ASSESSMENT THE SYNCHRONY BETWEEN UTERINE STATUS AND HORMONAL PROFILES IN MODIFIED OVSYNC PROTOCOLS IN RELATION TO FERTILITY IN BUFFALOES

Abstract

A total of 36 pluriparous buffaloes were used to study the uterine morphometry in response to serum estradiol concentrations and associated estrogen receptors (ERs) expression in modified ovsync protocols. The buffaloes were assigned to St-ovsync, CIDR-sync and Insulin- sync (n=12 for each). The St-ovsync consisted of two IM injections of 20µg buserelin on the Day 0 (GnRH1) and on the Day 9 (GnRH2) and an IM injection of 500 µg of cloprostenol sodium (Estrumate) on the Day 7. Buffaloes in CIDR-sync and Insulin-sync protocols were treated as in the St-Ovsync protocol in addition to intravaginal insertion of CIDR from the Day 0 to 7 in case CIDR-sync and SC injection of Insulin at a dose of 0.25 lu/kg on the Days 7, 8 and 9 in Insulin-sync. Blood samples were collected and the uterine wall thickness (UWT) was simultaneously measured by transrectal ultrasonography on the Days 0, 3, 5, 7, 8 and 9. Endometrial biopsy samples were collected from five buffaloes per group for quantifying the abundance of estrogen receptors. The UWT on the Days 3 and 5 showed a decrease (p<0.05) while the serum p4 concentration on the Day 3 showed an increase (p<0.05) in eventually diagnosed pregnant (EDP) buffaloes in CIDR-sync compared with their counterparts in either St-Ovsync or Insulin-sync. On the Day 9, although there was a decrease in the serum E2 concentration in CIDR-sync compared with either St-Ovsync or Insulin-sync in EDP buffaloes, there was an increase (p<0.05) in the ER mRNA expression in CIDR-sync compared with St-Ovsync. It could be concluded that modifying the St-Ovsync, by p4 supplementation through intravaginal insertion of CIDR from the Day 0 to 7 or by SC injection of insulin on the Days 7, 8 and 9, could modulate uterine morphometry such conductive to proper fertility response. Key words: Erα; uterine wall thickness; Ovsync