Genetic and Phenotypic Correlation Estimation for Growth Traits of Holstein Friesian X Boran Crossbred Dairy Cattle in the Central Highland of Ethiopia

Abstract

Genetic factors are unique to each population and might vary over time as a result of selection and management strategies. As a result, this study sought to explore the genetic and phenotypic relationships of growth traits in Holstein Friesian (HF) x Boran (Bo) crossbred dairy cattle raised at the Holetta Agricultural Research Center (HARC) dairy farm. The performance data of 14,062 crossbred calves gathered over 22 years (1997-2018) were evaluated. The significance of fixed factors, such as year of birth, season of birth, calf sex, and genotype, was assessed using the General Linear Model (GLM) approach in SAS software (9.0). The Average Information Restricted Maximum Likelihood (AI-REML) technique was used with WOMBAT software to assess genetic and phenotypic relationships for growth traits while fitting an animal model. The most significant direct genetic correlation was identified between yearling weight and post-weaning average daily gain, with a value of 0.944±0.02. This was followed by a correlation of 0.84±0.04 between weaning weight and six-month weight. In contrast, birth weight exhibited weaker genetic relationships with weaning weight (0.07±0.11) and pre-weaning average daily gain (0.10±0.12). The genetic correlations among various growth traits ranged from 0.94±0.02 to 0.07±0.11, whereas the phenotypic correlations spanned from 0.93±0.04 to -0.03±0.04. Early selection in calves is advantageous because the largely moderately positive genetic correlations imply little genetic antagonism and show that choosing for one trait is likely to enhance other growth traits.