IMPROVEMENT OF CATTLE FERTILITY USING INF ORMATION FROM MILK RECORDING AND AI

Data from milk recording and from the A.I. centre Neustadt/Aisch were combined and analysed. Information of the Simmental breed is included, starting 01. 10. 1986 until 30.06.1991. In the first dataset (N=389 0 63) the influence of some performance characteristics (milk yield, fat and protein content) at the end of lactation on fertility during the following lactation was analyzed. It could be established, that from a protein content difference of > 0. 6 % or a protein content of >4.1 % , respectively an increased fertility problem must be recogned with. T he relative part of the protein content difference on the explainable variance was 2.6 %, while the protein content explained only 1 %. The influence of performance in the first three test day yields on fertili ty was analysed in the second data set (N = 658 559). In the beginning of lactation, on comparing the three performance characteristics, fat - and protein content and milk performance, milk performance has the g reatest influence on the fertility. A protein content from > 3.2 % and a fat content of < 4% have a positive effect on fertility in beginnin g of lactation. It must be point out, that a too low protein content i n comparison with a too high fat content has a clear negative influenc e on fertility. In the third data set (N = 261 506) the passage of the lactation curve on fertility was analysed. The advantages of a balanc ed lactation curve on fertility are not important. The results could b e used in a PC-herd health programm (for instance ''MIAS-RIND''/LKV).