Equine Protozoal Myeloencephalitis (EPM)

Equine Protozoal Myeloencephalitis, or EPM, is a serious disease that can be difficult to dignose because its signs and symptoms can mimic other health problems in horses and the signs can range in severity. More than 50 percent of all horses in the country may have been exposed to the causative organism so it is important to be aware of the signs and symptoms of this disease. 

The causative organism is a protozoa called Sarcocystis neurona, and is spread by opossums. Opossums are the definitive host which is an organism that supports the adult or reproductive form of a parasite. Opossums aquires the causative organism from cats, raccoons, skunks, and armadillos. The infective stage of the protozoa, the sporocysts) is passed in the opossum's feces and horses can come into contact with it while grazing or eating contaminated feed or drinking contaminated water. Once the sporocysts are ingested by the horse, the sporocysts will migrate from the intestinal tract into the bloodstream and will then cross the blood/brain barrier. Once this barrier is crossed, the horse's central nervous system begins to be attacked. Disease onset may be slow or sudden and if left undiagnosed and untreated, EPM can cause devastating and lasting neurological damage. 

The clinical signs and symptoms of EPM will vary and can be different in different horses. Clinical signs are usually asymmetrical, meaning not the same on both sides of the horse. Signs may include:

Ataxia (incoordination)

Spasticity (stiff movements)

Abnormal gait or lameness

Incoordination and weakness which worsens when going up or down slopes or when head is elevated

Muscle atrophy mostly along the topline or in large muscle groups like the hindquarters but can sometimes involved the muscles of the face or front limbs

Paralysis of muscles of the eyes, face, or mouth evident by drooping eyes, ears, or lips

Difficulty swallowing

Seizures or collapse

Abnormal sweating

Loss of sensation along the face, neck, or body

Head tilt with poor balance - horse may assume a splay-footed stance or lean against something for support

There are several factors that can influence the progression of the disease but these four things seem to play an important role:

The extent of the infection (number of organisms ingested)

How long the horse harbors the parasite prior to treatment

The point(s) in the brain or spinal cord where the organism localizes and damage occurs

Stressful events following infection or stressful events while infected

Almost every part of the country has reported cases of EPM, however there is a lower incidence of the disease in the western United States because of the smaller opossum population. About one percent of horses exposed to EPM will show clinical signs of the disease and due to the transport of horses and feedstuffs across the country, almost all horses are at risk to being exposed.

Diagnosing EPM can be difficult because there is no specific assay for this disease and it's clinical signs mimic other neurological diseases. A veterinarian will fist conduct a thorough physical exam to asses the horse's general health and identify any suspicious signs. One clue that can help lead to the correct diagnosis is that EMP tends to affect one side or part of the horse more than another. 

Early diagnosis and treatment are key to increase the horse's chance at a full recovery. Sixty to 70 percent of EPM cases that are treated aggressively show significant or complete reversal of symptoms with many horses being able to return to normal activity. Although there are drug combinations available to treat EPM, there are propriety anti-protozoal drugs specifically labeled to treat the disease. Anti-inflammatory drugs may be prescribed to alleviate symptoms. Vitamin E, an antioxidant, supplementation aids in healing the nervous system tissue. Treatment duration generally lasts one month when using the proprietary products, but can be longer (up to six months) depending on which medication is used. Treatments for this disease can be expensive and may affect stallion fertility and may pose health risks for unborn foals. Despite the high success rates, not all horses respond positively to treatment, with approximately 10 to 20 percent of horses experiencing relapse. During treatment taking blood samples may be needed to monitor potential side effects sushc as anemia, low platelet count, and low white blood cell count. Horses undergoing treatment should be closely monitored for sings of improvement or decline and any changes should be reported to your veterinarian immediately. 

The best way to prevent this disease is good horse keeping practices that discourage opossums and other rodents from getting into and contaminating hay, grain, bedding, and water sources. Here are a few suggestions for how to do that.

Keep feed rooms and containers closed and sealed

Use feeders that minimize spillage and are difficult for wild animals to access

Clean up any dropped grain immediately to discourage scavengers

Feed heat-treated cereal grains and pelleted feeds sind these processes seem to kill the infective sporosysts

Keep water tanks clean and filled with fresh, clean water

Maximize your horse's health and fitness through proper nutrition, regular exercise, and routine vaccinations and vet visits

If you have more questions on the topic, please contact your local livestock Extension agent and your veterinarian. 

