Please Read General Information and Surgery Tips
Carefully observe the position of the stopper when disassembling the cannula for the first time.
Soak the cannula in hot water. Reach through center hole and grip inside flange. Pull flange through center hole, nearly turning cannula inside-out. The funnel-like flange is then pushed through the fistula into the rumen.
The rolled flange on the #1C will be on the inside of the rumen. The lip that holds the stopper in place goes toward the outside.
Insert the stopper at a slight angle using one or two fingers (or a small screwdriver) to position the stopper under the lip of the cannula. This may seem a little difficult to do the first few times but it will become easier with practice. The new #1EZ (easy out) stopper is very nice to use with the #1C. It also fits tightly in the #9C for a more permanent fit when needed.
To remove the stopper, insert thumb (or small screwdriver) between stopper and cannula. Hold onto stopper with thumb and fingers and push stopper into the rumen. Turn stopper sideways and remove. Or, use a small screwdriver and run it down the side of the stopper. Twist to lift stopper out.
The "nub" of plastisol on the #1S stopper goes toward the inside of the rumen.
The oblong washer (#1W) is for use with the #1C and is positioned on the inside of the rumen. Note the position of the tabs on the washer and how they fit with the rolled flange. The longest length of the #1W runs perpendicular to the ribs. Unless our cannula are used in an old fistula, there is usually no need to use a washer. The large cannula can be removed easily and a washer positioned at any time.
Carefully observe the position of the stopper and/or washer when disassembling the cannula for the first time.
After soaking the cannula in very hot water, turn short flange into center hole. This can be very difficult to do so don't wait until the last minute to practice. Starting with the edge of the short flange, invert it through the center hole as far as possible (this can only be done when the cannula is very hot). This should make the edge of the inner flange small enough to fit into the incision. When the cannula is in the animal, push the inner flange back through the hole and into the rumen. If necessary, use a sharply curved object to return the inner flange to its original position. A reshaped coat hanger works well but be careful not to gouge the rumen wall. If possible, turn the sharp end back and cover with tubing to protect the rumen wall. Practice before surgery!
Return the cannula to hot water until ready to insert.
Be sure the cannula is snug against the rumen wall with as little feed in between the cannula and the rumen wall as possible.
Do not worry if the cannula sticks out from the animal. These cannula tend to fit very tightly and can cut the inside of the rumen if they are too small. The pressure from the inside of the rumen will keep the cannula in place with little leakage even if the cannula sticks out from the animal. As the wool on sheep grows, the cannula can become very snug. Keep this in mind and clip the wool if the cannula is too tight. When the animal lays down, the cannula should always stick out at least one half inch. Small cannula cannot be removed except by cutting them out. Therefore, if a washer is desired, it must be inserted at the time of the surgery. We do not recommend the use of a washer unless the surgery site is old and the fistula is too large for the cannula. To insert the stopper, fold the funnel shaped portion by pressing the sides together with your index finger, folding the edge inward. Insert into the cannula and twist. To remove the stopper, insert a small screwdriver along the edge and lift gently. We recommend that the stopper be attached to the cannula with a string for small chain in case it is inadvertently pushed inside the rumen.The new design of the #8C eliminated the possibility of internal abscesses. However, this cannula may fit too tight on larger sheep or calves. If the cannula seems tight or is pulling out, cut "V" notches in the outside flange. This will spread the flange and reduce the pulling.
