Invasive Species Compendium

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Abstract

Effect of selection for fleece weight on liveweight, reproductive performance and wool characteristics in mixed age Romney ewes.

Abstract

This paper presents an analysis of 3525 annual production records of mixed-age New Zealand Romney ewes in a flock selected for fleece weight (HF) and a control flock (RC) over 11 years (1985-95). HF ewes were significantly heavier than RC ewes for autumn live weight (8%), winter live weight (9%), spring live weight (7%), greasy fleece weight (20%) and clean fleece weight (19%). Small but significant flock differences were found for fibre diameter and yellowness. HF fleeces were coarser and more yellow than RC fleeces. HF ewes significantly exceeded RC ewes for ovulation rate (1.80 vs. 1.73), number of lambs born/ewes lambed (1.63 vs. 1.56) and multiple births/100 ewes lambing (60 vs. 54), but had lower values for number of lambs weaned/lambs born (0.84 vs. 0.88). The results indicate that single-trait selection for fleece weight improves greasy and clean fleece weights, live weight and ovulation rate, with an associated increase in fibre diameter and yellowness of the fleece.