Report: Deliverable 2.2.1 Keeping cow and calf together – impacts on gut microbiota development (INRAE)

Summary

The objective of the present study was to investigate the possible influence of the calves’ rearing method, including or not contacts with the dam, on the development of gut microbiota of calves. At an INRAE experimental farm, we tested two different suckling strategies on animal performance and behaviour. A 14-cow ‘Classic’ rearing system (C group) was compared during 14 weeks to two suckling systems. In the C group, calves were separated from dams immediately after birth and fed with an automatic milk feeder until weaning. In the ‘Dam’ group (D), dam-calf contact was allowed from birth to weaning, between morning and evening milking. In the ‘Mixed’ group (M), calves were kept with dams until three weeks (as in D group) before being separated and reared as in C group. All calves were weaned at about 11 weeks. Calves rumen fluid and faeces samples were taken at weeks 3, 10, 13 and 20 of age (+/- 3 days) before the morning meal, in 9 calves group. DNA was extracted for PCR amplification using universal primers targeting the 16S rRNA gene. Sequencing data were analyzed by the QIIME2 default pipeline. Preliminary analyses of results revealed a clear separation between faecal and ruminal samples reflecting two distinct microbial communities. As expected, the age of the animal was a major factor influencing the installation of the microbiota: well-distinct communities were observed at 3 and 20 weeks of age, whereas 10 and 13 weeks of age were intermediate which can be explained by the feeding changes, as the 20 weeks-old calves are completely weaned. However, the calves’ rearing system did not significantly affect the structure of the ruminal microbiota. These preliminary results and data treatments do not confirm our hypothesis that the development of the gut microbiota in calves is changing according to calves’ rearing method, including or not contacts with the dam.