The ovulation rate in anoestrous female goats managed under grazing conditions and exposed to the male effect is increased by nutritional supplementation

This experiment was conducted to determine if feed supplementation before exposure of anoestrous does to males increases ovulation rate. Does (n = 50) grazing natural vegetation were divided into two groups (n = 25). One group received no feed supplementation, while the other was supplemented daily, with a mixture of 950 g of alfalfa hay, 290 g of rolled corn and 140 g of soy bean per animal for 7 days before exposure to bucks. On April 7, all females were exposed to four adult sexually active bucks (two per group) for 15 days. The ovulation rate at the ovulation detected within 5 days of exposure to males, assessed by transrectal ultrasonography, was greater (P < 0.05) in supplemented (1.6 ± 0.2) than in non-supplemented females (1.0 ± 0.2). In contrast, ovulation rate at the subsequent ovulation, detected between days 6 and 15 of contact with males, was not different (P > 0.05) between supplemented (1.3 ± 0.1) and non-supplemented females (1.3 ± 0.2). Feed supplementation 7 days before exposure to sexually active bucks of females managed under grazing conditions increased their ovulation rate at the first male-induced ovulation but the stimulatory effect of supplementation did not persist and was not observed at the subsequent ovulation.