of producing age in
the dairy herd had incurred broken bones, two of these animals
being shown in Figures 1 and 2. The herd records also mentioned
that the most prominent early sire used in the Station herd
"became down in the hip", and had to be killed when 10 years
old. The cows were all in good flesh, some even being quite fat,
as shown in Figure 3, indicating a total digestible nutrient intake
in excess of requirements for the amount of milk produced. The
protein supply was adequate in all rations of which there is
Calcium and phosphorus are two of the chief mineral constitu-
ents of bone and of milk ash. The concentrate mixtures used in
the past provided a goodly supply of phosphorus, but the home-
grown roughages contained little lime, as will be shown. More-
over, there was no lethargy nor marked stiffness among the cows,
such as is typical of extreme phosphorus deficiency in cattle(9).
The condition of the herd as to proportion of cows with broken
(and healed) bones, pointed toward a shortage of calcium in the
rations as the cause of the conditions observed.
The problem was to determine the approximate extent of de-
ficiency involved, to correct the deficiency in a practical way, and
to observe the effects of such correction.
PLAN OF WORK
The types of rations formerly used in feeding the Station
dairy herd were summarized from the Station records and an-
nual reports. Proximate and mineral analyses were made of corn
silage grown on the Station farm, as this was the principal rough-
age used to supplement grass pastures. Various pasture grasses
and velvet beans in the pods were analyzed. Since the concen-
trates were purchased on the open market, average published
analyses were assumed to be representative of those feeds used
during the period studied.
The rations were changed slightly, beginning in January, 1929.
A few of the higher producing cows were given a daily allowance
of five pounds of No. 1 green alfalfa hay. Grass pasture and corn
silage were continued as the principal roughages, and 1 percent
of common salt was left in the concentrates. In absence of a
10 Florida Agricultural Experiment Station
local source of calcium carbonate or calcium phosphate known to
be free from undesirable substances, bonemeal was selected as the
most practical mineral supplement to the ration. This was added
as 2 percent of the concentrate mixture, that level being assumed
to meet the daily requirements of the cows, and to allow a margin
sufficient to restore the reserves withdrawn from the skeletal
tissues for milk production.
Fig. 4.-Dorsal view of the pelves of cows No. 59 and No. 120, broken while
the cows received low-calcium rations. Arrows indicate breaks.
Breaking strength determinations, using an electrically driven
Riehle Brothers testing machine, were made upon the leg bones
of Cow No. 59 in the herd soon after she had suffered a broken
pelvis (Fig. 4). At various times after the addition of bonemeal
to the ration, bones were obtained from other cows in the herd for
breaking strength determinations. The average strength of can-
non bones from a group of steers grazed locally on similar pas-
tures was obtained for comparison.
Milk records were tabulated of all the Jersey cows that had
completed normal lactations on both the supplemented and un-
supplemented rations. These were computed to a uniform age
basis, using the factors obtained by Clark(6) on Jersey cows not
on official test, milked twice daily in experiment station herds.
The draft of reproduction upon mineral needs was computed by
using the birth weights of Jersey calves born in the Florida
Bulletin 262, Effect of Calcium Deficient Roughages 11
Station herd since 1929, and analyses of Jersey calves at birth,
as published by the Missouri Station(16).
PRESENTATION OF DATA
TYPICAL RATIONS USED
The data herein presented were accumulated under the condi-
tions of management prevailing over a period of years in the
Station dairy herd generally, rather than from an extensive in-
vestigation planned in advance. Monthly feed records were avail-
able for a part of this period on two of these cows. Typical
rations used from time to time have been assembled from the
herd records and from the Station annual reports. Detailed
search of these sources showed that grass pasture (Bahia, carpet
and centipede grasses predominating), corn silage and some cane
and sorghum silages, were the principal roughages. Summation
of published data from seven feeding trials between 1908 and
1917 showed that cows with an average body weight of 711
pounds received 22.25 pounds of silage, in addition to the concen-
trates. During these trials, the concentrates were mainly a mix-
ture of 2 to 4.4 parts of wheat bran with 1 part of cottonseed
meal, which on the Southeastern markets was then largely the
grade containing 36 percent of crude protein. Other feeds used
for short periods included coconut meal during one feeding trial,
wheat middlings, velvet beans and velvet bean feed meal. A
limited allowance of dried beet pulp was fed to some cows on
Register of Merit test. One test ration consisted of 300 parts of
wheat bran, 200 of velvet bean feed meal, 100 of corn meal and
80 of peanut meal (grade not stated).
The first legume hay mentioned in any of the rations was al-
falfa meal fed in the concentrates to cow No. 18 while on Register
of Merit test. After December, 1920, alfalfa meal was mentioned
as one-ninth to one-eighth of the regular concentrate mixture
used in connection with any feeding trials. Two special feeding
trials used larger amounts of alfalfa meal with 4 and 6 cows for
123 and 84 days, respectively, but not in excess of four pounds
in a day. Other than these, legume hays were not in general use.
