Treatment of Ovarian Inactivity in Mares during Breeding and Non-Breeding Season

This study was carried out on 100 pluriparous an-estrus mares in the breeding and non-breeding season of native and British breed mares. All mares were examined trans-rectally with ultrasonography for determination of the degree of ovarian activity. The animals were divided randomly according to type of treatment into 5 groups (n = 20 mares in each group and each group was sub-divided into two groups (A and B) according to season with 10 mares in each sub-group). Group I: each mare was received 5 ml GnRH. Group II: each mare was received 10 ml GnRH as one shot. Group III: each mare was received 10 ml GnRH as two shots in between 12 hours. Group IV: each mare was received intra-uterine wash with 1000 ml normal saline 0.9%. Group V: did not receive any treatment and was used as a control. Group I: Seven mares (7 ∕ 10, 70%) in the breeding season and 4 mares (4 ∕ 10, 40%) in the non-breeding season showed estrus behavior after injection of GnRH. Group II: Eight mares (8∕ 10, 80%) in the breeding season and 6 mares (6 ∕ 10, 60%) in the non-breeding season showed estrus behavior after injection of GnRH. Group III: Eight mares (8 ∕ 10, 80%) in the breeding season and 5 mares (5 ∕ 10, 50%) in the non-breeding season showed estrus behavior after injection of GnRH. Group VI: Six mares (6 ∕ 10, 60%) in the breeding season and 4 mares (4 ∕ 10, 40%) in the non-breeding season showed estrus behavior after injection of GnRH. Group V: two mares (2 ∕ 10, 20%) in the breeding season and one mare (1 ∕ 10, 10%) in the non-breeding season showed estrus behavior after 21 days of the start of the study. The proportion of sub-group A in groups 1, 2, 3 and 4 was significantly different compared to sub-group A in control group P < 0.001. However, there was no difference between groups 1, 2, 3 and 4 P > 0.05. The proportion of sub-group B was significantly different in groups 1, 2, 3 and 4 compared to sub-group B in control group P < 0.01. Although, there was no difference between groups 1, 2, 3 and 4 (P > 0.05). We concluded that, GnRH or normal saline 0.9% can be used effectively for induction of ovarian activity in an-estrus mares in the breeding and non-breeding seasons.