Perfil metabólico e hormonal no momento da inseminação artificial e no diagnóstico de gestação de vacas Bos indicus gestantes ou não

Abstract

Reproductive efficiency is one of the main factors associated with beef cattle performance and is directly influenced by the metabolic and hormonal status of females. In this context, the objective of this study was to evaluate the metabolic and hormonal profiles of pregnant and non-pregnant Bos indicus cows subjected to timed artificial insemination (TAI), through blood and follicular fluid collections performed at the time of TAI, eight days after insemination, and at pregnancy diagnosis. A total of 125 lactating Nelore cows were subjected to an ovulation synchronization protocol based on estrogen and progesterone. Blood samples were collected at the time of TAI and at pregnancy diagnosis (D40) for analysis of glucose, NEFA, BHB, IGF-1, and insulin. In a subgroup of animals (n = 20), follicular aspiration was performed on D18 to evaluate IGF-1 and insulin concentrations in the follicular fluid. Statistical analyses were performed using SAS software. Serum concentrations of glucose, NEFA, BHB, IGF-1, and insulin were similar between pregnant and non-pregnant cows at the time of TAI and at pregnancy diagnosis (P > 0.05). In addition, serum and follicular concentrations of IGF-1 and insulin on D18 also did not differ between experimental groups. It was concluded that pregnant and non-pregnant Bos indicus cows after the ovulation synchronization protocol exhibited similar metabolic and hormonal profiles, indicating that these parameters are not reliable fertility markers. These results reinforce that the fertility of Bos indicus cows subjected to fixed-time artificial insemination (TAI) is a multifactorial process, dependent on the interaction among metabolic, hormonal, physiological, and environmental factors.