Termografia digital por infravermelho do escroto, qualidade do sêmen, níveis séricos de testosterona em touros Nelore (Bos taurus indicus) e suas correlações com os fatores climáticos

Abstract

The objective was to study the relationship of climatic conditions with the temperature of the scrotum surface and sperm quality through digital infrared thermography in Nellore bulls, raised extensively. In six bulls held with scrotal thermography Flir E40® cameras, blood samples for serum testosterone and semen collection were taken by electroejaculation every 10 days, with six replications. Climatic factors: ambient temperature, relative humidity, dry globe temperature and temperature of the wet globe were recorded using a globe thermometer (InstruTemp®, ITWTG-2000). Thermal images of the scrotum were analyzed with the Flir Tools® software for the temperatures of scrotal surface, the right and left sides of the scrotum lap thirds: dorsal, middle and ventral testicles; and tails of the epididymis. The semen data and thermograms were submitted to ANOVA and Tukey's test at 5%. Pearson correlation was used for the surface temperatures of the scrotum, rectal temperature, quantitative and qualitative characteristics of semen and climatic factors. There was a positive correlation (P<0.05) for sperm motility x scrotal temperatures; sperm concentration x scrotal temperatures; climatic factors x rectal temperature. There was a negative correlation (P<0.05) between ambient temperature x sperm concentration. It was concluded that the temperature of the scrotum surface and climatic factors, temperature and humidity, influence the quality of semen. Thermography is recommended as a supplementary examination for reproductive evaluation of bulls. Key words: Climatic factors, scrotal thermogram, zebu bull, semen ResumoObjetivou-se estudar a relação dos fatores climáticos com a temperatura da superfície do escroto e qualidade seminal por meio da termografia digital de infravermelho em touros Nelore, criados extensivamente. Em seis touros realizaram-se termografia escrotal com câmera Flir E40®, colheita de sangue para a testosterona sérica e colheita de sêmen por eletroejaculação a cada 10 dias, com seis repetições. Os fatores climáticos: temperatura ambiente, umidade relativa do ar, temperatura do globo seco e temperatura do globo úmido foram registrados com globotermômetro (InstruTemp®, ITWTG-2000). Os termogramas do escroto foram analisados com o software Flir Tools® para as temperaturas da superfície escrotal, dos lados direito e esquerdo, colo do escroto, terços: dorsal, médio e ventral dos testículos; e caudas dos epidídimos. Os dados do sêmen e dos termogramas foram submetidos à análise de variância e teste de Tukey a 5%. Correlação de Pearson foi empregada para as temperaturas da superfície do escroto, temperatura retal, características quantitativas e qualitativas do sêmen e fatores climáticos. Houve correlação positiva (P<0,05) para motilidade espermática x temperaturas do escroto; concentração espermática x temperaturas do escroto; fatores climáticos x temperatura retal. Houve correlação negativa (P<0,05) entre temperatura ambiente x concentração espermática. Concluiu-se que as temperaturas da superfície do e...

Influence of Testosterone on Body and Testicular Development in Zebu Cattle in the Tropical Climate

“…The serum testosterone differed (P < 0.05) between 10 and 12 months ( Table 5), preceding a significant increase in morphological variables. At 12 months of age, the serum testosterone concentration in Brahman males was similar to that found in Nellore cattle aged 31 and 35 months by [37], and in crossbred Holstein × Thaparkar males between 9 and 12 months of age by [3]. In the present study, Brahman males produced similar levels of testosterone at younger ages than Zebus [37], and in the same age group as crossbred cattle [3], revealing sexual precocity.…”

“…Testicular volume was described as a suitable variable for the evaluation of post-pubertal Bos indicus males [8]. Measurements of the length, width and height of the testes axes are useful for evaluating testicular symmetry and calculating testes volume [23,37]. At 12 and 18 months of age, the length, width and volume of testes were higher than the values reported in Nellore cattle by [23] at the same age groups.…”

Scrotal thermography to assess the seminal quality in Nelore and Girolando bulls

“…Nogueira et al (2013) emphasized that room temperature and thermal comfort provided to the animals during the use of the equipment directly influence the thermogram results. In the present work, the absence of variations in seminal characteristics between collections indicate that oscillations in the temperature of scrotum surface in the two breeds were controlled, without affecting the seminal profile of the animals (Ruediger, Chacur, Alves, Oba, & Ramos, 2016). Kastelic (2014) reported that a moderate increase in testicular temperature in bulls drastically reduces sperm production, progressive sperm motility and live sperm count per ejaculate, and increases the percentage of morphologically abnormal spermatozoa.…”

“…temperature, frequent solar irradiation and high relative humidity of the air). This was demonstrated in Brahman and Nelore bulls (Chacur, Miyasaki, Oba, Souza, & Gabriel, 2017;Ruediger, Chacur, Alves, Oba, & Ramos, 2016), which present as main adaptive characteristics skin thickness, dark coloration, white pelt, higher concentration of sweat glands and greater skin irrigation than mixed or taurine animals (Silva & Pocay, 2001). It is known that the thermoregulation mechanisms of the male reproductive organ are not totally efficient (Losano et al, 2018).…”

Infrared thermography and Doppler ultrasonography to evaluate the effects of scrotal insulation on testicular blood flow dynamics in bulls

“…A probe with electrodes was inserted rectally and stimulated the animals by electric shocks (maximum 12 V) until the semen sample was obtained; the animals were kept in their trunk during this process. The semen analysis of Turbidity (TURB), sperm motility (MOT), vigor (VIG), percentages of major defects (MD), minor defects (mD) and total defects (TD) was performed according to Ruediger et al (2016) and Chenoweth, Hopkins, Spitzer and Larsen (2010). The criteria used for the spermatozoa evaluation were according to the Western Canadian Association of Bovine Practitioners (Chenoweth et al, 2010).…”