Mineral supplements, except common salt, were not used until
right at the close of the period prior to 1929, and then for only
a limited time.
Several of the rations used more recently are listed in Table II.
This list includes a more complex concentrate mixture used with
12 Florida Agricultural Experiment Station
corn silage and grass pasture during 1928 and early 1929. The
cows received as much as one pound of this grain for each two
pounds or less of milk produced, and were all in excellent flesh.
This study of the effects of the ration upon milk yield and welfare
of the cows was begun on January 1, 1929. For economic reasons,
ground oats since have been replaced with more wheat bran; corn
gluten feed and peanut meal discontinued; velvet bean feed meal
(grown locally) added; the cottonseed meal changed to a grade
with a higher protein content; and the proportions of these con-
stituents changed slightly, as shown in Table II. One percent of
common salt was continued, and two percent of finely ground
feeding bonemeal added. A few of the higher producing cows
and those on Register of Merit test were given an allowance of
about five pounds of No. 1 green alfalfa hay daily. During the
three years 1930 to 1932, a few of the cows on feeding trials have
received home-grown soybean silage, as outlined in Bulletin 255
of the Florida Agricultural Experiment Station.
TABLE II.-CONCENTRATES USED WITH SILAGES AND GRASS PASTURE IN FEED-
ING THE FLORIDA STATION DAIRY HERD FROM 1922 TO 1933.
Year ............... 1922 1923 1924 and 1925 1928 1929 to 1933
Concentrates ....... Ration 1 Ration 2 Ration 3 Ration 4 Ration 5
Wheat bran ......... 100 100 100 200 400
Cornmeal ........... 100 100 100 300 300
Ground oats ......... 75 75 100 300
Alfalfa meal ........ 50 50 50
Peanut meal ........ 50 ... ... 100
Cottonseed meal, 36% 50 100 100 100
Cottonseed meal, 41% ... ... ... ... 100
Corn gluten feed..... .. ... ... 100
Dried beet pulp ...... .. ....... 100 200
Linseed oil meal ..... .. ... .. 100 100
Velvet bean feed meal .. ... ... .. 200
Common salt ........ ... ... ... 13 13
Bonemeal ............... .. .. ... ... 26
CHEMICAL ANALYSES OF FEEDS USED
During the routine of other experimental work, many samples
of locally-grown feeds have been analyzed. These show a lower
content of calcium than do the feeds grown on soils that contain
more lime. A higher content of total phosphorus in the feeds
from the Station farm may be accounted for by the fact that
"complete" fertilizers sometimes have been used on part of the
crop lands. The lespedeza, beggarweed and soybean silage in-
cluded in this table were grown on residual soils of phosphatic
origin that contain some lime. On the acid sandy soils few
TABLE III.-RELATIVE AMOUNTS OF CALCIUM AND PHOSPHORUS CONTAINED IN LOCALLY-GROWN FEEDS AND IN COMMERCIAL
FEEDS, ON THE MOIST BASIS.
Number of Crude Crude Nitrogen-free Ether
Feed analyses Moisture protein fiber extract extract Calcium Phosphorus
percent percent percent percent percent percent percent
Corn Silage* ............. 9 68.82 2.33 7.49 19.37 0.74 0.088 0.083
Sorghum silaget ........... 72.76 1.72 7.20 15.99 .92 .092 .041
Kafir silaget ............. .. 72.36 1.76 6.83 16.41 .99 .067 .044
Soybean silage* .......... 23 75.43 2.03 9.50 8.40 .74 .289 .100
Beggarweed hay* ........ 2 8.98 14.36 33.57 36.62 2.03 1.054 .267
Alfalfa hay, No. 1 green*.. 9 8.35 14.44 29.57 38.87 1.92 1.116 .222
Lespedeza, air dry* ...... 7 9.66 13.49 23.79 45.81 1.96 .987 .228
Natal grass, dry matter*... 3 ... .... .. .... ... .495 .317 '
Wire grass, dry matter*... 50 .... 6.10 35.36 53.17 1.54 .167 .160
Corn meal* .............. 15 .... .... .. ... .... .013 .312
Velvet bean feed meal* .... 9 11.35 18.57 12.22 50.80 3.81 .223 .332
Wheat Brans .............. 10.80 15.00 9.50 54.00 4.40 .060 1.290
Corn gluten feed .......... 9.60 24.50 7.10 52.90 3.80 .250 .271 .
