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 Introduction and experimental
 Results and discussion
 Summary
 Literature cited
 List of Tables














Group Title: Department of Animal Science research report - University of Florida Dept. of Animal Science ; AL-1974-15
Title: Influence of late castration on performance, carcass characteristics and sexual odor of boars
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Permanent Link: http://ufdc.ufl.edu/UF00073066/00001
 Material Information
Title: Influence of late castration on performance, carcass characteristics and sexual odor of boars
Series Title: Department of Animal Science research report
Physical Description: 5 p. : ; 28 cm.
Language: English
Creator: Creswell, David Charles, 1943-
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: 1974
 Subjects
Subject: Boars -- Florida   ( lcsh )
Swine -- Carcasses -- Quality -- Florida   ( lcsh )
Castration   ( lcsh )
Meat animals   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Includes bibliographical references (p. 4).
Statement of Responsibility: D.C. Creswell ... et al..
General Note: Caption title.
General Note: "December, 1974."
General Note: Typescript on green paper.
Funding: Animal science research report (University of Florida. Dept. of Animal Science) ;
 Record Information
Bibliographic ID: UF00073066
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 50674318

Table of Contents
    Introduction and experimental
        Page 1
        Page 2
    Results and discussion
        Page 2
        Page 3
    Summary
        Page 3
    Literature cited
        Page 4
    List of Tables
        Page 5
        Page 6
Full Text



Department of Animal Science Florida Agricultural
Research Report No. AL-1974-15 Experiment Station
December, 1974 Gainesville, Florida


INFLUENCE OF LATE CASTRATION ON PERFORMANCE, CARCASS
CHARACTERISTICS AND SEXUAL ODOR OF BOARSi/

D. C. Creswell, H. D. Wallace, G. E. Combs,
A. Z. Palmer and R. L. West2-


The potential and problems of using young boars for meat production have
been the subject of several recent reviews (1,2,3). Boars were shown to have
equal or possibly higher growth rate, lower daily feed intake and required less
feed per unit of gain than barrows. Boars also produced a superior carcass than
barrows, with less backfat and a higher ratio of lean to fat.

The main problem preventing the exploitation of this potential is the
presence of a compounds) in the adipose tissue of the boar which gives rise to
an unpleasant aroma when the tissue is heated during cooking. The principal
compound responsible for this sexual odor in boars was recently identified as
5a-androst-16-ene-3-one (4). It is synthesized in the testicles and is found
throughout the fat and salivary glands of boars from 110-130 lb., increasing in
concentration at least up to 20tr6--f5)------
HUME LIBRARY
As part of a larger study designed to examine th response of boars and
barrows to supplemental lysine (7), the opportunity was taken to investigate
the possibility that castration 2-3 weeks'prior to slaughter would eliminate
or effectively reduce the level of sexual odor in the carcass. Effects of late
castration on performance, carcass characteristics and level of sexual odor in
boars were measured.

Experimental

Forty-two boars and 42 barrows averaging 55 pounds initially were used in
the trial. The pigs were housed in groups of 7 according to sex in concrete
floored pens equipped with automatic waterers and were fed corn-soybean meal
diets to appetite. Diets consisted of different levels of protein and lysine.
Composition of these diets and their effects on performance and carcass compo-
sition have been reported previously (7).


1/ The data presented in this paper were from swine unit experiment No. 228A.
2/ Creswell, graduate assistant; Wallace and Combs, Animal Nutritionists;
Palmer, Meat Scientist and West, Assistant Meat Scientist, Department of
Animal Science.



This public document was promulgated at an annual cost of
$ 98.56 or .10 cents per copy to inform county agricul-
tural directors, ranchers and growers of research results
in swine management and nutrition.


Department of Animal Science
Institute of Food and Agricultural Sciences







- 2-


From each pen of 7 boars, 4 were surgically castrated at a weight of
approximately 190 pounds. To ensure that boars being castrated were average
in growth rate for that pen, every second boar to reach 190 pounds within the
pen was selected. No dressing was applied to the castration wounds. Ten cc's
penicillin-streptomycin were given intramuscularly at the time of castration
and again 48 hours later.

Pigs were slaughtered at a weight of 210 + 10 pounds. Many of the late
castrates were slaughtered at weights above this range in order to allow adequate
wound healing. Cut out methods and carcass measurements were as previously
described (8).

