Preliminary Remarks in Hormonal Treatments Effects on Reproduction Period in Cows

The early resumption of estrous cycles following calving is important for high reproductive efficiency and for the cows which haven’t been observed in estrus during the first 60 days after calving have a significantly higher risk of being culled than cows that have displayed estrus (Opsomer et al., 2000). The aim of this study was to determine the effect of hormonal treatment on reproduction period in cows, but also to establish if there is any significant difference in some reproductive parameters between cows treated with hormonal medication and cows which resumed ovarian cyclicity before 60 days postpartum. This study was performed in a dairy cows farm in North-Eastern Moldavia, over a period of 2 consecutive years, on Romanian Black Spotted cows in order to determine hormonal treatments influence on reproduction period. Hormonal treatments used for the above mentioned diseases were represented by luteolytic agent prostaglandin F2I±, one of its potent analogues (Proliz, Biotur, Romania) and by administration of exogenous gonadotrophin releasing hormone (Receptal, Intervet, Romania). We noticed that average reproduction period (52.1 days) and the other breeding intervals that were taken under study (over a two years period), presented different values for cows that have been under hormonal medication treatment, compared to those that resumed ovarian cyclicity before 60 days postpartum (52.7 days). Thus, this preliminary study supports the development of a more detailed study on several dairy cows farms in order to investigate the answer of different types of hormonal treatments against persistent corpus luteum and cystic ovarian disease.