Selection for ultrafine Merino sheep in New Zealand: heritability, phenotypic and genetic correlations of live weight, fleece weight and wool characteristics in yearlings

Abstract

Merino yearling records from 1988 to 1992 birth years in ultrafine wool selection and random control flocks at Tara Hills High Country Station, New Zealand were analysed for live weight, fleece weight and wool characteristics. Estimates of heritability, genetic and phenotypic correlations among traits using REML methods are presented. Heritabilities (h 2 ) of birth, weaning, autumn, spring and summer live weights and greasy and clean fleece weights were estimated as being 0·35were found to be high among the live weights but low to moderate among fleece weight and wool characteristics. Heritability estimates of fibre diameter, fibre diameter variation and staple length were found to be higher in New Zealand fine wool Merinos than most of those reported in the literature. The results indicate that selection for reduced fibre diameter will have little effect on other major production traits such as live weight and fleece weight.

The estimation of variance components for prolificacy and growth traits of Sakız sheep

“…Reported estimates direct heritability for different sheep breeds range from 0.00 to 0.38 for lamb birth weight, 0.025 to 0.49, for weaning weight (Babar et al, 2003;Bahreini et al, 2007;Duru and Koyuncu, 2005;Hanford et al, 2006;Ligda et al, 2000;Maria et al, 1993;Carrillo and Segura, 1993;Hanford et al, 2003;Nakagawa et al, 2005;Noter and Hough, 1997;Ozcan et al, 2005;Reale et al, 1999;Sawalha et al, 2005;Szwaczkowski et al, 2006;Tosh and Kemp, 1994;Wuliji et al, 2001;Wyk et al, 2003) and 0.12 to 0.25 for yearling weights (Reale et al, 1999;Ozcan et al, 2005), and 0.11 to 0.33 for average daily gain (Carrillo and Segura, 1993;Maria et al, 1993;Noter and Hough, 1997;Ozcan et al, 2005).…”

Selection response to fleece weight, wool characteristics, and heritability estimates in yearling Romney sheep

“…Fogarty (1995) has presented an exclusive review of genetic parameters in sheep including some of wool traits, and our estimates are generally consistent with these published heritability estimates for crossbreed sheep. Heritability estimates for GF, CF, FD and bulk in Romney are comparable with the estimates in New Zealand Merinos (Wuliji et al, 2001), while they largely differed for other wool traits such as SL and wool colour. The heritability estimates in this trial appeared to be lower than estimates in some North American dual use sheep breeds (Okut et al, 1999;Bromley et al, 2000;Hanford et al, 2002Hanford et al, , 2003.…”

“…The genetic and phenotypic correlation was high among SW, GF and CF, and was moderate to high for GF and CF with FD, SL and SS, while there was a negative correlation between Y and Y-Z colour traits. Phenotypic and genetic correlations are within expectation and recently published literature (Fogarty, 1995;Wuliji et al, 2001). Breeding objectives in earlier selection experiments placed a strong emphasis on fleece weight, but wool quality traits are becoming increasingly important to meat-wool dual use sheep breeding.…”

Estimating heritability of wool shedding in a cross‐bred ewe population

“…The mean heritability found in the present study was around 0.65 times that reported by Wuliji et al . () and by Pollott & Greeff (), with means of 0.49 ± 0.12 and 0.47 ± 0.018, respectively, for live weight of Merino sheep when fitting animal models with and without maternal effects. However, the heritability estimate of BW obtained in the present study was very similar to those reported by Safari et al .…”