Equine Extension

Horse Racing Industry In Iowa Is Stronger Than Ever Before

The horse industry in Iowa is growing faster than ever before. From activities surrounding horse breeding, showing, racing, housing, training, riding and care, it employs more than 2,100 people and accounts for millions in revenue each year. The economic impact from horse breeding and owning is doing much to support our state’s ag-centric economy, and we need you to play an important part in making this message heard.

Water Quality for Horses

Water, the essential nutrient for life should be freely available for horses. The amount of water consumed by a horse is the best measure of water adequacy. The average daily intake of an idle horse weighing 1,100 lbs. under thermoneutral conditions is between 6 and 9 gallons. Heavy workloads and high heat and humidity may double to triple the requirement to 12 to 18 gallons per day. Lactation also increases water intake to a minimum of 8 gallons per day. Diet will affect water consumption. Grazing of lush, green pastures in the spring tend to decrease water consumption. Horses fed all hay diets drink more water then horses fed mixed hay and grain diets. In the winter, water below 45oF will reduce the horse’s voluntary intake and can lead to colic and/or impaction.

Horses drinking water
Figure 1. Horses Drinking Water. This Photo by Unknown Author is licensed under CC BY-SA

Interestingly the horse only spends 5–6 min/day drinking water over several visits to the water source. The bucket is the most common method of watering domestic horses. Heated buckets or adding warm water to the bucket help with water intake in the winter. Intake of water using automatic water systems is influenced by water receptacle and mechanism for dispensing water. Horses prefer float valve over pressure valve systems and prefer large bowls to small bowls.

Quality of water is important for a healthy horse. Water quality panel tests include nitrate/nitrite, total dissolved solids (TDS), sulfates, and coliform bacteria. The best indicator of water quality is total dissolved solids (TDS). The TDS sums the concentration of all substances dissolved in the water. The safe upper limit of TDS for horses is 6,500 ppm (parts per million or mg/L). Water below 1,500 ppm TDS is considered fresh water. Water greater than 5,000 ppm TDS is considered to be saline. Most human drinking water is less than 500 ppm TDS. The water can also be assessed by odor, color and temperature. Odor is affected by the amount of sulfates, manure or rotting vegetation. An increase of any of these can affect palatability and voluntary intake.

Coliform bacteria include total coliforms and fecal coliforms. These bacteria are considered indicators of the presence of animal wastes. Fecal coliforms are present in large numbers in intestinal contents of warm-blooded animals. Once outside the body they die fairly easily. Water containing fecal coliform bacteria should not be consumed without adequate treatment. Chlorinated water kills most bacteria. If the water is high in bacterial growth it may also be high in nitrates. Both may be due to surface contamination from runoff (fertilizers and manure).

Horses are more resistant to nitrate toxicity compared to ruminants. However, ingestion of large amounts of nitrates possibly due to contaminated water can cause gastrointestinal problems.  Water containing less than 400 mg/L of nitrate is generally safe, while a level over 1500 mg/L may be toxic. Nitrate can be converted to nitrite in the horse’s cecum. In horses, nitrite is 10 to 15 times more toxic, and concentrations exceeding 30 mg/L may be hazardous to a horse’s health. Generally, the only time a horse gets exposed to nitrite is ingestion of high-nitrite hay that was baled wet and the microorganisms changed the nitrate to nitrite. Thus, never feed moldy or wet hay to horses.

The Iowa State University Veterinary Diagnostic Laboratory will test the quality of water if you suspect a problem. The Water Quality Panel measures nitrate/nitrite, total dissolved solids, sulfates, and coliform bacteria.

  1. Equine Applied and Clinical Nutrition. 2013. Saunders Elsevier.
  2. Nutrient Requirements of the Horse. 6th Revised Edition. 2007 National Research Council. The National Academies Press. Washington, DC.

Horses Have A Highly Developed Sense of Smell

Olfaction (smell) is important for horse’s survival. Smell helps horse select what they eat (horses are sensitive to poisonous plants, moldy forage and grain, dirty water, etc.). Horses use smell to detect other horses by smelling feces, urine, and body odors. Smell is very important in detecting the sex and stage of estrous in mares.

Horses only breathe through their noses, or they can’t breathe through their mouths. The term for this is an obligate nose breather.  Horses have a large nasal cavity with structures called turbinate bones. Within the turbinate’s, inhaled air is mixed, warmed and distributes scents. Olfactory receptors are positioned towards the top of the nasal cavity. Olfactory epithelium lines the inside of the upper nasal cavity and connects olfactory neurons held in the turbinate’s to olfactory bulbs in the horse’s brain. The olfactory bulbs are relatively large in size and include numerous folds that increase the surface area over the receptor cells. Horses are thought to have about 300 million olfactory receptors, which is considerably higher than humans (five or six million olfactory receptors).

