Animal Husbandry and Nutrition Florida Agricultural
Mimeograph Series No. 60-13 Experiment Station
FEEDLOT PERFORMANCE.AND CARCASS
TRAITS OF GROWING-FINISHING SWINE
AS INFLUENCED BY SEX AND BREED
H. D. Wallace, G. E. McCabe, A. Z. Palmer, J. W. Carpenter,
M. Koger and G. E. Combs I/
It has long been recognized that barrows, gilts and boars do not
perform similarly In the feedlot nor do they produce carcasses of similar
quality. Intensification of meat type certification programs of the
various breeds has focused considerable attention on these differences,
particularly differences between barrows and gilts.
In recent work designed primarily to study slaughter weight influ-
ences on carcass value (Fla. An. Husb. and Nutr. Mimeo. Series No. 60-12.
1959) it was also possible to obtain information on sex effects and on
certain breed comparisons. It is the purpose of this report to present
a brief summary of these findings.
Feeding, management and slaughter procedures have been described in
previous reports (Fla. An. Husb. and Nutr..Mimeo. Series Nos. 60-11 and
60-12. 1959). Barrows and gilts were distributed as equally as feasible
throughout the various experimental treatments in the two trials. Several
pure breeds and certain crosses were involved. Only purebred Durocs,
purebred Spotted Poland Chinas and Landrace X Duroc crossbreds were used
in great enough numbers to provide adequate comparisons. Nevertheless,
data from the other breeds and crosses involved, although based on insuf-
ficient numbers, are also presented for the sake of completeness and
Four purebred boars sired the pigs used in the study. The group
included a Duroc, Hampshire, Yorkshire and Spotted Poland China.
j/ Wallace, McCabe, Palmer, Koger, Carpenter and Combs; Associate
Animal Husbandman, Graduate Assistant, Associate Animal Husbandman,
Animal Husbandman, Assistant Animal Husbandman and Assistant Animal
Husbandman respectively, Department of Animal Husbandry and Nutri-
tion. The assistance of W. E. Collins and L. S. Taylor, Swine
Herdsmen, is gratefully acknowledged. 34 E P0
Results and Discussion
Table I presents a performance and carcass comparison of barrows
and gilts. Barrows gained significantly faster than gilts (1.52 vs. 1.44
Ib. per day). The more rapid weight gains were apparent at all slaughter
weights. The differences in dressing percentages and carcass lengths
for barrows and gilts were very small and non-significant. There was a
clear trend toward increased dressing percentages for both barrows and
gilts as the slaughter weight increased. Backfat thicknesses increased
with increase in slaughter weights for barrows and gilts. Barrows pro-
duced carcasses having an average of 1.41 inches of backfat and gilts
1.27 inches. The difference was highly significant. Loin eye areas
increased with increases in slaughter weight for both barrows and gilts.
Gilts yielded carcasses with much larger loin eyes (4.18 sq. in. vs.
3.76 sq. in.). This difference was highly significant. Percent lean
cuts, regardless of whether expressed on carcass weight basis or live-
weight basis, decreased as slaughter weight increased for both barrows
and gilts. Gilts produced carcasses which were significantly higher in
A comparison of the breeds involved is presented in Table 2. Because
of the number of animals studied, only the first three breed groups will
be discussed in detail. The Duroc X Landrace crossbred pigs gained faster
(P L .01) than either the purebred Durocs or Spotted Poland Chinas. Car-
casses from the crossbreds were significantly longer (P f .01) and produced
significantly greater percentage of lean cuts ( P L .01) than those from
purebred Durocs and Spotted Poland Chinas. Durocs were significantly
thicker in backfat (P L .01) than the crossbreds and purebred Spotted
Poland China. The Spotted Poland China exhibited larger loin eyes
(P 1 .01) than either the Durocs or crossbreds. The Duroc X Landrace
crossbreds exhibited larger loin eyes (P L .01) than the purebred Durocs.