 

Signs and Stages of Labor in the Mare

 

Is your mare in foal this spring?  Are you ready for the big day and the new arrival?  I recently had a friend adopt a mare and has been surprised to find out she is expecting, and asked for help.  One tool for her, and anyone in this situation is to understand the stages of labor.  Mares may display some or all of the signs below. 

 

Signs that the time is near:

•  Filling of the udder (2-4 weeks)
•  Distention of the teats (4-6 days)
•  Waxing of the teats (1-4 days)
•  Obvious dripping of milk
•  Sagging muscles around tailhead
•  Sagging of vulva (up to twice normal length)

STAGE 1:  Contractions started  (1-4 hours)

• May act colicky and paw the ground
• Sweat around neck and flank
•  Frequently passing small amounts of urine or manure
•  Pacing or circling stall or paddock
•  Up and down; nervous
•  Dilation of birth canal; water bag may become visible
•  Rush of fluid when bag breaks.  Do not break the water bag

Breaking of the water bag is the transition from Stage 1-2

 

STAGE 2: Delivery of the Foal (15-20 minutes)

·      If this stage goes past 30 minutes or you see a red, velvety sack, call your vet immediately!

• Usually, the mare will lie down for delivery.  If not, be close to catch the foal.  The mare may get up and lie down again to reposition. 
•  Normal delivery is front feet first with the nose tucked level with the knees, Soles of the hooves should be pointed down. One foot may be slightly in front of the other. If soles are up, call the vet immediately!
•  The foal will be encased in a thin, transparent to whitish membrane (amniotic sac).  If it does not rupture during delivery, tear it open and pull back from the foal’s face.  
•  The mare and foal may rest with the foal half out, but if stage 3 goes longer than 30 minutes, call the vet.

 

STAGE 3: Expulsion of the placenta (1-3 hours)

·      If the placenta has not passed in 3 hours, call your vet!

 

•  A retained placenta is toxic to the mare in less than six hours. 
•  The mare will usually stand up after delivery and the umbilical cord should break naturally

·      Do not cut the umbilical cord!  If needed, the cord can be broken manually by a twist/pull method or tied with twine, but best to follow your veterinarian’s guidance

 

 

After foaling, the foal and mare should be monitored closely for at least 24 hours.  The foal should be breathing normally, bright and alert, and should stand within 30-60 minutes after delivery.  Nursing should happen within 2 hours,  If not, call your vet.  The first 8-12 hours are critical to absorb enough antibodies through the colostrum.  The foal should also pass the meconium within 12 hours.  It is recommended for the mare and foal to be seen by the vet within 24-36 hours after birth to examine them and the placenta/afterbirth.

 

Information in this article was compiled from The Equine Reproduction Lab at Colorodo State University, along with a Vocational Services, Inc. (VSI) foal kit and an article from the University of Illinois CVM.

iPhone, iPad, iSperm?

 

Let’s face it, technology has become a necessary evil in almost every sector of agriculture including the reproduction of livestock. . .enter iSperm.  iSperm boasts being “the first mini/mobile computer-assisted sperm analyzer (mCASA)”.  Since it is mobile, it can help the user monitor semen quality almost anywhere, including in the middle of a field.  Test concentration, motility, mobility and sperm kinetics with a user friendly interface on an iPad Mini.  Quickly calculate total number of doses and amount of extender needed.  Results are archived in the cloud so you don’t even have to write anything down.  

Like most new technologies, there is an upfront cost associated with the purchase of the app, iPad Mini and a few pieces of collection equipment; however, this does make semen analysis access easier and more affordable plus iSperm has been validated by The Ohio State University School of Veterinary Medicine.  It has been used all over the world for research purposes and by many zoos to ensure the quality of their breeding programs for endangered animal recovery.  No more sending off samples for analysis, no more having to wait for results,  this portable semen analyzer gives you accurate results quickly.

More information about the iSperm system is available on their website: https://www.isperm.co/ or on the Breeder's Choice website.

Preventing Thrush

 

Winters in North Carolina are notoriously cool and wet, making it incredibly challenging to keep feeding areas, pastures, and sometimes even stalls from turning into mud pits.  Muddy conditions can lead to thrush - a disease caused by anaerobic bacteria and fungal infection in the hoof frog.  Bacteria enters the hoof through cracks in the hoof wall - which has been weakened by excess moisture.  For example, think about how soft your nails are after washing dishes or showering - and eats away at the soft hoof tissue.  Thrush is usually quickly and easily identified by its foul smell and black, tar-like discharge.

