Group Title: Department of Animal Science mimeograph series - Florida Agricultural Experiment Station ; no. AN67-10
Title: Influence of protein level and hormone supplementation during the finishing period on feedlot performance, carcass characteristics and pork acceptability
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 Material Information
Title: Influence of protein level and hormone supplementation during the finishing period on feedlot performance, carcass characteristics and pork acceptability
Series Title: Department of Animal Science mimeograph series
Physical Description: 6 p. : ; 28 cm.
Language: English
Creator: Wallace, H. D ( Harold Dean )
University of Florida -- Dept. of Animal Science
University of Florida -- Agricultural Experiment Station
Publisher: Florida Agricultural Experiment Station
Place of Publication: Gainesville Fla
Publication Date: 1967
Subject: Swine -- Feeding and feeds -- Florida   ( lcsh )
Swine -- Carcasses -- Quality -- Florida   ( lcsh )
Proteins in animal nutrition   ( lcsh )
Hormones in animal nutrition   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
Bibliography: Includes bibliographical references (p. 6).
Statement of Responsibility: H.D. Wallace ... et al..
General Note: Caption title.
General Note: "June, 1967."
 Record Information
Bibliographic ID: UF00072988
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 78623706

Full Text
Department of Animal Science Florida Agricultural
Mimeograph Series No. AN67-10 Experiment Station
June, 1967 Gainesville, Florida


H. D. Wallace, A. Z. Palmer, J. W. Carpenter
L. A. Britt, A. C. Warnick and G. E. Combs-

Recent experimentation at the Florida Station (1,2,3,4,5,6) has emphasized the
important role of nutrition, particularly that of dietary protein, in the production
of lean pork. From these experiments it appears that commonly recommended protein
levels are too low to encourage optimum feedlot performance and lean pork yield of
present day meat-type hogs.

The experiment presented here was designed to obtain additional information on
this important aspect of swine feeding. It was also designed to study the feasibil-
ity of feeding a combination of the hormones diethylstilbesfrol and methyl testoster-
one. The interrelationship of dietary protein ievel, sex and hormone supplementation
was also a part of the experimental design.


Forty-eight carefully selected crossbred pigs (Duroc-Landrace x Hampshire) ini-
tially weighing an average of 103 pounds were individually self-fed in concrete con-
finement the diets described in Table 1. The experimental design is presented in
Table 2.

Hormone treatment was discontinued 72 hrs. prior to slaughter and all viscera
from treated animals were discarded at slaughter. The animals were slaughtered on
an individual basis as live weights reached the range of 205-210 pounds. The final
averageslaughter weight for all pigs was 208.3 pounds. The pigs were slaughtered
and dressed packer style for carcass study. Carcass weights and measurements were
taken after the carcasses had been chilled for 48 hours at 34-36 degrees F. Length
of carcass was obtained by a measurement from the anterior edge of the aitch bone
(pelvis) to the anterior edge of the first rib. Backfat thickness was calculated
as an average of measurements taken at the first rib, last rib and last lumbar ver-
tebra. A tracing was made of the perimeter of the longissimus dorsi muscle (loin
eye) exposed by cutting the loin perpendicular to the vertebral column equidistant
between the tenth and eleventh ribs. The area of the loin eye muscle was then de-
termined by use of a compensating polar planimeter. The carcasses were broken down
by a standard procedure (Reciprocal Meat Conference, 1951).

1/ Supported in part by a grant from Eli Lilly and Company, Greenfield, Indiana.

2/ Wallace, Animal Nutritionist; Palmer, Meat Scientist; Carpenter, Associate Meat
Scientist; Britt, Graduate Assistant; Warnick, Animal Physiologist; and Combs,
Associate Animal Nutritionist, Department of Animal Science.

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Table 1. Composition of diets

Protein level 10 10 12 12 14 14

Yellow corn 94.05 94.05 89.25 89.25 84.10 84.10
Soybean oilmeal (50%) 2.90 2.90 7.70 7.70 12.90 12.90
Defluorinated phosphate 1.80. 1.80 1.80 1.80 1.70 1.70
Ground limestone 0.50 0.50 0.50 0.50 0.50 0.50
Iodized salt 0.50 0.50 0.50 0.50 0.50 0.50
Trace minerals 0.05 0.05 0.05 0.05 0.05 0.05
Vitamin supplement
(Merck 1231)b 0.10 0.10 0.10 0.10 0.10 0.10
Vitamin B12 supplement
(Merck-20)c 0.05 0.05 0.05 0.05 .0.05 0.05
Tylan premixed 0.05 ----- 0.10 --- 0.10 ---
Bestrone ---0.05 --- 0.10 --- 0.10
100.00 100.00 100.00 100.00 100.00 100.00

a Contained 11% calcium, 10% manganese, 10% iron, 10% zinc, 1% copper, 0.3%
iodine and 0.1% cobalt.

b Contained 8,000, 14,720, 36,000 and 40,000 mg. per lb., respectively, of ribo-
flavin, pantothenic acid, niacin and choline chloride.

c Contained a minimum of 20 mg. B12 per pound.

d Tylan premix contained 10 gm. tylosin per pound and was added to the diets
not supplemented with Bestron so as to equalize tylosin fortification for all

e Bestron contained 2 gm. diethylstilbestrol and 2 gm. methyl testosterone and
10 gm. tylosin per pound. For the 12% protein diet the level of Tylan premix
and Bestron was reduced to 0.05% for the pig weight interval of 150 lb. to
slaughter weight.

