Establishment of intestinal ciliates in new-born horses.

The establishment of horse intestinal ci iates was investigated on 12 foals fed on a farm in Hokkaido, Japan, The ciliates not found in the feces directly after rhe birth of the foals, began to be detected in it on and after the 1lth 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 cemposition 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.-KEy woRDs: establishment, horse, intestinal ciliates. Some ciliates commonly inhabiting the large intestine, cecum and colon of adult horse are not fbund from the intestine of new-born foals, They are supposed to invade into the host by oral infection and settle in the large intestine like rumen ciliates [13]. Therefore, such several unknown points as their way of infectien, the time of their establishment and others are remained to be solved. Only Adam [1] reported that 2 species were successfully established in the large intestine of an adult horse by oral inoculation with the colon contents of another adult horse. However, no discussion was performed in this report on the time of the establishment. The present examination was carried out to make clear the route of infection and the time of establishment of intestinal ciliates in foals by daily microscopical observation on the feces. MATERIALS AND METHODS Collecting samples: The samples examined were the feces collected from 12 foals * cORREspoNDENCE To: K. Ike, Research Center for Veterinary Science, 7Zhe Kitasato Institute, 1139-l Matsugasaki, Kashiwa, Chiba 277, Japan .ipn J. Vet. Sci. 47(1) 39-43, 1985 born from March to June, 1982, in a farm in Hokkaido Japan. The feces were collected within 30 min after defecation to prevent the destruction ofciliates [14]. The feces oftheir mother horses were also collected as control samples, Preparation: The samples collected were fixed and stained with twice volume of methylgreen-formalin-saline (MFS) solution [13], Then they were filtrated through a double fblded sheet of muslin and observed. Identification andcounting ofciliates: Ciliate species were identified mainly in conformity to Hsiung [4-7], The identification of the species not described in his papers was confOrmed to Chavania [2], Strelkow [16], Imai [11], and Ike et al. [8, 101. Higher taxonomical names was used according to Corliss [3]. For counting ciliates, aplankton counter deck glass on which lines were cut at O.5 mm intervals was used [l3]. RESULTS AND DISCUSSION As mentioned previousiy, no study has been carried out on the time of establishment of ciliates in the large intestine of fbals. Figure 1 shows the number of intestinal ciliates excreted in the feces of foals from the Japanese Society of Veterinary Science NII-Electronic Library Service apaneseSociety f eterinary cience 40 IKE, IMAI, AND ISHII