Key points are not available for this paper at this time.
A study was made o the bacteria and protozoa present in the rumen of three calves from 1 to 13 wk. of age, raised under normal conditions. Ciliate protozoa were not established in these calves. A study of older calves in contact with mature animals after 13 wk. of age indicated that entodinia were first established, followed by diplodinia and holotrichs.
Bryant et al. (1958) studied this question.