Cottonseed meal, 36%$ .... 8.30 36.00 12.50 29.00 8.00 .250* 1.158* '
Beet pulpS ............... .8.20 8.90 18.90 59.60 .90 .656 .105
Oats$ .................... .. 9.20 12.40 10.90 59.60 4.40 .100 .350
Peanut meal, medium grade 12 6.22 44.91 12.08 23.05 8.84 .116 .529
Linseed oil mealS ......... 9.10 33.90 8.40 35.70 7.50 .360 .740
*Analyses of locally-grown feeds made at Florida Station; alfalfa hay from Kansas City market; soybeans, beggarweed
and lespedeza were from heavier types of soils.
$Average composition, Florida State Chemist Ann. Rept. 1928, and Ohio Sta. Bul. 255.
tFrom Oklahoma Sta. Bul. 177 and Ext. Circ. 246.
14 Florida Agricultural Experiment Station
These feeds are compared with the commercial feeds used in
the rations, and with typical feeds from other sources in the
literature (Table III).
To get an indication of the average daily intakes of calcium
and phosphorus by cows in the Station herd, rations have been
computed upon the basis of body weights of cows, average milk
yields and amounts of feeds used in representative feeding trials
from 1908 to 1917. Experimental rations used from 1922 to 1925,
the ration in use on January 1, 1929, and the present modification
of this latter ration were all computed similarly. During these
years, concentrates were purchased on the open market, and were
presumably representative of those same feeds, the average
analyses of which are published in the literature. The corn
silage is computed on the basis of recent analyses of that grown
on the Station farm (on acid sandy soil). The complete calcula-
tion of the ration for the first period is shown below:
CALCULATED REQUIREMENTS OF COWS ON EARLY FEEDING TRIALS
crude Digestible Calcium Phosphorus
protein* nutrients* (Ca) (P)
pounds pounds pounds pounds
Wellman's(30) mineral standard:
725 lbs. live weight,
maintenance .......... 0.5075 5.7456 .0260-.0519 .0094-.0158
15 lbs. of milk, 5%
butterfat ............. .9975 5.7300 .0540 .0300
Total .............. 1.5050 11.4756 .0800-.1059 .0394-.0458
Kellner's(18) mineral standard:
725 lbs. live weight,
maintenance ........ .... ..... .0519 .0158
15 lbs. of milk, 5%
butterfat ........... .. .... ..... .0270 .0165
Total .............. ..... ..... .0789 .0323
THE AVERAGE RATION BETWEEN 1908 AND 1917 CONTAINED-
22.25 lbs. corn silage ...... .2448 3.9383 .0171 .0196
9 lbs. wheat bran ..... 1.1250 5.4810 .0058 .1160
3 lbs. cottonseed meal,
36% .................. .9480 2.2440 .0077 .0349
Total ............. 2.3178 11.6633 .0306 .1705
Compared with the mineral feeding standard mentioned by
Wellman(30), this ration provided less than 40 percent of the
calcium and four times as much phosphorus as was required by
*Requirements for digestible crude protein and total digestible nutrients
were calculated according to the Morrison standard, given in "Feeds and
Feeding," 18th edition, page 746. 1923.
TABLE IV.-COMPARISON OF THE NUTRIENTS REQUIRED BY A TYPICAL COW IN THE STATION DAIRY HERD WITH THE NUTRIENTS
PROVIDED BY RATIONS IN USE BETWEEN 1908 AND 1933.
Rations Nutrients provided
Corn crude digestible Calcium Phosphorus
silage Concentrates protein nutrients (Ca) (P)
pounds pounds pounds pounds pounds pounds
725 lb. cow yielding
15 lbs. of 5% milk* ............... .... 1.5050 11.4756 0.0800-.1059 0.0394-.0458t
........... .... .0789t .0323*
Rations in use-
1908-1917 ..................... 22.25 12.0 2.3178 11.6633 .0306 .1705
1922-1925 ..................... 22.25 11.0 1.9070 11.6380 .0448 .1973
1928 .......................... 22.25 10.5 1.8733 11.6600 .0408 .1535
1929-1933 ..................... 22.25 11.0 1.6811 11.6075 .0776 .1032
*The average requirements are based on weights and milk records of cows in feeding trials conducted between 1908
and 1917 at this station.
tCalcium and phosphorus requirements calculated according to Wellman's(80) standard. o
$Calcium and phosphorus requirements calculated according to Kellner's(18) standard.
16 Florida Agricultural Experiment Station
this typical cow. Kellner(18) allows somewhat less calcium and
phosphorus than does Wellman, as shown by the calculations.
Rations have been calculated to meet these same requirements,
using typical concentrate mixtures that were fed from 1922 to
1925, in 1928, and since 1929. Details of these calculations have
been omitted, the end results of them being shown in Table IV.
In this connection it is well to mention again that the concen-
trates in use since January, 1929, contained 2 percent of finely-
ground feeding bonemeal. This bonemeal had a guaranteed
analyses of 65 percent of calcium phosphate.