Like in most cases, the phrase "An ounce of prevention is worth a pound of cure" applies here.  For thrush, the best method of control is clean, dry hooves.  Cleaning out hooves daily and keeping paddocks and stalls clean can prevent most cases of thrush.  However, if you notice that your pastures and feeding areas are prone to standing moisture and mud, grading pastures or installing geotextile filter fabric to allow rain to drain can be very helpful not only for your horse's hoof health but also for your sanity and boots! For more information on controlling mud, check out some of our previous articles:

• Managing Winter Mud: Sacrifice Pasture Design
• Mud Management
• Why Install an Equine Dry Lot?

If your horse does develop thrush, there are several products that can be purchased.  Always consult with your veterinarian or farrier for advice before beginning any sort of treatment plan.

Forage Amounts for Horses

It has always been a rule of thumb that a mature horse should eat 1-2% of its body weight a day in forages. That means a 1,000-pound horse should eat 10-20 lbs. of good quality hay a day. This number is based off of the dry matter of the feed they are eating. Hay is normally about 90% dry matter because it has been dried and cured. So, if you take that dry matter amount and apply it to standing lush pasture that is normally about 20-30% dry matter that means the dry matter is a lot lower, so in turn the horse has to consume a lot more forage. Eating anywhere from 40-60 lbs. of forage in a day. But we also need to keep in mind that horses shouldn’t be allowed to eat very rich lush pasture 24/7 because it can lead to digestive issues and over eating. Horses are more prone to digestive issues because of the way their digestive system is set up. When a horse eats, the material passes through most of its digestive tract before reaching the main breakdown area of forages which is the cecum. The cecum houses protozoa and bacteria that break down forages so that the horse can absorb nutrients, but because the cecum is near the end of the digestive tract past the small intestine this makes horses not the most efficient eaters. In the body the small intestine is where the majority of nutrient absorption occurs and since that is before where the major break down process of most of the food they are eating, makes them less efficient than other livestock. Just remember that it takes a lot of forages to keep your horses gut operating normally and correctly so make sure they are receiving enough forages. Weigh some flakes of your hay bales to see if they are receiving adequate amounts. They may not be the most efficient eaters but they are more fun to ride than a cow, trust me.

Avoiding Colic Issues in Winter

 

    As we head into winter, horse owners face many challenges dealing with the cold weather. Unfortunately, winter can lead to a higher incidence of colic in horses. There are several ways horse owners can help reduce the chance of colic this winter.

    The biggest factor to consider is the grazing behaviors of horses. Horses will spend 10-17 hours grazing each day. Their digestive tract is designed to handle a constant stream of forage. If hay and feed are restricted to only one or two times a day, this can create issues with the ability of the gut to digest the hay. Try to space your hay feedings out over the day or provide constant access to hay if possible. Slowing down the consumption rate by using a hay net can help increase the time spent eating. This can also help alleviate boredom in a stall setting. 

    Many horse owners try to increase grain and concentrates in their horses’ diet in response to cold weather. However, hay does a better job of providing heat without upsetting the digestive tract. Make sure plenty of quality forage is available to help your horse handle the colder temperatures.

    Since hay has much less water than pasture, it is important to ensure your horses are getting enough fresh water. Horses often drink less in the winter due to a combination of factors. Try to keep water temperatures above 45 degrees to encourage drinking. Horses also tend to drink more after a meal, so it is important to provide water when feeding. If you provide salt to encourage drinking, you must make sure there is abundant drinkable water. If water troughs are frozen or empty there is the possibility for issues with salt toxicity. 

    It is very important to have your hay tested. A lab can determine the quality of the hay, including factors such as digestibility. Look for the NDF value on a hay report. The higher the NDF, the less digestible and palatable the hay is. This indicates the hay has more structural carbohydrates which are harder for the gut to digest. Visually, the more stemmy the hay is, the less digestible the hay is and therefore has a greater likelihood of causing impactions. Various factors impact the leaf to stem ratio, including age or maturity of the grass at cutting as well as species of forage. Warm-season grasses like bermuda or bahia grasses tend to have a lower leaf to stem ratio and therefore higher NDF values. Mature plants with lots of seed heads generally have higher NDF values and lower protein and energy. 

