Reproductive performance and liveweight in Romney sheep selected for fleece weight and a control flock

T. Wuliji, K.G. Dodds, R.N. Andrews, P. Turner, R. Wheeler

AgResearch, Invermay Agricultural Centre, P.O. Box 50034, Mosgiel, New Zealand

Proceedings of the New Zealand Society of Animal Production. 1992, 52: 237-240

A high fleece weight Romney breeding flock (HFW) and a contemporary random control flock (RC) has been established at MAF Technology Woodlands Research Station by the intensive screening of ewe and ram hoggets from commercial flocks. This paper summaries production traits including reproductive performances, liveweight and fleece weight of the ewe flocks over the 7 years.

The ovulation rate and number of multiple births per ewe lambed were higher for HFW than RC ewes 1.84 vs 1.75 (SE0.02, p<0.01) and 0.62 vs 0.56 (0.02, p<0.05). Number of lambs born per ewe joined, number of lambs reared per ewe lambed, the number of lambs weaned per lamb born and number of lambs weaned per ewe joined in HFW were 1.49 (SE0.02), 1.37 (0.02), 0.84 (0.01) higher in HFW (65.4kg; SE2.4) than in RC (61.3 kg; 2.4). The greasy fleece weight averaged 4.55 kg (SE 0.21) for HFW and 3.87 kg (0.21) for RC. This represents an average advantage of 17.6% (P<0.001) to HFW over 7 production years. The results indicate that the single trait selection for fleece weight will be associated with increases in other important productive traits in long woolled sheep.

Keywords: NZSAPAB; Romney; ovulation; fleece weight; selection; lambs.

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Last Updated 25-01-1997