A genetic analysis of dairy calf health traits and survival
This thesis is an investigation of the genetic influences on morbidity and mortality in a population of Holstein calves from New York State. Calf mortality from arrival to the facility until weaning, and from weaning until exit were examined as separate traits. Also, survival from arrival to the facility until exit was examined as one trait. Preweaning calf health traits including undifferentiated bovine respiratory disease, bloat and umbilical disease, were also examined and each considered as a separate trait. Heritabilities, variance components, and breeding values were estimated for all traits of interest. Breeding values were also correlated with routinely evaluated traits in Canada and the US. The results of this thesis suggest that sufficient genetic variation exists between sires for health and survival of their daughters through the growing period. Furthermore, results from the proof correlations suggest that selection for routinely evaluated traits has negative and positive consequences on calf health and survival.