Abstract

The effect of the Inverdale gene (FecX) on wool production traits was measured in a trial where Romney carrier rams (I) were crossed and backcrossed with high fleece weight-selected (HF) Romney ewes, and Romney non-carrier rams (+) with unselected (RC) Romney ewes. The trial generated 248 female progeny in five genotype subgroups: non-carrier (++)½RC and ¼RC; heterozygous (I+)½HF and ¼HF; and homozygous (II) ¼HF. The live weight, fleece weight, wool characteristics and reproductive performance of these genotype subgroups were compared, and from corresponding genotype subgroups of male progeny (n = 307) were also evaluated for early growth and fleece traits. No differences were found for birth, hogget shearing and two-tooth live weights among genotypes. Greasy fleece weight was significantly (P<0.05) higher for I+½HF ewes shorn as lambs (9%), hoggets (8%) and two-tooths (10%) compared with ++½RC. The important wool characteristics of yield, fibre diameter, bulk, staple length and staple crimp did not differ significantly between genotypes. The ovulation rate (combining subgroups with the same Inverdale genotype) was significantly (P<0.05) higher for I+ (2.3) than ++ (1.5) progeny (SED: 0.3). The results suggest that introgression of FecXI into fleece weight selection flocks will improve prolificacy in these flocks while ensuring high fleece weight.

T, Wuliji, GH Davis, KG Dodds, RN Andrews, R Wheeler, and PR Turner

Proceedings of the New Zealand Society of Animal Production, Volume 57, , 29-32, 1997