New Zealand Journal of Agricultural Research abstracts
Genetic and phenotypic relationships among carcass measurements in beef
cattle
C. A. MORRIS
N. G. CULLEN
D. G. MCCALL
AgResearch
Ruakura Agricultural Research Centre
Private Bag 3123
Hamilton, New Zealand
Abstract Carcass data from three large beef-cattle breeding
experiments in New Zealand were analysed. Regressions of saleable meat weight
on carcass and liveweights were estimated as parameters for a modelling
exercise where pasture was converted to carcass and liveweight, finishing
cattle at different end points. The data were also used in order to estimate
heritabilities for nine carcass traits and the relationships among them.
Slaughter data were from 1962 cattle, sired by 199 different bulls from 13 sire
breeds. Relationships were first estimated between hot carcass weight and
either carcass components or pre-slaughter weight, and then an "animal" model
was used to estimate genetic parameters. On a log-log basis, the overall
regression of carcass weight on pre-slaughter weight was 1.089 +/- 0.008. The
corresponding log-log regression of saleable meat weight on carcass weight was
1.002 +/- 0.007, bone weight on carcass weight
0.779 +/- 0.015, and trimmed fat weight on carcass weight
1.265 +/- 0.041. The regression slopes indicate the percentage change
in one trait as a result of a 1% increase in another trait. The values for
saleable meat weight or bone weight were reasonably consistent across trials,
whereas the regression for trimmed fat weight varied with trial. Multivariate
heritability estimates were 0.48 +/- 0.07 for hot carcass weight,
0.31 +/- 0.06 for dressing percent, 0.42 +/- 0.10 for eye
muscle area, 0.38 +/- 0.12 for carcass fat depth,
0.49 +/- 0.12 for weight of high-priced cuts, 0.48 +/- 0.07
for saleable meat weight, 0.51 +/- 0.07 for bone weight, and
0.30 +/- 0.05 for trimmed fat weight. Genetic correlations showed a
strong negative relationship between meat percentage and trimmed fat percentage
(-0.94), whilst genetic correlations of each with bone percentage were not
significantly different from zero. The relationship between hot carcass weight
and fat percentage was small and positive in sign (significant
(0.05 +/- 0.02) for the phenotypic correlation but not significant
(0.06 +/- 0.12) for the genetic correlation).
Keywords cattle; carcass weight; saleable-meat weight;
heritability; regression
New Zealand Journal of Agricultural Research, 1999, Vol. 42: 415-421
0028-8233/99/4204-0415 $7.00/0 (c) The Royal Society of New Zealand
1999
PDF file of entire paper: medium quality (583K); (scanned from paper original: notes about this process)
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