From each carcass, 2 samples of flank fat and a loin roast were taken for
odor evaluation. One fat sample was taken from the hot carcass within 30
minutes of slaughter while the second sample was from the chilled carcass after
being held at 360 F for approximately 18 hours.

For odor evaluation of the fat samples, a 2 inch cube was macerated with a
knife and placed in a 500 cc beaker. One hundred cc's boiling water were added
and the beaker covered with a watch glass. Odor of the fat was scored by lifting
the watch glass and inhaling the vapors. The scale used for scoring was desig-
nated as 1 no odor; 2 slight odor; 3 moderate odor; 4 strong odor.

The loin roasts were trimmed to a weight of approximately 2 pounds, placed
in individual casserole dishes fitted with lids, and cooked in an oven at 3500 F
until an internal meat temperature of 1400 F was attained (approx. 2 hours). The
odor from each casserole dish was then scored using the same scale.

The panel used to evaluate sexual odor contained a total of 10 people. How-
ever, only 3 people were found who could reliably and consistently identify the
odor and only the results from these people were used. The panel was therefore
believed to be trained to recognize and evaluate the specific odor of boar meat.
Samples from barrows, late castrates and boars were presented to the panel in a
random order and were not identified as to sex.

Results and Discussion

Effects of late castration on performance and carcass characteristics
are shown in Table 1 while the effects on sexual odor scores are shown in
Table 2.

Feedlot performance

No significant differences (P> 0.05) in growth rate between barrows, late
castrates and boars were present, either for the entire experiment or the period
from 190 pounds to slaughter. There was a trend, however, for late castrates
to have a slower rate of gain than boars during the final stage of the experiment.

Although feed conversion data were not analyzed statistically due to the
experimental design, boars and late castrates combined required less feed per
pound of gain over the entire experiment than did barrows. During the period
from 190 pounds to slaughter, boars had a better feed conversion than barrows,
while late castrates were intermediate.







- 2-


From each pen of 7 boars, 4 were surgically castrated at a weight of
approximately 190 pounds. To ensure that boars being castrated were average
in growth rate for that pen, every second boar to reach 190 pounds within the
pen was selected. No dressing was applied to the castration wounds. Ten cc's
penicillin-streptomycin were given intramuscularly at the time of castration
and again 48 hours later.

Pigs were slaughtered at a weight of 210 + 10 pounds. Many of the late
castrates were slaughtered at weights above this range in order to allow adequate
wound healing. Cut out methods and carcass measurements were as previously
described (8).

From each carcass, 2 samples of flank fat and a loin roast were taken for
odor evaluation. One fat sample was taken from the hot carcass within 30
minutes of slaughter while the second sample was from the chilled carcass after
being held at 360 F for approximately 18 hours.

For odor evaluation of the fat samples, a 2 inch cube was macerated with a
knife and placed in a 500 cc beaker. One hundred cc's boiling water were added
and the beaker covered with a watch glass. Odor of the fat was scored by lifting
the watch glass and inhaling the vapors. The scale used for scoring was desig-
nated as 1 no odor; 2 slight odor; 3 moderate odor; 4 strong odor.

The loin roasts were trimmed to a weight of approximately 2 pounds, placed
in individual casserole dishes fitted with lids, and cooked in an oven at 3500 F
until an internal meat temperature of 1400 F was attained (approx. 2 hours). The
odor from each casserole dish was then scored using the same scale.

The panel used to evaluate sexual odor contained a total of 10 people. How-
ever, only 3 people were found who could reliably and consistently identify the
odor and only the results from these people were used. The panel was therefore
believed to be trained to recognize and evaluate the specific odor of boar meat.
Samples from barrows, late castrates and boars were presented to the panel in a
random order and were not identified as to sex.

Results and Discussion

Effects of late castration on performance and carcass characteristics
are shown in Table 1 while the effects on sexual odor scores are shown in
Table 2.

Feedlot performance

No significant differences (P> 0.05) in growth rate between barrows, late
castrates and boars were present, either for the entire experiment or the period
from 190 pounds to slaughter. There was a trend, however, for late castrates
to have a slower rate of gain than boars during the final stage of the experiment.

Although feed conversion data were not analyzed statistically due to the
experimental design, boars and late castrates combined required less feed per
pound of gain over the entire experiment than did barrows. During the period
from 190 pounds to slaughter, boars had a better feed conversion than barrows,
while late castrates were intermediate.






