Effect of the Genotype by Environment Interaction on the Productive and Reproductive Performance of Livestock in Ethiopia: A Review

Abstract

The review was undertaken with the aim of assessing the effect of genotype-environment interaction (GEI) on the productive and reproductive performance of livestock across tropical countries, including Ethiopia. This review is based on published scientific research investigating the effects of genotype-environmental interaction on the productive and reproductive performance of selected livestock species in tropical countries. Genetic correlation and heritability estimates were assessed as indicators for the presence of GEI for traits among the environments. Spearman’s ranking correlation was also assessed as a means for appropriate sire re-ranking for selection. According to the reviews, significant GEI was observed over productive milk traits such as lactation milk yield, initial milk yield, and average milk yield. Similarly, a significant GEI effect was also observed in the body weight gain performance of livestock in Ethiopia and other tropical countries. Reproductive traits such as age at first service, service period, and age at first lambing were also affected by GEI. The chicken egg traits such as shell thickness, egg weight, egg width, and egg length were also affected by the differences in environments and management conditions. The influence of GEI on the phenotypic expression of traits among environments was assessed based on assumptions indicating that GEI has significant importance if the genetic correlation of traits between environments is less than 0.80. General, genetic correlation, and heritability estimates in the tropics showed significant GEI for the productive and reproductive performance of animals, and hence the genetic evaluation and selection of sires require information from both locations to accurately select the most appropriate sire for each location.