    Another factor to consider is exercise. Movement and exercise help move feed and hay along the digestive tract. Make sure your horse has access to turnout or some form of exercise throughout the day. Even hand walking a horse can help provided needed exercise. This is especially important for horses kept in stalls frequently. 

    The cold weather is approaching but by taking these simple precautions, you can help prevent colic and impaction issues in your horses this winter.

To Blanket or Not to Blanket?

Courtesy of: Nettie R. Liburt, MS, Animal Science Doctoral Student and Carey Williams, Ph.D., Extension Specialist in Equine Management

As fall arrives and temperatures are cooling, many horse-people may be wondering if blanketing their horses is appropriate. The answer really depends on the individual horse, its physiology, shelter type, tolerance to cold and its activity schedule. Typically in early fall, horse’s coats get a little thicker. Despite even warm fall temperatures, horses naturally begin to grow more hair as the days get shorter. There are no scientific rules about what temperature a horse should have a particular blanket, but if one decides to do so, there are several things to consider.
Clipping
Many owners/riders clip their horses to prevent them from getting a chill if their long winter coats are wet after a workout. Sounds ironic, but clipping a horse for winter can actually help the horse cool out from a workout and prevent a chill caused by a wet coat. However, proper management of a clipped horse is necessary. Whether your horse has a full body clip, trace clip, hunter clip or any kind of clip, one should blanket when the temperature drops, especially for turnout. Some people recommend starting to put sheets on clipped horses when temperatures drop below 60 degrees Fahrenheit, however, you should monitor your horse to decide what is best.
If one dreads clipping their horse, but doesn’t want a sweaty horse in January, one can blanket to help prevent a thick winter coat. Training intensity usually diminishes in the winter, and some horses rarely work up a lathered sweat. The catch with this approach is, once the sheeting and blanketing begins, it must continue throughout the season. When horses wear blankets and sheets all the time, it can tend to “flatten” the coat, causing it to lose insulating ability. That doesn’t mean that blanketing this year means an obligation to blanket next year, but once one starts blanketing, expect blanket duty all season long. Another option to help thin a heavy winter hair coat is to implement an artificial light regime, which will lengthen the amount of light in a day to 16 hours; this protocol is similar to that used to stimulate the reproductive cycle earlier in the spring.
Cold Adaptation
There are lots of other factors one can consider when deciding on winter horse clothing. Does your horse have trouble keeping weight on? Does the aged horse have trouble staying warm? Or, will the horse just tear the clothing off its body 30 seconds after it is in place? In any case, one can find a solution that works best for each individual horse.
Remember that when temperatures drop, horses have an increased energy (calorie) requirement to stay warm. Horses ferment fiber in their large intestine, and a byproduct of this process is heat. Thus, more hay added to the diet will help keep the horse warm during cold months. This process only works for hay; so increase hay and NOT grain. As a general rule, a 1% increase in energy requirement is needed to replace energy loss from cold weather for each degree the temperature falls below the horse’s critical temperature. Critical temperature is the temperature below which a horse starts to expend additional energy to provide warmth. This temperature for individual horses will vary because of fat cover, hair thickness, acclimatization of the horse to cold, wetness, and wind-chill.
Adaptation to cold is also important. The climate in the Northeast usually changes gradually, so horses have time to adjust to temperature changes. If one opts not to blanket, the horse will grow its coat naturally. If blanketing, one may find changing blankets is needed in response to day/night temperature changes during seasonal transitions. Studies in beef cattle concluded that the lowest comfortable temperature an animal with a full, dry winter coat can stay comfortable at is 18oF. However, this temperature is 59oF if the animal is wet, clipped, or has a summer coat. It is likely that the numbers are similar in horses.
How does one know if a horse should have a blanket? Just because a person is cold doesn’t necessarily mean that a horse is cold. Imagine a horse with snow on its back. Normally, the snow should be accumulating on its back. If the snow melts and the horse’s coat is getting wet, it is losing heat and is at risk for getting too cold. A note of caution here – you don’t want to put a blanket on a wet horse. Wet blankets will keep in the wetness creating an even colder horse, and potentially create a skin fungus if not allowed to dry out properly. In this case, coolers come in handy. Fleece or wool coolers will wick the moisture away from the horse, keeping it warm while it dries. Once the coat is dry, a heavier blanket can be put on.
