;- DEC 07 1971
Agricultural Research Center, Ona I.F.A.S.- Univ. of Fl rid '
Mimeo Report 71-11 _------ .2 1971
REPLACEMENT VALUE OF COTTONSEED HULLS FOR DRIED
CITRUS PULP IN*CALF FINISHING RATIONS
W. G. Kirk, F. M. Peacock, A. Z. Palmer and J. W. Carpenter/
The usual practice in feeding quality calves is to provide a finishing ration
that will promote rapid and economical gains, with a substantial improvement
in slaughter and carcass grades. This is accomplished by feeding rations
containing considerable roughage in the first weeks of the feeding period and
gradually replacing much of it with energy rich feeds such as citrus pulp,
corn meal and molasses, as animals are conditioned to confinement and on full-
feed. Recent developments minimize roughage in finishing rations in many
Hay and silage are the conventional roughages in finishing rations. Cottonseed
hulls, ground corn cobs, straw and bagasse, and many other products are avail-
able in different sections of the United States to furnish roughage. Many
feeders consider oat, barley and citrus pulp as combined roughage and concentrate
feeds because of their fiber content and bulkiness. Ration ratios of roughage
to concentrates as wide as 15:85 to 85:15 have given satisfactory liveweight
gain in finishing cattle. Economic factors dictate the choice and amount of
roughages to use.
The objectives of two finishing trials with steer calves were to study the
effect of feeding different amounts of pangolagrass (Digitaria decumbens Stent.)
hay (hay) and the-replacement of 15%, 25% and 35%of the citrus pulp in the mixed
ration with an equal weight of cottonseed hulls. Cottonseed hulls was selected
because this feed was available and mixed readily with the ratian concentrate
The National Research Council (NRC) (5)2/ suggests that when the concentrate
part of finishing rations is 80% or more special management practices should
be employed such as self-feeding, a supply of feed in the troughs at all times,
proper balance of essential nutrients, and adequate trough space to allow all
animals to eat when hungry. More information is needed on feeding practices
and nutritional requirements of growing and finishing calves.
Kirk et al. (2), found yearling steers self-fed roughage and complete mineral
and adequate cottonseed meal ate either 84.45% pangolagrass hay or 85.59%
pangolagrass silage. Limited feeding of 4.13 pounds citrus pulp and 4.61
pounds citrus molasses daily reduced hay to 53.11% and silage to 51.47% of
the ration. Steers self-fed roughage, citrus pulp and molasses ate 33.85%
of their total intake as hay and 34.31 as silage. The average daily gains for
the three lots self-fed hay were 1.15, 1.66 and 2.27 pounds, respectively, and
for the three self-fed silage lots 1.29, 1.94 and 2.50 pounds. The hay and
grass silage were of excellent quality, the reason for the high level eaten.
1/ Animal Scientist Emeritus Associate Animal Husbandman, Ona; Meat Specialist,
and Associate Meat Specialist, Animal Science Department, Gainesville.
2/ Numbers in parenthesis refer to literature cited.
The roughage levels when hay or silage any- citrus pulp and molasses were all
self-fed are considered too high to promote the highest rate of gain and grade
improvement in finishing yearling steers. High hay and silage rations increased
feed costs $7.05 and $5.77, respectively, per 100 pounds gain mer steers self-
fed roughage and citrus pulp and molasses.
maintenance of initial slaughter grade of weanling calves by varying the
ratio of roughage to concentrates according to Kirk et al. (2) was not too
successful. Low Utility grade calves fed a balanced ration containing 63%
total digestible nutrients (TDN) made moderate gains with a carcass grade of
Good when full-fed for 210 days. Standard calves fed a 66% TDN ration, Good
grade calves fed 69% TDN and Choice calves fed 70.5% TDN ration had Low Choice,
Low Choice and High Choice carcasses, respectively. Citrus pulp replaced the
reduced amounts of cottonseed hulls fed the Standard, Good and Choice calves.
Data from these trials indicate that rapid gain, economical feed utilization
and improvement in carcass grade can be accomplished more successfully with
Utility and Standard calves than with Good and Choice grade animals.
Kirk and Koger (4), show that the relationship (r) between average daily gain
and per cent roughage in the ration for 73 groups of cattle was r = -0.29.
