Testicular Size, Caudal Epididymal Size and Semen Quality of Duroc Boars at Different Ages

Abstract

Seventy-two Duroc Boars were equally divided into six groups according to age intervals which were:group 1:7-9 months, group 2:10-12 months, group 3:13-15 months, group 4:16-18 months, group 5:19- 24 months and group 6:25-36 months. The age intervals had significant effects on testicular size, caudal epididymal size, semen volume and semen concentration. The boars of group 6 had the widest testis, longest testis and biggest caudal epididymis with the means of 8.2±0.48, 16.3±1.82 and 4.6±0.81 cm, respectively. The highest semen volume at the average of 190.8±33.97 ml was found in group 4 whereas the best semen concentration with the average of 4.24 x 10⁸±2.00 x 10⁸ spermatozoa/ml was produced by the boars in group 2. However, the sperm motility, the percentage of dead spermatozoa and abnormal acrosome were not significantly affected by the age intervals. Using simple linear regression analysis for all traits on boar ages also ahowed corresponding results. The significant regression coefficients of testicular width, testicular length, caudal epididymal size and semen concentration on boar ages were 0.704, 1.256, 0.468 and -0.065, respectively. Additionally, the significant influence of boar ages on semen volume was quadratic trend with the first and second degree regression coefficients of 14.24 and 0.314, respectively,