A Syringe-Type Rumen Fistula Mechanism

A fistula mechanism which is simple and economical to construct is described in detail. A disposable plastic syringe has been modified to serve as the cannula and cannula plug. The inside and outside washers that support the cannula are made of clear, semiflexible, vinyl plastic. Braided nylon twine is used to adjust for tissue pressure and keep the fistula mechanism intact in the animal's body. The features of this rumen fistula mechanism are: (1) it can be constructed by the researcher; (2) it is simple to prepare; (3) it can be installed within a matter of minutes; (4) it protrudes no more than 6 to 7 mm from the skin of the animal; (5) it weighs approximately 40 g; (6) the current material cost is less than $1.50; (7) it yields to physical obstructions and internal contractions; and (8) it can be completely removed and/or replaced in the rumen at any time.