Artificial breeding of adult goats and kids induced with hormones to ovulate outside the breeding season

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A total of 28 336 adult goats of the Saanen and Alpine breeds were induced to ovulate before the breeding season with either a 21 day fluorogestone acetate (FGA) treatment administered vaginally and associated with Pregnant Mare Serum Gonadotrophin (PMSG; 10 745 females) or an 11 day FGA treatment, also administered vaginally but associated with PMSG and cloprostenol (17 591 females). After the first treatment, goats were inseminated twice during the induced oestrus with either liquid semen stored for a few hours at + 4°C ( n = 4505) or frozen-thawed spermatozoa stored up to 6 years at −196°C ( n = 6240): the percentage of goats delivering kids was higher when frozen-thawed spermatozoa were inseminated (56.7% vs. 52.1%; P < 0.01). Goats inseminated twice with frozen-thawed spermatozoa after administration of the second treatment ( n = 6970) were more fertile than those inseminated under the same conditions after administration of the first treatment ( n = 6240): 61.1% vs. 56.7%; P < 0.01. Following administration of the second treatment, goats inseminated once during the induced oestrus ( n = 10 621) were more fertile than those inseminated twice with the same frozen-thawed spermatozoa ( n = 6970): 63.0% vs. 61.1%; P < 0.01. In Alpine goats, when treatments ended from 10:00 a.m. to 2:00 p.m., the fertility rate was higher than for treatments which ended from 3:00 to 9:00 p.m.: 65.7% ( n = 4338) compared with 60.7% ( n = 2671), respectively, P < 0.01. After one insemination, fertility rates for all goats increased with time from the non-breeding to the breeding season (58.7%; 61.1% and 65.9%). This was more pronounced for Saanen goats (56.0%; 61.3% and 63.7%) than for Alpine goats in which fertility increased only in the 45 day period preceding the beginning of the full breeding season (61.0%–66.4%). Attempts were also made to adapt hormonal treatments to the anatomy and physiology of the female kid. For the same reason, artificial insemination (A.I.) conditions differing from those prevailing in adult females were tested. The vaginal administration of progesterone by means of a CIDR (Controlled Internal Drug Releaser) resulted in fertility levels as high as those obtained after administration of FGA through vaginal sponges. The insemination of 0.2 ml inseminates containing 100 × 10 6 spermatozoa produced fertility levels above 60% and no lower than those obtained with 0.5 ml inseminates containing 150 × 10 6 or 200 × 10 6 spermatozoa.