Of the 12 Jersey cows included in this study, No. 59 and No. 81
were in milk during the earlier period when monthly feed cards
were kept in the herd records. Unfortunately, body weights
were not recorded regularly during that period. The feed records
cover part or all of three lactations, excluding the dry periods.
These six records were calculated to a daily basis, as listed in
Table V. They show especially the proportions of silage and
concentrates fed to milk produced daily.
TABLE V.-AVERAGE DAILY MILK YIELD AND FEED INTAKE, EXCLUDING GRASS
PASTURE, OF COWS NOS. 59 AND 81 DURING PARTS OF THREE LACTATIONS
Cow Interval Time Milk Silage trates
days pounds pounds pounds
No. 59 Dec. 1, 1916, to Sept. 30, 1917.. 305 18.90* 11.58 12.28
Jan. 1 to Aug. 13, 1918........ 243 14.02 17.96 7.24
Feb. 5, 1919, to Jan. 31, 1920... 361 18.35 30.66 8.42
No. 81 Jan. 1 to July 31, 1917........ 212 9.51 15.73 7.50
Dec. 1, 1918, to July 31, 1919.. 243 11.43 26.32 7.76
Aug. 20, 1919, to June 13, 1920t 299 10.46 22.85 7.10
*Body weights obtained during a 12-week feeding trial averaged 574
tA complete lactation, excluding dry period.
BONE STRENGTHS BEFORE AND DURING USE OF BONEMEAL
Five of the 34 cows in the Station dairy herd on January 1,
1929, had one or more broken (and healed) bones, as follows:
No. 59-Pelvis, three (new) fractures; No. 120-both hips and
the right 12th rib; No. 223-right 13th rib; No. 225-left hip
and last four ribs on the right side; No. 229 (Dutch Belt)-left
hip. Even a 10-year-old bull-Florida's Majesty-formerly used
in the Station herd, was slaughtered in the summer of 1927 be-
cause he "became down in the hip," which affected his usefulness.
Cow No. 59 had 11 consecutive lactations averaging 6,338
pounds of milk, and 303.5 pounds of butterfat. Her last lactation
extended from May 13, 1927, to October 24, 1928, during which
Bulletin 262, Effect of Calcium Deficient Roughages 17
time she produced 8,159 pounds of milk with 406.73 pounds of
butterfat. During the last week in December, 1928, her pelvis
broke in three places, as shown in Fig. 4, it being unable longer
to bear her weight. The femurs and humeri were obtained upon
post-mortem, and breaking strengths were determined according
to the method described previously(4). These four bones had an
average strength of only 335 pounds. The mineral reserves had
been drawn on to such an extent that the bones were weakened.
That cow No. 59 was not an isolated instance is shown by the large
proportion of the milking cows that had broken one or more bones
in the past.
The rations and routine management of the herd were changed
only as considered expedient. Pasture grasses and corn silage
continued to be the principal roughages, although a few cows on
Register of Merit test were allowed about five pounds of No. 1
alfalfa hay daily. The grain ration was changed slightly, as
described in Table II, and with the addition of 2 percent of bone-
As cows subsequently have been eliminated from the herd,
breaking strengths have been determined on selected bones.
Bones also were obtained from three range cows not in milk that
had received neither concentrates nor bonemeal. One hundred
and twenty cannon bones were obtained from 24 steers and six
Aberdeen Angus cows. The steers had grazed pasture grasses
grown on acid sandy soil, and had received peanut hay with a
limited grain allowance in winter. They had free access to bone-
meal and common salt during the year prior to slaughter. The
Aberdeen Angus cows were not in milk. They were on grass
pasture most of the year, with corn and cane silages during the
winter, supplemented by a limited allowance of mixed concen-
trates that contained 1 percent of bonemeal.
