Lyme Disease in Horses

Ticks can transmit a number of disease-causing organisms to horses, including Lyme disease. Lyme disease is caused by the bacterium Borrelia burgdorferi. Many horses are exposed to this organism through tick bites, but few develop clinical illness, usually months post tick bite.

As in dogs and people, the possible diagnosis of Lyme disease often arises when more common causes of lameness, joint swelling, kidney disease, moon blindness or incoordination have been ruled out.

Typically, two blood samples are taken 2 to 3 weeks apart to see if anti-Borrelia antibody levels have changed significantly to indicate active infection. The two samples are important because many normal horses may carry high antibody levels. The disease can also be diagnosed by finding the organism in tissue taken by biopsy from an affected joint or lymph node. The SNAP test kits utilized for testing dogs for Lyme disease are likely valid for use in the horse, but so far are not licensed for that purpose.

If evidence of Lyme disease is found, a veterinarian may try a course of antibiotics to see if this will improve the horse’s clinical abnormalities. There are currently no Lyme vaccines approved for use in the horse.

Horse owners need to be tick-vigilant and manage their horses’ environment to reduce tick habitat. Clearing brush out of pastures and along both sides of fence lines is recommended. Keeping pastures mowed may also be helpful. Before riding through long grass or brush, use of topical insecticides is highly recommended.

Author:  Julia Wilson, DVM, MN Board of Veterinary Medicine.

This article was shared with permission from University of Minnesota Equine Extension Program. Make sure to follow them on Facebook and YouTube for even more equine information & education!

Is Your Horse Displaying Self-Mutilation Traits?

A characteristic that is often times difficult to pin-point, self-mutilation is sometimes an overlooked concern. The challenge lies in determining whether it’s truly a self-mutilation concern, or a behavior caused by colic or other health concerns.

So what is self-mutilation in horses? Generally, it’s much more common in males (often stallions) than in females. The pattern can develop as a colt, where they may begin to nip at their chest or flank. It is often brought by the on-set of sexual maturity. It can start as missing patches in the hair coat, and progress to more prevalent wounds.

It is important, if your horse is displaying signs of self-mutilation, to consult your veterinarian to rule out internal or external sources of pain. This can often times be the reason for the self-mutilation, so it’s important to troubleshoot these issues with your veterinarian.

Eliminating the pain (if present) is the first step in combating the problem. Other options could include a ridged neck cradle, providing more time out of confinement, adding a stall-mate or increasing work or exercise.

Like with cribbing, feed management can also play a factor. Providing free-choice hay, with a slow feeding haynet can sometimes ease that boredom that can be associated with the cause of self-mutilation. Again, consult your veterinarian on a treatment plan that will best fit you and your horse.

Avoiding a Hay Belly

I’ve often heard, ‘my horse has a hay belly, what should I do differently?’ Or,” he’s really big in the belly but he doesn’t have good muscles.”   Apart from a broodmare belly, post-colic surgery effects or a parasite situation, the answer sounds like a nutritional imbalance.  The good news is, once you know what a nutritional imbalanced hay belly is and what causes it, you can make adjustments in your program and avoid it in the future.

What does it look like?

Willow has had 4 foals, and as a result, tends to show characteristics of a hay belly.

Willow has had 4 foals, and as a result, tends to show characteristics of a hay belly.

Have you ever seen a young or growing horse with a big belly while the rest of their body looks small? Or a mature horse that has a midsection that hangs low, while ribs are visible and muscles along the back and hindquarter are hard to find?  How about the ‘pregnant gelding’ situation?  All of these are describing a hay belly.  On a regular basis, you should conduct a body condition score on your horse to check for muscle mass as well as appropriate fat deposition in key areas.  It’s important to check all areas indicated, since a rib or belly check alone doesn’t provide all the information.

What causes it?

When too many low-value calories are consumed without adequate protein (including essential amino acids), the body stores the calories as energy in cells yet the needed protein isn’t available to maintain muscle mass. In the absence of adequate protein, muscles atrophy while stored energy increases. Over time, a hay belly emerges as muscle mass over the top is lost and gut size may expand.

