Dr. Getty’s Tip: Calculating with PPM in Two Easy Steps

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Written By Dr. Juliet M. Getty, Ph.D.

The trace mineral content of most feeds and supplements is provided in terms of parts per million (ppm). A ppm is the same as mg/kg (1 mg is a millionth of a kg).

To do calculations, you need to convert lb or oz to kg using the following conversions:
·         1 lb equals 0.454 kg
·         1 oz equals 0.0284 kg

Example #1: Your hay contains 140 ppm of iron.  How much iron is in 20 lbs of hay?
Step 1: 20 lb X 0.454 kg/lb = 9.08 kg
Step 2: 9.08 kg X 140 mg/kg = 1271 mg of iron

Example #2: Your supplement contains 12 ppm of selenium in each ounce and you are feeding 2 ounces per day. How much selenium are you feeding?
Step 1: 2 X .0284 kg/oz = 0.057 kg
Step 2: 0.057 kg X 12 mg/kg = 0.68 mg of selenium

Formulas to remember:
·         Convert lb or oz to kg: lb X 0.454 = kg; oz X 0.0284 = kg
·         Calculate to find mg: kg X ppm (or mg/kg) = mg

About Dr. Juliet M. Getty

Juliet M. Getty, Ph.D. is an internationally respected, independent equine nutritionist who believes that optimizing horse health comes from understanding how the horse’s physiology and instincts determine the correct feeding and nutrition practices. She is available for private consultations and speaking engagements. Hear Dr. Getty address issues in horse nutrition at the Kirkland House Foundation in Delta, British Columbia, sponsored by “Hay…Girl!” on May 2, 2015. For more information, contact Pam Janssen at precioushaygirl@gmail.com or call 604-961-7265.

Dr. Getty’s comprehensive resource book, Feed Your Horse Like a Horse, is available at Dr. Getty’s website, www.gettyequinenutrition.com, as well as from Amazon (www.Amazon.com) and other online book retailers. The seven separate volumes in Dr. Getty’s topic-centered “Spotlight on Equine Nutrition” series are also available at her website (where Dr. Getty offers special package pricing) and from Amazon (in print and Kindle versions) and from other online retailers. Dr. Getty’s books make ideal gifts for horse-loving friends.

Dr. Getty’s website, www.gettyequinenutrition.com, offers a generous stock of free, useful information for the horseperson. Sign up for her free monthly newsletter, Forage for Thought; browse her library of reference articles; search her nutrition forum; and purchase recordings of her educational teleseminars. Reach Dr. Getty at gettyequinenutrition@gmail.com.

Water Losses in Horses

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Written By Dr. Kris Hiney

This month we will discuss the most important nutrient in your horse’s diet, but maybe the most overlooked. Because providing our horse with water may seem obvious, many believe water requirements may not warrant discussion. But how much do you really know about how much your horse should be drinking per day?

The amount of water a horse needs to consume per day is directly related to how much water the horse loses per day. Horses lose water through four ways: their manure, urine, sweat, respiration, and if a broodmare, lactation. All of these variables must be taken into account when determining how much water our horses should be drinking. When we increase these losses due to variations in diet, work or environment, we must allow the horse greater access to water. Sometime that may mean we need to be creative in encouraging the horse to consume more water.

One of the greatest water losses to a horse is often overlooked, horse manure. While we tend to think of it as a rather solid form that we must continually scoop, pick up or shovel, horse manure is mainly water. This is especially true if the horse is eating primarily roughages. On an all forage diet, horse manure contains as much as 72-85% moisture. In fact, the water lost through their manure may represent almost 60% of a horse’s daily water intake. If we switch the horse to a grain based diet, the manure actually becomes much drier. Now, that does not mean that this may be a great strategy to minimize water losses. Overly dry feces can lead to impactions and colic, which is certainly to be avoided! When a horse consumes forage, it must be digested through fermentation which requires a fairly liquid environment in the hindgut and therefore normal gut health. In part, this is why it is recommended to always provide at least 1% of a horse’s body weight in forage per day. Consumption of forage therefore encourages water intake.

Variations in diet beyond just forage versus grain, can influence water losses in horses. The total amount of feed the horse eats will alter its water requirements. As consumption of feed increases, the horse must consume more water in order to allow normal digestive processes to occur. While we mentioned already that forage does increase water losses and thus water intake, the type of forage the horse consumes alters its water needs. Obviously fresh pasture grass contains a much higher moisture content compared to dry feed which is typically only 10-15% moisture. Growing grass may contain as much as 80% moisture. When taking into account the total amount of grass a horse can consume, simple grazing may approach a horse’s basic water requirements. Don’t be surprised then if your horse visits the water trough less frequently while he is grazing compared to when you feed hay.

Urine obviously contributes to water losses in horses, but remember that the volume of urine may reflect the water balance in the horse. Urine actually represents the most variable water loss in the horse, as other losses are more directly tied to diet, metabolic demands and environment. Some horses simply consume more water than others, and as a result will excrete more dilute urine in order to rid the body of excess water. Alternatively, if we fail to adequately meet our horse’s water needs, the kidneys will act to limit water losses and concentrate the urine. Additionally, if the feed contains components that need to be excreted by the kidney, water losses will increase. For example, when horses are fed protein beyond their requirements, the extra amino acids are broken down into components that can be used for fuel. This process involves the removal of the nitrogen found in amino acids. The kidney incorporates the excess nitrogen into urea, which is then excreted through the urine. Excess electrolytes, in particular sodium and potassium, must also be excreted by the diet. If you have a horse that likes to consume his salt at a greater rate, you may notice that his stall may be wetter than horses which do not perform such a practice. If you own an enthusiastic salt eater, you may want to limit his intake to strictly his salt requirements.

