Nutritional supplementation improves ovulation and pregnancy rates in female goats managed under natural grazing conditions and exposed to the male effect

摘要

Two experiments were conducted to determine if nutritional supplementation improved ovulation and pregnancy rates in female goats managed under grazing conditions and submitted to the male effect. In Experiment 1, one group of does did not receive nutritional supplementation, while the other group was supplemented daily for 7 days starting at the time when the males were introduced to the females. The ovulation rate at the second male-induced ovulation was greater(P < 0.05) in supplemented (2.0 +/- 0.1) than in non-supplemented (1.6 +/- 0.1) does. For Experiment 2, female goats were supplemented for 0, 7,14 or 28 days, starting 9 days following buck introduction. The proportion of does that were pregnant in the group supplemented for 28 days was greater (P < 0.05) than in the non-supplemented group. but did not differ from 14-day and the 7-day supplemented groups. The proportion of pregnant does was greater (P < 0.05) in the group supplemented for 14 days compared to the group supplemented for 7 days and the non-supplemented group. These latter two groups did not differ (P > 0.05). In conclusion, feed supplementation for 7 days, starting at the time when males were introduced increased ovulation rate and feed supplementation for 14 or 28 days starting 9 days after males were introduced improved pregnancy rates in goats managed under grazing conditions and exposed to males.