The biggest factor is overfeeding fiber high in Neutral Detergent Fiber (NDF) while under feeding adequate levels of quality protein. NDF is a measurement of cell wall content in plants such as grasses.  As the plant matures, it builds up stronger cell walls so that it may hold itself upright.  The stronger these walls, the less digestible these cells are for a horse.  So when fed very mature hay, your horse is less able to digest that hay, as compared to hay with a lower NDF value (less mature).  In addition to being higher in NDF, the grasses also tend to be lower in the quality proteins; important nutrients for developing and maintaining muscles.

How to prevent a hay belly

First, feed the best quality hay that you can find in the correct amount for your horse’s body weight, age and activity level. The hay that is smooth and ‘leafy’ tends to have levels of NDF that are better for the horse to digest. Hay that is pointy to the touch or looks like it’s a green version of straw should be avoided as it simply offers little nutritional value for the horse.

How do I get rid of a hay belly if my horse has one?

First, check the quality and quantity of hay your horse is eating. If the quality is adequate, then it’s time to reevaluate the quantity fed.  A horse should be fed 1.0-1.75 pounds/100 pounds of body weight of hay per day.  Not a fan of math? Yea, me neither.  Here’s a quick answer: for a horse weighing 1,000 pounds, that would be between 10-17.5 pounds of hay each day, ideally divided into 2 or even 3 feedings. Check to be sure you’re not inadvertently overfeeding, or underfeeding if your horse is actually bigger than 1,000 lbs. Learn to estimate your horse’s weight accurately here.

The last piece of the puzzle is feed. Make sure that the concentrate you provide is offering adequate quality protein.  Total protein alone can’t support or develop ideal muscles.  The right balance of amino acids is needed to build and maintain muscle quantity and quality.  Look for feeds that guarantee levels of Lysine, Methionine and Threonine.  These three key amino acids are the most important for your horse. And lastly, check to be sure you’re feeding the appropriate amount of concentrate.  Feeding a balanced diet and adding some exercise to help develop muscle mass and tighten up that tummy is a great way to reclaim that belly!

Quidding – More Than Just a Funny Word

Quidding of HayIf you’ve walked by your horses feeding area or water trough and noticed slimy balls of half chewed food laying on the ground, your horse may be quidding. Quidding is a response to mouth pain in which the horse loses or spits balls of semi-chewed food stuffs out of their mouth.

The most common cause of quidding is teeth that are uneven or that have sharp points. This does not allow the mouth to close properly and makes chewing extremely difficult.  There is a host of other mouth issues that can lead to this problem as well, including cavities, abscesses, and unseen injuries. This problem most commonly occurs in older horses, however all ages can be affected.

Besides the fact that quidding is an indicator that there is something wrong (and probably painful) in your horse’s mouth, this is an issue for a very simple reason: if the feed is falling on the ground, it is not being ingested and used by your horse. This can result in loss of weight and body condition as the horse may only swallow a fraction of what is being fed.  In fact, one of the first things you should check if your horse starts dropping weight and losing body condition is the condition of the teeth and mouth.

The good news is that quidding can be greatly improved or even cured all together with regular dental care by your veterinarian or an equine dentist. Often a process called floating the teeth can help file down sharp or uneven places on the teeth. Dental exams should happen at a minimum of once per year, even on healthy horses with no known problems. For horses who have dental issues, the check ups and/or treatments may be prescribed more often.

In addition to regular dental exams, a horse with dental issues should be fed a feed that is easy to chew and digest. Make sure the ration is nutrient-dense to make the most out of what they do take in and, if necessary, consider switching the horse with severe dental problems over to a complete feed that may be soaked to soften before feeding.

Feeding the Hard-Keeper Horse that has Ulcers

My horse is a hard keeper, and is also prone to ulcers.  What should I feed?

Horses vary a great deal in what level of nutrition is required to maintain desired body condition and muscle mass.  Horses have not been selected or bred based on feed efficiency, feed conversion or rate of gain, so there a lot of variation between horses.

