Genetic evaluation of female fertility for Walloon dairy and dual purpose cows using a parity random regression model: first results

in INTERBULL Bulletin (2006), 34

Correlations of longevity evaluation with type traits in Walloon Region.

in Proceedings of the 8th World Congress on Genetics Applied to LivestockProduction, Belo Horizonte, Minas Gerais, Brazil, 13-18 August, 2006 (2006)

Approximated genetic correlations between direct longevity and type traits were computed for a sire Holstein population. Data were based on results for type traits (77,965 records) and for direct ... [more ▼]

Approximated genetic correlations between direct longevity and type traits were computed for a sire Holstein population. Data were based on results for type traits (77,965 records) and for direct longevity (74,289 records) from the INTERBULL routine run of November 2005. Most of type traits presented a high relationship with direct longevity (from 0.06 up to 0.29). The strongest positive correlation with longevity was for udder depth (0.29) and the strongest negative correlation was for chest depth (-0.21). According the different results, an animal with a good direct longevity seemed to be smaller and less heavy than an animal with a shorter longevity. [less ▲]

Variabilité intra- et inter-races du profil en acides gras de la matière grasse du lait

Master's dissertation (2005)

Currently there is no cattle selection program which is based on fatty acid profile in milk fat. According to several publications, both the saturated and insaturated fatty acids have positive as well as ... [more ▼]

Currently there is no cattle selection program which is based on fatty acid profile in milk fat. According to several publications, both the saturated and insaturated fatty acids have positive as well as negative effects on human health. So using overall milk fat as the only criteria in selection may be considered not appropriate. The aim of this research was to evaluate the potential effectiveness of selection on higher nutritional quality of milk fat. The variability within and across breeds for Dual Purpose Belgian Blue, Holstein-Friesian, Jersey, Montbeliarde and Red and White animals were analysed. The quantity of fatty acids in milk and milk fat was measured by medium infrared and were analysed using mixed model methodology; this analysis showed that several differences between the five dairy breeds for the profile of fatty acids exist. High repeatability estimates suggest that high additive genetic variance for fatty acid profile exists within each breeds. Moreover the variability for each component was demonstrated in the population. This first investigation showed that genetic improvement of the nutritional quality of milk fat, therefore on the fatty acid profile, is possible and researcher or development dairy selection progress is justified. [less ▲]