Sweat represents a tremendous variable in water losses for the horse, dependent on temperature and exercise. Remember that horses are most similar to humans in that we both dissipate heat through sweating, compared to other species that may rely primarily on respiratory cooling or panting. As horses must breathe through their nostrils, panting is simply not an option for them. Increasing the environmental temperature can increase evaporative losses between 45 to almost 400% of the horse’s normal water losses. The addition of exercise on top of environmental losses can quickly lead a horse to dehydration and heat stress if water losses are not replenished. For example, cross country horses have been reported to lose as much as 50-75 lbs of water during a competition due to the sustained duration of activity. Respiratory water losses are also directly tied to temperature and work load as these have the greatest influence on respiration rate. Horses increase respiration rate, either to aid in cooling, or due to the increased demand for oxygen delivery to the muscle tissue. However, relative to sweating, respiratory losses are relatively minimal.

The good news is that horses, through training or adaptation to their environment, do become more efficient at heat dissipation and begin to minimize their water losses. However, full acclimation to increased environmental temperatures may take up to 3 weeks. While it would be nice if weather patterns would gradually increase over time allowing our horses to adapt, we all know that this is simply not reality. Therefore, when the temperature gage rises dramatically, or even sporadically, we must acknowledge that our horses may not easily be able to dissipate heat. This will require more caution on our part when working our horses during this abrupt changes in temperature.

Lactating mares also have a significant loss of water through the milk. The amount of milk produced can be very variable between mares, with an average of 2 to 3% of their body weight per day. This will increase their water requirements somewhere between 50 and 75% over their normal requirements. If we also remember that lactating mares have a very high energy demand on their bodies, their feed intake increases as well. Remember that as feed intake increases, the horse must increase their water consumption to maintain digesta flow, and to counter the losses of water through the manure.

So what does all of this mean relative to what we need to offer our horses? My basic recommendation is to always allow the horse access to water beyond what they are willing to drink. In general a horse will consume around 10 gallons of water per day. This is easily accomplished by offering two full buckets twice a day. However, if you find that the bucket is empty when it is time to refill it, consider hanging an additional bucket. Your horse will thank you!

Next month we will delve more deeply into the current research on strategies to maximize your horses water intake. We all are familiar with the adage that you can lead a horse to water but you can’t make them drink. However, sometimes we really need them to drink! We will also discuss some feeding strategies that may help your horse stay hydrated through the various activities he may encounter such as traveling, endurance exercise, or exercise during hot temperatures. Remember, there is more to know about water than just filling a bucket!

Omega Fields Presents Keys to Preventing Laminitis Article by Dr. Kris Hiney

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Newton, Wisconsin – Omega Fields’ Equine Nutrition Advisor, Kristina Hiney, Ph.D., has introduced a new article about key strategies in preventing laminitis in the equine. The article has been published in one of our Health E Letter issues, Omega Fields’ monthly, digital newsletter, and is also posted on their website, www.OmegaFields.com.

In the article, Dr. Hiney draws on her extensive personal knowledge, experience with equine nutrition and physiology, and scientific studies to try to identify which individuals may be at risk, and other strategies that may be employed to reduce your horse’s risk.

Dr. Hiney states, “While the outward appearance of your horse may give you an indication to whether they are susceptible to laminitis, there may be more to it than just which horses are overweight. There certainly appears to be a genetic link to laminitis.”

If owners wish to try and avoid the development of insulin resistance, the diet the horse receives may be critical. There is evidence that diets which avoid high amounts of sugars and starches, and have a low glycemic response, resulting in less insulin release. For horses which still need a significant amount of calories, diets which are fat and fiber based and properly formulated, rather than those which provide a higher glucose or insulinemic response, may prevent the development of insulin resistance. Certainly just monitoring body condition in the horse may be the easiest way to avoid insulin resistance. Although, if you ask any horse owner if that is easy you may get a different response! In addition, horses which receive regular exercise seem to be fairly protected against laminitis. However, it is difficult to know whether the exercise regimen aids in increasing insulin sensitivity, or is simply protective against obesity.

To read the complete laminitis article by Dr. Hiney that discusses the genetic role, obesity and insulin resistance, diet and lifestyle management, please visit our horse articles section on our website. <http://www.omegafields.com/blog/cat/articles-equine-articles/post/keys-to-preventing-laminitis/>

Dr. Hiney has been working with Omega Fields since 2008 to expand our connection with our customers, giving them the nutrition and health information from scientific perspective they would like to know. Each month, Kris presents a feature article concerning horse health in Dr. Kris’s Korner, her column in the Health-E-Letter. Click here to sign up for your free Health-E-Letter subscription delivered to your email address!

About Omega Fields
Omega Fields® is recognized as a minority-owned business. Its mission is to offer the finest quality, most nutritious products at fair prices, and to provide outstanding customer service. Omega Fields wants its customers to have exceptional experiences with their products, staff, websites and retailers.

Omega Fields is the first manufacturer in the animal health industry to use human-grade, non-GMO stabilized ground flaxseed, rich in fiber and antioxidants, and containing the optimum ratio of the full spectrum of Omega 3, 6, and 9 Fatty Acids for equine, goat, canine, poultry and human nutrition. The innovative use of flaxseed milled with a unique stabilization technology ensures long shelf life and superior quality for Omega Fields’ products.