The Jersey cow No. 59 had received the unsupplemented rations
listed in Table II, with pasture grasses, corn and cane silages as
the only roughages. Guernsey cow No. 297 received the same
grain rations and the bonemeal supplement for one month. She
was a low producer, and had been dry for 81 days prior to slaugh-
ter. The Dutch Belted cow was on the supplemented ration for
29 months. Guernsey No. 296 and Jersey No. 228 received the
supplemented rations for 42 and 46 months, and were then utilized
as dry cows in feeding trials on new legume roughages for periods
of 81/2 and 5 months, respectively, prior to slaughter. All other
Jersey cows listed were fed the dairy rations described in Table
TABLE VI.-AVERAGE BREAKING STRENGTHS OF 239 LEG BONES F ROM FLORIDA CATTLE UNDER DIFFERENT FEEDING CONDITIONS.* I
Average breaking strength of bones from left and right legs
Radius Tibia and Fore Rear
Cattle Type of ration Humerus Femur and ulna fibula cannon cannon Average
pounds pounds pounds pounds pounds pounds pounds
No bonemeal available
Cow No. 59 ...........Dairy ration, unsupplemented..... 330a 340b .... .... .... .... 335
No. 1 .............. Range on sand and muck lands.... .... .... .... 1,530 1,998 1,764
No. 2 ................Range on sandy lands............ 2,240 2,405 1,923 2,602 1,883 2,155 2,201
No. 3 ................Range; peanut hay in winter..... .. .... .... 2,120 2,380 2,250 C
Two percent of bonemeal in concentrates
Cow No. 297 ......... .Dairy ration; bonemeal 1 mo... ... ..... .... .... 3,470 3,440 3,455
Cow No. 296 .......... ; bonemeal 42 mo. ... 5,055 4,665 4,585 4,040 3,215 4,045 4,268
Dutch Belted Cow ..... ; bonemeal 29 mo. ... 3,535 3,645 3,710 3,240 3,255 3,868 3,542
No. 81, 120, 195, 225 .. ; bonemeal 19-27 mo. 3,244 3,636t 2,848 3,299 2,228 3,302 3,037
No. 177, 188, 218 ......" ; bonemeal 13-23 mo. 2,700 3,788 3,244 'z
No. 228 .............. ; bonemeal 46 mo. ... 2,815 3,420 3,245 3,095 2,160 3,410 3,024
One percent of bonemeal in concentrates
6 cows ............. Grass, silage, concentrates ....... .... .. .. .... 2,689 3,370 3,030
Access to bonemeal, ad libitum
8 grade Angus .......Grass pasture, with peanut hay in
winter ....................... .... ... ... .... 2,059 3,059 2,559
16 natives and grade
Herefords ..........Grass pasture, with peanut hay in
winter .................. .... . .. .... .... .... 2,426 3,184 2,805
*Breaking strengths were determined by using a 6-inch span, with weight applied slowly in the middle from above, except (a)
a 5-inch span, and (b) a 7-inch span with cow No. 59.
tOne femur of cow No. 195 not available.
Bulletin 262, Effect of Calcium Deficient Roughages 19
II, with the bonemeal supplement during the 13 to 27 months
prior to slaughter.
Only cannon bones were obtained from such carcasses as were
slaughtered for market. All of the shaft bones were secured,
however, from five of the Jerseys, the Dutch Belted cow, a Guern-
sey and one range cow. Average breaking strengths of the right
and left humeri, femurs, radii and ulnae, tibiae and fibulae, fore
and rear cannon bones are presented in Table VI.
The 120 cannon bones from the steers and Angus cows had an
average breaking strength of 2,784 pounds, when the weight was
applied slowly from above in the middle of a 6-inch span. This
value is used as a median or normal for cattle past three years
old, that are in an average good state of mineral nutrition. The
dairy cows receiving 2 percent of bonemeal in the concentrates
built stronger bones, apparently by storing mineral matter in
these tissues as available reserves.
The three range cows represent lower degrees of strength
(mineral storage), and the cow No. 59 an extreme stage of de-
pletion which occurred with persistent milk production on rations
deficient in calcium. With cows that had previously suffered
broken bones, it is of special interest to note bone strengths after
a period of feeding on the supplemented rations. Cow No. 120
had broken both hips and the right 12th rib (see Figs. 1 and 4).
Later, she received the supplemented ration for 19 months. Her
femurs then had an average breaking strength of 2,630 pounds;
humeri, 2,072.5 pounds; fore cannon bones, 1,800 pounds; and rear
cannon bones, 3,047.5 pounds. The average of these breaking
strengths was 2,387.5 pounds. No. 225 had broken the left hip and
last four ribs on the right side, as shown in Fig. 2. Later, this cow
had the bonemeal supplement for 23 months prior to slaughter.
She died when 16 years 7 months and 7 days of age. Her femurs
then had an average strength of 3,745 pounds; humeri, 3,885
pounds; radii and ulnae, 3,965 pounds; tibiae and fibulae, 3,500
pounds; rear and fore cannon bones, 3,692.5 and 2,587.5 pounds,
respectively. Her leg bones, two of which are shown in Fig. 5,
had an average breaking strength of 3,562.5 pounds. It is inter-
esting to note in Table V that the humeri and femurs usually
were stronger than the cannon bones. Yet the 120 cannon bones
of steers and Angus cows were over eight times as strong as the
depleted femurs and humeri of cow No. 59. All of these facts are
evidence that the 2 percent level of bonemeal in the concentrates
was sufficient to meet the requirements of maintenance, a medium
20 Florida Agricultural Experiment Station
milk production, and reproduction, and to restore a reserve sup-
ply of these mineral elements to the skeletal tissues.
Fig. 5.-Cannon bone (above) and humerus from Cow No. 225, showing
thickness of shaft walls after bonemeal had been added to the low-calcium
rations for 23 months.