A horse’s weight should also be taken into account when deciding on blanketing. Overweight horses have an extra layer of fat under their skin that adds to their insulation and helps keep them warm. So if this is the case with a particular horse it might not need blanketing as soon as other horses in the barn. On the other hand, for a horse that is underweight, the extra layer of insulation is not present so they may be one of the first in the barn to need blanketing. Keep this in mind when removing blankets in the spring as well.
If deciding not to blanket, remember, horses evolved without our help; and unlike us, they do already have a natural fur coat. One may even see some frozen whiskers, or ice-balls on fetlocks – as long as the horse isn’t shivering and its coat is dry, it is probably doing well! It is still important to monitor the horse’s well being in the cold, and to help out with some extra warmth if need be. Whether a horse is blanketed or not, it still needs some kind of shelter from the elements (stall or run-in shed). Horses in a shelter conserve up to 20% more body heat than if completely exposed to the elements, and about the same if they can lie down on clean bedding.
Selecting a Blanket
Once blanketing is decided upon, how does one choose from the myriad of choices? What size does one buy? What style is needed (i.e. sheets, turnouts, stable blankets)? What is right for the horse?
Size
Fit is very important for a horse’s blanket. Blankets and sheets that are too big or too small can cause painful sores on the horse’s withers, rubs on its shoulders and general irritation. Measuring a horse is easy. Use a flexible tape measure (one used for sewing is best.) Measure, in inches, from the center of the horse’s chest, straight back along his body to the center of his thigh, just next to the tail. Ponies usually measure in the 60’s, average size horses somewhere in the 70’s and larger warmblood or draft breeds in the 80’s. Use this number to select the size of the blanket. It may be necessary to round to the nearest even number when ordering blankets and some companies only use even numbered sized (i.e. 76, 78, 80, etc.)
Type
Sheets are the lightest, and come in many forms. Light cotton sheets are great for the start of the fall season in dry weather. Sheets also come in tougher material which may be a good choice if the horse has a destructive streak. Sheets also come in waterproof form, and are especially useful in wet areas.
Stable blankets and medium weight turnouts are the next step up. In tack catalogs or the local tack shop, one will see medium weight turnouts in the neighborhood of 200 grams of fill. Stable blankets are typically not waterproof, however, some turnout blankets are water-resistant, and some are fully waterproof. For turnout, a waterproof blanket is recommended. That way a roll in the snow or a sudden snow shower or cold rain won’t put the horse at risk of a chill.
Heavy weight blankets are around 300 grams of fill. Their weight is noticeable when a heavy blanket is placed on the horse, or when it is washed at the end of the year! These are typically used for a fully clipped horse at the peak of winter, or during a drastic cold spell.
How does one know if a horse is too warm? This can be a problem when deciding when to remove blankets in the spring. If a horse breaks a sweat under its blanket, removing it or using a lighter one is warranted. Sweating under blankets is just as undesirable as putting a blanket on a wet horse. To be sure, check the horse a short time after blanketing. If the horse is sweating, a lighter blanket is recommended. On the other hand, if the horse is shivering, increase the warmth level. Remember in the spring, just because it is raining doesn’t necessarily mean horses need to be blanketed! It is best to check the temperature and the wind chill before deciding on blanketing.
Destructive Behavior
If the horse likes to rip blankets off (or the pasture mate does), make sure there isn’t an underlying problem, such as an ill-fitting buckle or strap, which is causing the blanket-ripping behavior. Assuming all is well, one can try anti-chewing applications (that are non-toxic of course) to help stop such behavior.
Finally, don’t just blanket a horse and forget it during the winter. There can be changes going on that the blankets hide (i.e. weight loss/gain, skin fungus or bacterial infections, blanket rubs, etc.). At least once a week, the blanket should be removed for a good grooming and to check for any problems.

Suggested Reading

Cymbaluk, N. 2001. Management and Feeding of Horses in Cold Weather. Ministry of Agriculture, Food and Rural Affairs, Ontario, Canada. Online at: http://www.omafra.gov.on.ca/eng­lish/livestock/horses/facts/info-coldweather-man.htm

Lewis, L.D. 1996. Feeding and Care of the Horse, 2nd Ed. Williams & Wilkins, Media, PA.

Mowrey, R. 1998. Horse Feeding Management: Cold Weather Feeding Practices for Horses. North Carolina Cooperative Extension Services. AG-558-6.

Williams, C.A. 2005. Are you ‘Stressing Out’ your horse? Rutgers Cooperative Research and Extension. FS656.

Source: https://esc.rutgers.edu/fact_sheet/to-blanket-or-not-to-blanket/