EVALUATION OF GENETIC AND NON-GENETIC FACTORS ON GROWTH AND REPRODUCTIVE PERFORMANCE OF FOGERA CATTLE AT CHAGNI RANCH, NORTH WEST ETHIOPIA

Abstract

This study was carried out with the objectives of evaluating genetic and non - genetic parameters affecting growth and reproductive traits of Fogera cattle. The data used in the study included pedigree records, weight and reproductive data of animals born between 2009 and 2018. Least squares means were analyzed using General Linear Model (GLM) of Statistical Analyses System (SAS) while genetic parameters and breeding value of the sires were estimated by using Wombat spoftware. In this stady the effects of Sex, parity, year of birth / calving and season of Birth / Calving were consider as the main fixed effects and their effects on birth weight (BWt), weaning weight (AWWt) and reproductive traits. Result of fixed effect analysis revealed that fixed effects of year were highly significant (p<0.001) for all traits. For age at first service (AFS) and age at first calving (AFC) only year had a significant influence (p<0.001). The overall least squares means for birth weight (kg), weaning weight (kg), age at first service (AFS)(month), age at first calving(AFC)(month), calving interval (CI)(month), days open (months) and number of service per conception (NSC) were: 21.18, 96.27, 42.77, 51.64, 19.93, 10.68 and 1.29 respectively. Estimates of direct heritability from the best model were 0.26 ± 0.13 for birth weight (BWt) and 0.43 ± 0.17 for weaning weight (AWWt). For reproductive traits the estimates were 0.08 ± 0.05, 0.07 ± 0.04, 0.164 ± 0.07, 0.161 ± 0.08 for calving interval, for days open, AFS, and AFC respectively. The error variance was high for both growth and reproductive traits.The phenotypic correlations between BWt and AWWt was 0.066, for AFS and AFC was 0.53, for CI and DO was 0.63. Genetic correlations between BWt and AWWt was 0.20, between AFS and AFC was 1.00 and between CI and DO was 0.999. The result of genetic correlations between considered traits ranged from moderate to high. Therefore selection for any particular trait (s) must be carried out with attention as it could have an adverse effect due to correlated response on the correlated traits. Estimated overall mean sire breeding values ranges for BWt and AWWt were 2.25kg and 32.75kg respectively.