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.: Home > Animal Science Papers and Reports > 2016 > Volume 33 Number 3 > Katarzyna Rzewuska* Tomasz Strabel

The genetic relationship between reproduction traits and milk urea concentration

Katarzyna Rzewuska* Tomasz Strabel
Department of Genetics and Animal Breeding, Poznan University of Life Sciences, Wolynska 33, 60-637 Poznan Poland
Abstract :

The aim of this research was to investigate the genetic relationship between reproduction traits and milk urea concentration (MU) during the first lactation of Polish Holstein-Friesian cows. The following reproduction traits were considered: interval from calving to first insemination, interval from first to last insemination, interval from calving to conception, number of inseminations to conception, first insemination conception rate and first insemination non-return rate to the 56th day. Data consisted of more than 1.2 million test-day records from 148,700 primiparous cows, for which fertility traits were available. Daily genetic correlations between MU and fertility traits were estimated with a random regression animal model. The Bayesian Gibbs sampling method was used to estimate the (co)variance components. Heritability of reproduction traits was low and ranged between 0.01 and 0.06. Heritability for MU was higher and relatively constant throughout the lactation (0.16-0.19). The genetic correlation between reproduction traits and MU in midlactation was close to zero, which suggests that MU measured close to the first insemination is of limited use in the indirect selection for fertility. Moderate genetic correlations between MU and reproduction traits, which were observed in the first two months of lactation, are sufficient for genetic improvement of fertility. However, better fertility was genetically related with higher MU, and an increase of MU concentration is undesirable.

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Date Deposited : 06 Jan 2016 09:43

Last Modified : 06 Jan 2016 09:43

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Volume 33, Number 3, - 2016 , ISSN 109-117

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