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Table 2. Experimental design

Dietary protein level (%) 12 12 14 14
(103 lb. 150 lb.)

Dietary protein level (%) 10 10 12 12
(150 lb. slaughter)

Hormone supplement none 2 lb./ton none 2 lb./ton
(103 lb. 150 lb.)

Hormone supplement none 1 lb./ton none 1 lb./ton
(150 lb. slaughter)

Number of barrows 6 6 6 6

Number of gilts 6 6 6 6

Blade loin roasts were wrapped for freezing, frozen at -600 F., and stored at
00 F. Prior to cooking the roasts were defrosted overnight at 500F. The roasts
were cooked in covered Pyrex ovenware in a preheated 350 'F. oven for 30-40 minutes
per pound to an internal temperature of 1700 + 5 F. Aroma and flavor were deter-
mined by a trained eight member panel with degree of sex odor and flavor being the
only palatability factors considered; panelists scored degree of odor and flavor on
the following scale: 1 designated none; 2, slight; 3, moderate; 4, strong. Aroma
was evaluated on the hot roasts by lifting the lids of the ovenware containers to
allow rising vapors to be tested. Each panelist sliced a portion of each roast for
flavor testing to assure that all testing would be on warm meat.

Results and Discussion

Feedlot performance and carcass data are summarized in Table 3.

Daily feed intake Pigs fed the lower protein level tended to consume more
feed. Such an effect has also been observed in previous trials. The reason for
this observation is not clear, but it may be explained by a compensatory effect
wherein the pig is attempting to obtain needed protein. The addition of the hormone
supplement caused a marked decrease in feed consumption (P < .01). Intake of the
barrows was reduced relatively more than that of the gilts. Gilts consumed signifi-
cantly less feed than barrows (P < .01).

Daily gain Hormone supplemented pigs gained significantly less than control
pigs and gilts gained less than barrows (P < .01). Gains of barrows were depressed
more than gains of gilts by the hormone treatment. This interaction between sex and
hormone treatment was significant (P < .05). Pigs on the higher protein level gained
1.96 lb. per day compared to 1.87 for pigs on the lower protein level. This differ-
ence was not statistically significant.

-.4 -

Table 3. Influence of dietary protein level, oral hormone intake and
sex on the feedlot performance and carcass development of
swine during the finishing period.

Main expt. variables Protein level Hormone Sex
Comparison 12-10% 14-12% + Males Females

Number.of animals 24 24 24 24 24 24
Av. daily feed intake, lb. 6.50 6.9: 6.82 6.08** 6.69 6.20**
Av. daily gain, lb. 1.87 1.96 2.03 '1.79* 1.99 1.83**
Feed required per lb.
gain, lb. 3.50 3.28** 3.38 3.40 3.38 3.39
Dressing percent 70.8 71.3 71.4 70.7 71.0 71.0
Backfat thickness, in. 1.35 1.38 1.41 1.33* 1.41 1.33*
Carcass length, in. 31.13 30.96 30.90 31.19 30.89 31.20
Loin eye area, sq. in. 3.51 3.73 3.62 3.61 3.52 3.72
Percent 4 lean cuts 48.55 49.36 48.65 49.27 48.50 49.41
Loin eye marbling score 15.1 14.8 14.6 15.1 15.1 14.8
Loin eye marbling score 15.1 14.8 14.6 15.1 15.1 14.8

a Higher protein level fed from 100'lb. to 150 b. 'liveweight.
from 150 Ib. to slaughter.

Lower level fed

b Devoid, 0;:traces, 5; small, 11; moderate, 17; very abundant, 32.

P < .05
** P < .01

Feed required per unit gain The higher protein diet induced a significant
saving in feed (P < .01). Neither hormone supplementation nor sex influenced feed
conversion significantly. A significant interaction of protein level and hormone
supplementation (P < .05) indicated that hormone supplementation favored improved
feed conversion in the presence of adequate protein.

