Observations on the Ruminal Microorganisms of Isolated and Inoculated Calves

Abstract

A study was made of the protozoa and culturable bacteria in the rumen of 3 calves, that were drenched with whole rumen contents from a mature cow at 1, 3 and 6 weeks of age, at 1, 3, 6, 9, 13 and 17 weeks of age. A similar study was made of two calves maintained in the same manner, except that they were not inoculated and were strictly isolated from other ruminants at birth. Data obtained were compared with previously collected data on calves maintained under identical conditions to the 1st group but not inoculated. Inoculation of normally raised calves had little effect on the time of establishment of predominant culturable bacteria typical of mature cattle but greatly speeded the establishment of ciliate protozoa. In strictly isolated calves, the protozoa did not become established and the bacterial flora was modified from normal through 17 weeks of age as indicated by higher total bacterial counts during the 6 through 17-week period, the failure of many species of bacteria normally predominating in calves or mature cattle to become predominant and the apparent effect of inoculation after 17 weeks resulting in lower total bacterial counts, in drastically raised counts of cellulolytic bacteria, and finally in a normal distribution of predominant bacterial species. It was apparent that the lack of a normal rumen microbiological population did not have any drastic effect on the animals'' feed consumption, growth, or health through an age of 17 weeks.