A horse that is a hard keeper may require more Calories per day to maintain body condition than an easy keeper doing the same work.  One way to help this horse will be to feed high quality forage that has a high Relative Feed Value (RFV) that is associated with higher Digestible Energy (DE) per pound.  A good choice might be an alfalfa or alfalfa grass mix that was cut at early maturity so it has fine stems and lots of leaves.  This hay could be fed free choice or at least 3-4 times per day at a rate of about 2% or above BW/head/day.

The hard keeper may also benefit from a commercial feed that is high fat (8-9 % or higher) and controlled starch and sugar (so it can be fed at higher levels) with amino acid fortification (lysine, methionine and threonine) to help maintain muscle mass.  This feed can be fed a minimum of 2 times per day, and preferably 3-4 times per day so that the quantity being fed can be increased while controlling risk of starch overload through smaller individual meals.  The quantity can be increased with the desired forage to produce weight gain, and then adjusted to maintain desired weight.

A high fat supplement that is 20+% fat can also be used as a top dress.

This feeding plan may also be useful in reducing the risk of having ulcers redevelop after a horse has been treated with appropriate medication.  Free choice forage or pasture is a good option so the horse’s stomach is not empty for long periods of time.  Alfalfa contains levels of calcium and magnesium that may be useful in buffering acid in the stomach.  High fat, controlled starch feeds fed in small meals at frequent intervals may also be useful in reducing the risk of re-occurrence.   A feed that contains specific metal amino acid complex trace minerals may also help improve gut health and digestive tract tissue integrity in the stomach.

Cribbing: Not Always Just a Bad Habit

Cribbing, the process of a horse biting down on a stationary wooden structure, applying pressure and then breathing in deeply, can be destructive to more than just your barn and stalls!

A wooden fence that has been chewed by a cribber.

While cribbing has traditionally been thought to be just a vice or bad habit, new information indicates that a horse that cribs may be responding to a digestive upset. The act of cribbing produces excess saliva. This saliva helps to buffer the stomach and can calm the pain of things like ulcers and other digestive problems.

If you have a horse that cribs, the first step should be determining why the problem started. This may very well include a trip to the vet to rule out gastric ulcers or digestive issues. In cribbers who are diagnosed with ulcers, the behavior often stops or is reduced when treatment for the ulcers is started. Cribbing can also be caused by extreme boredom and is usually associated with horses who spend most of their time in stall situations.

It is important to note that cribbing is not a learned behavior – horses don’t start cribbing because they see their stablemates doing it. Rather, in a group of horses that all begin to crib the catalyst may be management practices that lead to some type of gastric distress. Some of these practices that can lead to cribbing include:

  • Not providing enough long stemmed forage
  • Feeding large grain meals all at one time
  • Not providing a properly balanced diet
  • Not giving adequate access to salt
  • Inadequate turn out time

The bad news is that once a horse has started cribbing, it can be a hard habit to break. As the horse bites down on the wood and inhales, endorphins are released that can give the animal a “high”. That is why it can be very difficult for the horse that has started cribbing to stop – they get addicted to what it does to their body. Unfortunately, cribbing is a very good way to cause colic (as well as destroy property), so all possible steps should be taken to end the behavior.

Once the source of the cribbing is confirmed and addressed, some recommendations to help stop the behavior and break the addiction can include:

  • Adequate long stemmed forage provided throughout the day
  • Plenty of turn out time with opportunities to interact with other horses
  • Stall toys to help ease boredom
  • Placing feed in multiple locations around the pen to make the horse mimic his natural grazing behavior
  • Feeding grain meals in small amounts several times per day rather than all at once
  • Providing a balanced diet
  • Giving ample access to loose white salt
  • Using a special cribbing collar or strap
  • Covering wooden surfaces with anti-chew paint

Treating the cribbing horse can be a challenge, but remember that the first step is figuring out why the problem started. Your horse’s cribbing may just be his way of telling you that he is in pain and needs your help.  

 

 

Starch Levels in Feed

In my previous blog post on this topic, we explored the role starch plays in the horse’s diet.  After (hopefully) warming you up to the idea of how useful this nutrient can be, I’d like to now dig in to how you can compare and contrast the varying levels of starch (and sugar*)  in feeds and hopefully this information will  help you compare and contrast to choose the best option for your horse.

