Testicular biometrics characteristics to evaluate the Nellore zebu breed bulls

[摘要] - The objective of this study was to analyze the testicular volume and shape in young males of Nellore Zebu breed and their importance for the evaluation and selection of sires. Four hundred and forty two males, from 12 to 18 month of age, were examined for scrotal circumference (CE), length (COMP), width (LARG) and testicular volume (VOL). The animals were divided in two groups (G1 and G2) according to their date of birth. The VOL was calculated by the formula: VOL = 2[(r2) x P x h], where r, h and P are LARG/2, length and 3.14, respectively. The mean values of CE, COMP, LARG and VOL at 12 month of age were 184.89±15.79 mm, 65.96±6.48 mm, 2.58±4.63 mm and 113.80±42.03 cm3, and at 18 months of age were 236.81±mm, 79.31±11.16 mm, 42.92±5.83 mm and 239.26±90.56 cm3, respectively. The parameters at 12 and 18 months of age were influenced by contemporary groups, being highly correlated. The testicular shape was considered as a length to width ratio, being recorded five forms: long (ratio £ .5), long moderate (.51 to .626 ratio), long/ovoid (.626 to .750 ratio), ovoid/spheroid (.751 to .875 ratio) and spheroid (> .875 ratio). 87% of the animals presented the long shape and, in 74%, the testicular shape changed with the age. All the parameters were influenced by testicular shape, and the testis grew in width. The results suggest that the selection of young bulls should consider the testicular volume besides the possible change in the testicular shape.

[学科分类] 兽医学

[关键词] testicular shape;Nellore;bulls;testicular volume     IntroduçãoConstam do processo de seleção de reprodutores várias características morfo-fisiológicas do aparelho reprodutor;como a circunferência ou o perímetro escrotal e;ainda;mais recentemente;a avaliação quanti-qualitativa do sêmen