Breeding Season is Upon Us!

Breeding Season is Upon Us!

The holidays are now over, which means breeding season will soon begin.

We start breeding in February, typically wind down by July. Breeders focused on aged events or sales often want the advantage of an earlier foal. Those mares are bred in February and March. In order to get the mares to cycle well early in the season they are put under lights starting in December. If an early foal is not important, breeders may choose to breed later in the spring or early summer. The main advantage to this is having a foal born during warmer weather may make it easier to manage depending on the climate and facilities. If you are considering breeding your mare what should be considered prior to the endeavor?

First, is the mare a good candidate? The main factors are age, breeding history, and overall health. If there are questions regarding your mare, a breeding soundness exam is a good investment before moving forward. Your veterinarian can evaluate the overall health of the horse, examine the reproductive tract by palpation and ultrasound, and possibly do tests such as a uterine culture and cytology to ensure all is well. Most mares are healthy and normal but it is good to answer questions before planning insemination. This can save time and money.

When choosing a stallion be aware of breeding history.

Some stallions are more fertile than others so it is good to know how many foals they have on the ground and by what means. The three main options are live cover, cooled transported semen, and frozen semen. Live cover can be less costly as there is less need for veterinary involvement and the chances of conception are generally high. There is innate risk to both the mare and stallion for physical injury. The other issue is geography. Shipped semen allows the mare owner to choose from stallions anywhere in the country and outside the country as well. Cooled transported semen is collected upon request. It is shipped same day or overnight. The advantage is it can lead to higher conception rates (50-65% chance of pregnancy per cycle) than frozen semen in some cases. The collection and shipment of the semen must be timed in sync with the mare’s cycle. Frozen semen can be stored indefinitely on the mare’s end. This allows for insemination anytime, independent of outside factors. Frozen semen requires careful handling and very specific timing of insemination. Conception rates with frozen semen are statistically lower at 30-40-% chance for pregnancy per cycle. It is good to review the stallions breeding contract before making the final decision to fully understand costs and parameters.

When it is time to breed the mare we want her to enter into a good heat cycle. This cycle needs to accommodate shipment schedules if we are using cooled transported semen. The time of ovulation must be predicted properly for success with cooled, and especially frozen semen. Mares’ heat cycles can be difficult to track so we typically use a simple protocol of hormonal therapy to bring them into heat and induce ovulation. This can eliminate costs variables.

After your mare is bred, your veterinarian will ultrasound her to check for pregnancy after about 14 days.

If she is in foal a second check is typically done around 25 days to check for a fetal heartbeat and normal development. It is also important to rule out twins during these exams. We always hope to catch the mare on the first cycle. Sometimes it takes more than one try to get the mare pregnant. Three attempts at artificial insemination leads to about a 90% chance of pregnancy. If the mare is not pregnant after a few tries, the situation should be re-evaluated from all angles. Sometimes further diagnostics are indicated to look for problems in the mare. Even if the stallion is proven fertile, it can be helpful to switch stallions as incompatibility can exist between certain mares and stallions.


Selenium Supplementation: Part 2

Selenium Supplementation: Part 2

Tips On Selenium Supplementation

Having mentioned the importance of selenium in the diet, I would like to bring up a few important points about supplementing this essential nutrient.

Having practiced in a selenium deficient region for almost 20 years, I can say the problem is real. We often test horses who are on high quality forage but no supplements that are low in blood selenium levels. Horse owners in such regions as the PNW will likely need to address deficiencies, especially if the horses are used for riding or breeding purposes. 

When choosing a supplement, look for organic selenium yeast as it provides the more stable and absorbable form. Selenium’s important role as an antioxidant to prevent cell damage is dependent on Vitamin E. Therefore, the horse must receive adequate amount of vitamin E. This is important for all horses, especially those who are stabled or on dry lots as fresh green pasture is the main dietary source of vitamin E.

If you are adding selenium to your horse’s diet it is important to consider balance with other trace elements. This is often overlooked when selenium is simply added to the diet on top of other basic supplements. I learned about the details of this when we created Meganutril Ultra. We loved the results we were getting from the Meganutril but we knew we needed a practical basic supplement that could accommodate all horses in our selenium deficient area. We asked Klaus to create that for us by adding more selenium to the original Meganutril product. I expected it to be a matter of adding the selenium and increasing the level of vitamin E. I was wrong.  Klaus and the scientists at Miavit adjusted all the other ingredients to optimize the new supplement and to accommodate the higher selenium.

In addition to vitamin E, vitamin C is another important, and sometimes under recognized teammate for selenium when it comes to antioxidant effects and preventing cell damage. Horses with high workloads can benefit from the addition of vitamin C in a pH neutral form. 

Selenium Supplementation: Part 1

Selenium Supplementation: Part 1

Signs That Your Horse May Lack Selenium

Signs of selenium deficiency in the adult horse often relate to performance and muscle function. Horses that lack selenium become stiff and prone to soreness associated with exercise, which can lead to reactive behavior and poor performance. Cardiac and respiratory function are affected as well. They may have a poor hair coat with a scant mane and tail. Hoof quality can also be affected, as can joint health. In addition, low selenium levels can suppress the immune system, leaving horses susceptible to infection. Mare and stallion fertility can be compromised in horses used for breeding. Finally, foals born with selenium deficiency can develop white muscle disease, which compromises their heart. These foals often fail to stand and nurse. 

The need for selenium supplementation is based on geography, as some areas produce forage that contains significant amounts of selenium, while other regions have selenium-deficient soil. Parts of the east and west coasts are selenium deficient, as well as the Great Lakes region. There are variations throughout the United States, so it is important to consult your veterinarian and know your area. 

Horses in deficient areas can be managed with a daily oral supplement. Most products contain 1-3mg of selenium per dose. Individual horses seem to vary in what they require. A simple blood test can accurately measure selenium levels. This provides an excellent tool for evaluating supplementation. It is important to be aware that selenium toxicity can be just as problematic as deficiency, so over-supplementation needs to be avoided as well.