Making the Most of Your Stallion

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Believe it or not, it’s already time to begin thinking about next year’s breeding season. Perhaps you are looking to stand a new stallion or add a young one to your roster. Whether you plan to breed your stallion to five mares or 50, it is important to track his reproductive success so that you can quickly identify and address any problems that might arise. Proper record keeping and good management practices will help ensure the breeding success of your stallion.

“If the pregnancy rates are low, then a breeding soundness exam should be conducted...”

Michelle Morgan, who owns Mandolynn Hill Farm in Aubrey, Texas, feels that the key ingredient in maintaining fertility is keeping the stallion happy. She stands seven purebred Arabian stallions at her facility and five reside there year round. They do not do any live cover at the farm. Rather, all the horses are collected for artificial insemination. Her stallions are housed together in the same barn and receive daily turnout from 7:30 a.m to 3:00 p.m. “Turning a horse out allows him to be a horse,” she says. She also knows that nutrition plays a critical role and feels the stallion should go into breeding season a little heavier than normal. Poor body condition due to improper nutrition has a detrimental effect on semen quality. However, to get a more accurate reading once the body condition improves, you should wait 60 days before evaluating the semen.

Another area Morgan feels strongly about is the stallion’s routine and handler. When the horse is brought in to tease or breed, the handler has to be in control, but he shouldn’t be abusive. He really has to know what he’s doing and let the stallion express himself. Decreased libido has been seen due to improper handling or abuse. “I usually keep one person handling the horse when he breeds. When that person goes to get him, he (the stallion) knows what’s happening,” she says.

Maintaining breeding records is another important step. “If we have a stallion and he’s breeding really well and then not, we can go back and follow what he’s done,” Morgan says. This can be accomplished by simply hand writing them in a notebook to tracking them on a computer that then performs statistical analysis on the results. It makes little difference what method you use as long as it is done consistently. Morgan keeps a list of each mare’s name, owner, date bred, status of the mare (foaling barren, or maiden) and due date.

Maintaining Breeding Efficiency

Breeding efficiency is important to properly manage both your time and your stallion’s efforts. The three statistics that evaluate efficiency are cycles per pregnancy (less than two), first cycle pregnancy rate (65-70%) and pregnancy rate per cycle (60-65%).?If the numbers are higher than that, chances are you’re spending more money and your stallion is working harder without good results.

After you’ve examined your breeding records, if the pregnancy rates are low, then a breeding soundness exam should be conducted. The typical breeding soundness exam performed by a veterinarian consists of completing his reproductive and health history, performing a physical examination, examining external and internal reproductive organs and collecting and evaluating semen.

“Be cautious when administering drugs to a. . .future breeding prospect.”

The physical exam includes the stallion’s ability to properly mount the mare or breeding dummy. Difficulties here are usually due to issues in the back or hind legs. It is important to address these before psychological problems start.

Next the ejaculate is evaluated for semen quality, output and insemination dose. If any problems are diagnosed, adjustments can be made. The following traits are measured:

  1. Volume—amount of gel-free semen in milliliters in one ejaculate
  2. Concentration—approximately 7 billion spermatozoa per ejaculate
  3. Motility—examined under a microscope for the approximate percentage of normal spermatozoa. 60% is good. Less than 60% is questionable.
  4. Sperm morphology—examined under a microscope for bent tails, no tails, no heads, two heads and immature sperm cells.

The total sperm output equals the volume x concentration. The total number of progressively motile spermatozoa is the total sperm output x % progressively motile sperm cells. About 500 million normal progressively motile sperm cells are needed for an artificial insemination dose.

An acceptable year-end pregnancy rate is 85-90%. Anything below that indicates a problem.

Causes of Low Fertility

If you believe your stallion is subfertile or infertile, you need to determine the cause. While there are many, one common reason is testicular degeneration, which is a premature decrease in normal sperm production by the testes. Early on, the testes become soft and may decrease in size. Overall sperm numbers go down and the number of abnormal sperm goes up. This condition may be temporary or permanent.

“Decreased libido has been seen due to improper handling or abuse.”

A second cause is too many drugs. It’s common, particularly in performance horses, to administer a variety of medications. Many of these, especially anabolic steroids, can seriously impact fertility. They cause testicular degeneration and a decline in sperm production and quality. Often drugs that are used on a young horse do not show detrimental results until the horse is a mature stallion. It is wise to be cautious when administering drugs to a colt that is a future breeding prospect.

Spermiostasis, or plugged ampullae, seems to be increasing in frequency. The ampullae are the distal portions of the deferent ducts. Some stallions, after being sexually rested, are not able to clear spermatozoa in this area. Symptoms include large testicles, no sperm in the ejaculate, low motility and/or poor morphology. However, this situation can usually be rectified by 10 to 20 ejaculates over a one to two week period.

There are many other causes of infertility including infection, fever, obesity and injury. However, the bottom line is that careful monitoring can catch minor problems before they become severe. Appropriate changes or management practices can then be made to improve the stallion’s record for the next breeding season.