Fall Health Concerns for Horses

Fall HorsesFall can be a beautiful time of year for horseback riding. However, falling leaves and frost can negatively impact horse health.
Ingestion of dried or wilted, but not fresh, maple leaves is associated with the toxicosis. Dried leaves are not generally believed to retain toxicity the following spring. Toxicosis normally occurs in the autumn when normal leaf fall occurs. Although studies indicate that leaves collected after September 15 are more toxic, cases of toxicosis in horses due to wilted leaves after summer storms have been observed. Horses are the only species for which maple leaf toxicity has been reported. Horses are often depressed, lethargic, and anorexic with dark red or brown urine after the first day of ingestion. They may progress to going down with labored breathing and increased heart rate before death. Horses should be fenced out of areas where wilted maple leaves are plentiful.
Prunus species (species in the cherry family) contain cyanide and should be removed from horse pastures. Cyanide is released after chewing the plant or seed, or when the plant material wilts (after a frost). Animals are most commonly found dead within minutes to a few hours of ingestion of the plant.
There are no reports of toxicity of horses grazing frost damaged pastures (includes grass and legume species). Frost damaged pastures can have higher concentrations of nonstructural carbohydrates, leading to an increase in potential for founder and colic, especially in horses diagnosed with or prone to obesity, laminitis and Equine Metabolic Syndrome. To reduce the chance of adverse health effects, it is recommended that horse owners wait up to a week before turning horses back onto a pasture after the first killing frost. Subsequent frosts are not a concern as the pasture plants were killed during the first frost.

This article is reprinted with permission from Krishona Martinson, University of Minnesota. This and other horse nutrition articles can be found at http://www.extension.umn.edu/agriculture/horse/nutrition/.

Horses, Heat and Humidity

Water into bucketSummer is in full swing, including the heat and humidity. Horses, similar to humans, may have a difficult time coping and cooling off with the combination of heat and humidity. The added challenge of cooling off partially results from the inability of the sweat to evaporate in humid weather. The combination of sweat and humid weather acts like an insulation, making horses even hotter. Some horses have diagnosed trouble sweating (anhidrosis) during hot and humid weather, which adds other challenge to cool off. Consult Veterinary support if your horse has trouble sweating.

Some ways to help you and your horse cope with hot humid weather is to calculate the temperature-humidity index (THI). Add the air temperature (in degrees Fahrenheit) to the humidity percentage. For example, if it is 80 degrees Fahrenheit and the humidity is 60%, the THI is 140. When the THI reaches 150, horses will have difficulty cooling off, at 180 working a horse can be unsafe to the horse’s health and you should actively help the horse cool off.

Another supportive tool is to take your horse’s temperature. Normal is between 99.5 and 100.5 degrees Fahrenheit at resting, and can range between 103 to 104 degrees during exercise. When a horse’s temperature reaches 105 this is dangerous and the risk of overheating or health damage can occur. Above 105 degrees horses are likely to suffer heatstroke and require immediate Veterinary attention.

Helpful ways to keep horses cool in hot humid weather:

1. Clean and cool water available at all times

Horses prefer fresh, cool water in sufficient amounts when it is hot and humid. Keeping clean and cool water in deep buckets in the shade will help keep water cool. In addition to the automatic waterers (if available) additional deep buckets may be required to allow horses to gulp water versus sip smaller amounts. I often will consume a substantial amount of cool water in one sitting in a light colored container when it is hot and humid.

2. Provide appropriate feed for the horse’s activity

Feeding excess hay in hot humid weather can contribute to added body heat from the digestive process. Feeding smaller amounts more frequently or use of a slow feeding hay bag may be beneficial. Feed a quality balanced feed that is designed for the exercise requirements of the individual horse. If I am a daily jogger, my nutrient requirements vary significantly from a marathon runner in training.

3. Consider individual fitness

Physical fitness and environments vary between individual horses. Research has shown horses well-conditioned and of optimal physical fitness tend to cope with hot humid weather more easily than those who are out of shape. Horses residing in climates with extreme heat and humidity tend to cope better than horses traveling and adjusting to different climates. Although the horses may cope better if they are acclimated to the heat and humidity, it is still important to observe safe exercise and offer healthy ways to help horses keep cool.

Proper Horse Hydration and Electrolyte Use

Although summer officially kicked off just this week, the heat has already been in full force throughout much of the country. Here are some helpful tips to keep your horse safe and hydrated throughout these steamy summer months.

Cold Weather Care and Feeding of Horses

Horse in pasture during snow fall

Cold weather, particularly below freezing temperatures and cold rains, requires that owners pay careful attention to their horses to make certain that the horses maintain weight through the winter months.

