A terminal sire breeding programme based on screening for hogget
liveweight
G.B. Nicoll, M.J. Alderton, D.D. Annandale, I.D. Coleman, T.J.
Grimwood, J.A. Thomson
Landcorp Farming Limited, P O Box 1235, Hamilton, New Zealand
Proceedings of the New Zealand Society of Animal Production.
1992, 52: 125-128
A large-scale screening operation over two seasons by Landcorp
Farming Ltd has established a terminal sire-breeding programme for
sheep. Within the North and South Islands, screened hoggets were
transferred to Huirimu Station and Kepler Station respectively. In
1989, 2,046 ewe hoggets (0.8%) were screened on liveweight from 248,500
animals in 114 flocks. Mean pooled population weight (adjusted to 18
December) was 43.2 ± 0.5 kg; screened hoggets averaged 52.7 ± 0.6 kg
(P<0.001). In 1990, 1,819 hoggets (0.7%) were screened from 252,500
animals in 102 flocks. Mean pooled population weight was 42.6 ± 0.6 kg;
screened hoggets averaged 52.1 ± 0.7 kg (P<0.001). Progeny out of ewes
screened in 1989 were sired by Dorset, Synthetic, Romney or Wiltshire
rams on Huirimu Station, and by unrelated Dorset (two sources), Romney
or Coopworth rams on Kepler Station. Within stations, Dorset-sired
lambs were heavier than those by the other sire groups at weaning (19.6
vs 17.6, 17,9 and 18.0 kg respectively on Huirimu; 19.9 and 19.6 vs 18.1
and 17.8 kg respectively on Kepler; P<0.001). Sire group effects on
progeny weights in July showed similar trends (38.6 vs 34.6, 34.0 and
35.4 kg on Huirimu; 40.6 and 40.0 vs 36.7 and 35.9 kg on Kepler;
P<0.05). On Huirimu, Dorset- and Synthetic-sired hoggets had greater
weight-adjusted muscle depths than Romney- or Wiltshire-sired hoggets
(22.3 and 22.1 vs 21.4 and 21.7 mm respectively, P<0.001). On Kepler,
hoggets sired by Source I Dorset rams had greater adjusted muscle depths
than those by the other sire groups (25.7 vs 25.1, 23.7 and 24.8 mm
respectively, P<0.05). Weight-adjusted fat depths were significantly
less for Romney-sired hoggets than for the other sire groups on both
stations.
Keywords: NZSAPAB;
Sheep; screening; liveweight; sire breed.
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Last Updated 25-01-1997
