Effects of Fistula Size on Rumen Internal Pressure and Passage Rate of Feed in Goats

This study investigated the effect of fistulation (two size fistulae; small and large) on the amplitude and frequency of contraction of the rumen and on the passage rate of feed in the goat. With the small-size fistula, the amplitude and frequency of contraction of the rumen were the same before and after fistulation. With the large-size fistula, the amplitude of the contraction of the rumen was lower after fistulation, but the frequency of contraction of the rumen was not different before and after fistulation. Passage rate of feed had a tendency to be slow in the large-fistula group. It is suggested that the primary variation in rumen contraction and passage rate of feed due to fistulation was a change of the rumen contractile force. Therefore, because amplitude and frequency of contraction of the rumen and passage rate of feed did not differ before and after fistulation with the small fistula, it is concluded that the fistulate region, method of fistulation and adhesions are related to the rumen internal pressure and passage rate of feed.