Lack of relationship between testicular echotexture and breeding soundness evaluation in adult Nelore bulls

The objective of this study was to describe the pattern of testicular echogenicity and the degree of commitment caused by fibrotic lesions in semen quality in adult Nelore bulls. A total of 402 extensively raised adult Nelore bulls were evaluated for breeding soundness and submitted to ultrasound examinations of their testes. Additionally, a testicular fibrosis score ranging from 0 to 5 was assigned to each bull to quantify the patterns, sizes and frequencies of the fibrotic lesions. No correlation was detected among the studied semen features and the pixel intensity values of the studied images. The testicular fibrosis score was only slightly correlated with scrotal circumference, testicular volume, and animal age. The other examined features did not correlate with the studied ultrasound parameters (p>0.05). No correlation was detected between the fibrosis score and testicular sperm quality (p>0.05). Thus, the appearance of the testicular parenchyma of the adult bulls did not correlate with breeding ability. Moreover, the varying degrees of testicular fibrosis did not appear to affect sperm quality. As a result, ultrasonic evaluation of the testes is not a useful tool for evaluating breeding soundness in old Nelore bulls.