干旱区生态环境知识资源中心

The objectives of the present study were to investigate the effects of breed, sex, parity, year of birth and season of birth on birth weight, weaning weight and yearling weight recorded on 713 calves born between 1996 and 2008. The data included offspring from five local cattle breeds (Dhanni, Lohani, Dajal, Red Sindhi, Cholistani) and crossbreds (Holstein or Jersey crosses) maintained at Barani Livestock Production Research Institute (BLPRI, Attock, Punjab, Pakistan). The data were analyzed using a mixed linear model with PROC MIXED. Overall means +/- SD of birth, weaning and yearling weights, pre-and post-weaning growth rates were 18.67 +/- 2.60 kg, 72.88 +/- 18.98kg, 116.05 +/- 30.63 kg, 301.18 +/- 104.03 g and 239.86 +/- 117.32 g, respectively. All growth traits (birth weight, weaning weight and pre-and post-weaning growth rates) varied with breed, sex, parity of dam and season and year of birth. The calves of Lohani cattle (a short stature breed) had the lightest birth weights (16.4 kg) as compared to other breeds and crossbreds (> 18 kg). The heaviest weaning weights (91.25 kg) were found in calves from the Dajal breed, followed by weaning weights for Dhanni (78.54 kg), Cholistani (70.68 kg), Red Sindhi (70.46 kg) and Lohani (64.0 kg). The heaviest yearling weights were found in Dajal calves (148.48 kg) while the lowest yearling weights were found in Lohani calves (99.81 kg). Overall, birth, weaning and yearling weights were greater in male as compared to female calves (P < 0.05). The calves born to first parity cows had lighter birth and yearling weights as compared to calves from later parity cows. However, similar trends were observed for weaning weight of calves born to first and later parity cows. Spring born calves had heavier weaning weights (77.39 kg) than summer born calves (70.34 kg). Summer born calves had lighter yearling weight (110.04 kg) than calves born in other seasons (119-121 kg). The observed between breed variation for growth indicates an untapped potential for beef production and results have useful implications for breed improvement and management decisions for cattle breeds being raised under arid conditions.