Improvement of breeding and management resulted in a considerable increase of production traits in Austrian dairy cattle. Apart from production systems with a high intensity farm management, sustainable and organic dairy production systems are an integral part in Austria. Possible genotype by environment interactions (G×E) depending on the method of production and intensity of farm management might exist and lead to a re-ranking of animals. Thus, an adaptation of the breeding programs would be required. Therefore, genotype by environment interactions were estimated between milk yield, persistency, functional longevity, somatic cell score, clinical mastitis, early fertility disorders, cystic ovaries, milk fever, non-return rate at 56 days of cows and interval from first to last insemination in Austrian Fleckvieh cows milked in three different production systems (organic, conventional low and high level of farm intensity). Genetic correlations between production systems were estimated using an approximate multivariate two-step approach applied to yield deviations and de-regressed breeding values. In general, no severe G×E were found. Genetic correlations between the production systems organic and conventional low level of farm intensity, organic and conventional high level of farm intensity, conventional low level of farm intensity and conventional high level of farm intensity ranged from 0.952 to unity, 0.890 to unity and 0.886 to unity, respectively. The lowest genetic correlations were observed for non-return rate at 56 days of cows (0.890) between organic farms and farms with high intensity management and for functional longevity (0.886) between farms with low and high intensity management. For all other traits, genetic correlations were close to unity. From the breeding perspective, autonomous breeding programs for different production systems within Austria are currently not needed.
Reference:
Pfeiffer, C., Fuerst, C., Schwarzenbacher, H., Fuerst-Waltl, B., Genotype by environment interaction in organic and conventional production systems and their consequences for breeding objectives in Austrian Fleckvieh cattle, Livestock Science, Volume: 185 Pages: 50-55 Published: MAR 2016.