For further information, contact Allison Kuhl, Omega Fields Director of Business Development at 920-550-4061, ext. 119; email Allison@omegafields.com; or visit www.OmegaFields.com or www.FLAX.com

 

Does the Season Affect Your Feeding Management?

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Written By Dr. Kris Hiney

Does the season affect your feeding management? Winter is the season of short days, long cold nights and reduced riding time for us and our horses. Often what we feed our horses in the winter shifts as their energy requirements change, as well as the feedstuffs we might be using. That shift in seasons may mean we need to look at our feed sources and our supplement regimen more closely.

To begin our discussion, remember that a horse’s energy requirements do change with the seasons. Cold weather creates additional caloric demands on the horse’s body in order to regulate its body temperature. When temperatures drop below a certain point, referred to as an animal’s lower critical temperature, it must expend more energy in order to maintain its own body temperature. For horses which are acclimated to cold temperatures (meaning we have allowed them to grow a hair coat and they have been housed outdoors), this lower critical temperature is usually around 5° Fahrenheit. When temperatures drop below this point, we really should be feeding our horses more. In general, for every two degrees drop in temperature, the horse needs 2.5% more calories to maintain its’ body temperature. Therefore, if it gets down to about 10 below, your horse will need 20-25% more feed! These numbers do not consider wind chill factors, which can drive up heat loss substantially. Bottom line, in light of this year’s extreme cold, if your horse is living outside this winter, you may find yourself going through your hay supply much faster than you had anticipated.

How you choose to supply that energy to your horse may be important as well. There are several strategies which may be employed to augment your horse’s calorie deficiency. One easy way to meet energy requirements, along with adding to the heat produced by the process of fermentation in the hindgut, is to simply feed more hay. Consumption of hay has a higher heat increment (or heat associated with digestion) than other feeds, therefore it helps to keep your horse warm at the same time. In addition, more calories can be provided by choosing a higher energy concentrate, such as one with higher concentrations of fat. There are many commercial feeds available with added fat, or choosing rice bran or a flax source may be an option. If choosing a fat-added feed, it will provide more calories to the horse without having to increase as greatly the volume of feed that you are using. Many horse owner’s also like to add warm mashes to their horses diet in the winter. This provides more energy to the horse as bran or pellet mashes are higher in caloric density than forage. The additional benefit is that you can increase your horse’s water consumption, which may have decreased in the winter if they do not have access to heated water. Finally, it just may make you feel good to feed your horse a nice warm mash on those cold days and nights.

Obviously the manner in which we feed our horses also changes with the season. Ideally, horses are allowed opportunities to graze pasture grass in the temperate part of the year. However, with the fall and winter, horses in northern climates much be switched to an all harvested forage diet. While many of the nutrient components in harvested forage may be completely adequate for your horse, realize that the composition of plants does change with advancing maturity. In order to be tall enough to produce hay, grasses and legumes must reach a more mature state than a horse would typically select left to its own devices. In addition, some nutrients, such as vitamin A, do diminish over time. In particular, omega three fatty acids are found in smaller quantities in hay than in fresh growing grass. As we have changed how we manage all of our production animals and switched to more grain based diets, they now consume much more n-6 fatty acids versus n-3 fatty acids than when they were more pastorally raised. In fact, knowledge of the higher content of n-3 fatty acids in grass is in part what has led to the rising consumer popularity of grass fed beef. Grazed cattle consume much more n-3 fatty acids compared to traditionally raised feed lot cattle which have diets much higher in n-6 fatty acids. The diet the animal is on directly influences the n-6 to n-3 fatty acid ratio in their body tissues. Diets higher in n-3 fatty acids have been shown to be anti-carcinogenic, anti-inflammatory and cardio protective. While we may not think about horses in quite the same way, or feed them a concentrate based diet like feed lot cattle, the same process of incorporation of more n-3 fatty acids into their tissues occurs when horses graze or are supplemented with n-3 fatty acids. Ideally, our horses also should be consuming more grass and n-3 fatty acids, and less n-6 fatty acids which are found so abundantly in concentrates. However, even switching to a harvested forage based diet can alter the n-6 to n-3 ratio compared to a fresh grazing. Hay making can result in a loss of fatty acids of more than 50%, especially of linolenic acid, with a comparative increase in n-6 fatty acids. In a study using ewes, grass fed ewes had more milk and tissue n-3 fatty acids than ewes fed a hay diet. But obviously we cannot always feed grass to our horses. Therefore, in order to mimic the natural diet of the horse, and provide them the positive benefits of n-3 fatty acids, we can supplement them in other ways. Flax is a rich source of linolenic acid which horses readily consume. Therefore, in the winter, why not try a flax supplement and at least return your horse’s diet to summer, even if the wind is still howling!

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!

Strategies to Reduce your Horse’s Chance of Colic

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Written By Dr. Kris Hiney

Last month I encouraged all horse owner’s to develop a preparedness plan in the event their horse colics.  This month we will discuss strategies that will hopefully minimize the chance that you will need that plan.  We will discuss feeding strategies as well as other important management techniques that will help keep your horse happy and healthy.

Feeding your horse properly is one of the easiest ways to help prevent episodes of colic.  Remember  the digestive anatomy of the horse, with its small stomach and large hindgut for digesting forage does not often fit well with  modern management practices.   The horse is designed to forage continuously throughout the day, typically for almost 18 hours.  This provides a continuous input of material to the hindgut without overwhelming the stomach.