Carcass characteristics Dressing percent and carcass-length were not signif-
icantly influenced by protein level, hormone supplementation or sex. Backfat thick-
ness was reduced by hormone supplementation and gilts showed a greater backfat
thickness than barrows (P < .05). Loin eye area measurements favored the pigs fed
higher protein (3.73 vs. 3.51 sq. in.) and gilts were superior to barrows (3.72 vs.
3.52). These differences approached significance at the 5% level of probability.
Lean cut out data showed higher values for carcasses from the higher level of pro-
tein, hormone supplemented and female pigs. Differences were not statistically sig-
nificant. Loin eye marbling scores indicated that none of the main variables had
much effect on intramuscular fat deposition.

- 5 -

Secondary glands., ovaries and uteri At the time of slaughter secondary sex
glands, ovaries and uteri were examined and weighed. Seminal vesicles from hormone
treated barrows weighed an average of 17.9 gm. compared to 1.4 gm. for untreated an-
imals. Cowper's glands from treated barrows weighed 39.0 gm. compared to 4.2 gm.
for untreated animals. It was evident that the hormone treatment also stimulated
ovaries and uterine tissue, as measured by gross tissue weights. The stimulation
was especially marked on the 14% protein diet. The ovarian weights were stimulated
by hormone feeding on the 14% protein diet, but not on the 12% diet.

Aroma and flavor of loin roasts -.Since one of the hormones fed was methyl tes-
tosterone, a male sex hormone, it seemed important to check the pork for boar aroma
or undesirable flavor. Results of a panel evaluation are presented in Table 4. 'Nei-
ther protein level nor sex showed much influence on the scores recorded for flavor
and aroma. However, a marked influence was observed due to hormone supplementation.
Several supplemented pigs yielded roasts which, when cooked, exhibited a very un-
desirable aroma and flavor. Both gilt'sand barrows were affected, and to about the
same degree. It is not'clear from this study which of the hormones was responsible
for impacting the odor'and off-flavor to the pork. However, in view of the informa-
tion available from other experiments, it is likely due to the testosterone.

Table 4. Influence of hormone supplementation on aroma and flavor of
cooked loin roastsa

Protein level 12-10 12-10 14-12 14-12
Hormone none + none +
Sex M M F M F M F

No. animals 6 6 6 6 6 6. 6 ; 6
Av. aroma score 1.07 1.11 1.88 1.73 1.07 1.14 1.85 1.85
Av. flavor score 1.06 1.03 1.65 1.55 1.08 1.10 1.67 1.78

a Scores coded as follows: none, 1; slight, 2; moderate, 3; strong, 4.


Forty-eight pigs were used in an experiment to study the effects and interrela-
tionships of protein level, hormone supplementation and sex on feedlot performance,
carcass characteristics and pork acceptability. The experimental period extended
from an initial weight of 103 lb. to a final slaughter weight of 208 lb.

Pigs fed the higher level of protein (14-12%) gained faster and much more ef-
ficiently than those fed the lower level of protein (12-10%). Carcass measurements
indicated that the higher protein level was desirable in terms of carcass leanness.

Hormone supplemented pigs consumed less feed, gained slower and yielded some-
what leaner carcasses than non-supplemented pigs. The hormone treatment imparted!an

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undesirable aroma and flavor to the pork. This effect was about equally noticeable
in barrows and gilts.

Barrows ate more feed, gained faster and yielded fatter carcasses than gilts.

Literature Cited

1. Wallace, H. D., M. E. Palmer, A. Z. Palmer, J. W. Carpenter and G. E. Combs.
1963. The influence of protein level on feedlot performance and carcass char-
acteristics of barrows and gilts. Fla. Animal Sci. Mimeo. Series AN64-7.

2. Wallace, H. D., A. Z. Palmer, J. W. Carpenter, Ghazi Taki and G. E. Combs.
1964. The influence of protein level on feedlot performance and carcass char-
acteristics of barrows and gilts. Fla. Animal Sci. Mimeo. Series AN64-16.

3. Crum, R. C., Jr., H. D. Wallace, A. Z. Palmer, J. W. Carpenter and G. E. Combs.
1964. The influence of protein level on feedlot performance and carcass char-
acteristics of barrows and gilts. Fla. Animal Sci. Mimeo. Series AN65-3.

4. Wallace, H. D., A. Z. Palmer, J. W. Carpenter and G. E. Combs. 1965. A study
of the relationship of feed restriction and dietary protein level in finishing
hogs. Fla. Animal Sci. Mimeo. Series AN65-9.

5. Wallace, H. D., A. Z. Palmer, J. W. Carpenter and G. E. Combs. 1966. Feed
restriction of swine during the finishing period. Fla. Agr. Exp. Sta. Bul. 706.

6. Wallace, H. D., L. A. Britt, J. W. Carpenter, A. Z. Palmer and G. E. Combs.
1966. Effects of dietary protein levels and amino acid supplementation on the
feedlot performance and carcass characteristics of growing-finishing swine.
Fla. Animal Sci. Mimeo. Series AN67-3.

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