Comparison of growth and carcass traits of ram lambs of three
breeds from a flock screened for prolificacy and a Romney control flock
J.C. McEwan, G.H. Davis, K.G. Dodds, P.F. Fennessy, J.N. Clarke,
M. Hishon
Invermay Agricultural Centre, Ministry of Agriculture and
Fisheries, Private Bag, Mosgiel
Proceedings of the New Zealand Society of Animal Production.
1990, 50: 397-402
Relative to an industry Romney control line, three lines derived
from screening for high prolificacy, consisting of Romneys, Perendales
and Coopworths had significantly heavier weaning weights after
adjustment for non-genetic factors with weights of 19.9 (100), 22.3
(112), 24.0 (121) and 23.9 (120) kilograms (percentage relative to the
Romney controls) for the respective flocks. The differences increase
post-weaning and when slaughtered, between 175 and 219 days of age, the
carcass weights (kg) were 12.0 (100), 14.3 (119), 16.1 (134), 15.7 (131)
respectively for the different strains. Although the base populations
of Romneys are not genetically comparable the results suggest that the
intensive screening for prolificacy has indirectly resulted in animals
capable of more rapid growth to slaughter. The differences between
strains in their carcass weight adjusted subcutaneous fat depths were
minor except that the high prolificacy Perendales had lower increases in
fat depths with increasing carcass weight and had the lowest
subcutaneous fat depths at heavy weights. Additionally the high
prolificacy Perendales had 2 to 6 percent larger estimated L.
dorsi areas than the other genotypes.
Keywords: NZSAPAB;
sheep; breeds; Coopworths; Perendales; Romneys; prolificacy;
liveweights; carcass; fat depths; L.dorsi area
Download abstract in text format
Last Updated 25-01-1997
