Ritar A J, Robertson J A, Evans G
Department of Primary Industry and Fisheries, Marine Research Laboratories, Taroona, Tas., Australia.
Reprod Fertil Dev. 1994;6(6):737-47. doi: 10.1071/rd9940737.
Reproductive parameters of young Cashmere and Angora goats born between 1988 and 1990 and grazed on temperate pastures in southern Australia were examined with a view to reducing the age of first breeding. Females born in August or October of 1989 and 1990 were examined each month by laparoscopy to determine natural ovulatory activity when 6-19-months old. Cashmeres commenced ovulating as young as 7 months of age or as light as 12 kg. Almost all Cashmeres were ovulating by 8-10 months of age at a liveweight of at least 18 kg, and their breeding season extended from April to October. By comparison with Cashmeres, Angoras grew more slowly, fewer ovulated, they commenced ovulation later, their ovulation rates were lower and their breeding season was shorter. A stratified sample of these females was injected with 200 I.U. or 400 I.U. of pregnant mare serum gonadotrophin (PMSG) after treatment with controlled internal drug release (CIDR) devices for 16-18 days to induce ovulation at 6, 9, 12, 15 and 19 months of age. Ovulation rates after CIDR-PMSG treatment were higher for Cashmeres than for Angoras and tended to be higher for females injected with 400 I.U. PMSG than 200 I.U. PMSG. The proportion of females remaining anovulatory after exogenous hormonal treatment was higher for Angoras than for Cashmeres (38% and 10% respectively) but it was not affected by the dose of PMSG or age. For kids born in 1989, the kidding rates to insemination (with follow-up mating) after CIDR-PMSG treatment for 8-month-old and 20-month-old Cashmeres (in the breeding season) were similar (75.0% and 83.8% respectively) but the rate for 14-month-old Cashmeres was only 10.0% (in the non-breeding period). The kidding rates for Angoras bred at 8, 14 and 20 months of age were 8.4%, 20.0% and 30.0% respectively. Ovulatory activity and fertility in the non-breeding period, with or without CIDR-PMSG treatment, did not improve with melatonin treatment.
对1988年至1990年间出生并在澳大利亚南部温带牧场放牧的幼年绒山羊和安哥拉山羊的繁殖参数进行了研究，目的是降低首次配种年龄。对1989年和1990年8月或10月出生的雌性山羊，在其6至19月龄时每月通过腹腔镜检查来确定自然排卵活动。绒山羊最早在7月龄或体重低至12千克时开始排卵。几乎所有绒山羊在8至10月龄、体重至少18千克时开始排卵，其繁殖季节从4月持续到10月。与绒山羊相比，安哥拉山羊生长较慢，排卵的较少，开始排卵较晚，排卵率较低且繁殖季节较短。对这些雌性山羊的一个分层样本，在用控制内部药物释放（CIDR）装置处理16至18天后，注射200国际单位或400国际单位的孕马血清促性腺激素（PMSG），以诱导其在6、9、12、15和19月龄时排卵。CIDR - PMSG处理后的排卵率，绒山羊高于安哥拉山羊，且注射400国际单位PMSG的雌性山羊往往高于注射200国际单位PMSG的。外源激素处理后仍不排卵的雌性山羊比例，安哥拉山羊高于绒山羊（分别为38%和10%），但不受PMSG剂量或年龄影响。对于1989年出生的羔羊，8月龄和20月龄绒山羊（在繁殖季节）经CIDR - PMSG处理后（后续进行配种）的产羔率与授精率相似（分别为75.0%和83.8%），但14月龄绒山羊（在非繁殖季节）的产羔率仅为10.0%。8、14和20月龄配种的安哥拉山羊的产羔率分别为8.4%、20.0%和30.0%。无论有无CIDR - PMSG处理，非繁殖季节的排卵活动和生育力在褪黑素处理后均未改善。