There were negative correlations also between per cent ration roughage and
days cattle were on feed, -0.56; and feed conversion -0.37. The greatest
positive correlations between ration roughage were initial, slaughter and cold
carcass weights, r = 0.47, 0.35, 0.34, respectively. These data indicated
that older and heavier feeder cattle utilize roughage to better advantage for
maintenance and gain than do calves. A high level of roughage reduced daily gain
and feed and TDN conversion and increased total feed eaten on a daily basis.
NRC (6) suggests that calves weighing 441 to 661 pounds require a ration with
12.2% total and 8.1% digestible protein and 74% TDN to have an average daily
gain of 2.43 pounds.
Calves fed in two trials of 182 days and 185 days, were raised at the Range
Cattle Experiment Station (RCES): Trial I in 1959-60 and Trial II in 1960-61.
The average complete rations fed throughout the two trials are given in Table
1. The calves in Trial I were fed 1 pound hay daily while in Trial II limited
hay was fed the first 14 days to prevent digestive disturbance until the
animals were on full-feed. As the cottonseed hulls were'increased from 14% of
the mixed ration to 33.1% in Trial I and from 14.9% to 24.9% and 34.9% in
Trial II citrus pulp was decreased a like amount. All lots had free access to
complete mineral (1) mixture even when it was included in the mixed ration,
1% in Trial I and 2% in Trial II. Rations were considered adequate in protein,
minerals and vitamin A to meet the needs of weanling calves but low in TDN
according to NRC (61 Calves were not fed or implanted with diethylstilbestrol.
Calves were fed free-choice after becoming accustomed to the finishing ration.
They were confined in protected drylot pens except when weighed individually
at 2-week intervals.
There were six calves in each of the five lots: two 3/4 Shorthorn-l/4
Brahman; two 1/2 Shorthorn-1/2 Brahman; and two 3/4 Brahman-1/4 Shorthorn.
The calves selected were from three cow-calf herds of the same breed composition
but maintained on different quality pastures.
Calves in Trial I were placed on feed when weaned at 231 days of age, while
those in Trial II were on pasture three weeks before being confined at 252 days
of age. The steers at the completion of both trials were hauled 190 miles
to the Meats Laboratory, University of Florida, Gainesville, weighed, given
access to water and slaughtered the next morning. Shipping loss was based on
RCES and Gainesville weights and dressing percentage on Gainesville and chilled
carcass weights. Each carcass was graded by a federal beef grader.
RESULTS AND DISCUSSION
Composition of rations eaten by the five lots of steers in the two trials are
given in Table 1, with calculated TDN and crude protein and fiber of each.
Increment in roughage in Trial I was from 25.0%, Lot 1, to 43,0%, Lot 2, and
in Trial II from 20.3%, Lot 3, 30.2%, Lot 4, and 40.2%, Lot 5. The five rations
fed in the two trials were from 8.4% to 15.3% below the 74% TDN level recommended
by NRC (6) for finishing steer calves weighing from 441 to 661 pounds.
Increasing roughage reduced crude protein slightly but all rations were above
the crude protein standard for calves. The production results of the two
trials are summarized in Table 2.
It is seen from Tables 1 and 2 that Lot 2 calves fed a ration containing
43.0% roughage, 21.3% crude fiber and 58.7% TDN for 182 days had a daily gain
of 1.90 pounds while Lot 1, fed a 25.0% roughage ration with 16.7% fiber and
63.8% TDN gained 1.75 pounds daily. There was no apparent reason for calves
in Lot 2 gaining more rapidly other than greater TDN intake on a daily basis,
11.09 pounds total and 1.62 pounds per 100 pounds live weight than 10.08
pounds and 1.56 pounds, respectively, for Lot 1. Apparently Lot 2 had a
greater appetite or the increment of cottonseed hulls from 14% to 33.1% made
the ration more palatable. The calves from both lots were of the same breed
composition and from outward appearances they were all in good health.
The production results of Trial II are summarized in Table 2. Five calves are
considered in Lot 4 as one died the 133rd day of the trial. Autopsy did not
reveal any cause for its death. Lots 3, 4 and 5 were fed rations having 20.3%,
30.2% and 40.2% roughage and 14.6%, 17.1% and 19.6% crude fiber, respectively,
with mixed concentrate feeds making up the balance. Average daily gains for
the three lots were higher than in Trial I. Lot 3 calves fed a ration with
20.3% roughage and 65.6% TDN made the lowest gain, 2.02 pounds daily; Lot 4
fed a ration with 30.2% roughage and 62.7% TDN made the highest gain, 2.21
pounds daily; and Lot 5 fed a ration with 40.2% roughage and 59.8% TDN had
a daily gain of 2.08 pounds. Average daily ration of Lots 3, 4 and 5 supplied
11.6 pounds, 12.4 pounds and 11.5 pounds TDN, respectively. As in Trial I Lot
5 calves fed 40.2% roughage gained faster than Lot 3 fed 20.3%. Lot 4, however,
fed 30.2% roughage gained the fastest.