1.Maximize intake of good quality forage.

To mimic nature, ideally a horse should consume 2% of its body weight in high quality forage per day.  This allows the best match to the horse’s normal feeding strategies.  Remember high quality forage does not necessarily mean rich or high energy forages which can lead to obesity.   Simply put, high quality hays do not contain molds, potentially toxic weeds or insects, or are not excessively coarse and stemmy.  Of course, toxins and molds can easily cause digestive upsets or result in feed refusals.

2.Avoid very coarse hay or staw as feed.

Excessively coarse hay may be harder for the horse to masticate and may lead to impactions.

3.Prolong feeding/chewing  time.

If your horse needs to consume less than 2% of its body weight due to the need to maintain proper body condition, using a slow feeding hay net will help prolong the horse’s feeding time.  As we increase the amount of time the horse spends chewing, more saliva will enter the stomach and buffer the acid that is continually secreted.  As horses only salivate with oral stimulation, this increase in chew time is extremely important.  This helps to maintain a healthy stomach and avoid ulcer formation.

4.Split up concentrate meals to smaller portions.

If the horse needs substantial amounts of concentrates in order to maintain body condition or support athletic performance, be sure to spread feedings into smaller amounts.  High volumes of concentrate may overwhelm the horse’s ability to digest it properly in the small intestine.  When concentrates escape to the hindgut they are fermented by a type of bacteria which produces organic acids and lowers the pH of the horse’s gut.  By lowering the volume fed at one time, this will avoid fluctuations in pH of the horse’s tract and promote a healthier population of microflora.

5.Slowly introduce new feeds.

If new types of feeds are to be introduced to the horse’s diet, be sure to do so gradually to allow time for bacteria to adjust.   Due to the ability of bacteria to either proliferate or reduce in population with changes in substrate offered to them, a change in the horse’s diet can wreak havoc in bacterial populations. Often this is what results in the overproduction of gas, a frequent cause of colic.

6. Maintain a consistent feeding schedule.

If your horse does not have free choice access to hay or pasture, be sure to maintain a consistent feeding schedule.  Horses are certainly creatures of habit that do best with consistent schedules.  This will avoid periods of time with the horses’ stomach in an unnatural empty state, or overeating due to excitement of feeding.
7.Avoid feeding horses off the ground.

Ingestion of sand can lead to the development of impactions or colitis from irritation of the gut wall.  Routine feeding of psyllium can aid in sand removal from the hind gut.  Feeding off the ground will also limit the exposure to parasites which are a frequent cause of colic through either blockages or disruption of blood flow.

8. Practice strategic deworming and parasite management.

Regular parasite control is therefore key to colic prevention.  Remember from previous articles that this does not mean indiscriminate deworming of horses without knowledge of their true parasite load.  In fact, an increase in colic in young horses due to ascarid impactions may be in part due to the anthelmentic resistance occurring in these worms.   Rather, remember to follow strategic deworming practices in consultation with your veterinarian.   Follow good pasture management practices and avoid overgrazing. This will help to limit your horse’s exposure to parasites.

9. Allow adequate water intake.

As winter approaches, it is especially important to remember that proper water intake is vital to maintaining normal flow of digesta through the horse’s tract.  Normally horse’s drink about 8-12 gallons of water per day.  We often think about increasing a horse’s water intake when it is hot or the horse is heavily working, but fail to think about water intake in the winter.  Horse’s actually don’t like cold water, and will greatly reduce their water intake if not offered warmer water.  Providing a heated bucket or tank will encourage your horse to drink water at the same rate throughout winter.  Be sure that it isn’t sending off any stray shocks however!  That will easily lead to dehydration as the horse is too frightened to drink!  You can also increase a horse’s water intake by offering a mashed feed.  Don’t forget however not to rapidly alter his diet!

10. Provide regular dental care.

While all of these tips primarily refer to the feeding management of the horse, other factors can influence his risk of colic.  Providing regular teeth maintenance will allow your horse to chew his feed properly.  As mentioned previously, coarse hay or poorly chewed hay can create impactions in the horse’s tract.

11. Exercise the horse on a consistent schedule.

Regular exercise for stalled horses is equally key.  Horses naturally travel several miles per day while foraging. We have created a rather artificial, sedentary life style for most of our horses. It is up to us to help provide a form of regular exercise and stick to a schedule.  While this may be difficult owners, it truly is best for the horse.   In fact, some companies are working towards creating automatic feeders which force a horse to travel through its paddock to obtain its feed. Such systems also have the added benefit of prolonging feeding time as well.

Next month we will discuss additional management strategies that will reduce your horse’s risk of colic which are linked to your horse’s lifestyle, breed or even sex!

 

Equine Colic: Are You Prepared?

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Written By Dr. Kris Hiney

Most horse owners at one time or another have experienced that dreaded sight of finding their horse rolling or kicking at their belly in their pasture or stall.  After all, almost 1 million horses colic in the United States each year, or about 11 in every 100 horses. It really is not a matter of if, but when a horse in your care will colic.  But now is not the time to panic, but to act logically and calmly.  The keys?  Be prepared, and have a plan.  This month we will discuss what symptoms you may see, what to do, and how to create a firm plan of action.  Next month we will discuss several important strategies you may implement to decrease the likelihood of your ever needing this plan.