Contrary to what you may have been told or read, most horses can tolerate a moderate level of starch each day.  If you have a horse that has been diagnosed with a form of equine metabolic disease, you will need to limit your horse to a ‘low’ controlled starch and sugar diet….which includes forage (hay and pasture).  Fructans, the sugars in forages, are too often overlooked when assessing the total diet of an EMS horse.  

Even if your horse has not been diagnosed with EMS, it is still important to understand the starch level in his diet and take it into consideration for your overall program. Think you know how to compare starch levels from one feed to another?  You might be surprised to find out that a bit of math is required. Simply comparing the percentage of starch on feed tags doesn’t quite tell the whole story.  To get to a true comparison, it is important to factor in the recommended feeding rate, which is, after all, what the horse experiences.

Let’s compare two feeds that are marketed as ‘low starch’; one has a starch maximum guarantee of 7% while the other has a maximum of 11%.  Pretty easy to tell which one is the lowest, right? 

Look beyond the percentage to find what's really in the feed

Not quite.  For our example,  let’s say we have a 1,000 pound horse at maintenance level activity.  Feed A, with 7% starch is recommended to be fed at a rate of 6 pounds per day, meanwhile, Feed B has a starch maximum of 11% and is recommended to be fed at a rate of 2.5 pounds per day.

Here is the formula to use:  Starch % * pounds fed/day *454 (converts to grams) = grams of starch fed/day

 

Applied to our example scenario, here’s how the math works out:

Feed A:  7% starch x 6 pounds fed x 454 = 190.68 grams of starch per day.

Feed B: 11% x 2.5 pounds of feed x 454 = 124.85 grams of starch per day.

Wow – a big surprise!  Not only is the 11% starch feed actually lower in grams of starch per day than the 7% product, the difference is actually rather significant given how different the percentages were.   It is important to keep in mind that it all comes down to what your horse actually ingests, so understanding the recommended feeding rate in pounds and then weighing your feed to hit that mark is what will make the difference.

It’s also important to understand that horses who do not experience a form of EMS have a higher tolerance for starches and sugar in their diet…and in fact, the performance horse will actually need those nutrients to support their activity levels.  It all comes to down to understanding what’s in your feed and how much you’re giving them.

*Though this blog article addresses ‘starch’ the same principles apply to determining the amount of other nutrients in a feed. 

Feeding HYPP Horses

HYPP horses need low potassium diets when compared to “normal” horses – less than 1% potassium in total diet including hay + grain.  But, a percentage in a feed is really only a percentage and doesn’t tell you what you really need to know – which is, how much potassium your horse is actually getting in the total diet.  This number will depend on the percent of potassium in each feedstuff, and how much of each feedstuff is being fed. 

Hay Selection:  Hay makes up the majority of the diet so typically contributes the most potassium. It’s best to have your hay tested if possible, but if you can’t do that, keep in mind the following:

  • Oat hay and grass hay are the lowest in potassium
  • Orchard grass is high in potassium so stay away from that.

Feed Selection:

  • Textured/whole grain based feeds tend to be lower in potassium then pelleted feeds, since whole grains are naturally low in potassium, where some ingredients used in pellets tend to be higher potassium sources.
    • “Sweet” feeds may or may not use a lot of molasses, which is high in potassium. The “wetness” of a sweet feed may come from vegetable oils rather than molasses, so don’t automatically rule sweet feeds out. 
    • Some pelleted feeds can be a good choice if the horse is N/H and doesn’t have many episodes, but may not work for horses that are H/H and have severe or many episodes.   
  • Higher fat and calorie feeds may allow you to feed less, and this can lower total potassium as well when you can feed less to maintain body condition.
  • Do not feed electrolytes containing potassium. 
  • Do not use high levels of cane, molasses, or bran mashes because they may be high in potassium.

Doing the math: To determine how much potassium is in your HYPP horse’s total diet, you’ll need to do some good old fashioned math!

