Abstract:
Proc. Aust. Soc. Anim. Prod. Vol. 19 FERTILITY OF CASHMERE AND ANGORA GOATS BRED AT 7 OR 19 MONTHS A. J. RITARA, J. A. ROBERTSONA and G. EVANS B *Dept of Primary Industry, PO. Box 180, Kings Meadows, Tas. 7249. BDept of Animal Science, University of Sydney, N.S.W. 2006. Breeding of fibre-producing goats at a young age may increase their total life-time production of kids and reduce the generation interval, leading to more rapid improvement toward the selected trait. By late autumn (May), 7 and 19 month-old does commence natural ovulatory activity if heavy enough and almost all does may be hormonally-induced to ovulate (Robertson et al. 1991). In this study, we investigated the fertility of Cashmere and Angora does bred at 7 or 19 months old. Female goats were treated in May with intravaginal Type G CIDR devices which remained in place for 15 days and then injected with 200 iu PMSG. Cashmere and Angora does aged 7 months or 19 months were inseminated (AI) laparoscopically with frozen-thawed semen 40 h after CIDR-PMSG treatment (Ritar et aZ. 1990). Bucks wearing crayon harnesses were introduced 14 days later for followup mating until 45 days after AI, crayon colours were changed at 14-day intervals and does were checked for crayon marks. Fertility after AI was higher (PcO.05) for Cashmeres than for Angoras and for 19 than for 7 monthold goats, which appeared to be related to liveweight (Table 1). For Angora does, the kidding rate after AI was low, and no 7-month females and only one 19-month female kidded to follow-up mating. Thus most does remain non-pregnant. In contrast, few Cashmeres remained non-pregnant, especially at 19 months of age. 1. Fertility liveweights (mean k s.e.) of Cashmere and Angora does kidding and follow-up mating at 7 or 19 months laparoscopic AI These preliminary data indicate that fertility of young Angora does is low and may be a significant reproductive problem, whereas fertility is high in Cashmere does as young as 7 months. RITAR, A. J., BALL, l? D. and O' MAY, P. J. (1990). Reprod. Fert. Dev. 2: 377-84. ROBERTSON, J. A., RITAR, A. J., BALL, P D. and EVANS, G. (1991). Aust. Sot. Reprod. Biol. 23: 20. This work was supported by Rural Industries Research and Development Corporation. 286