Establishment of intestinal ciliates in new-born horses.

The establishment of horse intestinal ciliates was investigated on 12 foals fed on a farm in Hokkaido, Japan. The ciliates not found in the feces directly after the birth of the foals, began to be detected in it on and after the 11th day. The ciliate density reached to almost the same level as that in adult horses, 104/ml, on about the 35th day after birth. The higher the composition rate of a ciliate family in the adult host was, the earlier the family appeared in the feces of the foals. After the birth, the foal actively ate their mothers' feces, being followed by the oral infection with the ciliates present in the feces. Of 46 species belonging to 19 genera which were identified in this examination, one species, Spirodinium nanum, was newly recorded in Japan.