Genetic Analysis of Longevity in Dutch Dairy Cattle using Random Regression

Abstract Text: Records for monthly survival up to 72 months in productive life were used to estimate genetic parameters for longevity in dairy cattle with a random regression sire-maternal grandsire model using Legendre polynomials. Heritabilities for monthly survival were below 0.011, but the heritability for lifespan across the entire period of 72 months was 0.146. Genetically survival was more similar between months close together and survival was a different trait when months were further apart with genetic correlations ranging from 0.16 to 0.99. The genetic correlations suggest that in the current genetic evaluation, reliabilities are overestimated when only information of early productive life is available, survival in first six months predicts entire lifespan with a maximum reliability of 0.64. This low reliability might explain the observed changes in estimated breeding values despite the apparent high accuracy coming from the current model assuming genetic correlations of unity.

Keywords: dairy cattle, survival, genetics