Walkthrough the surgery photo gallery
Surgery photo gallery from Africa
Animals should be off feed for at least 24 hours prior to surgery. This is not always feasible or advisable with lactating dairy cows.
Soak cannula in very hot water to make insertion into the fistula easier.
Shave animal thoroughly; use local anesthetic; do surgery on standing animal. [see picture]
Cannula must be as high as possible on the animal. Diameter of fistula must be the same as center diameter of the cannula. [see picture]
For the best results, the fistula must be perfectly round. This is best accomplished by carefully drawing a circle before surgery. Try making a "compass" with a needle, string and loops at each end (slightly larger than the desired radius) and a felt marker. A "cookie cutter" of sharpened steel is handy for researchers doing a large number of surgeries. Score the animal deep enough to cause slight bleeding or your line will be hard to follow. [see picture]
Make a skin incision following scored skin. Continue incision through first muscle layer and then "grid" or tear through the rest of the muscles to expose the rumen wall. [see picture] Insert one loop of umbilical tape on the edge of the exposed rumen wall, leaving a large enough loop to use as a hand hold. [see picture] Make a 1 or 2 inch incision through the rumen wall (use umbilical tape loops to hold rumen wall out) and suture rumen wall to skin. [see picture] Repeat this process doing 1 or 2 inches of the circumference at a time until complete, being sure to keep rumen contents out of the abdominal cavity. [see picture]
Insert the cannula as described under large or small cannula information. [see picture]
The fistula should be washed with a very mild bleach solution daily for approximately one week and then every five or six days or as necessary to keep the animal clean. This is especially necessary in hot weather. During cold weather, very little post-surgery maintenance is necessary other than removing the stitches.
Administer antibiotic daily for approximately four days following surgery or as per veterinarian recommendation.
Aspirin is helpful to the animal -- just remove the stopper and drop them in the rumen!
Mineral oil is a good lubricant to help remove the stoppers. However, we prefer a small screwdriver (not too long) to carefully lift the stopper out. With practice, the stoppers will become very easy to work with. We suggest replacing stoppers that become black and hard.
Washers are available for all cannula except #8C for #9C if
there is a problem with leakage. Washers can be inserted at
any time with large cannula but only during surgery with
small cannula (small cannula cannot be removed once they
have been inserted in the animal).
