For years, when a stallion manager called Exodus about poor results from shipped semen, Exodus sent back a list of questions. Most answers pointed to something that happened before the semen ever reached the box. This guide is that list, in order.
Work through it with your veterinarian. Some of the tests below are lab work they will need to arrange.
1. The artificial vagina
- Which A.V. do you use, and is it the same one every time?
- Do you weigh it before every collection? A consistent weight matters to most stallions. Write down the weight that works for yours.
- Do you check the water temperature with a thermometer and fill to the same temperature each time?
- Which lubricant, and how much? Is the whole A.V. lubricated the same way every time?
Setting up a Missouri A.V. covers filling and weighing in detail.
2. The collection
- Is the breeding shed heated or cooled, and to what temperature?
- How does the stallion behave at rest and in the shed? How many mounts does it take to collect? Does he rush the phantom or the jump mare?
- Where does he usually ejaculate: in the body of the A.V. or into the cone?
3. Processing and handling
- Do you count every collection? By hemacytometer or by a counting device? Note concentration per mL, total motility and progressive motility each time.
- Do you warm the semen after evaluating it?
- Where is the extender kept, in an incubator or at room temperature?
- How do you mix semen and extender, and at what temperature? Exodus’s rule is to let both reach the same room temperature before they meet. Adding semen that has started to cool to warm or cold extender causes reverse shock.
4. Extension
- In a normal dose, how many mL of semen and how many mL of extender?
- Do you know the total sperm per extended mL in the dose you ship? Exodus recommends about 25 million per extended mL and no fewer than 20 million.
5. A longevity test
- Has anyone run a longevity study on this stallion: cooling a dose under shipping conditions and checking motility over time?
- How long did it run, and how many extenders were compared? An Equine Express II with a frozen coolant pack is a realistic way to run one.
Different stallions do better on different extenders, which is why Exodus makes two formulas. Testing both is the cheapest experiment on this list.
6. Lab tests to discuss with your veterinarian
Exodus’s list ended with tests that need a lab or a veterinarian:
- seminal pH (pH paper is not accurate enough)
- seminal osmolarity
- urethral and seminal cultures
- an acrosome stain to check acrosome integrity
The pattern
Exodus’s view, going back to its first Equine Express patent work in 1997, is that cooling rate is only part of the answer. How the semen is processed matters as much: concentration, extension, and the pH and osmolarity of the extender. When a dose is too concentrated, lactic acid builds up, pH falls and motility drops with it. That is why Exodus has always argued for broad extension. Check the processing steps above before you blame the box.
Adapted from Exodus "My Stallion's Semen is not Shipping Good, Why?" questionnaire (2009) and Breeder Tips. This guide covers handling and use only; breeding timing, insemination and anything involving medication are for your veterinarian.