Relationship Between Scrotal Circumference, Testicular Growth and Semen Quality Parameters in Guzerat Breed Bulls, from Puberty to 36 Months of Age

Abstract

<em>Objective</em>: To investigate the association between scrotal circumference size and sperm characteristics in 194 males of Guzerat breed. <em>Methods</em>: The bulls were divided by age groups from 12 to 36 months of age. The length and width of the testicle and scrotal circumference were measured. Semen was collected from the animals that showed a circumference ≥ 19 cm through transrectal electrostimulation in order to induce ejaculation. The characteristics assessed in the semen were motility, speed, sperm concentration and presence of rounded cells. <em>Results</em>: the correlation between the scrotal circumference with the sperm motility by group of age was positive (r = 0.94; p < 0.005). The present study showed that the presence of proximal cytoplasmic droplet, the rounded cells in the semen and the defects on the head of the spermatozoids are objective evaluation features, which can be used for early selection of sperm production in Guzerat males. <em>Conclusions</em>: The production of sperm with normal rates in the Guzerat breed is achieved when males reach the age of 28 months and a scrotal circumference close to 30 cm.