Setting up and filling a Missouri artificial vagina

A Missouri A.V. is a heavy gum-rubber liner, with its cone, inside a leather or insulated cover. The cover gives the liner the rigidity it needs and holds its temperature until collection. Water goes in through a two-way valve.

Exodus’s single most repeated piece of advice about A.V.s is this: use the same temperature and the same weight for every collection of each stallion. Consistency can head off breeding-shed habits before they start, and it removes a variable when semen quality changes.

Find your stallion’s numbers before the season

• Water temperature. Start filling at about 46 °C (115 °F) and never go above 55 °C (131 °F). Inside the liner you are aiming for roughly 40 to 52 °C (105 to 125 °F). Every stallion has a preference. Find it before the season starts, not on a busy breeding day.
• Weight. A filled liner usually weighs 12 to 15 lb. Do not go over 15 lb without the cover. Weigh the A.V. and write the weight down for each stallion.

Filling with the Next Generation A.V. Fill Kit (Exodus’s recommended method)

1. Stand the liner valve-side up in the sink.
2. Unscrew the brass air valve and the black plastic ring from the filling assembly and set them aside.
3. Screw the fill kit’s brass fitting onto the valve threads, no more than finger-tight.
4. Bring the water to your stallion’s temperature. A digital thermometer makes this quick.
5. Fill through the funnel, lifting the funnel now and then so air “burps” out of the liner. Air bubbles cause uneven filling and can over-stretch the liner or pull apart glued seams, and that damage is not covered by the warranty.
6. Stop when the water sits steadily about halfway up the clear tubing.
7. Lift the bottom of the funnel so the water in the tubing drains back into the liner. Hold the base of the valve and lift the A.V., then spin off the fill device.
8. Refit the brass pin finger-tight and wipe off any water.
9. Weigh the A.V. and adjust to your stallion’s weight.
10. Assemble the cover. Seat the valve in the hole in the cover, press the leather stabilizer disc onto the pin, screw the black ring on finger-tight, then buckle or Velcro the straps so the A.V. is one solid unit.

Timing

The A.V. starts cooling as soon as it is filled, and how quickly depends on the temperature of your shed. Keep the gap between filling and collecting short and the same each time.

Faster methods, and their cost

Filling from a faucet through the air valve, or with a hose pushed over the open valve, is quicker. It suits farms collecting several stallions a day. But it puts the liner under much more stress, with over-stretching, separated seams, dry rot and a shorter life, and the manufacturer will not warrant that damage. Exodus did not recommend it.

Off-season care

Exodus’s line was that good A.V. care is only appreciated when you pull one out of the closet in spring and find it has dry-rotted. At the end of the season:

1. Clean and rinse the A.V. thoroughly.
2. Take the pin out of the valve and lay the A.V. flat in a sink, valve down toward the drain, for 2 to 3 days until all the water has drained.
3. Refit the pin finger-tight and pump in just enough air that the sides do not touch (3 or 4 pumps of a small hand pump).
4. Dust it with baby powder inside and out.
5. Bag it and store it in a freezer, with nothing laid on top of it.

During the season, store cleaned A.V.s capped and hanging in a clean, dark cabinet. Soaking gum rubber in alcohol shortens its life.

Prefer disposables?

Next Generation all-in-one disposable liners come with the bottle and filter attached, for a fresh sterile liner every collection.

Adapted from Exodus "Properly Setting Up a Missouri A.V. for Collection" and Breeder Tips. This guide covers handling and use only; breeding timing, insemination and anything involving medication are for your veterinarian.