Testicular shape and andrological aspects of young Nellore bulls under extensive farming

Abstract

-Aiming to determine the relationship between the frequency of testicular shape and the andrological aspects in young Nellore bulls, 18,676 animals were assessed. All andrological examinations were performed between the years 2000 and 2008. Animals were classified as able for breeding, able for breeding in natural mating system, unable for breeding and discarded. The testicular shape was classified as long, fairly long, oval-long, spherical-oval, and spherical. The analysis of Pearson correlations was performed for testicular shape with scrotal circumference, testicular volume, progressive motility, sperm vigor, major defects, minor defects and total defects. Testicles with oval shape prevailed (99.61%). It was obseved that 76.34; 66.34; 64.34; 58.33 and 50.00% of the animals were classified as sound for breeding for shapes long, fairly long, ovallong, spherical-oval, and spherical, respectively. Correlations between testicular shape with scrotal circumference, testicular volume, progressive motility, sperm vigor, major, minor and total defects were 0.26; 0.08; 0.00; 0.11; -0.02; 0.02 and -0.01, respectively. Testicular shape had no influence upon the andrological examination results. Testicles of long shape were prevalent within the population.

Evaluation of Scrotal Temperature in Different Testicular Shapes by Infrared Thermography in Braford Bulls

“…In addition, scrotal circumference was similar for shapes that were long-moderate (29.9) and longoval (30.6), demonstrating that Braford animals have a higher scrotal circumference than animals with testicles that are more oval at 22-24 months of age [20]. The size and shape of the testicles are determined by genetic mechanisms and environmental effects, such that Bos taurus indicus bulls that have longer testicles and thinner scrotal skin compared to Taurine bulls [8,20].…”

Potencial reprodutivo (PR) de touros Nelore avaliados por parâmetros andrológicos e comportamento sexual. Classificação por pontos: nova proposição

“…O aumento do parênquima testicular ocorre com o decorrer da maturidade sexual (Ayala et al, 2016;Fonseca et al, 2019), processo associado com desenvolvimento testicular, multiplicação de células germinativas (Brito et al, 2004), proliferação de células de Leydig e aumento dos níveis de testosterona (Araguren-Méndez et al, 1995;Dias et al, 2014;Ayala et al, 2016). Há décadas se reconhece que o PE apresenta alta correlação com volume e peso testiculares (Willet e Ohms, 1975;Pastore et al, 2008;Siqueira et al, 2012). Além do aumento do PE, a cor do pelame também se intensifica com a idade (Fonseca et al, 2019), características influenciadas pelos níveis de testosterona que se elevam à medida que a idade avança (Devkota et al, 2008).…”

“…De acordo com Siqueira et al (2012), a forma testicular alongada foi a prevalente em animais Nelore com idade média de 21 meses. Para o prognóstico do tamanho testicular em animais Nelore, a seleção por circunferência (ou perímetro) escrotal é medida adequada e apresenta adequada confiabilidade na predição do tamanho testicular, mesmo com a maior frequência de animais com testículos longos.…”

Testicular shape, scrotal skin thickness and testicular artery blood flow changes in bulls of different ages

“…The evaluation of testicular and scrotal biometric parameters is important to determine possible changes in reproduction and growth that are related to seminal quality performance in different animal species (McGowan et al., 2002; Siqueira et al., 2012). The size and shape of the testicles are determined by genetic and environmental mechanisms.…”

“…The size and shape of the testicles are determined by genetic and environmental mechanisms. These two factors, combined with the weight of the testes and the action of male hormones on testicular migration during organogenesis, define the format of the scrotum for the entire animal life (Kastelic & Brito, 2012; Siqueira et al., 2012; Unanian et al., 2000).…”