- 3-


Carcass characteristics

Significant differences (P < 0.05) were present between boars and barrows
for dressing %, carcass length, backfat thickness and percent 4 lean cuts.
There was no significant effect (P > 0.05) of late castration on dressing per-
centage, carcass length and percent 4 lean cuts. The late castrates had
significantly greater (P < 0.05) backfat thickness than boars and were similar
to barrows in this characteristic. Differences between sexes for loin eye
area, marbling, color and firmness of lean were not significant (P> 0.05).

Odor scores

Results of odor scores from the 2 fat samples and the loin roast were
similar. Odor scores from late castrates and barrows were not significantly
different (P > 0.05) while scores for boars were significantly higher (P< 0.05).

During the period from castration to slaughter, late castrates underwent
some reversion towards the performance and carcass characteristics of the
barrow. This is evident from the data for feed conversion and backfat thickness
and the trends in the data for gain, percent 4 lean cuts and loin eye area.
The higher slaughter weights of the late castrates may partly explain the greater
backfat thickness of this group. However, using an adjustment factor of
0.0022 in./lb. bodyweight (9) it was apparent that differences in slaughter
weight did not influence backfat thickness to any large extent. Loss of the
anabolic hormone testosterone in the late castrates was believed to be responsi-
ble for these changes. The short time period (16 days) was apparently not long
enough for complete reversion, and the late castrates retained most of the per-
formance and carcass characteristics of the boar.

Late castration was shown to be an effective means of eliminating the
sexual odor from the carcass. This would suggest that the odor compounds)
had a fairly rapid turnover rate, allowing metabolic clearance within a short
period of time. A recent Canadian report reached similar conclusions as to
the effect of late castration on sexual odor of boars (10). While the severity
of the castration operation on the animal is likely to limit the practical
application of this technique, the experiment has confirmed that steroid
production in the testicles needs to be blocked for only a short time to
effect a reduction in sexual odor. This fact may assist in the testing of
more practical methods.

Summary

Forty-two barrows and 42 boars averaging 55 pounds initially were used to
determine the effects of late castration (average of 16 days prior to slaughter)
on performance, carcass characteristics and on degree of sexual odor in the
carcass.

Late castration did not influence rate of gain for the period from castra-
tion to slaughter. Although not analyzed statistically, feed conversion of
late castrates was poorer than that of boars during this period. Dressing
percentage, carcass length, percent 4 lean cuts and loin eye area were not
affected by late castration but backfat thickness was increased. While per-
formance and carcass characteristics of the boar were essentially maintained






- 3-


Carcass characteristics

Significant differences (P < 0.05) were present between boars and barrows
for dressing %, carcass length, backfat thickness and percent 4 lean cuts.
There was no significant effect (P > 0.05) of late castration on dressing per-
centage, carcass length and percent 4 lean cuts. The late castrates had
significantly greater (P < 0.05) backfat thickness than boars and were similar
to barrows in this characteristic. Differences between sexes for loin eye
area, marbling, color and firmness of lean were not significant (P> 0.05).

Odor scores

Results of odor scores from the 2 fat samples and the loin roast were
similar. Odor scores from late castrates and barrows were not significantly
different (P > 0.05) while scores for boars were significantly higher (P< 0.05).

During the period from castration to slaughter, late castrates underwent
some reversion towards the performance and carcass characteristics of the
barrow. This is evident from the data for feed conversion and backfat thickness
and the trends in the data for gain, percent 4 lean cuts and loin eye area.
The higher slaughter weights of the late castrates may partly explain the greater
backfat thickness of this group. However, using an adjustment factor of
0.0022 in./lb. bodyweight (9) it was apparent that differences in slaughter
weight did not influence backfat thickness to any large extent. Loss of the
anabolic hormone testosterone in the late castrates was believed to be responsi-
ble for these changes. The short time period (16 days) was apparently not long
enough for complete reversion, and the late castrates retained most of the per-
formance and carcass characteristics of the boar.

Late castration was shown to be an effective means of eliminating the
sexual odor from the carcass. This would suggest that the odor compounds)
had a fairly rapid turnover rate, allowing metabolic clearance within a short
period of time. A recent Canadian report reached similar conclusions as to
the effect of late castration on sexual odor of boars (10). While the severity
of the castration operation on the animal is likely to limit the practical
application of this technique, the experiment has confirmed that steroid
production in the testicles needs to be blocked for only a short time to
effect a reduction in sexual odor. This fact may assist in the testing of
more practical methods.

