Vol. 9, Issue 8, Part J (2025)

This five-year retrospective study (2015-2019) evaluated reproductive performance parameters in 415 Thoroughbred mares across five different age groups in a stud farm in India. Data recorded on age, parity, breeding cycles, conception rates, twin pregnancies, early embryonic death (EED), late fetal death (LFD) and foal heat (FH) breeding outcomes were analysed. A total of 706 breeding cycles resulted in 349 pregnancies, with an overall per-cycle conception rate of 49.43% and a seasonal conception rate of 92.05%. Age significantly influenced conception rates (p < 0.05), with younger mares (4-7 and 8-11 years) exhibiting higher fertility. FH breeding occurred in 20.96% of foaled mares, yielding a 52.63% conception rate but higher EFD (15.79%). Statistical analyses were done using chi-square and Fisher's exact tests revealed trends in age-related declines in reproductive efficiency. These findings underscore the importance of age-specific management strategies to optimize breeding outcomes in Thoroughbreds under tropical conditions.