COMMERCIAL CROSSBREEDINGS OF GERMAN BROWN WITH BLONDE DAQUITAINE AND GERMAN SIMMENTAL .1. INFLUENCE ON FERTILITY, CALVING TRAITS AND CALF MORTALITY

The analysis was based on milk recordings and AI-data from the years 1 985 to 1990 of the German Brown cattle in Bavaria. The objective of th e analysis was to compare the sire breeds Blonde d'Aquitaine and Germa n Simmental with purebred German Brown in fertility and calving traits . Furthermore, breeding values should be predicted to rank terminal si res for their suitability for commercial crossing. 485749 observations in 5110 herds were available for the fertility parameters non-return rate 90 days after first insemination (NR90), successful first insemin ation corrected for cullings due to fertility reasons and due to all k inds of reasons except for selling of breeding animals and when a herd was given up (CR1 and CR2, resp.), to first breeding after calving, i nterval between first and second insemination (IFB). Calving ease and calf survival could be investigated in 652125 observations from 5240 h erds. The basic linear model included the following effects: herd, yea rseason, calving age*lactation number, milk production, days of first breeding after calving, sex of calf, sire of calf and breed, resp. Br own-Swiss blood proportion, maternal grandsire with its Brown-Swiss bl ood proportion and mother of calf. Numerator relationship matrices wer e regarded for sires and maternal grandsires. Fertility results based on first insemination increased significantly in Blonde d'Aquitaine si res compared to German Brown and German Simmental. NR90 showed a devia tion of 2.3 %, CRI a deviation of 1.5 % and IFB a deviation of - 2 day s if a Blonde d'Aquitaine sire was used. Calving difficulties were mor e frequently observed in Blonde d'Aquitaine crossbred calves than in p urebred calves and even more than in German Simmental crossbred calves . The frequency of stillborn calves only increased by 0.2 % in crossbr eds. There were no differences between the two sire breeds regarding c ommercial crossing. The large variation of breeding values of Blonde d 'Aquitaine bulls showed that it is necessary to estimate each bull for fertility and calving traits.