First, make certain the horses are at least a body condition score of 5 or 6, meaning that the horses are carrying some fat cover over their ribs. Body condition should be monitored by physical examination at least monthly as long hair can hide weight loss. This is particularly important for older horses. The horses should also be kept up to date on dental care and overall health care, including appropriate deworming. It is a good idea to let horses go barefoot with proper hoof care during the winter.

Second, adequate water, above 40 degrees Fahrenheit, should be available at all times. If water sources freeze, the ice should be broken at least twice per day. Owners should NOT rely on horses eating snow for their water supply. A 1200-pound horse will require 12-15 gallons of water per day during cold weather. Having inadequate water available or water that is too cold for horses to drink comfortably may contribute to impaction colic. A horse that does not have adequate water available will also decrease feed intake, which may lead to loss of body condition. Salt should be available free choice, preferably loose salt rather than a salt block as horses may not lick a cold salt block.

Third, provide shelter from cold rains and wind. Horses remain remarkably comfortable in cold weather if they are dry and have shelter from the wind. Cold rains mat down the hair coat, reducing the insulation value of the hair and causing the horses to lose body heat.

Fourth, feed more! A horse’s digestible energy requirement increases for each degree below the thermal neutral zone. Wind chill increases the energy requirement also. Hay or high fiber products produce more heat during digestion than do grains, so adding extra good quality roughage to the diet is a good option. Grain intake can also be adjusted to maintain the desired body condition, but needs to be adjusted gradually.

  • A 1200 lb. horse at maintenance requires about 17.7 Mcal (17,700 Calories) of DE for maintenance.
  • Each degree C below Lower Critical Temperature (Anywhere from 5 degrees C or 40 degrees F down, depending on what the horse is used to.) increases DE requirement about 2.5%. (NRC, 6th Edition, page 10-11.)
  • Converting to Fahrenheit, each degree drop requires about 1.375%, so if the temperature drops from 10 degrees F to 0 degrees F, the DE requirement may increase 13.75% to 20.13 Mcal or 20,130 Calories.
  • This increase of 2430 Calories would require an additional 2.8 pounds of alfalfa grass hay to maintain body condition.
  • If the horse does NOT get the additional DE, the horse could lose a little over a quarter of a lb. per day.
  • If we have 3 months of cold weather, it is very easy for a horse to drop a full body condition score.

Proper winter care will help assure that your horse is ready for winter activities and is ready for spring when it finally arrives!

Estimating Winter Hay Needs

Cooper and Ferris in a snowstorm

Question: We recently purchased a farm and will be housing our two quarter horses over the winter. They are trail horses who are not ridden during the winter. Because I’ve always boarded my horses, I’m not sure how to estimate how much hay I will need for the winter. Can you provide some guidelines?

Response: An adult horse at maintenance will consume between 2 – 2.5% of their bodyweight in feed (hay and grain) each day. For example, a 1,000 pound horse fed a 100% hay diet would consume 25 pounds of hay each day.

  • From October 15 to May 15 (when there is no pasture in MN), the horse would consume about 5,350 pounds of hay or 2.7 tons.
  • This would equal 107 fifty pound small square‐bales or six 900 pound round‐bales during this time.
  • For two horses, this amount would be doubled; 214 small squarebales or 12 round‐bales.
  • It is critical to know the weight of the hay bales; not all bales weigh the same.

If the same horse was receiving 5 pounds of grain each day, their hay needs would be reduced to 20 pounds each day.

  • From October 15 to May 15 the horse would consume about 4,280 pounds of hay or 2.1 tons.
  • This would equal 86 fifty pound small square‐bales or five 900 pound round‐bales during this time.
  • For two horses, this amount would be doubled; 172 small‐square bales or 10 round‐bales.

These estimates assume good quality hay is fed in a feeder to reduced hay waste. When feeding small squares‐bales, hay waste when a feeder was not used (hay fed on the ground) was approximately 13% compared to only 1 to 5% when a feeder was used. When feeding large round‐bales, not using a feeder resulted in 57% hay waste compared
to 5 to 33% hay waste when a feeder was used. Its always best to purchase some extra hay since horses may require additional hay during the cold winter months (depending on their access to shelter).

Author: Krishona Martinson, PhD, Univ. of Minnesota. Reprinted with permission of the author. For other topics from the Univ. of Minnesota Equine Extension, visit their website.

Blue-Green Algae – A Potential Hazard for Horses, Pets and People

drinkingCurrent weather and water conditions in many parts of the country have created conditions favorable for the rapid growth of blue-green algae. Please be on alert with your horses and dogs, and use precaution when around unfamiliar water sources.

