Physico-chemical and microbiological characterization of ruminal fluid from gastrointestinal contents of Holstein calves in artificial fed milk conventional or fractionated

The fractional artificial feeding has allowed provide an adequate amount of milk to calves in the first weeks of life and restrict at weaning, stimulating growth and favoring better adaptation to diets with forage and concentrates. The aim was to evaluate the ruminal characteristics and gastrointestinal microbiota of dairy calves in different feeding systems. Holstein calves were evaluated in randomly assigned to feed milk conventional that consisted of four liters of milk daily for 60 days or fractionated systems, six liters of 6° to 25°, four liters of 26o to 45o and two liters of 46o to 60o days old. At an end of the experimental period, the animals were euthanized, and approximately 15 mL of rumen, abomasum and intestine contents were collected for physicochemical and microbiological analysis to detection of fungi, protozoa and Enterobacteriaceae. Feeding systems did not influence characteristics of color, odor and viscosity of rumen fluid. The analysis of pH and quantification of Enterobacteriaceae, mycelial fungi and yeast showed no significant difference between treatments at the different sites. The Escherichia and Proteus genus were the most frequent for the gastrointestinal tract for both feed system. However, E. coli was significantly more frequent among isolates from the rumen fluid of calves in conventional feeding, which could suggest an imbalance in this ecosystem. Thus the artificial fed milk systems influenced the genus profile of Enterobacteriacea in the rumen and small intestine of calves.