MILK PRODUCTION BEFORE, AND DURING, THE INCLUSION OF
BONEMEAL IN THE RATIONS
Milk records of every Jersey cow in the herd that had one or
more normal lactations while on the unsupplemented and the sup-
plemented low-calcium rations, were used in a study of the influ-
ence of bonemeal in the ration upon milk production. Lactations
were tabulated by 10-day periods, including the date of calving
as the first day. An average lactation curve was computed for
Bulletin 262, Effect of Calcium Deficient Roughages 21
each cow, corrected to the age of maximum production by using
Clark's conversion factors (6) for Jersey cows milked twice daily
in experiment station dairy herds.
Days in milk
s50 00 150 200 250 400 I o
Fig. 6.-Average daily milk yields of 12 Jersey cows before and during use
of bonemeal as a supplement to low-calcium rations. The upper curve
represents 22 lactations on the supplemented and the lower curve 44 lacta-
tions on the unsupplemented rations, computed to a uniform age basis.
Twelve Jersey cows had a total of 44 lactations previous to and
22 after the addition of bonemeal to the rations. Graphs com-
paring these two combined average lactation curves (Fig. 6) show
a materially higher level of production by these cows upon the
addition of bonemeal to the low-calcium rations. The greater
persistency of lactation when the bonemeal had been added to the
inadequate rations is indicated very clearly in Table VII. The
point of maximum daily production was attained a few days later,
and the subsequent decrease in milk secretion was less rapid on
the supplemented ration. When on the inadequate ration, the
cows tended to go dry sooner. The level of production was ma-
terially higher, even in the first month after calving. The actual
milk yields of each cow in the several lactations are shown in
The point must be stressed again that the cows during the ear-
lier period were in excellent condition, indicating an adequate
intake of total digestible nutrients. The rations provided an ex-
cess of protein from several plant sources, yet the mAlk yield
was low. Bonemeal was added to the ration during January,
1929. Under the feeding practice since that time, fewer cows
have carried excess fat and their milk yields have increased. The
22 Florida Agricultural Experiment Station
TABLE VII. -PERSISTENCE OF MILK PRODUCTION OF 12 JERSEY COWS AS
AFFECTED BY ADDITION OF BONEMEAL AS A SUPPLEMENT TO A LOW-CALCIUM
Production on low-calcium ration Production of supplemented ration
Rate of Rate of base
Month Milk yield production* Milk yield production*
pounds percent pounds percent
1 644.3 13.84 765.1 16.43
2 636.2 13.66 789.9 16.96
3 572.1 12.29 732.1 15.72
4 525.5 11.29 681.3 14.63
5 464.0 9.96 622.2 13.36
6 420.6 9.03 553.2 11.88
7 378.2 8.12 525.3 11.28
8 328.2 7.05 493.7 10.60
9 281.2 6.04 464.1 9.97
10 201.9 4.34 406.7 8.73
11 112.6 2.42 359.0 7.71
12 55.4 1.19 295.4 6.34
13 27.6 .59 237.7 5.11
10 days 8.4 .18 66.2 1.42
Total ......4,656.2 100.00 6,991.9 150.16
*The total production in the first lactation (4,656.2 pounds of milk) is the
base figure used in computing the rate of production. These are obtained by
computing the individual lactations to age of maximum production, using the
factors of Clark(6), so as to place lactations at different ages upon a com-
cows have been in position, with an adequate calcium intake, to
utilize protein and other digestible nutrients for milk production
rather than for storage as body fat.
