Abstract

Breed, sex and birth rank differences in follicle density and S/P ratio were examined for South African (SA) and SAxNZ Angora goats. All primary (P) follicles but few secondary (Sf) follicles were mature at birth. Density of mature secondary (Sf) follicles increased by 150% and 250% in the first month after birth, in SA and SAxNZ kids respectively. Change in P and Sf+Si follicle density followed an asymptotic slope. S/P ratio was 8.4 at birth and 9.9 at 6 months. Breed differences were apparent early in life but were not persistent to 6 months of age. Sex by birth rank interactions at 4 and 6 months of age showed that single males had an advantage over twin males in P and S density (P<0.05) while twin females had an advantage over single females (P<0.05). These differences are a likely result of differences in nutritional advantage and changes in body size. S/P ratio was unaffected by breed, sex and birthrank. The results show that initiation of S follicles after birth was likely but inconsequential. Follicle density and S/P ratio do not explain breed differences in fibre and kemp production. Comparisons with other studies suggest that the SAxNZ Angora would have a higher S/P ratio than the NZ Angora.

PD, Muir, NB Smith, and LD Staples

Proceedings of the New Zealand Society of Animal Production, Volume 53, , 275-280, 1993