FACTORS AFFECTING REPRODUCTIVE PERFORMANCE OF ZARAIBI GOATS

ABSTRACT
A total 4601 records collected from El-Serw experimental station, Animal Production Research Institute, were used to investigate the effect of early growth rate, season of mating and age of doe at kidding on reproductive performance of Zaraibi goats. Data were analyzed using stepwise forward, univariate logistic regression analyses. Goats with birth weight lower than 1.6 kg were likely 1.2 times less to become pregnant (P<0.05) than goats with heavier birth weights. Mid-age does (2 to 6 years) were likely 1.6 times more to become pregnant (P<0.05), compared with either younger does (<2 years) or does aged more than six years. Season of mating can be considered as a significant risk factor for pregnancy rate; goats mated in fall had greater chances of getting pregnant than goats mated in summer. Mid-age does were likely half to abort (P<0.05) when compared with younger or older goats. Goats with the lowest daily gains (<86 g/d−1) were at increased risk of abortion (P < 0.05). The oldest does were likely 70% more having stillbirths than younger and older does (P<0.05). The risk of stillbirth was lower (P < 0.05) in goats less than six years. The risk of stillbirth was also lower in does bred in the fall, as compared with does mated in summer. Goats with the highest body weights at 30d of age had higher odds of multiple births than goats with moderate or low weights at 30d of age. Goats bred in the fall had lower (P<0.05) odds of multiple births than goats mated in summer. The present findings indicate that reproductive success in Zaraibi goats increased with birth weight of doe >1.6 kg, body weight at 30d of age >6 kg, growth rate from birth to 30d of age higher than 150g /d−1, age of doe at kidding not more than six years and breeding in fall.