Effect of Ciliate Protozoa on the Productivity of the Host Ruminant

Abstract

Ciliate protozoa occur naturally in all wild and domesticated ruminants. A protozoal population becomes established in the rumen of young animals in the first few weeks of life through maternal contact and by transfer from other members of the flock or herd (Coleman, 1980; Chapter 9). However, the protozoa are not essential for the development and survival of ruminants because animals can be reared without a ciliate population developing and maintained ciliate-free providing all contact with faunated animals is avoided (Becker and Hsiung, 1929; Eadie, 1962a). Alternatively, protozoa may be eliminated from the rumen of mature animals by specific chemical or physical treatments (Section 4.2). Comparisons of ciliate-free (or defaunated) animals with (re)faunated animals have yielded much information on the effects of the protozoa (e.g., Jouany et al., 1988; Nolan et al., 1989; Veira, 1986; Williams and Coleman, 1988). The initial studies were undertaken over fifty years ago (Becker et al., 1929; Becker and Everett, 1930) and despite the many studies since then there is still no common concensus on the value of the protozoa to the host animal.