Table 1. Ration fed with calculated TDN and crude
Feed ingredients, %:
Crude protein %
Crude fiber %
J/ NRC (6) recommendation for calves finished as short yearlings, 74% TDN
in ration dry matter.
Table 2. Production data for calves fed different amounts of roughage.
Trial I II
Lot 1 2 3 4 5
Calves/lot 6 6 6 51 6
Days on feed 182 182 185 185 185
Roughage in ration, 2/ 25.0 43.0 20.3 30.2 40.2
Average weights, lb:
Initial 486 511 517 472 513
Final 805 856 890 881 897
Gain 319 345 373 409 384
Daily gain 1.75 1.90 2.02 2.21 2.08
Average feed eaten, lb:
Daily/calf 15.8 18.9 17.7 19.7 19.9
Feed/pound gain 9.0 10.0 8.8 9.2 9.5
TDN/pound gain 5.8 5.9 5.8 5.8 5.7
Daily/l0 pounds live wt. 2.4 2.8 2.5 2.9 2.8
1/ One calf died on 133rd day of trial.
2/ Hay, cottonseed hulls and alfalfa.
Increment of hulls from 14.9% to 24.9% and 34.97o decreased level of TDN in
the rations and increased total feed consumed daily and per 100 pounds live
weight as in Trial I. More feed was required per pound gain as roughage was
increased, as would be expected, with essentially the same TDN level per unit
gain by all lots. Daily gains were similar to that suggested by NRC (_) for
calves not implanted with stilbestrol.
Analysis of varianceS/showed that there was a significant positive difference
in both of the two trials in rate of gain due to increase of roughage in the
rations. There were too few replicates, however, to make a valid test in both
trials by this method. It is estimated that 20 steers per lot in Trial I and
10 steers per lot in Trial II would be required to obtain statistical signifi-
cance if gain differences obtained are of practical importance and need to be
Roughage in the Ration
Roughage is an essential part of the maintenance and finishing calf ration.
In addition to the available nutrients, roughage regulates the digestive
system and helps to maintain a calf on full feed. Roughage, hay and cotton-
seed hulls, furnish about 63% as much available nutrients on a unit basis
compared to citrus pulp.
NRC (5) suggests that the roughage level in the ration should be from 0.5
to 0.8 pounds daily per 100 pounds live weight. It is seen in Table 3 that
the rations fed Lots 1 and 3 are within this level, 0.60 and 0.51 pounds,
while rations fed Lots 2 and 5 are above, 1.19 and 1.13 pounds. The ration
fed Lot 4 in Trial II is slightly above the suggested roughage range, 0.88
pounds daily per 100 pounds live weight, and this lot averaged the highest
daily gain, 2.21 pounds.
There was considerable variation in feed eaten per pound of gain between the
five lots, Table 2, but the difference in ratio of roughage to concentrates
in the rations did not materially affect the TDN required per pound gain.
Slaughter and Carcass Data
It is seen from Table 4 that there was no difference in initial slaughter and
carcass grades of calves fed in Trial I, although Lot 1 increased 319 pounds
and Lot 2, 345 pounds per animal. An improvement in Trial II from High
Standard to High Good and Low Choice, Table 4, was accomplished when average
gain per steer ranged from 373 to 405 pounds per lot. The most significant
slaughter data is the variation in dressing percentage, 59.1% for calves fed
43.0% roughage in Trial I to 63.2% for calves fed 20.3% roughage, Trial II.
The variation in shipping shrink between the five lots appears to be the
result of the difference in higher carcass grade in Trial II as compared to
Trial I as does the slightly higher tenderness panel scores of broiled loin
3/ Statistical Analysis by Frank G. Martin, Associate Statistician,
IFAS, University of Florida, Gainesville.
Table 3. Roughage eaten daily per 100 pounds live weight.
Trial Lot Roughage Ration eaten
% daily, lb.