To check for total potassium in the diet:

(Pounds of hay x percent potassium in hay) + (pounds of grain x percent potassium in grain) / total lbs of feed

Example: If you feed 15 lbs of hay at 1% potassium and 6 lbs of grain  at 0.8% the calculation would be:

((15 x .01) + (6 x .008))/21 lbs of total feed = 0.942% potassium in total diet

From this example, the horse should do well on this diet.  If the horse can maintain body condition on less hay or grain, or if the hay tested lower in potassium, then that would be less potassium in the total diet as well. 

Other Considerations:

  • Starch Intake: It is a misconception that HYPP horse need low starch.  They actually need sufficient starch as a source of glucose, because glucose stimulates the release of insulin and this promotes potassium uptake by the cells.
  • Management:  HYPP horses should be turned out as much as possible and/or placed on a regular exercise program. 

Hay Soaking: All Washed Up or Good Management?

This article is courtesy of Krishona Martinson, PhD, University of Minnesota.

Soaking hay in water is a common strategy used to manage the nutrition of some diseased horses.  Current hay soaking recommendations include soaking hay for 30 minutes in warm or 60 minutes in cold water for removal of carbohydrates (Watts, 2003).  Soaking hay is commonly done to manage horse diagnosed with laminitis, Polysaccaride Storage Myopathy (PSSM), hyperkalemic periodic paralysis (HYPP), and chronic obstructive pulmonary disease (COPD). 

  • Researchers have suggested that diets contain less than 12 and 10% nonstructural carbohydrates (NSC) for horses affected with laminitis (Frank, 2009) and PSSM (Borgia et al., 2009), respectively. 
  • Reynolds et al. (1997) determined that a diet less than 1% K is necessary for horses diagnosed with HYPP.
  • Moore-Colyer (1996) determined that soaking hay for 30 minutes reduced respiratory problems for horses diagnosed with COPD or heaves. 

However, how efficient is hay soaking, and are additional essential nutrients lost during the soaking process?  Researchers at the University of Minnesota set out to determine the impact of water temperature and soaking duration on removal of NSC, crude protein (CP), minerals, and dry matter (DM) from alfalfa and orchardgrass hays. 

Four hay types were soaked, including bud and flowering alfalfa, and vegetative and flowering orchardgrass.  Individual flakes were submerged for 15, 30 and 60 minutes in 25 liters of cold (72°F) and warm (102°F) water, and for 12 hours in cold water.  A control (non-soaked) sample was also evaluated.  Water temperatures were determined by using the cold or warm only faucets, similar to practices implemented by horse owners and managers.  Subsamples of entire flakes were submitted for nutrient analysis at a commercial laboratory.

  • Prior to soaking, both alfalfa hays were below the 10 and 12% NSC threshold for horses diagnosed with PSSM and laminitis, respectively, and would not have required soaking. The orchardgrass hays were above these thresholds, however, after soaking for 15 to 30 minutes were at or below 10 to 12% NSC. 
    • Although soaking hay for longer durations did further reduce NSC content, it is not recommended.  All horses, even diseased ones, require carbohydrates in their diet. 
    • The severely limited NSC content in hay soaked for greater than 1 hour, combined with increased fiber amounts (fiber components are not water soluble, thus they are concentrated in soaked hay), brings into question the palatability and availability of nutrients in hay soaked for longer periods of time.
  • Crude protein leaching was variable in soaked hays, something other researchers have also observed (Moore-Colyer, 1996).  More importantly, previous research looked at the nutrient availability and quality of rained-on hay fed to steers and suggested the nitrogen remaining in rained-on hay is more stable, water-insoluble (Rotz and Muck, 1994), and possibly less digestible by ruminants (Licitra et al, 1996).  Additional research is needed to evaluate this concept when feeding soaked hay to horses.        
  • Calcium (Ca) is not as prone to leaching during soaking compared to other minerals, and appears to be dependent on hay maturity.  As soaking duration increased, leaching of Ca increased in alfalfa bud and vegetative orchardgrass hays (immature hays).  However, soaking had no effect on Ca leaching in the more mature hays. 
    • Conversely, magnesium (Mg) Mg and phosphorus (P) levels were reduced in all hay types as a result of soaking, with longer soaking durations leading to greater reductions.  Because Ca is not as water soluble as P, high Ca:P ratios were observed in hays soaked for  longer durations, specifically after 12 hours. 
    • Ideally, Ca:P ratios should range from 1:1 to 3:1 (up to 6:1) in horse diets (NRC, 2007).  The high Ca:P ratios observed after longer soaking durations were exaggerated in alfalfa hays which had higher Ca:P ratios prior to soaking. 
    • After 12 hours of soaking, a deficiency in P was observed and ranged from a shortage of 1 to 8 grams for a 500 kg horse in light work (NRC, 2007), and Krook and Maylin [32] suggested that osteochondrosis may be associated with excess dietary Ca. 
  • Soaking both alfalfa and orchardgrass hay for 12 hours was necessary to sufficiently reduce K concentration to recommend levels prior to feeding horses diagnosed with HYPP (Reynolds et al, 1997).  Although K levels can be reduced by soaking, neither alfalfa nor orchardgrass hay is an appropriate option for horses diagnosed with HYPP due to the naturally high levels of K. 