MINERAL DEMANDS FOR REPRODUCTION
Birth weights of calves were not recorded regularly in the
Florida Station dairy herd prior to 1929. The Jersey calves born
since that time have ranged in weight from 28 to 70 pounds, the
average being 50.58 10.53 pounds. Assuming that these calves
contained the same proportion of ash as was found in five new-
born Jersey calves at the Missouri station(16), they represent a
mineral demand of 1.19 to 2.98 pounds, or an average of 2.15 0.45
pounds of ash in their bodies. Ash of these Missouri Jerseys
consisted of 30.04 percent calcium (Ca) and 16.97 percent phos-
phorus (P). In addition, Eckles(7) found that the amniotic fluid
and membranes in one of these instances contained 0.37 pounds
Reproduction in Jersey cows, then, is calculated to involve a
drain in addition to that of lactation, of approximately 2.5 pounds
of ash at the beginning of each lactation. At least 0.65 pounds
of this are calcium, and 0.51 pounds are phosphorus. This amount
TABLE VIII.-ACTUAL MILK PRODUCTION IN EACH LACTATION BEFORE, AND WHILE, RECEIVING BONEMEAL AS A SUPPLEMENT TO A LOW-CALCIUM
On original rations While receiving bonemeal in addition
Dry From Dry From
period calving period calving
before to before to
Cow Age lactation conception Lactation Milk Age lactation conception Lactation Milk
yr. mo. days days days days pounds yr. mo. days days days days pounds
81 2 5 7 ... 70 256 2,524.5
3 4 24 98 87 271 3,138.1
4 2 12 20 126 292 3,131.8
5 2 14 69 98 316 4,530.2
6 3 6 74 76 288 4,573.2
7 2 23 65 98 318 5,191.8
8 3 4 59 137 372 5,641.1
9 4 23 45 89 281 4,456.8
10 4 9 70 103 331 6,128.6
11 5 10 67 90 302 5,804.7 13 7 6 56 100 368 8,508.8
12 5 10 64 132 368 5,756.2 14 7 15 7 (cystic ovaries) 376 5,719.1
151 1 8 24 ... ... ... no milk record
2 11 4 ... 71 305 3,348.2
3 10 12 39 71 292 3,608.9
4 9 27 59 214 322 4,405.7
6 2 2 172 50 317 5,358.8 8 2 24 54 27 287 4,809.5
7 1 18 25 107 349 5,037.0 9 0 25 19 open 400(470) 9,027.2 (9,743.3)
156 2 5 23 ... 76 300 4,101.6
3 5 0 43 104 317 5,306.6
4 5 16 65 118 310 5,460.5
5 7 27 129 197 ... incomplete
6 11 11 ... ... ... no milk record 8 2 20 63 70 2593 6,607.9$
171 2 1 22 ... 148 351 3,697.3
3 3 9 74 258 400 (491) 6,218.9(7,366.9) 7 4 4 69 92 358 9,334.2
4 9 2 38 176 400 (431) 6,656.3(6,875.5) 8 4 9 12 366 392 6,238.8
5 11 22 16 214 400 (433) 6,562.6(6,802.1) 10 1 18 257 210 400(446)10,472.5(11,041.0)
188 2 4 2 ... 123 282 2,975.2
3 5 11 124 open 213 2,810.7 5 5 0 508 (cystic ovaries) 400(608) 4,891.2 (6,096.3)
TABLE VIII.-ACTUAL MILK PRODUCTION IN EACH LACTATION BEFORE, AND WHILE, RECEIVING BONEMEAL AS A SUPPLEMENT TO A LOW-CALCIUM
On original rations While receiving bonemeal in addition
Dry From Dry From
period calving period calving
before to before to
Cow Age lactation conception Lactation Milk Age lactation conception Lactation Milk
yr. mo. days days days days pounds yr. mo. days days days days pounds
195 2 6 23 ... 65 276 2,497.9
3 6 4 71 61 217 2,027.8 5 6 27 42 301 400(433) 4,947.6 (5,081.4)
4 8 4 210 44 288 3,534.1 7 2 4 152 open 400(609) 9,979.6(12,440.7)
214 2 3 25 ... 114 329 4,909.1
3 4 29 71 84 320 4,777.6 5 7 19 11 117 400(539) 8,751.3 (9,991.1)
4 4 23 41 170 400 (442) 6,089.5 (6,125.1) 7 8 19 143 110 400(478) 9,282.5 (9,930.8)
216 2 11 28 ... 74 215 3,643.0 4 10 24 24 21 282 4,587.5
3 10 11 53 103 354 5,134.2 5 8 16 15 open 400(572) 6,843.7 (7,795.2)
218 1 5 9 ... ... ... no milk record
3 7 18 ... 69 219 2,094.7
4 4 29 130 299 348 3,084.7 5 11 21 224 322 367 4,714.7
225 10 9 19 110 34 264 4,730.7
11 8 1 52 21 222 4,644.4
12 6 5 92 21 292 3,690.5 14 6 0 52 300 400(416) 4,783.0 (4,815.8)
13 5 0 39 48 314 3,787.0 16 1 5 157 died 180* 3,424.3*
228 1 11 24 ... 52 191t 3,170.3 t
2 10 21 144 64 280 2,332.1 4 8 10 52 302 400(522) 5,344.2 (6,241.0)
3 10 0 33 40 264 3,278.2 6 3 10 55 open 400(752) 6,001.3 (8,744.0)
241 2 3 9 ... 91 338 3,636.7 4 7 21 227 65 400(631) 5,750.9 (7,362.4)
3 3 15 34 55 267 2,536.1 6 8 13 123 126 389 6,658.5
Average, weighted by cows 80 105 299 3,980.0 86 169 382 6,425.4
Average of all lactations 73 103 303 4,227.8 90 170 366 6,667.2
*This cow died during the lactation period.
"tThe milk records were discontinued while this cow was milking 13 pounds daily.
SThis lactation ended with an abortion.
These averages omit one extreme case (Cow No. 188).