These primative organisms are actually algae-like bacteria instead of being true algae and are also referred to as Cyanobacteria.  They grow rapidly and may produce the pea-soup green color in some bodies of water, along with some foul odors.  These rapid growth periods, called “blooms” most frequently occur when there is a combination of warm weather, intermittent or limited rainfall and an accumulation of nutrients, particularly phosphorus and nitrogen.

The planktonic groups produce the pea green water while the mat-forming groups produce dark mats that start on the bottom and float to the surface.  The planktonic species (Anabena, Aphanizomenon and Microcystis) are believed to be most likely to produce toxins which can be harmful or fatal to animals when ingested. (Fact Sheet on Toxic Blue-Green Algae, Purdue University, Carole A. Lembi)

These toxins may be ingested when animals drink the water or when they lick their coats after being in the water.  Animals are more likely to consume the water if fresh water supplies are limited from other sources.  Any animals that drink the water during a period when toxins are being produced may be affected, but toxins are not always produced when there is a bloom.

Providing a source of fresh, clean, safe drinking water is the best way to avoid causing animals to consume questionable water.  If pets go swimming, they should be cleaned off before they have a chance to lick their coats.

Toxic symptoms may include:

  • Vomiting
  • Diarrhea
  • Rash and skin irritation

Preventing run-off of nutrients into ponds and lakes is also important to help reduce the risk of these algae blooms.  Prolonged drought conditions in some areas have also increased the concentration of nutrients in the remaining water in ponds and lakes.

While not all “blooms” may produce toxins, avoiding exposure to or consumption of suspect water is recommended.  More information is available from local and state pollution control sites or extension sites.   A recent case in Minnesota reported that 2 pets had been killed and a boy was sent to the hospital (MPLS Star Tribune, July 4, 2015, Liz Sawyer) due to exposure to blue-green algae.

Spring Pasture Time for Horses!

Toby GrazingIntroducing horses to growing pasture is a welcome event each year, yet must be approached with caution. Introducing the horses to pasture too soon in the season or for too long a time period can be bad for both the pasture and the horses.

The following are some guidelines to consider:

  1. Do not turn the horses out on pastures too early. Grass needs time to recover from the stress of winter and should be allowed to re-grow to 6 to 8 inches in height, depending on the species, to allow roots to grow and to store some energy before being grazed.
  2. Horses should be fed hay before going out on pasture the first time. Do not turn them out with empty stomachs!
    1. Initial grazing should be limited to 15 to 20 minutes and gradually increased each day by 15 minutes until the horses are out for about 4 or 5 hours, at which time they can be allowed unrestricted time.
    2. If horses are allowed too much initial grazing time, the risk of digestive disturbance is increased as it takes the microflora in the gut some time to adjust to the difference in forage source.
  3. Do NOT overgraze! Pastures should not be grazed to below 3-4 inches in grass length or you will wind up with a dirt lot fairly quickly. Some weeds are also hardier than most grasses, so if pastures are over grazed, weeds will become more prevalent.
  4. Remember that cool season grasses growing very rapidly can be high in plant sugars (fructans), so caution is in order.
  5. Grazing muzzles might be an option for helping reduce rapid intake.

Proper introduction of horses back on pasture needs to be managed for the health of the horses and the health of the pastures!

Dehydration in Horses – A Year Round Concern

We sometimes think of dehydration as only a hot weather concern. Horses (and people) can experience dehydration any time they are losing more water from their body than they are taking in to maintain fluid balance. This can be a problem in warm humid conditions, but can also be a problem in warm dry conditions or cold dry conditions. This is a definite concern in cold weather when access to water may be restricted due to frozen water supplies.

Dr. Lon Lewis presented this very handy table on dehydration several years ago in his book Equine Clinical Nutrition: Feeding and Care.

% Dehydration Possible Symptoms
Less than 5%
  • No detectable abnormalities are generally present.
  • Skin becomes slightly inelastic with a pinch test time of longer than 1 second
  • Capillary refill times goes from normal of 1.5-2 seconds to about 3 seconds
  • Mouth and mucous membranes may be dry
  • Generally the feces will be dry and urine output may decrease
  • Severe skin elasticity
  • Capillary refill time will be over 3 seconds
  • Extremities will be cold and there may be weakness
12% and greater
  • Inability to stand
  • Shock
  • Muscle twitching
  • Weak pulse
  • Death can occur at or above this level

For an 1100 pound horse horse, 5% dehydration would mean the horse has lost about 55 pounds of water or about 6.875 gallons (1 gallon = 8 pounds of water).  At 12% dehydration, the 1100 pound horse has lost 132 pounds of fluid or about 16.5 gallons.

