Follicular size, luteinizing hormone (LH), and progesterone (P4) levels in postpartum Santa Inês ewes subjected to ram effect combined with suckling interruption

Abstract

The objective was to evaluate the role of ram effect combined with temporary weaning on P4, LH, follicular size and reproductive performance of hair ewes during postpartum. Pluriparous Santa Inês ewes (n = 99) during 15 to 30 days postpartum were selected and isolated from rams for an additional period of 30 days. Before exposure to rams, ewes were allocated to experimental groups, where on SI0, no suckling interruption was performed, and in SI24 and SI48, suckling interruption was performed for 24 and 48 hours, respectively. Mean P4 was according to anestrus condition before the introduction of rams, and it reached cyclicity levels after contact between genders. Ewes displaying a single estrus were more frequent in SI24 than SI48 (P 〈 0.05). The LH pre-ovulatory peaks were detected within 44 hours and 60 hours after introduction of rams, irrespectively of the group. Ovulatory follicles reached a more significant size in SI24 than SI0 and SI48 (P < 0.05). Pregnancy rates differed at first service since SI24 was higher than SI48. Moreover, prolificacy was similar among groups (P 〉 0.05). Ram effect combined with temporary weaning for 24 hours is more efficient for Santa Inês reproduction, since it leads to larger ovulatory follicle size, increased the P4 level and higher pregnancy rate at first service.