Eficiência reprodutiva de búfalas leiteiras e fatores de risco associados no pós-parto

Abstract

The objective of this study was to evaluate the reproductive efficiency of dairy buffaloes submitted to different reproductive management besides investigating the impact of some factors on reproductive performance. Data regarding the reproduction and lactation of Murrah dairy buffaloes during the period from 2016 to 2018 were evaluated. The animals were submitted to different hormonal protocols from 35, 45 or 60 days postpartum according to the reproductive season and year. In the group 1, two protocols of TAI were used, being Ovsynch and the protocol GnRH + P4 / eCG + PGF2α / GnRH, in and out of the reproductive season, respectively; in the group 2, GnRH+P4/eCG+PGF2α/BE was used; in the control group no treatment was performed and the animals were mated by bull. The diagnosis of gestation was performed at 35 days after TAI and/or mating by ultrasonographic examination. For the variables calving interval and the number of semen doses per conception, the variance analysis was used, and, once statistical difference was evidenced, the Tukey test was performed. To evaluate the risk effect factors, the binary logistic regression model was used. It was observed that multiparous females had a higher conception rate than primiparous females. In 2016, a higher conception rate has been noted compared to the years 2017 and 2018. Within the breeding season, it was demonstrated greater chances to conceive. In TAI, the chances of conceiving were greater than mating, except for those mated at 60 days postpartum. Group 1 had a higher conception rate, but between the reproductive periods, there was no difference between the protocols (p> 0.05). High production animals had a higher conception rate as well as those submitted to reproductive management at 35 days postpartum who still had a shorter calving interval (361.47 ± 0.299). The number of semen doses per conception was significantly higher (p <0.05) in the animals belonging to group 2, (1.86 ± 0.14) low production (1.21 ± 0.06) and in primiparous animals (2.10 ± 0.22). Thus, the category, year, level of production, type of reproductive management and the period in which it was been carried out can be considered as risk factors for the reproductive performance of dairy buffaloes. In addition, became evident that TAI can be performed in the early postpartum at 35 days, making it possible to reduce the calving interval.