IMPLICATIONS OF HIGH AND LOW-PROTEIN LEVELS ON PUBERTY AND SEXUAL MATURITY OF GROWING MALE GOAT KIDS

Baladi male goat kids (n = 16) were divided at 28 days of age into two groups to study the effect of feeding two protein levels in the conce ntrate on performance, puberty and fertility. The kids were allowed eq ual amounts of feed with concentrates providing either 18 (high) or 12 % (low/control) CP, and 3120 versus 2980kcal kg(-1) of DE on DM basis, respectively. The observed changes in BW (18.2 versus 17.1 kg), heart girth (59 versus 59 cm), body length (48.5 versus 45.8 cm) height (55 .0 versus 53.3 cm), testicular measurements, i.e. volume (62.8 versus 54.0 ml) and circumference (12.5 versus 11.3 cm), and prepucial (2.0 v ersus 1.5 units) and urethral process (2.6 versus 1.8 units) scores, w ere not significantly different(P > 0.05) among the protein concentrat es during the prepubertal period until 105 days. Puberty was achieved at an earlier (P < 0.05) age (+/- SE), (22 +/- 0.88 versus 31 +/- 2.50 weeks) and BW (23.8 +/- 0.24 versus 20.9 +/- 0.24 kg) on the high pro tein concentrate leading to higher (P < 0.05) testicular measurements, prepucial and urethral scores, At 22 weeks of age, semen volume, and sperm viability and concentration as indicators of fertility were high er (P < 0.05) (0.5 versus 0.0 ml; 30.0 versus 0.0% and 0.29 versus 0.0 cells x 10(9), respectively) on the high protein diet. This spermiogr am remained significantly higher (P < 0.05) at 31 weeks (1.2 versus 0. 6ml, 85 versus 53% and 1.88 versus 0.98 cells x 10(9) respectively), o n the high protein ration. It is concluded that when protein intake is increased above that needed for maintenance and growth, puberty and f ertility can be achieved at an earlier age in young growing male kids.