Owners should rely on forage analysis as the primary method of determining the appropriate hay for horses, especially when feeding horses diagnosed with laminitis, PSSM, HYPP or COPD.   Hay soaking for short durations (15 to 30 minutes in duration) is an acceptable management method, but should only be used if ideal hay is not available.  Hay should not soak hay for greater than 1 hour.  Soaking hay for long durations resulted in severely reduced NSC content, high Ca:P ratios, shortage of P in the diet and significant losses in DM.

My Horse Doesn’t Feel Good, What Should I Feed It?

Strangles abscess under a horse's jaw.

There are a number of potential illnesses which can cause horses to go “off feed” for varying periods of time.  Upper respiratory issues, such as strangles and influenza, may cause the horse to lose appetite and reduce feed intake.

There is a bit of a trade off with the nutrient requirements of the horse that is off feed due to illness.  On one hand, the horse may be moving around less because it does not feel good, so it is not burning up as many calories.  On the other hand, immune response and maintaining/building new tissue requires adequate Calorie intake, along with amino acids, minerals and vitamins, and adequate water intake.  There is also a difference between a healthy horse that is experiences reduced feed intake, and a sick horse that experiences reduced feed intake.  The body of the healthy horse conserves resources, while the sick horse has to expend resources to get well.

The following steps may be useful for the horse that is experiencing reduced feed intake due to fever or upper respiratory issues:

  1. Horses with a contagious condition such as strangle or influenza should be properly isolated with appropriate biosecurity measures to prevent the spread to other animals.  Biosecurity is a separate topic and is very important.
  2. Water should be available free choice, preferably from buckets, so that consumption can be monitored and so that the buckets can be cleaned regularly.
  3. Palatable forage should be used.  If a horse already has a respiratory issue, care should be taken to make sure the forage is dust free.   It may be dampened or soaked if needed.
  4. A palatable well fortified feed should be used to help maintain intake and provide the nutrients required to support immune response and healing, particularly adequate amino acids, trace minerals and vitamins.  Anti-oxidants such as selenium and Vitamin E may be useful.
  5. A feed with added fat may provide easily digestible Calories with reduced risk of metabolic disturbances.
  6. The goal should be to support the horse during the illness, and minimize weight loss and muscle wasting.

Regardless of the age of the horse, a senior horse feed may be a good option.  Senior horse feeds are very safe, highly digestible, highly palatable and well fortified.  They are designed to be used as complete feeds or with limited forage intake and can be made into a mash if needed.  They work well for many recovery conditions.

If a horse is in training, care must be exercised in that even a few days of stall rest can result in some loss of bone density and soft tissue strength, so training needs to be adjusted accordingly to reduce the risk of injury.  Also, lung function may not be back to 100% for several weeks following a respiratory infection.

Horses that are ill, and particularly ones that are severely emaciated, should be under the direction of a veterinarian.