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Genetic Relationship Between Culling, Milk Production, Fertility, and Health Traits in Norwegian Red Cows

M. Holtsmark^*,1, B. Heringstad^*,, P. Madsen and J. Ødegård^*,

^* Department of Animal and Aquacultural Sciences, Norwegian University of Life Sciences, PO Box 5003, N-1432 Ås, Norway
Geno Breeding and AI Association, PO Box 5003, N-1432 Ås, Norway
Department of Breeding and Genetics, Faculty of Agricultural Sciences, University of Århus, Research Centre Foulum, DK-8830 Tjele, Denmark
AKVAFORSK, Institute of Aquaculture Research, PO Box 5010, N-1432 Ås, Norway

¹ Corresponding author: marte.holtsmark{at}umb.no

First-lactation records on 836,452 daughters of 3,064 Norwegian Red sires were used to examine associations between culling in first lactation and 305-d protein yield, susceptibility to clinical mastitis, lactation mean somatic cell score (SCS), nonreturn rate within 56 d in heifers and primiparous cows, and interval from calving to first insemination. A Bayesian multivariate threshold-linear model was used for analysis. Posterior mean of heritability of liability to culling of primiparous cows was 0.04. The posterior means of the genetic correlations between culling and the other traits were –0.41 to 305-d protein yield, 0.20 to lactation mean SCS, 0.36 to clinical mastitis, 0.15 to interval from calving to first insemination, –0.11 to 56-d nonreturn as heifer, and –0.04 to 56-d nonreturn as primiparous cow. As much as 66% of the genetic variation in culling was explained by genetic variation in protein yield, clinical mastitis, interval of calving to first insemination, and 56-d nonreturn in heifers, whereas contribution from the SCS and 56-d nonreturn as primiparous cow was negligible, after taking the other traits into account. This implies that for breeds selected for a broad breeding goal, including functional traits such as health and fertility, most of the genetic variation in culling will probably be covered by other traits in the breeding goal. However, in populations where data on health and fertility is scarce or not available at all, selection against early culling may be useful in indirect selection for improved health and fertility. Regression of average sire posterior mean on birth-year of the sire indicate a genetic change equivalent to an annual decrease of the probability of culling in first-lactation Norwegian Red cattle by 0.2 percentage units. This genetic improvement is most likely a result of simultaneous selection for improved milk yield, health, and fertility over the last decades.

Key Words: genetic correlation • culling • fertility • health

This article has been cited by other articles:

				M. Holtsmark, B. Heringstad, and J. Odegard Predictive abilities of different statistical models for analysis of survival data in dairy cattle J Dairy Sci, November 1, 2009; 92(11): 5730 - 5738. [Abstract] [Full Text] [PDF]

				M. Holtsmark, B. Heringstad, P. Madsen, and J. Odegard Short Communication: Use of Culling Information in Genetic Evaluation of Fertility and Mastitis in Norwegian Red Cows J Dairy Sci, November 1, 2008; 91(11): 4429 - 4432. [Abstract] [Full Text] [PDF]