Correlations among production and linear type traits in Holstein cows: A meta-analysis study

Articles in Press

Document Type : Research Paper

Authors

1 Department of Animal Science, Faculty of Agriculture, University of Tehran.Karaj. Iran

2 Department of Animal Science, Faculty of Agriculture, University of Tehran, Karaj. Iran

3 Department of Animal Science, Faculty of Agriculture and Natural Resources, University of Tehran, Karaj, Iran

Abstract

The objective of this research was estimation of genetic correlations between production and linear type traits in Holstein cows, through a meta-analysis study. Using a systematic search of the literature, we found 27 papers in which the estimation of genetic correlations among production and type traits were reported. On the whole, the published data had been recorded from 1407598, 1252515 and 1159124 animals, respectively corresponded to milk yield, fat and protein content. Analyses were performed by using the metafor-package of R environment. The obtained results showed that there are low to moderate genetic correlations among production and type traits. Milk yield showed higher genetic correlation with angularity 0.36, body condition score -0.31, udder depth -0.30, and rear udder width 0.26. Fat content also was genetically correlated with angularity 0.39 and body condition score -0.25. In addition, protein content had high genetic correlation with angularity 0.46, rear udder width 0.39, udder depth -0.29, and rump angle 0.28. According to the meta-analysis, angularity was distinguished as a main type trait that displayed the highest genetic correlation with production traits. Test of heterogeneity (I^2 statistics) indicated that there was significant heterogeneity (variance among studies) at the highest level (more than 99%). All type traits which had high genetic correlation with production traits would be recommended for being used as indicator traits of production by virtue of the size of their correlations with production traits. Results of this study can be used for estimating of type traits economic values in Holstein cow’s selection indices.

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Iranian Journal of animal Science

Articles in Press, Accepted Manuscript
Available Online from 10 July 2024

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History

  • Receive Date: 27 January 2024
  • Revise Date: 05 May 2024
  • Accept Date: 11 May 2024

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