Summary

Forty-two barrows and 42 boars averaging 55 pounds initially were used to
determine the effects of late castration (average of 16 days prior to slaughter)
on performance, carcass characteristics and on degree of sexual odor in the
carcass.

Late castration did not influence rate of gain for the period from castra-
tion to slaughter. Although not analyzed statistically, feed conversion of
late castrates was poorer than that of boars during this period. Dressing
percentage, carcass length, percent 4 lean cuts and loin eye area were not
affected by late castration but backfat thickness was increased. While per-
formance and carcass characteristics of the boar were essentially maintained







-4-


after late castration, there was some degree of reversion towards the charac-
teristics of the barrow.

Odor scores in fat samples and loin roasts were determined by a panel to
be reduced in late castrates when compared to boars and were not significantly
different (P> 0.05) from that of barrows.


Literature Cited

1. Walstra, P. and D. Kroeske. 1968. The effect of castration on meat production
in male pigs. World Rev. Anim. Prod. 4:59.

2. Wismer-Pedersen, J. 1968. Boars as meat producers. World Rev. Anim. Prod.
4:100.

3. Field, R. A. 1971. Effect of castration on meat quality and quantity. J.
Anim. Sci. 32:849.

4. Patterson, R. L. S. 1968. 5a-androst-16-ene-3-one: compound responsible for
taint in boar fat. J. Sci. Food Agr. 19:31.

5. Gower, D. B. 1972. 16-Unsaturated C19 steroids a review of their chemistry,
biochemistry and possible physiological role. J. Steroid Biochem. 3:45.

6. Newall, J. A. and J. P. Bowland. 1973. Sexual odor development in boars.
Dept. of Animal Science, University of Alberta. 52nd Annual Feeders Day,
1973. p. 15.

7. Creswell, D. C., H. D. Wallace, G. E. Combs and R. L. West. 1974. Influence
of lysine on performance and carcass characteristics of boars and barrows.
Fla. Animal Sci. Research Report AL-1974-14.

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

9. Corcoran, K. D., D. R. Ricker and G. A. Isler. 1974. Boar testing to 240 vs.
200 lb. Research Summary 78, Ohio Agricultural Research and Development
Center, Wooster. p. 39.

10. Newall, J. A., L. H. Tucker, G. E. Stinson and J. P. Bowland. 1973. Influ-
ence of late castration and diethylstilbestrol implantation on performance
of boars and on incidence of boar taint. Can. J. Anim. Sci. 53:205.

11. Duncan, D. B. 1955. Multiple range and multiple F tests. Biometrics 11:1.







- 5-


Table 1. Performance
of Barrows,


Item
No. pigs
Daily gain, lb.
-190 lb. to slaughter!/
55 lb. to slaughter
Feed/gain, lb.
-190 lb. to slaughter
55 lb. to slaughter
Liveweight at slaughter, lb.
Dressing %
Carcass length, in.
Backfat, in.
% 4 lean cuts
Loin eye area, sq. in.
Marbli g g
Colors/
Firmness./


and Carcass Characteristics
Late Castrates and Boars
Barrows Late Castrates
42 22


1.96
1.67

3.65
3.32
212
72.9a
30.8a
1.29a
53.6a
4.35
11
3
3


2.04
1.69

3.55

223
70.4b
31.6b
1.23a
54.7b
4.35
10
3.2
3.2


Boars
17

2.15
1.67


3.35
3.14 --
211
70.6b
31.7b
1.1 b
55.2
4.19
11
3.1
3.6


1/ a,b-values on the same line with a common or no superscript
letter are not significantly different P > 0.05 (11). Feed/
gain data was not statistically analyzed.
2/ Scores were coded from 0 to 33; small = 10-12, modest = 13-15,
moderate = 16-18, etc.
3/ Very dark color designated by 1; slightly dark, 2; greyish-
pink, ideal, 3; slightly light, 4; very light, 5.
4/ Very firm designated by 1; firm, 2; slightly soft, 3; very
soft, 4.





Table 2. Odor Scores of Barrows Late
Castrates and Boars-l/


Treatment Barrows Late Castrates Boars


Hot carcass fat 1.05a 1.10a 1.61b

Chilled carcass fat 1.05a 1.06a 1.48b

Loin roast 1.04a 1.04a 1.97b

1/ Panel scores of sexual odor designated as 1 = no odor, 2 =
slight odor, 3 = moderate odor, 4 = strong odor.
2/ a,b values in the same line with a common superscript letter
are not significantly different P > 0.05 (10).







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