Wool quality and growth traits of Tasmanian pasture-fed crossbred lambs and relationships with plasma metabolites
journal contributionposted on 2023-05-26, 11:22 authored by Malau-Aduli, AEO, Ranson, CF, Bignell, CW
Wool quality, growth and plasma metabolite traits of 500 F1 progeny from Merino dams sired by 5 ram breeds were investigated to study the influences of sire breed, sex and their interactions with plasma metabolites aimed at dual-purpose crossbreeding options. Coopworth, Texel and White Suffolk sired progeny had significantly (P<0.05) heavier weaning weights (WWT) and average daily gains (ADG) than those sired by Dorset or East-Friesian rams. Coopworth-sired sheep had the highest WWT (31.3¬¨¬±1.7Kg) and East-Friesian sired sheep the lowest (22.9¬¨¬±3.1Kg) with ADG ranging from 0.15kg/day in East-Friesian to 0.23 Kg/day in Texel and White Suffolk sire breeds. Highly significant (P<0.01) sex by sire breed interaction were evident; Coopworth-sired ewe lambs had the highest WWT and ADG (34Kg, 0.27 Kg/day) and Dorset-sired ewe lambs the least (22kg, 0.15 Kg/day). Greasy fleece weight ranged from a minimum of 964g to a maximum of 1303g in Dorset and Coopworth-sired lambs respectively, with Coopworth and Texel sire breeds having significantly heavier (P<0.05) fleece weights than either Dorset, White Suffolk or East-Friesian. Texel-sired sheep had significantly larger (P<0.05) micron fibre diameter (23.4˜í¬¿m) than the 21˜í¬¿m recorded in White Suffolks and East-Friesians. There were also highly significant differences (P<0.01) between sire breeds in staple length (range 50-68mm) and staple strength (range 39-52Nktex), with males having finer fibre diameter (21 vs 23˜í¬¿m) and shorter staple length (55 vs 60mm). Regardless of sire breed or gender, blood plasma metabolites were well within the normal range. A strong, positive and significant phenotypic correlation of 0.72 existed between marking and weaning weights. There were no significant correlations between the wool quality and growth traits, essentially implying that producers can select for finer wool without compromising growth. Coopworth x Merino first cross was the overall best performing sheep breed studied because of its heavier liveweight, faster daily gain, heavy fleece weight and a comparatively lower micron fibre diameter than the other crossbreds.
Publication titleJournal of Animal Science