Untersuchung der einflussfaktoren auf den zuchtfortschritt beim Bayerischen Fleckvieh

The objective of the study was to investigate the genetic progress for milk yield in the Bavarian Fleckvieh breed as well as the respective factors that determine the genetic gain. In a first step, the theoretically achievable genetic gain was derived by assuming a breeding program put into action in an optimal way. Next, data sets consisting of pedigrees and information about inseminations as well as estimated breeding values were utilized to ascertain the factors of influence found in practice and thus to predict the expected genetic gain in the population. Finally, the realized genetic progress was estimated via the regression coefficient of averages of estimated breeding values on birth years of bulls. The genetic progress estimated based on breeding values was 109.3 kg in milk yield and was concordant to the expected genetic gain that was calculated to amount of 105.7 kg in milk yield. The theoretically achievable genetic gain of 134.2 kg in milk yield was comparatively higher by 27 % and 23 %, respectively. Reasons for this finding are given by the higher generation intervals found in practice for all selection paths and substantial lower selection intensity on the dam-cow-path. The decreasing generation intervals observed mainly for bull sires and bull dams along the last decade indicate that breeding organisations and breeders have reacted accordingly. With 74.5 %, the major proportion of genetic progress is due to selection of parents for the next generation of bulls for progeny testing. The relative contributions of the particular selection paths are 38.7 % for the sire-bull-, 22.0 % for the sire-cow-, 35.8 % for the dam-bull-, and 3.5 % for the dam-cow-path. These figures agree with older studies in Fleckvieh and with other breeding programs for dairy cattle that are based on artificial insemination. The results show that Fleckvieh as a dual purpose breed successfully met the challenges of modern dairy cattle breeding by consequently following the set-up of the breeding program.