Colic Prevention Part 2

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Written By Dr. Kris Hiney

This month we will finish our discussion of common causes of colic in the equine, and what you might do to prevent them. Previously we discussed the importance of having a thorough emergency plan in place in order to make a potential colic less stressful for you. We followed that with a discussion of the most common management practices which will help minimize your horse’s risk of colic. These included quality and consistency of the diet, proper hydration and parasite control to name a few. This month we will focus on some of the less common reasons horses may colic. Although less common, they are no less important for the owner to be aware of these possibilities.

The sex of your horse may increase its likelihood of colic. Remember that colic just refers to general abdominal pain. Some mares experience discomfort relative to their estrous cycle. If your mare routinely shows mild colic at three week intervals, her ovaries may be the culprit. Normally cycling mares will ovulate every 21 to 23 days and this event can be associated with discomfort. Having a reproductive exam can also rule out if she has an ovarian dysfunction exacerbating her discomfort. If you choose to breed your mare, you must also be aware of the possibilities of colic associated with pregnancy. During gestation, the mare may experience colicky symptoms due to movement of the fetus. That does not mean that colic signs during gestation should be discounted. Follow your normal procedures of a thorough exam and consult with your veterinarian. Finally, mares are often crampy after foaling, as the uterus continues to contract in order to expel the placenta. Additionally there is a greater potential for twisted bowels post foaling due to the extra “room” in the abdominal tract. Typically these mares will experience very severe pain. As I have personally had to suffer the loss of a mare with a new foal at her side, realize that these are very real possibilities. Monitoring mares closely in the post foaling period may allow you to catch symptoms early and perhaps save her life. All in all, realize that there are risks one has to assume when choosing to breed horses.

The lifestyle of your horse may also cause it to colic. Some horses experience far more stress due to competition or travel than other horses. Some horses dislike horse shows or competitions so intensely that they work themselves into spasmodic colic. If this is true, you really need to closely examine why your horse is experiencing stress. Are you asking too much of them? Do you warm-up or ask the horse to perform at a different level than at which you train? Is the change in environment or the close proximity of other horses too much? Try to acclimate the horse gradually to stressful scenarios. Be reasonable in your expectations of your horse. Consider how nervous or anxious you may be at shows. Isn’t it likely that your horse may also experience anxiety (albeit for perhaps different reasons)? Ultimately, it may be possible that that type of career may not be a great fit for your horse. Consider a less stressful type of competition or even re-homing the horse where it may be more comfortable. After all, competitions and events serve as recreation for most horse owners. Is it really fun if your partner is miserable?

When traveling to events, also consider how long the horse is in the trailer. Hauling in a horse trailer for long periods of time is actually fairly tiring for the horse. Ideally you should let the horse rest every 5-6 hours. Coupling that with a change in a horse’s normal feeding schedule and reduced access to water, can set the horse up for colic. At rest stops, consider offering your horse flavored water to ensure he maintains his water intake. Begin to accustom him to the flavoring at home to ensure he actually likes it. This is especially critical in hot weather, when the temperature in the trailer can exceed the external temperature. Horses may lose a substantial amount of water through sweating that they may not have the opportunity to replenish. Horses may also be more likely to develop respiratory issues while confined in a trailer as well. While we often try to help the horse by keeping hay in front of them, open windows or sides can force dust and particulate matter into the horse’s airways. This can cause the horse to develop pleuritis, which is inflammation of the lungs. While it is a respiratory issue, the horse may still show colic-like symptoms. All in all, plan your travel with your horse’s comfort and health in mind.

What breed your horse is may also pre-dispose him to certain gastrointestinal disorders. Arabians and Arabian crosses are more likely to develop enteroliths than other breeds of horses. Enteroliths are essentially an accumulation of mineral within the intestine which forms a rock-like object. This can range in size from very small to the size of a softball or larger. While the reason is not yet known, this risk increases when these horses are fed alfalfa. This is especially true in the California and in other parts of the Southwest. However, this does not mean that a Quarter Horse in Iowa can’t develop an enterolith, they are just less likely to do so. High alfalfa diets are thought to cause enteroliths due to the high level of magnesium and protein combining to form crystals which make up the enteroliths. Diets higher in wheat bran have high levels of phosphorous which also contribute to enterolith formation. It is also possible that feeding highly digestible, lower fiber feeds like alfalfa may reduce gastric motility, allowing crystals to form more easily. Other lifestyle factors which lower gastric motility, such as lack of exercise or low frequency of feeding, increase the risk factor of enteroliths. Even the type of bedding chosen to be used can affect a horse’s risk of developing enteroliths. Horses on straw bedding, which allows an opportunity to nibble on high fiber feedstuffs, experience less enteroliths. While many believe that adding vinegar to the horse’s diet to lower colon pH may prevent enterolith formation, this has not been proven. Ideally, lower the amount of alfalfa in the horse’s diet, feed frequently and allow ample exercise are the best management choices.

While we can never completely ensure that our horses will never colic, following practical management strategies can lower these risks. Informed horse owners are those whose horses usually experience less health issues. Hopefully if you follow these tips from our last series you can have a colic free 2014! Until next month, enjoy some winter riding!

