Send ANY horse, horse farm, or equine industry-related question to the Equine Science Center and our faculty and staff have the knowledge, expertise, and resources to provide individual answers based on your inquiry. Please note that while we do have faculty with veterinary expertise, if your horse appears to need medical attention or is in pain, please contact your veterinarian immediately.  While we specialize in equine nutrition, care and management of the equine athlete and the older horse, equine exercise physiology, environmental stewardship and best farm management practices, and horse industry economics and policies, we can reach out to our colleagues from around the world to find the most knowledgeable person in the field to answer your question. Send your questions in our provided form below. Your response will be emailed back to you, and may be posted to our website for future reference.

Questions & Answers

While it is unlikely, it would still be possible to have live sperm within the remaining ductus deferens.  However, to result in a pregnancy, not only would live sperm have to be present, but these sperm would also have to be healthy and motile in order to fertilize the egg in the mare.  The risk is low, but not impossible.


There is definitely an advantage with respect to knowing the horse intimately for over a year.  You already know the mare’s strengths and weakness, not to mention how you would “get along together.”  So some of the uncertainty is not an issue.  A pre-purchase evaluation in this case would help investigate any conditions that might not be readily apparent and get a veterinarian’s perspective on the horse’s suitability for what you want to accomplish with the horse.  It is suggested that you speak directly with your veterinarian for guidance on what type and how extensive an examination you both deem appropriate before purchasing this horse.  It is always difficult to predict the future, particularly when working with horses.  In general, as horses age, a multitude of different issues such as arthritis, deteriorating teeth, digestibility of foods, weight gain/loss, etc. can become a problem.  Over the years, horses have been living longer.  You also need to consider the financial commitment when accepting this horse permanently into your family.  No doubt, your veterinarian can help you with all these questions and concerns.

The best way to move your horse without added stress is to minimize the things that will be different for a long as you can. For example, take some hay and grain from your old barn so the change to a new feed can be made gradually over 5-7 days. Slowly take away old feed and replace with new feed. If he is used to a certain bedding, do the same with the bedding. To acclimate your horse to new pasture and turn-out areas, the best thing to do is introduce your horse to these areas gradually as well. If there is a stall, he can be kept inside for part of the day and only turned out for short periods of time at first. You can increase the length of turn-out time over a period of several days. Also, if he will have new horse buddies, it is best to find him a single buddy that he can make friends with before turning him out in a larger group. This will help that transition so that he will hopefully have a companion to keep him from being by the entire group. If he is typically a nervous horse, it is a good idea to add 7-10 grams of vitamin C for the week prior and the week after the move. This is a good antioxidant to use for the short term during stressful times. However, when removing the supplement make sure your horse is not still stressed. The horse’s liver produces vitamin C except when getting it from an external source. High doses during stress cut down on the liver’s production and that production needs a few days to start back up again when the supplement is removed.

Weaning is going to be tough on both horses, especially when there are no other horses for companionship. It would be advisable to have company for both horses in this process. Therefore, if possible, you could borrow a friend’s horse to bring to your farm or send your mare to another farm (or both). Hopefully you will be able to find a temporary buddy for each horse during this process. Once the colt is weaned, you need to keep them separated until the colt settles down and is gelded. If the colt is not gelded, he will never be able to have a mare as a buddy. If a buddy is not an option, it will be difficult to get him to settle. However, keeping a good quality forage (with a legume mix) available free choice will help keep him busy during this process. As for the mare, she needs to dry up. To help with this, remove any grain she is receiving and just feed a good quality grass hay free choice.

As I understand your question, you are unsure whether you horse is swallowing the medications that you are administering. The first suggestion that I have is that you should administer the meds when the horse does not have hay or any other feed in his mouth. This will ensure that it does not fall out of the horse’s mouth attached to a wad of hay/feed. Also, you should try to make the medication more on the paste side so that it does not “drip out” of his mouth as much (add a little less water). Many horses will hold the medications in their mouth until you walk away and then simply spit it out. You can do a couple things to accomplish the task at hand. Consider combining the medications with something more palatable like molasses, or even a little bit of syrup. You will need to check with your veterinarian to ensure that you are “allowed” to use a sugar substitute with the medications. As a last resort, you can close off the horse’s nostrils for a few seconds, which might encourage him to take a swallow. The best way to ensure that the horse has swallowed the medications is to open the horse’s mouth. They cannot hold this in their cheeks when you open their mouth. Unfortunately, if it is still in their mouth, you will most likely wear some of it! I hope these couple tricks help you.

Herpes viruses in general are very unique in that they go through an infected shedding phase as well as a latent carrier phase. Much like a cold sore on a person’s lip, the individual is contagious when the skin lesion blisters. Usually they “flare” when the individual’s immune system is depressed or compromised. While in the latent (quiet – quiescent) phase, the individual is only a carrier but not contagious. This is no difference in Equine Herpes Virus. The neurological form of Equine Herpes Virus is rather unique in that it shows up in these brief outbreaks. In the abortion strain of this virus, there are similar outbreaks. On a large breeding farm, there would be “abortion storms” where a large percentage of mares abort. The challenge with preventing these outbreaks is that you have asymptomatic carriers, and you don’t know who those are. When those individual horses become stressed (such as pregnancy), the virus becomes symptomatic again. Herpes viruses are a very ubiquitous type of virus in all species. The cold sore example in people is a prime example. Think about how many individuals are carriers. This is similar in young horses being exposed, but not necessarily being symptomatic. All carriers have the ability to “flare up,” become clinical, and spread the virus to others at any horse at any time, but are more likely to show problems when compromised.

 Thumps, also known as synchronous diaphragmatic flutter, is a condition that is caused by a combination of dehydration and electrolyte imbalance. The cause is usually thought to be low calcium, however other electrolytes of concern include magnesium, potassium, sodium and chloride. The low calcium and other electrolytes lowers the depolarization threshold of nerve impulses. The phrenic nerve, which controls the diaphragm, is the most sensitive to depolarization and will start to fire rapidly.  Usually, the firing is in rhythm with the heart rate.  Sometimes this is not the case, but typically the ‘thumping’ will occur as rapid as the heart rate.

Some research has shown that horses on excessively high calcium supplements may have an increased incidence of thumps due to their inability to mobilize the excess calcium rapidly enough to be used for exercise demands. Therefore, horses on alfalfa-based diets tend to have problems with thumps more often than horses on grass hay-based diets because alfalfa is high in calcium.  Additionally, horses consuming large quantities of digestive supplements which contain high calcium can experience thumps.  Horses given diuretics may get thumps due to the dehydration induced. Therefore, the best prevention to maintain the horse on a balanced diet including grass hay and grain concentrate with electrolyte supplementation only during race days or when sweating profusely during training.  These electrolyte supplements should be formulated for horses (not humans, such as Gatorade) and have salt as the first ingredient.  Paste electrolytes are usually the best because they can be administered like a dewormer at a specific dose and only when the horse is sweating.