Development and genetic influence of the rectal bacterial flora of newborn calves.

The aim of the study was to investigate a dynamic change in the rectal flora of calves as well as to study a genetic influence on the intestinal microflora of calves. The bacterial community of fecal samples from calves was examined by PCR single strand conformation polymorphism (PCR-SSCP) in two independent studies. In study one 14 newborn calves of the same farm were examined. Sampling was conducted directly after delivery (meconium) and after 6 h, 12 h, 24 h, 48 h, 3 d, 7 d, 14 d and 42 d of life. In study two 6 twin calves and their coresident of the same age and farm were analysed in order to study for the first time whether genetic predisposition of the host may influence the fecal microflora. All calves were weaned directly after delivery and received pumped colostrum without direct contact to other farm animals. After delivery and during the first 12h of life the SSCP profiles were simple, but became more complex since the bacterial diversity increased with time in all calves. It became obvious that the intra-individual band-pattern similarity decreased over time and inter-individual similarity was low. The analysis of fecal samples from twin calves revealed higher similarity in SSCP profiles for twins compared to their coresident indicating that the individual microflora might be genetically or epigenetically influenced. The insight that there are several conformities between intestinal microfloras of healthy calves and that there might be genetic influence on the fecal flora could help to prevent diarrhoeal diseases in the future.