Phenotypic and genetic parameters of calf growth traits for Malawi Zebu

ABSTRACT

Malawi Zebu form the back-bone of the Malawian cattle industry. They are used as the base population for dairy and beef production and development. Very little has been done to improve them genetically, and data on their current productivity are scanty. This study was carried out to refresh information on Malawi Zebu calf growth traits (birth weight, 205-day weight, weaning weight and pre-weaning growth rate) as part of their conservation program. Data from 1985 to 2014 from Mbawa Research Station in Mzimba District were used. Single trait best linear unbiased mixed models were used to estimate fixed and random effects for each trait.Estimated least squares means and standard errors were 19.4±0.532, 82.6±2.26, 89.6±3.25 and 0.388±0.00119 kg for birth weight, 205-day weight, weaning weight and pre-weaning growth rate, respectively. All the traits showed decreasing trends over the years and seasonal effects on growth traits support the idea of having breeding seasons. The estimated direct heritability and standard errors of the traits were, 0.33±0.144, 0.47±0.160, 0.61±0.204 and 0.43±0.211 for birth weight, 205-day weight, weaning weight and pre-weaning growth rate, respectively. The moderate to high heritability of the growth traits imply that selection for these traits is likely to be worthwhile. The estimated breeding values of birth weights have been declining while those of the other traits have been constant, implying lack of genetic improvement. The results from this study have refreshed the phenotypic parameter values for the Malawi Zebu and the estimated genetic parameters may be useful for future genetic evaluation of this important genetic resource.