Obesity in Horses

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Written By Dr. Kris Hiney

Just like in people, many horses suffer from obesity related health issues. Overweight horses can have more trouble with joint issues, suffer from exercise intolerance and can even develop metabolic problems. While many horse owners know the risks of having an overweight horse, it may be difficult to reduce weight in these horses – certainly the horse is usually an unwilling participant!  In this article we will address management techniques and dietary strategies designed to reduce weight, but still keep the horse physically and mentally healthy.
First of all, which horses are good candidates for losing weight? Ideally most performance horses should have a body condition score around five. Horses that are slightly overweight, or have a body condition score of 6 or 7, shouldn’t be at a great risk for health issues, but certainly will perform better at a condition score of 5 or 5 1/2. Horses above a 7 have more risk of developing health issues such as insulin resistance, metabolic syndrome, or even Cushings in their later years. If the horse with a high body condition score also has uneven fat distribution, he is more likely to have metabolic issues, and may even be harder to remove weight from than a horse with a more even fat distribution (personal observation). Horses that have cresty necks, substantial amounts of fat over the tailhead, enlarged abdomens and fat in the area of their mammary glands or sheath fit this category.   It is more critical for these individuals to lose weight. Now that we have identified the horses which need to lose weight, let’s address a healthy weight loss plan.
One of the first issues to address is the quality of the horse’s forage. Ideally we will feed dieting horses harvested forage/hay, rather than pasture as it is easier to monitor their intake. Horses that are overweight will do better on mature grass hay which has less caloric density than alfalfa or alfalfa-grass mix. When selecting hay, look for more mature hays that have been cut at a later stage of growth. Typically these will be coarser stems and have seed heads present in the hay. However, when looking for lower energy hays, don’t sacrifice the overall quality of the hay – it should not contain weeds, debris, dust, mold, etc. We are just looking for fewer calories, not hay that your horse shouldn’t eat! Once we have the correct hay type, the owner will have to limit their horse’s intake. This can often be confusing, as we typically teach owners to feed based on a percentage of the horse’s body weight. However, in this case, we have a horse that weighs too much, and is consuming more hay/forage than it should. Let’s take a look at the math involved to determine how much the horse should eat.
For an example, we will start with a 1300 lb horse who has a body condition score of 8. If we looked up this horse’s energy requirements for maintenance, it would need 19.7 Mcals per day. But that energy requirement is based on a horse that is in a lean body condition. Remember that it takes more calories to maintain metabolically active tissue like muscle than it does fat.   So even if we fed our horse at its maintenance requirement, it is still receiving too much energy for its body type. We will now assume that for every body condition score we want the horse to lose, it should lose about 45 lbs. For our 1300 lb horse, our target weight is actually closer to 1165 lbs [1300 lbs-(45lbs x 3 body condition units)]. The maintenance requirement for the lean 1165 lb horse is 17.7 Mcal per day.    Using these numbers, we will calculate out how much hay this horse would need to provide that amount of energy. For this example, I will use a grass hay of advanced maturity with a caloric density of .86 Mcal/lb as fed. The amount of hay the horse would consume using our 19.7 Mcal figure would be 23 lbs of hay (19.7 Mcal/0.86 Mcal/lb), while the horse would receive 20.6 lbs of hay if we intend to provide 17.7 Mcal (17.7 Mcal/ 0.86 Mcal/lb). Let’s compare that with the standard feeding guidelines for horses based on body weight. If the target weight of our horse is 1165 lbs, and we fed at 2% of the target body weight, our horse would receive 23 lbs of hay. That certainly wouldn’t work because that would provide enough calories to maintain his current weight of 1300 lbs! So how much do we need to reduce his hay intake? If we feed the horse at 1.75% of its target body weight, the horse would receive 20.4 lbs of hay per day. However, even feeding at this rate will probably not get us to their target weight. Therefore, in order to really achieve weight loss in our horse, we should probably feed closer to 1.5 % of the horse’s target weight. That means our horse would only be eating 17.5 lbs of hay per day. For the horse owner, this means that in order to successfully achieve weight loss, we need to get a scale out to the barn, and physically weigh out the amount of hay the horse will consume in one day. While this may be time consuming, it is the most accurate technique to deliver the correct and consistent amount of calories.
Now let’s talk about some other practical issues. A horse that is only consuming 1.5% of its target body weight is going to have some “free time” that it is not used to having. We need to provide mental stimulation for this horse or it may development unwanted stereotypies such as cribbing or wood chewing. Continual stalling would not be ideal as this will certainly lead to a great deal of boredom and frustration. If possible, the horse should be kept in a dry lot (free access to pasture certainly won’t help!) with secure fencing. Do not underestimate the horse’s ability to get through the fence to graze! Also, providing other horses with which to interact, stable toys, etc. will help relieve boredom. If you find your horse finishing his meals too quickly, putting the hay in a hay net which is tightly woven may also slow down his rate of intake and alleviate boredom. While these strategies may sound tedious, it is important in order to improve the overall health of your horse.
Next month we will continue to discuss the dietary needs of a horse in a weight loss program, as well as how to safely use an exercise program to encourage weight loss.