Interaction between genotype and geographic region for milk production traits in Tunisian Holstein cattle

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Interaction between genotype and geographic region for milk production traits in Tunisian Holstein cattle

Journal Title: International Journal of Farming and Allied Sciences - Year 2014, Vol 3, Issue 6

Abstract

This study was designed to examine the existence of a genotype × region interaction on milk production traits in Holstein dairy cows in Tunisia. The data set for this study was provided by Tunisian Center for Genetic Improvement of the Livestock and Pasture Office. A total 63569 TD milk record of 6912 Holstein cows of Tunisia were used. Data were classified as belonging to three regions of the country: Northern, Central and Southern. Only data from sires with daughters in three regions were used in each analysis. Genetic parameters were estimated using residual maximum likelihood (REML). A multivariate model was applied. The estimated heritability for the milk production traits ranged between 0.11 to 0.14 for the Central region; 0.09 to 0.19 for the Northern region and 0.30 to 0.39 for the Southern region. The Pearson’s correlations of the 26 sires represented in three regions were estimated. Genetic correlation estimates among milk yields traits in different regions in Tunisia were lower than the threshold of 0.80 suggested by Robertson (1959). These results indicate the existence of genotypeenvironment interaction which may have several implications for the genetic improvement of Holstein cattle in Tunisia. It also encourages further studies oriented toward the identification of specific environmental effects related to these interactions.

Authors and Affiliations

A. Hamrouni, M. Djemali and S. Bedhiaf

Keywords

EP ID EP32606
DOI -
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