Termografia Digital por Infravermelho do Escroto e Qualidade do Sêmen em Touros Nelore (Bos taurus indicus)

Abstract

Reproductive efficiency is one of factors for improving livestock production indices cutting factors. The contribution of the bull to the reproductive efficiency of the herd is of great importance. Bovine testes should be kept below the core body temperature for the production of morphologically viable, normal sperm. The scrotal and testicular thermoregulation is a system for maintaining the physiological temperature of the testicles. Infrared thermography is a noninvasive technique that is used to measure the surface temperature of the scrotum bulls. The objective of this work was to study the relationship of scrotal temperature on semen quality by use of infrared thermography in Nellore bulls bred extensively. 6 Nellore by performing scrotal thermography and semen collection every 10 days were used, totaling 36 ejaculates. Climatic data were collected through globe thermometer. The thermograms of the scrotum were obtained by digital infrared thermography and analyzed by software to the scrotal surface temperatures, the right and left sides, neck of the scrotum, dorsal thirds, middle, and ventral of the testes and cauda epididymis. We conducted ejaculates through electroejaculation for analysis of quantitative and qualitative characteristics. For the data, we used analysis of variance and subsequently applied the Tukey test at 5%, and Pearson correlation. There was a positive correlation between sperm motility and the temperatures of the scrotum; between concentration and temperature of the scrotum; between climatic factors and rectal temperature. There was a negative correlation between temperature and sperm concentration (p <0.05). There was no correlation between the climatic data, and temperatures between the scrotum and rectal temperature and temperature of the scrotum. It was concluded that the surface temperatures of the scrotum and climatic factors, temperature and humidity, influence the quality of semen. Thermography is recommended as a complementary test in the evaluation of reproductive bulls.