Studies on the comparative efficacy of different analogues of prostaglandin F2 alpha for estrus synchronization in cows

Abstract

In cattle reproduction, luteolysis is a crucial event that regulates the estrous cycle. Both endogenous and exogenous PGF_2α induce luteolysis in most cows with a mature corpus luteum (CL). A study was conducted on 30 normally cycling cows, divided into three groups of 10 animals each. The investigation was conducted in nearby villages at farmers' homes from February 2023 to June 2024. The objective was to evaluate the efficacy of cloprostenol, D-cloprostenol, and dinoprost tromethamine when administered intramuscularly. In these groups, prostaglandins were administered eight days post-ovulation, followed by transrectal ultrasonography (TRUS) to assess the diameter and functionality of the CL using color Doppler to evaluate blood perfusion. Ovarian examinations to monitor luteolysis and subsequent estrus were performed every 24 hours until ovulation. Cloprostenol resulted in a greater but statistically non-significant percentage reduction in CL size (-43.23%) compared to D-cloprostenol (-39.35%) and dinoprost (-42.45%). A significantly (P<0.10) larger final increase in follicle size was observed with cloprostenol (57.84%) compared to D-cloprostenol (55.15%) and dinoprost (51.79%). The most substantial decrease in progesterone (P₄) concentration and percentage was observed with D-cloprostenol (1.42 ± 0.49 ng/ml; -84.6%), followed by cloprostenol (1.76 ± 0.18 ng/ml; -79.9%) and dinoprost (1.66 ± 0.98 ng/ml; -73.2%). Progesterone levels in all groups reached basal concentrations after 96 hours. Among the treatments, cloprostenol achieved the highest conception rate (50%), followed by D-cloprostenol (40%), with the lowest conception rate recorded for dinoprost (30%).