Genetic Relationships under Different Management Systems and their Consequences for Dairy Cattle Breeding
Birgit FUERST-WALTL, Hermann SCHWARZENBACHER, Christian FUERST
Pages: 183-186
Summary
Advances in breeding and management resulted in a considerable increase of production traits in Austrian dairy cattle. Besides, low input systems were also established. Possible genotype by environment interactions (G x E) and genetic antagonisms dependent on production level might indicate the need for separate breeding programmes for dairy farms differing in management intensity. Thus, G x E and genetic correlations (ra) between milk yield and selected fitness traits were estimated for Upper Austrian Fleckvieh cattle under high and low production levels. Data of the current herdbook cow population and their dams were extracted. Two data sets were selected based on the herd average of milk; extensive (≤6,000 kg herd average) and intensive (≥9,000 kg herd average) farms. Yield deviations were used for the analysis of yield traits, functional longevity, reproduction traits and milking speed; raw data were used for somatic cell count (SCC). For yield deviations, a model including the effects year of birth (fixed) and animal (genetic, random) was applied, while a model close to the routine evaluation was run for SCC. The lowest ra between extensive and intensive farms was found for protein yield (ra = 0.89) while ra values close to unity were found for all functional traits. Genetic antagonisms between milk yield and functional traits were stronger in intensive systems, however, standard errors were large. Currently, separate breeding programmes for different management intensities do not seem to be necessary.
Keywords
dairy cattle; genotype environment interaction; genetic correlation; breeding programmes
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