The Development of Rumen Microbial Populations in Lambs and Calves Under Various Conditions of Management

Summary: The development of the rumen flora and fauna has been followed by microscopic observations of rumen fluid from 58 young lambs and calves kept under different conditions of management; including remaining with the dam, early weaning and artificial inoculation into the rumen. Ciliate-free animals were successfully maintained by isolation from direct contact with other ruminants from an early age, but it was noted that greater space should be left between cattle than between sheep. The general effect of different diets and treatments proved similar in calves and lambs but certain differences were noted in their flora. Certain large bacteria developed in isolated lambs without direct contact between animals. Some generalizations, particularly the effect of a high concentrate diet, were applicable to all animals examined, but there were variations between individual animals. In the establishment of rumen ciliates diet was the governing factor and artificial inoculation with ciliates proved as effective as constant contact with the dam. Although the ciliate-free animals showed no differences in performance certain differences in the rumen flora common to isolated calves and lambs were noted.