Growth performance of crossbred dairy cattle at Asella Livestock Farm, Arsi Ethiopia
Genetic and non-genetic factors affecting growth traits and growth performance at 50% and 75% upgrading levels were studied, in the Arsi highland, Ethiopia. The traits studied were: weight at birth, 6, 12, 18, 24 and 36 months. The analyses were carried out using Harvey's Mixed Model Least-squares and Maximum Likelihood Computer Program. The breed groups compared were: 1/2 Friesian 1/2 Arsi (F1FA), 1/2 Friesian 1/2 Zebu (F1FZ), 1/2 Friesian 1/4 Jersey 1/4 Arsi (F(JxA)), 3/4 Friesian 1/4 Arsi (75%FA) and 3/4 Friesian 1/4 Zebu (75%FZ). The 75% FA were significantly heavier than F1FA at birth, 6 and 30 months. No significant differences were found between F1FZ and 75%FZ at all ages. The differences between F(JxA) and F1FA were not significant except at 6 months. The 75% FA were significantly heavier than the F(JxA) at birth, 30 and 36 months. However, 75% FA were significantly lighter than 75% FZ at 12 and 36 months. No significant effect of sex were observed at birth, though males were slightly heavier. Parity of the dam did not show significant influence on body weight except at birth and 24 months. Year of birth of the calf did not have significant effect except at 12 months. The effect of season of birth was significant at birth and 12 months. Animals born during the main rains were the heaviest at birth. Heritability estimates for weights at birth, 6, 12, 18 and 24 months were: 0.20-0.15, 0.14-0.23, 0.04-0.21, 0.68-0.34 and 0.33-0.29, respectively. From the results obtained, it may be concluded that the management and feeding conditions at Asella Livestock Farm would warrant the limitation of upgrading level to 50% exotic inheritance. The smaller weights for the three-breed crosses, i.e., (F(JxA), may be advantageous to the smallholder, as such animal could be maintained by smallholder farmers as they have lower maintenance requirement as compared to the larger animals.
SINET: Ethiopian Journal of Science Vol. 24, No. 1 (June 2001), pp. 35-49
Key words/phrases: Crossbred, dairy cattle, growth, heritability