There is clear evidence from these data that the Duroc X Landrace cross-
bred pigs were superior in daily gain as well as in all carcass value
measurements over the purebred Durocs. The increase of 3.18 percent in
lean cuts represents a tremendous improvement in quantity of lean pork.
It should be pointed out, of course, that great differences exist
within breeds and in some instances these may be greater than differences
between breeds. The data presented here must be considered with this in
mind and should not be interpreted as a condonement or condemnation of
any of the breeds or breed crosses involved in the study. The data do
reveal that rapid improvement in commercial hog production, particularly
In terms of carcass merit, can be attained by judicious crossing of
Table I. A Comparis n of Gains and Carcass Characterjstics
Different Weights, .
of Barrows and Gilts Slaughtered at
, Slaughter Weight. ...
.-... -240. 21.0 .-80 .. .150 Av.
240 210 180
Number of pigs .
Daily gain, lb.
Carcass length, In.
Av. backfat thickness, in.
Loin eye area, sq. in.
Percent lean cuts
(carcass wt. basis)
Percent lean cuts
35.5 36.0 37.0
36.3** 36.3 37.3 38.5
* Significantly difference from
_ __ __
gilts (P L .01).
Table 2. Comparison of Daily Gain and Certain Carcass Evaluations for Swine of Different
Breeds and Breed Crosses. ./
Number Daily Carcass Av. Loin Eye Percent
Breeding Group Animals Gain, Length, Backfat Area, Lean Cuts,
lb. in. Thickness, Sq. In. Carcass
in. wt.. basis
Duroc X Landrace' 29 1.58 29.5 1.19 4.13 54.4
Duroc X Duroc 24 1.49 28.2 1.41 3.53 51.2
Spotted Poland X Spotted Poland 22 1.50 27.6 1.23 4.62 51.7
Yorkshire X Spotted Poland 1 1.44 28.2 1.52 3.89 50.2
Duroc X Berkshire 9 1.39 28.0 1.36 4.01 51.5
Hampshire X Hampshire 8 1.40 28.4 1.52 3.77 49.9
Yorkshire X Yorkshire 8 1.39 30.8 1.40 2.98 51.8
Spotted:Poland X Tamworth 8 1.54 29.3 1.33 4.55 50.2
Spotted Poland X Berkshire 5 1.53 27.6 1.19 3.81 51.7
./ Data havo been adjusted as necessary for uneven sex and slaughter weight allotments.
Summary of statistical analysis for first three breed groups
Daily gain Duroc X Landrace gained faster than others -(P I.01)
Carcass length Duroc X Landrace longer than.others (P L .01) ....
Backfat Duroc X Duroc thicker than others (P L .01)
Loin eye area Spotted Poland China greater than Duroc X Landrace (P L .05) and Duroc X Duroc (P L .01).
Duroc X Landrace greater than Duroc X Duroc (P L .01)
Percent loan cuts Duroc X Landraco greater than others.(P L .01).
One hundred and twenty-eight animals were used to study the influence
of sex and breed on feedlot performance and carcass traits of growing-
Barrows gained significantly faster than gilts (P L.O0).
Difference in dressing percent and carcass length between the sexes
were small and non-significant.
Barrows were significantly thicker in backfat (P L .01) than gilts.
Gilts produced significantly larger loin eyes and greater percent
lean cuts (P L .01) than barrows.
Breed comparisons revealed that Duroc X Landrace crossbred pigs
gained faster and produced significantly longer carcasses with a higher
percentage of lean cuts (P L .01) than either purebred Durocs or purebred
Spotted Poland Chinas. The purebred Durocs exhibited significantly
greater backfat- (P / .01) than the Spotted Poland China or Duroc X
Landrace crossbreds. The Spotted Poland China produced the largest loin
eyes (P L .01).
Limited data on other breeds and breed crosses are presented.
Marked differences are apparent in certain carcass traits. The limited
number of animals involved however, precludes a meaningful detailed
analysis of these data.