Effects of weaning age on export lamb production
K.G. Geenty
Templeton Agricultural Research Station, Ministry of Agriculture
and Fisheries, Templeton
Proceedings of the New Zealand Society of Animal Production.
1979, 39: 202-210
Five experiments were conducted over a period of 4 years (1973-
7) in which lambs were weaned at 4, 5, 6, 9, 12, 15 or 18 weeks of age.
Slaughter ages ranged from 12 to 30 weeks. Early weaning at 4, 5 or 6
weeks caused varying post-weaning growth checks, lasting from 1 to 4
weeks, the most severe following 4-week weaning. Subsequent growth
rates were similar to those for later weaned lambs. The reductions in
final slaughter weights (up to 21%) were associated with lower killing
out percentages, reduced carcass fat, and lower economic returns. In
one experiment, where adjustments were made for differences in carcass
weight, 4-week weaning resulted in 8 to 12% lower levels of chemical
carcass fat and 6 and 4% higher values for water and protein,
respectively, than in later-weaned lambs. Weaning lambs at 9 weeks of
age resulted in similar final liveweights to weaning at 12 or 15 weeks.
The desirability of a liberal supply of milk and grass prior to early
weaning and the lack of subsequent compensatory growth are discussed.
Application of the practice for reducing carcass fat and removing the
competition of ewes or in conjunction with sheep dairy production,
accelerated lambing and progeny test programmes, is suggested. It is
recommended that conventional lamb weaning ages be reduced to between 8
and 9 weeks.
Keywords: NZSAPAB;
Last Updated 12-09-1998