First of all, horses can colic for a variety of reasons. As colic just means a generic abdominal pain, any discomfort in the organs associated with the gastrointestinal tract can be described as colic.  Even other organs, such as the ovaries or uterus in mares, can causepain and thus may show symptoms of colic. So what may lead you to suspect your horse may be colicking?

My first and strongest recommendation is to know your horse. Every horse has individual quirks of behavior, appearance etc.  The key to successful outcomes in colic, or in many cases of disease or injury, is catching a change quickly.  Any change in a horse’s normal behavior or appearance should immediately trigger a thorough investigation of the horse by the owner or manager.  So what might the horse be doing differently? Colic symptoms can range from the subtle to the severe and downright alarming.  Typically the severity of the colic will mirror the severity of the symptoms, but that is not always true.  Individual horses have a greater or lesser degree of pain tolerance. It is important to know if your horse is the stoic individual that works through an injury, or the type that becomes hysterical if they stubbed their hoof on a ground pole!  Subtle signs include horses which are off feed or water, but may not yet be completely refusing to eat or drink.  A change in behavior, being more depressed, less active or having a duller appearance may be signs of colic. Horses which are restless, or perhaps laying down more than normal, or laying in an unusual position may be colicking.  Pay close attention to foals, as foals can quickly develop abdominal discomfort related to disease, diarrhea ulcers etc.  A foal lying on its back is certain to be experiencing some sort of abdominal pain.  As pain becomes more severe horses may continually look at their belly or flank, kick at their abdomen, repeatedly get up or lay down.  They may begin to roll or thrash violently and can even injure themselves.  In severe pain, horses may break out into a sweat or grind their teeth together.

Depending on the severity of the colic, your next step is to step in and gather some information.  Obviously, if your horse is in uncontrollable pain, call the veterinarian immediately.  Otherwise, if you can safely evaluate your horse, perform a physical exam on your horse.  That will help your veterinarian know how soon they may need to arrive.  Record your horse’s heart rate, respiration rate and temperature.  It is important that you practice these techniques before you need them!  A horse’s heart rate can be detected in a number of locations, near their eye, under their jaw, on their pastern etc.  Make sure that you have a working thermometer. Now is not the time to discover a dead battery in your thermometer.  Listen to your horse’s abdomen to hear if there is the normal gurgle of healthy gut movement.  An absence of sound indicated gut motility may have ceased.  If you horse is stalled, check his manure. Is there as much as there should be?  What consistency is it? Is it drier or harder than it should be?  How much feed has the horse eaten since his last feeding?  Is his water consumption normal?  Finally, check your horse’s gum color and capillary refill time.  Pale white or blueish gums may mean the horse is severely dehydrated, or may be going into shock.    This information may be critical in making decisions that may save your horse’s life.

Now that you have some basic information, call your veterinarian.  It is important to have the veterinarian’s phone number readily available. Think about all cases of emergencies.  What if your cell phone has no reception or has a dead battery? Does your veterinarian make emergency farm calls? Will they be able to get here quickly enough to help you?  Discuss these issues with your veterinarian before colic strikes. They may offer some helpful advice on other colleagues they may trust when they may not be able to make the call.  Therefore you may want to post several numbers of veterinarians near your horse.
You also need to do some hard thinking about the financial reality of colic cases. Some colics can only be resolved surgically.  Are you prepared for this?  Can you financially afford colic surgery?  Realize that is possible for colic surgeries to cost nearly $10,000.  Looking into an insurance plan for your horse can help cover major medical costs.  Do your research and see which plan may be best for you and your horses.  You may also need to at least consider that the outcome of surgery may not be positive.  Discussing these scenarios with family and your veterinarian before your horseever colics is critical.    It will make this emergency scenario much easier on you and allow you to make decisions more quickly.

If you have made the decision that surgery is a viable option for you, add more details to your plan.  Do you have ready access to a truck and trailer? If you do not own your own, you need to have numbers of individuals absolutely willing to help, and located nearby, close at hand. The last thing you want at this point in time, is knowing your horse needs to get to a clinic, but you can’t find transportation.  Finally, know where the nearest veterinary hospital with surgical capabilities is located.  How long will it take to get the horse there?  This may affect your decision on when to load your horse on the trailer. Should you wait for your veterinarian to arrive at the farm, or should the horse immediately go to the clinic. Know where the clinic is located.  Now is not the time to be looking for directions or get lost in the middle of the night.  Practice!  The more that you have mentally and physically prepared yourself for these emergencies, the better the outcome for both you and your horse!
 

Strategies to Modulate Insulin Concentrations

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Written By Dr. Kris Hiney

Much recent research in the horse industry has centered on fluctuations in insulin concentrations under a variety of conditions and the effects on the health of the horse.  Many horse owners are aware that traditional feeding practices which rely on a larger proportion of concentrate feeding may result in prolonged insulin secretion by the pancreas.  In young horses, it is thought that prolonged elevations in insulin may lead to cartilage abnormalities, promoting epiphysitis and osteochondrosis.  High starch diets are linked to behavioral issues such as more excitable or reactive horses;  and certain typing up disorders such as polysaccharide storage myopathy and recurrent exertional rhabdomylosis. Finally, high concentrate diets can certainly contribute to the development of insulin resistance and laminitis. As a result of this information, many  current horse feeds are now designed to minimize insulin fluctuations in the horse.  These feeds are typically low in traditional cereal grains such as corn and oats, may be higher in fat and fiber, or may be processed differently.   All of these techniques are designed to either minimize or slow the absorption of glucose out of the small intestine, and thus lower the need of the pancreas to secrete insulin to regulate blood glucose.  But what if switching feeds or eliminating concentrate is simply is not enough?  Are there other options available to the horse owner which can potentially help regulate insulin and glucose in their horses?
One of the concerns for owners of insulin resistant horses is the frequent bouts of laminitis which occur if the horse is allowed access to pasture high in fructans.   Owners of these horses need to monitor their horses grazing carefully.  In order to avoid plants with high fructan content owners are advised against allowing access to pasture during the afternoon (when photosynthesis is at its peak rate), the spring, late fall or when grasses are stressed.  Further, warm season grasses offer a lower fructan concentration than cool season species of grasses and make better grazing choices for insulin resistant horses.