Bulletin 262, Effect of Calcium Deficient Roughages 25
of ash is equivalent to the total ash found in 166 to 416 pounds
of whole milk. The average calcium and phosphorus in these
calves, however, was equal to that found(3, 9) in 535 to 543
pounds of mixed whole milk. Reproduction entails a relatively
smaller drain on the body for calcium and phosphorus than does
DISCUSSION OF RESULTS
This study represents the effects of long-continued feeding of
a calcium-deficient ration to dairy cows, under conditions more
extreme than have been studied experimentally heretofore. The
degree of depletion of mineral reserves in the skeletons of Jersey
cows under such feeding practice was sufficient to weaken the
bones to such an extent that a conspicuous proportion of the
animals had suffered broken bones. The extreme weakness of
the bones, which allowed them to break easily, has been pointed
out especially in the case of cow No. 59. When a 2 percent level
of bonemeal was added to the concentrates and a daily allowance
of about five pounds of alfalfa given the better producers,
strength of the shaft bones was increased even above that noted
for steers having free access to bonemeal on grass pastures. This
suggests the possibility of placing cows in excellent mineral
storage in preparation for milk production.
Twelve Jersey cows produced much more milk, without any
evidence of bone weakness, while receiving the supplemented
rations than they did on the earlier unsupplemented rations. The
advisability of adding bonemeal as a supplement to rations used
in commercial dairies under similar feeding conditions is sug-
gested from the increased level of milk production observed here.
Reproduction creates a far smaller demand for calcium and
phosphorus than does lactation. An average Jersey calf contains
only as much of these elements as is present in 400 to 650 pounds
of whole milk.
Study of the records for possible contributing factors arising
from management of the cows disclosed that the dry periods
prior to lactation averaged 80 days in length preceding use of
bonemeal, as against 86 days while bonemeal was available. This
excludes the 12 lactations after the first parturition of each cow
in the former period, and one instance of difficult conception
among the 22 lactations in the latter period. The average date of
conception was at 105 days after parturition in the former inter-
val, as against 169 days (including 5 cases of difficult conception
26 Florida Agricultural Experiment Station
of 300 days or over) in the latter period. In addition, cystic
ovaries were encountered in two old cows, and four failed to con-
ceive. The observation of Dr. C. H. Eckles (Minn. Sta. Bul. 258)
was borne out that older cows conceive less readily.
From statistical analysis of differences in rate of decline be-
tween milk production on the low-calcium rations and that on
the supplemented rations, it was found that the standard error
of difference, divided into the difference, is 1.73, or that the prob-
abilities are 9 in 10 times that the differences are not due to
chance. In other words, these differences are due to actual
inherent differences in the rate of monthly milk production rather
than to chance. This took the entire lactation curves into con-
sideration from the 2nd to the 13th months, inclusive.
The entire lactations include the period immediately after
calving in which the mineral matter stored in the skeleton during
the dry period was available. After this available supply is de-
pleted by lactation, the cows become dependent upon the limited
amounts in the feed, and milk secretion is checked. When the
curves for the 7th to 13th months are analyzed similarly, the
factor 72.17 is found in place of 1.73. In other words, it is highly
significant that these differences are inherent, rather than due
SUMMARY AND CONCLUSIONS
Grass forages and silages grown on acid sandy soils contain
relatively small amounts of calcium. Dairy cows dependent upon
these home-grown roughages withdrew mineral matter from the
bones to such an extent that they were weakened and easily
broken. Under these conditions, less milk was produced, even
when the cows received high protein concentrates in such
amounts that they were quite fat. A 2 percent addition of bone-
meal to the concentrates, and a daily allowance of five pounds of
alfalfa hay to part of the cows, resulted in a material increase in
milk production without a corresponding degree of fatness being
evident in the cows. Minerals were stored in the skeleton to the
point that the shaft bones were even above average strength.
Reproduction is a far smaller drain on calcium and phosphorus
than is lactation.
With Jersey cows producing about 6,000 pounds of milk per
lactation, a 2 percent level of bonemeal in the concentrates was
slightly in excess of the current requirements when used with
the type of low-calcium rations described.
Bulletin 262, Effect of Calcium Deficient Roughages 27
The original milk and feed records obtained prior to May 15,
1928, used in this study, were accumulated by Professor John M.
Scott, formerly Animal Industrialist and Vice-Director of the
Florida Agricultural Experiment Station. Dr. D. A. Sanders con-
ducted the initial postmortem in this study on the cow No. 59
from which bones were obtained. Professor C. H. Willoughby
permitted the use of cannon bones from six Aberdeen Angus
cows in the College of Agriculture herd. Professor Charles C.
Brown and Mr. C. O. Partridge of the College of Engineering
assisted in part of the bone strength determinations and provided
the facilities for that work. Mr. Alex R. Mathers assisted in
assembling and tabulating the milk records. Mr. P. T. Dix
Arnold aided with the records and manuscript. Mr. Bradford
Knapp, Jr., and Dr. L. W. Gaddum directed the statistical test of
the data presented herein.
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