COMMERCIAL CROSSBREEDING OF GERMAN BROWN WITH BLONDE DAQUITAINE AND GERMAN SIMMENTAL .2. INFLUENCE OF DYSTOCIA AND SIRE BREED ON FERTILITY,MILK-PRODUCTION AND SURVIVAL IN THE CONSECUTIVE LACTATION

The impact of calving problems on the consecutive lactation period was estimated on 427497 calvings in 5106 herds. The linear model was exte nded by the effect of interaction of sire breed x calving assistance s core, calf mortality or twins, resp. Fertility of the consecutive serv ice period of the mother of the calf was impaired due to calving probl ems in the same extent whatever sire breed was used. Non-return rate 9 0 days after first insemination (NR90), successful first insemination corrected for culling due to infertility (CRI) and due to other manage ment reasons and diseases (CR2) decreased by 8.3 %, 9.7 % and 11.6 %, the interval from calving to first breeding was prolonged up to 6.8 da ys. Depression of 305 day milk yield due to stillbirth reached values of - 192 kg milk yield, - 6.2 kg fat and - 5 kg protein. The differenc es between all observed terminal sire breeds were not significant. Aft er stillbirth of Blonde d'Aquitaine crossbred calves, culling of mothe rs was more frequent (8.8 % increase) than after calvings with German Simmental crossbred calves (5.2 %). After veterinary assisted calvings in German Simmental crossbred calves, culling rates were higher than after veterinary assisted calvings of Blonde d'Aquitaine crossbred cal ves, comparatively 10.9 % to 6.7 %. As above, no significant differenc es between terminal sire breeds could be found.