I 1 25.0 15.8 3.9 645 0.60
2 43.0 18.9 8.1 683 1.19
II 3 20.3 17.7 3.6 703 0.51
4 30.2 19.7 5.9 676 0.87
5 40.2 19.9 8.0 705 1.13
Table 4. Slaughter and carcass data.
Trial T -_ _TT
Lot 1 2 3/ 4 5
Ration roughage % 25.0 43.0 20.3 30.2 40.2
Initial slaughter High Standard High Standard
Final slaughter Good High Good H. Good H. Good L. Choice
Carcass H.Stand. H.Stand. L.Choice H.Good H.Good
Shipping shrink, / 5.7 5.7 5.3 5.4 5.7
Dressing per cent4/ 62.7 59.1 63.2 63.0 62.3
Sq. In. rib eye/cwt
of carcass 1.8 1.9 1.9 1.9 1.9
Estimated yield, % 48.8 47.4 48.3
short loin steaks:
By shear, lb6/ 14.8 14.4 14.8 14.6 14.2
By test panel/ 4.3 4.0 4.7 4.6 4.6
Steer died at Meats
Steer died while on
Weights at RCES and
/ Live weight at Gainesville and shrunk carcass weight.
.5/ Per cent chilled weight obtained in fat-trimmed boneless retail cuts:
round, rump, loin, rib and chuck.
/ core, pounds pull to shear by Warner-Bratzlor machine.
/Panel score: 4-average tenderness; 5-above average tenderness.
Factors affecting utilization of roughage in finishing rations were discussed.
Five lots of six calves each, all lots of the same breed composition, were
fed: two lots in Trial I for 182 days and three lots in Trial II for 185
days. Rations fed in Trial I contained 25.0% and 43.0% roughage and in
Trial II 20.3%, 30.2% and 40.2% roughage. The same mixed rations for each
lot was fed throughout their respective trials.
Palatable hulls and pangolagrass hay, within the limits fed, increased feed
eaten and rate of gain. Lot 4, however, fed a ration with 30.2% high
quality roughage had the greatest daily gain, 2,21 pounds, with little
variation in conversion of nutrients for gain by the five lots.
Lot 2, fed a 43% roughage ration had a 59.1 dressing percentage compared to
62.3 to 63.2 for the other four lots.
The average initial slaughter grade of High Standard was the same for all
five lots of calves. Daily gain of 1.75 and 1.90 pounds, Trial I, resulted
I' -, change in initial sl;ughtor and carcass grades. In Trial II, with
daily s ii" racing from 2.02 to 2.91 pu n-Cra. grades improved either
to High Good or Low C~hoir.o
Increasing roughage slightly reduced pounds shear of 1/2' core and tepAr m-~rn o
score by panel of broiled short loin steaks.
Good quality roughage: has approximately 63% the nutrient value of citrus
pulp, 56% of No. 2 yellow corn meal and 87% of molasses; maintains the
digestive system of fed cattle in good condition; is an essential part of
most well balanced finishing mrtions; and reduces the concentrate feed
required per unit gain. The amount of roughage to use in a finishing
ration will depend on the relative cost per unit of digestible nutrient from
different feed ingredients.
1. Cunha, T. J., R. L. Shirley, H.L. Chapman, Jr., C. B. Amnerman,
G. K. Davis, W. G. Kirk, and J. F. Hentges, Jr. 1964. Minerals
for beef cattle in Florida. Fla. Agr. Exp. Sta. Bull. 683.
2. Kirk, W. G., F. M. Peacock, A. Z. Palmer, and J.W, Carpenter. 1970.
Maintenance of different grades of steer calves. Fla. Agr. Exp. Sta.
3. Kirk, W. G., F. M. Peacock, E. M. Hodges, and J. E. McCaleb. 1960.
Value of pangola hay and silage in steer fattening rations. Fla. Agr.
Exp. Sta. Bull. 621.
4. Kirk, W. G., and Marvin Koger. 1970. Citrus products in cattle finishing
rations: A review of research at the Range Cattle Station 1946-1960.
Fla. Agr. Exp. Sta. Bull. 739.
5. Nutrient requirement of beef cattle. 1963. National Research Council
Pub. 1137. Washington, D. C.
6. Nutrient requirement of beef cattle. 1970. National Research Council
Pub. No. 4. Fourth Revised Edition. Washington, D. C.
10-71 100 copies