Puberty and sexual maturity in Anglo-Nubian male goats raised in semi-intensive system

[摘要] The objective of this study was to characterize the sexual development in Anglo-Nubian male goats raised in semi-intensive system. Eight animals were monitored every fifteen days, from the 12th to the 44th week for age at penis detachment, live weight, scrotal circumference, seminal parameters (volume, aspect, concentration, wave motion, progressive individual motility, vigor and spermatic abnormalities) and serum testosterone levels. Serum testosterone levels were determined in blood samples collected at the 20th, 28th and 38th weeks of age. Penis detachment occurred at 102.9 ± 15.4 days of age. Live weight and scrotal circumference at 20th and 44th weeks of age ranged from 25.9 ± 3.5 to 44.7 ± 4.7 kg and from 21.2 ± 1.6 cm to 26.0 ± 1.5 cm, respectively. The ejaculate volume ranged from 0.38 ± 0.05 to 0.96 ± 0.04 mL, concentration ranged from 1.33 ± 0.64 to 3.54 ± 0.14.109 mL-1 and the progressive individual motility varied from 48.0 ± 10.52% to 82.0 ± 3.74%, at the same age. The number of defective spermatozoa (major and minor) was 32.2 ± 5.8% vs. 8.80 ± 2.9% at the 20th and the 44th week of age, respectively. Serum testosterone level was 2.70 ± 1.40 ng.mL-1 at the 20th week, 8.50 ± 4.66 ng.mL-1 at the 28th week and 2.21 ± 2.28 ng.mL-1 at the 38th week of age. Age showed a correlation with live weight, scrotal circumference, and all the qualitative parameters of semen except for volume, with all other qualitative parameters of semen, and the correlation among sperm abnormalities and the other traits was negative. Serum testosterone levels and andrological parameters of Anglo-Nubian goats raised in semi-intensive system are closely related to age. In those animals, puberty is reached at the 20th week and sexual maturity is reached at the 38th week of age.

[学科分类] 兽医学

[关键词] andrologic parameters;semen;spermatic abnormalities;testosterone    IntroductionGoat production plays an important role in the socioeconomic development in northeastern Brazil;especially concerning the subsistence and the supply of high biological value animal proteins to the low-income population (Carvalho Junior et al