Progeny test of selected lean and fat rams
P.F. Fennessy, G.J. Greer and J.J. Bass
Invermay Agricultural Research Centre, Mosgiel
Proceedings of the New Zealand Society of Animal Production.
1982, 42: 137-140
The fat thickness over the 12th rib was measured ultrasonically
on 41 Coopworth ram lambs (7 months of age, 34 to 57 kg live weight).
Four of the 7 fattest and 4 of the 7 leanest were selected on the basis
of their deviations from the overall fat thickness - live-weight
relationship. Ten to 12 male progeny of each of these rams generated
from Perendale ewes were slaughtered at 4 to 7 months of age and 4
parameters of carcass fatness measured. The difference between the
progeny of the 4 lean sires and that of the 4 fat sires was significant
for 2 fat measurements, namely C (P<0.05) the backfat thickness over the
12th rib, and S2 (P<0.01) a fat depth in the shoulder region.
Differences in GR and total chemical fat failed to reach significance.
The data indicate that selection of sires on the basis of backfat
thickness could be an effective means of reducing carcass fat thickness
in lambs.
Keywords: NZSAPAB;
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