RESUMO
The current study was aimed to establish the impact of progesterone supplementation (norgestomet progestagen) between days 4 to 10 post-ovulation on subsequent luteal profile and conception rate in buffaloes. The 28 Murrah buffaloes of second to fourth parity, having normal reproductive organs, were estrus synchronized by double PGF(2α) protocol at 11 days apart. The buffaloes were inseminated during mid- to late estrus and thereafter repeated at 24 h interval. The buffaloes were randomly assigned into two groups: (1) control (no treatment, n = 14) and (2) treatment group (CRESTAR ear implant, n = 14). The CRESTAR ear implant (3 mg, norgestomet progestagen) was inserted subcutaneous between days 4 to 10 post-ovulation. The ovaries were scanned at estrus and thereafter on days 4, 10, 16, 21, and 40 post-ovulation to examine the preovulatory follicle (POF) and corpus luteum (CL) diameter. Each ultasonography was followed by blood sample collection for analysis of plasma progesterone concentrations following ovulation. The conception rate was similar (p > 0.05) between treated and control buffaloes. The pregnant buffalo of the control group had larger (p < 0.05) POF diameter than nonpregnant counterparts. The CL diameter was similar (p > 0.05) in both treated and untreated control as well as in their pregnant and nonpregnant buffaloes of the respective groups. The plasma progesterone concentrations were higher (p < 0.05) in the treatment group on the day 10 post-ovulation as compared to the control buffaloes. It is concluded that norgestomet supplementation had no impact on conception rate and CL diameter but enhances the plasma progesterone concentrations following treatment in buffaloes.