But why are fructans such a concern?

One of the theories addressing the laminitis inducing effect of high fructan content in plants is that fructans when consumed by the horse ,create changes in the bacterial population of the hindgut.  They undergo rapid fermentation, can alter pH of the gut and may result in bacterial endotoxin release.  However, this explanation does little to explain why insulin resistant horses in particular are so sensitive to fructans.  It may be that fructans trigger an increase in insulin itself that creates alterations to the vasculature of the hoof and the accompanying painful syndrome.   Insulin, while typically thought of as having a primary role in glucose disposal, has tremendous effects on the vasculature.  Insulin can act as both a vasodilator, or a vasoconstrictor.   Insulin resistance has been repeatedly been shown to cause cardiovascular dysfunction in many other species.  However, this role has not been fully explored in the equine.

In attempt to explore this issue, researchers conducted a trial examining changes in insulin and glucose in horses allowed access to pasture during two different eight hour periods.  Horses were allowed to graze between 7 am and 3 pm or between 12:30 pm and 10:30 pm.   In this experiment, nonstructural carbohydrate content of the grass varied from 13.5% to 19.1% from 8 am to 10 pm.  The study did find a detectable, though not large, increase in insulin, in the horses fed during the afternoon grazing period when NSC values were there highest.   While the number of horses used in the study was small, and the grazing period did overlap, this study does indicate that the concentration of insulin in the horse may be sensitive to fructan content of grasses. The horses used in this study were also not insulin resistant horses.   Insulin resistant horses  may have differed in their insulinemic response to the feeding schedules.  However, this study may offer information as to why bouts of laminitis are triggered in the insulin resistant horse exposed to the wrong type of grasses.

While we know that insulin resistant horses need to be stringently maintained on low soluble carbohydrate diets, other horses may benefit by paying attention to how we feed them.    While simply avoiding feeding grain may be an easy solution to avoiding insulin and glucose fluctuations, some horses  may require a diet higher in concentrates to meet their energy needs.  A common sense approach is to divide the horse’s meals into several smaller meals.  This is certainly an effective strategy in lowering glucose and insulin response.  However, one approach rather than running out to the barn multiple times per day to split up your horse’s meals, is to use a feeding system designed to slow down the horse’s consumption rate.  Researchers interested in this technique attempted to slow feed intake by adding grids to feed buckets, small hard balls or soaking the feed completely in water.   Using physical obstructions to feeding did prove to be successful  in increasing total feeding time, while adding water did little to alter consumption rate.  The best technique to lower insulin response was to add bocci balls to the bucket so that the horses had to move the balls around to gain access to the feed.  This idea has been elaborated to produce commercial feeding balls, which trickle out small amounts of concentrate as the horse rolls it about.  This also provides the added benefit of increasing the mental stimulation of the horse simultaneously!

An interesting new theory is that perhaps the stress we expose our horses to may contribute to elevated insulin levels.  Chronic stress does increase cortisol concentrations which may have inhibitory effects on insulin, thus creating a greater need for insulin secretion, or in essence an insulin resistant horse.  In humans, stress and high cortisol can result in insulin resistance and a shift in the deposition of fat in the body. Perhaps stress in horses may also be contributing to insulin resistance and why we see regional adiposity in these animals.  In an initial foray into stress evaluation in horses, researchers examined whether different feeding schedules resulted in an elevation in cortisol.  However, in this study feeding schedules were not a sufficient stressor to elicit any dramatic increase in cortisol.   It is interesting that equine researchers are starting to look in new directions to solve the puzzle of insulin resistance in the horse.  While at this time, the effect of stress on cortisol and thus insulin in the horse is just a theory, maybe it wouldn’t hurt us to avoid stressing our horses unnecessarily!

Much about insulin resistance and developing best practices still remains unknown.

For example, in a study in which pregnant mares were fed high concentrate diets and gained rapidly in body condition in the last trimester of pregnancy, foals from the grain fed mares were actually more sensitive to insulin and had lower resting blood glucose. This does indicate that fetal programming, or the in utero environment can have long lasting effects on the offspring, but not what management protocols may be best are unknown.  While we have learned much about insulin resistance in horses, so much remains unknown. We often have to look at studies in other species and try to extrapolate this information to our management practices.  So over all, the willingness to try new methods and incorporate new information may be our best option.  Continue to monitor grazing tightly in insulin resistant horses, get creative when feeding grain, and don’t stress your horse!