You may also see loss of performance and visual signs without doing these tests. I see this in the arena when I am judging, particularly during the hot humid conditions. I confess I have experienced some of the same symptoms when judging a long horse show while wearing a coat and tie! It takes me about 24 hours to rehydrate!

If you are not familiar with the pinch test or capillary refill time, it is a good idea to discuss these tests with your veterinarian as these are important quick tests to check the status of your horse as a part of general first aid along with being able to check pulse and heart rate. In general terms, the skin pinch test is best done over the shoulder or over the back. Capillary refill time can be checked by pressing on the gum to compress the blood vessels, then timing the return to normal color.

Dehydration may be due to many different factors and can contribute to impaction colic as well as heat stress or heat stroke. Dehydration may occur in cool or cold weather as well as hot weather. Horse owners should visit with their veterinarians to make certain they know how to recognize the various symptoms of dehydration.

Having fresh clean water available at all times and providing access to salt free choice (loose salt may be preferred during cold weather) all year long are required to help reduce the risk of dehydration.

Lewis, Lon D. DVM, PhD., Equine Clinical Nutrition: Feeding and Care, Williams & Wilkins, 1995, Table 17-1, page 392.

The Importance of Clean Water

Would you drink dirty water? Water that had algae, mud, maybe even feces in it? Would you be able to put it to your mouth and swallow?

I would, if it was a matter of survival. Chances are, if it was a matter of life or death, you would too. If that was the only water available and the choice was to drink that water or die, I am betting there are not many people who wouldn’t take at least a sip. But, would you drink your fill of that dirty, nasty water? Would you drink deeply so that your thirst was satisfied and your body was hydrated, all the way down to a cellular level? Probably not. And neither would your horse.

We all know that water is the most important nutrient that any animal can have. It is essential for almost every function, from digestion and respiration, to reproduction and lactation. But what we may often forget is that even though our animals have access to water, that doesn’t mean they are well hydrated. If their water is teeming with algae or full of mud or excrement, chances are that they are choosing not to drink as much as they could.  In the winter, if it is too cold or even frozen over, horses will have lowered intake as well.

A horse that is not well hydrated can run into a myriad of problems, not the least of which can be impactions that can lead to colic. Veterinarians will tell you that winter is prime-time for colic episodes that are directly related to lack of water. This is why it is important to monitor your horse’s water intake and make sure they are getting their fill on a daily basis.

The bare minimum amount of water that a horse needs on a daily basis is 0.5 to 1 gallon for every 100 lbs. of weight in a maintenance environment with a temperate climate. Add in performance demands, lactation, hot weather, humidity, etc. and the demand for water increases significantly. Your best bet? Keeping free choice clean cool water available at all times.

But how do you know if your water supply is up to snuff? There is a pretty easy test to tell. Ask yourself these questions as you stand at your horses’ pond, water trough or bucket:

  • Is it the right temprature? (between 45 – 65 degrees farenheit is preferred)
  • Is it fresh?
  • Is it clean?
  • Is it abundant?
    Would I want to drink it?

If you can answer “yes” to these questions, then you are providing a good water source that your horse should be happy to drink their fill from.

Take this “water quality quiz” today, and then take it again in the middle of winter, when the way you supply water to your horse may be entirely different. Because no matter what the season, water is key to a healthy, active horse.


Can You Feed the Flies Away From Your Horse?

In warm months, it seems like flies and other biting insects are always the #1 enemy of horses. They annoy, they bite, they cause itching, bumps, swelling and skin reactions. Often times horse owners go to great lengths to lessen the impact of flies on their horses. But can what you feed your horse actually have an impact on your fly population?

There are fly preventatives that may work for some horse owners which involve feeding a certain ingredient to the horse. Many people claim that giving apple cider vinegar daily will keep the flies away, while others swear by garlic powder or brewer’s yeast. The fact more often than not is that it is very difficult to get the horse to eat enough of these items to make a difference where flies are concerned because they typically have a strong taste and smell; the trick is getting the horse to ingest them at all. The important thing to remember is that horses are all unique and what works for your neighbor’s horse may not have the same effect on your horse.

Another alternative to feed the flies away is using a feed through IGR additive that is labeled for horses. This active ingredient does not get absorbed by the gut, but instead passes through into the manure, hence the “feed through” name. Once in the manure, the Insect Growth Regulator (IGR) causes the fly pupae to not mature into adult flies. With disciplined feeding, these products can be effective but may be expensive. One warning with this type of fly control – if you have close neighbors who aren’t controlling their fly populations you will likely see little difference because their flies will continue to come snack on your horse.

More traditional methods of fly control should not be discounted, including finding an effective fly spray, using fly sheets, and changing turn out times to when flies are less active. Cleanliness in your stable and proper manure management can also have an impact on fly populations.