Selection for reduced risk of early culling in dairy cattle: Comparison of alternative approaches to improve animal welfare

Ane Skjelfjord

Prosjektleder: Jørgen Ødegård

Both health and fertility problems increase the risk of early culling in dairy cattle, and are directly or indirectly connected to animal welfare. Hence, length of productive life may be used in selection for improved animal welfare through its relationship with health and fertility of the animal.

The first main goal is to compare the relative efficiency of selection for reduced risk of early culling on basis of either length of productive life or recorded health and fertility traits. Further, the potential value of productive life as an additional source of information in Norwegian dairy cattle breeding will be examined. The first step is to estimate (co)variance components and genetic trends for culling, health, fertility and milk production traits in first lactation. The next step is to do genetic analyses of length of productive life, using alternative models. The results of the first two studies will be used in a third study, aimed at comparing efficiency of selection based on health and fertility records versus recorded length of productive life, with respect to risk of early culling.

The second main goal is to implement large-scale multi-trait genetic evaluations of productive life, health (e.g. mastitis) and fertility traits (e.g. non-return rate, calving interval), following a Bayesian approach for multivariate analysis of Gaussian, Weibull, and binary distributed traits.

This study is important for evaluating the potential advantages of direct selection on health and fertility (as in the Nordic countries), versus more indirect selection (using traits such as productive life). The results and knowledge obtained will be of large importance in cattle breeding programs as well as breeding programs for other species.

Oppdatert: 03.08.06
Utskriftsvennlig versjon : Arkiv : Tips en venn