Keys to Preventing Laminitis

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Written By Dr. Kris Hiney

In previous articles we have discussed some of the key strategies in preventing laminitis in the equine.  Many of these have centered on grazing strategies which limit the horse’s access to pastures high in fructan content.  Remember that fructans are carbohydrates which are enzymatically unable to be digested in the small intestine of the horse.  These fructans pass into the hindgut of the horse where they are fermented by the microbial population, specifically gram positive bacteria. The production of certain organic acids and amines enhance the permeability of the gut wall allowing these and other endotoxins to enter the bloodstream of the horse and ultimately effect  the circulation to the digit.  However, it is not practical to simply right off all horses’ ability to graze.  Rather, we should try and identify those individuals which may have a susceptibility to fructan content in the grass.  With this month’s article, we will try to identify which individuals may be at risk, and other strategies that may be employed to reduce your horse’s risk.

While the outward appearance of your horse may give you an indication to whether they are susceptible to laminitis (See Carbohydrates III: Metabolic Syndrome), there may be more to it than just which horses are overweight.  There certainly appears to be a genetic link to laminitis, with pony breeds leading the list of susceptible horses.  Their comparatively thrifty genotype may make their utilization of carbohydrates and insulin sensitivity differ from breeds which typically do not possess these characteristics. For example, thoroughbreds, which typically have the reputation for being “harder keepers” do not experience the same rate of laminitis.  However, the lifestyle and management of thoroughbreds may differ significantly enough to partially explain the decreased incidence of laminitis.  Even within ponies, there does appear to be a decided link to genetics.  In a study examining the pedigrees of an inbred herd of ponies, 37% of these ponies had experienced laminitic episodes.  Of those, half had at least one parent which had also experienced laminitis.  Even in controlled research trials which attempt to examine the effects of various carbohydrate loads on horses, wide variability exists between individuals. This leads to the supposition that individual variation, thus genetics, is at play.  Thus, if you aware of your horse’s pedigree and know of relatives which have experienced laminitis, you might want to manage your own horse more carefully.  Perhaps some day the genes which make a horse more susceptible to laminitis will be identified, and we can use genetic tests in developing management protocols.

As mentioned previously, development of obesity and insulin resistance certainly predisposes the horse to laminitis.  One theory behind the development of laminitis in the insulin resistant horse is the glucose deprivation model.  When a horse becomes insulin resistant, more and more insulin release is needed to elicit a normal tissue response.  In essence, the tissues become “desensitized” to insulin.  One of the key roles of insulin in the body is to allow cellular uptake of glucose.  Due to the polarity of glucose, it cannot freely enter the cell without the presence of specialized protein transporters. Glut 4 is a protein transporter which is located internally in the cell until insulin binds to the cell membrane.  Binding of insulin to the receptor causes a cascade of intracellular reactions to occur and initiates the translocation of Glut-4 to the cell membrane.  The insulin insensitivity may result in Glut 4 no longer moving to the cellular membrane, and the inability of glucose to enter into the lamellar tissue of the foot, thereby starving it of glucose.  A recent study looked at the presence of different glucose transporters  found in skeletal muscle, the coronary band and lamellar tissue.  Glut-4 is the insulin dependent transporter found primarily within muscle, while Glut 1 is found in other tissues which have non-insulin dependent uptake of glucose, such as the brain.  While Glut 4 was heavily expressed in skeletal muscle, only Glut 1 was found within hoof tissues of both normal and insulin resistant ponies.    Therefore, glucose uptake in the hoof is thought to be insulin independent  and glucose deprivation within the hoof is unlikely to be the cause behind laminitis.  However, in a subsequent study, laminitis was induced in normal healthy ponies using a hyperinsulinemia-euglycemia clamp technique.   In this model, insulin is infused into the ponies at a constant rate, while glucose is infused at a sufficient rate to maintain euglycemia, or normal blood glucose levels.   Therefore, it is not an absence of glucose which causes laminitis, but perhaps the sustained levels of insulin or other hormones which causes this disorder.  This would certainly support the observation of the increased laminitis risk to the insulin resistant horse which suffers from hyperinsulinemia.

If owners wish to try and avoid the development of insulin resistance, the diet the horse receives may be critical.  Diets which avoid high amounts of sugars and starches, and have a low glycemic response, result in less insulin release.  For horses which still need a significant amount of calories, diets which are fat and fiber based and properly formulated, rather than those which provide a higher glucose or insulinemic response, may prevent the development of insulin resistance.   Certainly just monitoring body condition in the horse may be the easiest way to avoid insulin resistance.  Although if you ask any horse owner if that is easy you may get a different response!  In addition, horses which receive regular exercise seem to be fairly protective against laminitis.  However, it is difficult to know whether the exercise regimen aids in increasing insulin sensitivity, or is simply protective against obesity.

Many horse owners wonder if there is a magic pill or supplement that they can provide their horse in order to prevent laminitis.   One approach is to reduce the gram positive, lactate producing bacteria which prefer to ferment sugars and fructans.  Antibiotics are commonly used in the livestock industry in order to promote growth by shifting the microbial population within the gut. Some antibiotics select against gram positive bacteria, thus have been studied in the horse as a way to prevent laminitis.  While this may work, the use of anti-biotics in livestock for growth promotion has been banned in the Europe Union over concerns of anti-biotic resistance.  Similarly many in the United States have followed suit, searching for other ways to influence growth and increase immune status.  The use of probiotics and prebiotics may influence the gut microflora in favor of less potentially problem causing bacteria.  Ironically enough, short chain fructo-oligosaccharides have been demonstrated to improve insulin sensitivity, if not glucose levels, in obese horses.   However, none of these methods have been proven to prevent laminitis.  I would caution individuals to monitor diet, grazing patterns, and body condition first, before relying on supplements to prevent laminitis.

Laminitis In The Equine

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Written By Dr. Kris Hiney

Earlier we posted an article on the typical causes of laminitis and some feeding strategies that may help in preventing laminitis (Feeding Horses for the Prevention and Management of Laminitis).  We also discussed how we might approach feeding a horse which has already experienced  laminitis.  This month we will begin to delve deeper into the causative factors of laminitis and how to prevent its development.

Remember that laminitis is actually a systemic disease, with just the symptoms being visualized within the hoof.  Some insult to the horse’s system creates an alteration in circulation, ultimately leading to tissue damage of the sensitive laminae.   This period of time, referred to as the development phase or prodromal phase, includes the actual insult prior to the development of symptoms.    It is thought to be due to some change within the vasculature, that leads to ischemia, or lack of blood flow to the digit.  Whether it is a lack of nutrients or oxygen due to the decreased blood flow, tissue damage or death results.  This initial insult is then followed by the acute phase of laminitis.

In the acute phase, blood flow returns to the foot, typically at an increased rate, as this is the body’s normal response to tissue injury.  Even this reperfusion response can cause tissue damage.  This is when the owner now recognizes the development of symptoms. The horse will appear very stiff and reluctant to move, and may even lie down.  A particular stance may be assumed by the horse as he appears to rock back on the hindquarters and place the forefeet forwards in order to limit weight bearing.  Due to the pain and anxiety the horse is experiencing, his heart rate and respiration rate may both be elevated.  Finally, the owner may even be able to detect an increase in temperature of the hoof wall and a bounding or throbbing digital pulse.

If permanent changes to the architecture of the foot occur, whether in PIII displacement, permanent changes to the normal lamellar architecture of hyperkeritization of the hoof wall, the horse has entered into the chronic phase. These horses are typically more susceptible to recurrent episodes of laminitis. Diet restrictions and specialized hoof care are typically required to allow the horse to lead a comfortable life (Feeding Horses for the Prevention and Management of Laminitis).
Obviously laminitis can be a devastating disease for the owner, and most would strive to prevent the disease, rather than address a symptomatic horse. If we look more closely at the causative factors in these alterations to circulation of the horse’s digit, we may be able to do a better job at identifying horses at risk.
We will begin with a review of pasture associated laminitis, which has been addressed in previous articles (Feeding Horses for the Prevention and Management of Laminitis and Carbohydrates III: Metabolic Syndrome). Remember that pastures grow more rapidly at certain times of the year, and may store their energy as different types of polysaccharides depending on the species of the plant. Frequently fructans are noted as the culprit in causing laminitis. Fructans are found in greater quantities in cool season grasses, as well as during periods where photosynthesis is favored over plant growth. As fructans contain beta bonds, which are not digested enzymatically by the equine small intestine, they pass through the tract and arrive at the large intestine where they then undergo bacterial fermentation. Other types of carbohydrates may act similarly, including sugars and starches which escape the small intestine undigested (the classic carbohydrate overload model of the horse in the grain bin), as well as other types of carbohydrates that may be rapidly fermented (pectins, resistant starches etc). (For more information on carbohydrates, please revisit Carbohydrates: Definitions and Relationship to Equine Diseases.)

In this first model of carbohydrate/rapidly fermentable fiber overload, too much of this rapidly fermentable material reaches the hindgut of the horse. These feedstuffs favor the proliferation of a particular bacterial population. These bacteria produce more lactate as their excretory waste. Excess lactate production lowers the pH of the hindgut which allows the mucosal cell wall to become permeable. In addition, too low of a pH stresses the bacteria causing them to either die or release endotoxins. Furthermore, altering the bacteria’s environment also changes their metabolism, releasing vasoactive amines into the hindgut. As the gut wall becomes more permeable, these toxins and amines are able to cross the mucosal wall and enter the bloodstream of the horse, where they then can exert their effects at the level of the hoof.

Horses which need to be restricted from pasture typically include ponies, as they are highly susceptible to laminitis.  In addition, any horse that has a history of laminitis, or has been diagnosed with PPID (pituitary pars intermedia disfunction)(Carbohydrates III: Metabolic Syndrome) should be grazed with care.  Horses with elevated insulin levels, or insulin resistant horses, also have a greater sensitivity to pasture associated laminitis, due to the influence of insulin on the vasculature of the horse.  Hyperinslulinemia increases the production of endothelin-1, and down regulates the production of nitric oxide.  A decrease in nitric oxide production has been linked to an elevation of homocysteine.  Incidentally, elevations in blood homocysteine are also linked to heart disease in humans. There has even been a suggestion, although with no scientific data to support this theory, that excessive supplementation of sulfur amino acids to horses with insulin resistance is unwarranted.  Typically sulfur amino acids (ie methionine) are included in hoof supplements, and homocysteine originates from methionine metabolism.   To further confuse the issue, it does appear that individuals are more susceptible to this disease, even if they are the same age, sex, breed and are managed the same as non-effected individuals.

Obviously preventative measures aimed at reducing carbohydrate related laminitis issues center on diet management. Certainly it is not practical or even advisable to state that all horses must be kept away from pastures. However, knowledge of which horses are susceptible to pasture associated laminitis is key. Once these individuals are identified, they should be placed on a principally harvested forage diet. The forage chosen should have very little rapidly fermentable material. However, horse’s which do not have these susceptibilities can continue to be managed with relative ease.
Next month we will continue to discuss laminitis at a more detailed tissue level, and address further strategies to limit your horse’s chances of acquiring this disease.