The horses nasal cavity
The horse's nasal cavity

Horses have an accessory olfactory system known as the vomeronasal organ that detects pheromones and volatile odors. When a horse breathes in strong odors, the vomeronasal organ expands, contracts, and sends the aroma to the brain. In response, the horse will display the flehmen response where they extend their neck, raise their nose, open their mouth slightly and curl the upper lip. The flehmen response is commonly demonstrated by stallions, but mares and geldings may also demonstrate the response. The flehmen behavior can appear as early as the first day of life in foals.

Flehmen response in horses
A horse displaying the flehmen response

Remember, odors can be used to smell predators, stage of estrous cycle, and social recognition of other horses and even people. It is beneficial to allow the horse to smell your hand, tack, or whatever is causing them to be anxious when working around a horse.

Resources

  1. Beaver, B. 2020. Equine Behavioral Medicine. Academic Press.
  2. Rorvang, M V., B L Nielsen, and A N McLean. Sensory Abilities of Horses and Their Importance for Equitation Science. Front. Vet. Sci 2020 7:633

Heat Therapy and Electrotherapy in Equine

Heat therapy is used to address low circulation, muscle spasms and nerve pressure. Arthritis is caused by the loss of cartilage that can lead to bones rubbing together and causing a tremendous amount of pain. Figure one shows the common areas where arthritis occurs in equine. Heating the localized area begins the repair process and prepares the muscle tissues for movement. Heat allows for increased circulation and according to (Worster, 2011), heating the tissues at least 5 oF allows for the relaxation of the collagen molecules.

Types of Joint Injections

Joint injections are a way to control inflammation and treat joint issues in horses, specifically equine athletes. Joint disease generally has inflammation (see the image below). Reducing inflammation is a goal in the treatment of joint disease.  Depending on the horse and their need, they may be treated with joint injections only a few times or receive treatments on a regular basis. There are three types of joint injections, depending on where the treatment is injected. These include intra-articular, intramuscular, and intravenous injections.


Inflamed equine joint


Intra-articular joint injections are injected directly into the affected or injured joint. This allows for a direct treatment of the problematic joint or area, however, it does have its risks. These include joint flares and/or joint damage. Caution should be taken if these joint injections are paired with corticosteroids as there is a risk of laminitis developing. The most common areas and joints injected on an affected horse are the hocks, stifles, and knees as well as the fetlocks, pastern, and coffin joints. There are only a few intra-articular joint injections that are FDA approved for equine athletes. This includes Legend, Adequan, and Depo-Medrol.


The second type of joint injections is intravenous injections. These injections are injected directly into the largest vein in a horse’s neck, the jugular vein. This method of injection is not as common and although it does not appear to have any side effects, horses have experienced depression, lethargy, and fevers post-injection. The only FDA approved intravenous injection is Legend, which requires a prescription from a veterinarian to be purchased.


The third type of injection is intramuscular injections. This type of  joint injections is most commonly utilized to treat non-infectious degenerative joint diseases and joint dysfunction. Lameness of the of the knee and hock joints fall into this category. The only FDA approved intramuscular joint injection is Adequan. This joint injection must be prescribed by a veterinarian. These joint injections have no known side effects or harmful reactions.


Joint injections are made up of many different components depending on the type of injection method, age of horses, targeted joint, etc. The first composition of joint injections is called the standard blend. The standard blend consists of some form of hyaluronic acid, steroids, and antibiotics. The ratios of these components vary by needs and application. Hyaluronic acid concentrations are varied to create long term relief of joint pain or simply a fast inflammation reduction. Antibiotics are included in the blend as a proactive preventative against joint injections, whether it is related to the injection sites or injury. Lastly, the steroid volumes depend mostly on how the horse has reacted to prior injections or if it has a known history of not taking up the joint injections well. An example of this is a horse experiencing laminitis as a side effect of joint injections.


The second type of joint injection blend is called the regenerative mixture. The regenerative mixture consists of stem cells as well as other components to improve the health of a joint rather than fix the current issue or cause of inflammation. There are three types of stem cells that are used in these regenerative mixes; platelet rich plasma (PRP), interleukin receptor antagonist protein (IRAP), and Pro-Stride. PRP can regenerate the soft tissue found within the skin and bones. These stem cells are primarily used to treat tendons and ligaments. IRAP is a natural anti-inflammatory product found in the joints of horses. This protein is produced by the horse’s blood to promote healing in injured regions of the body. Lastly, Pro-Stride is a combination of PRP and IRAP. This mixture promotes healing and reduces inflammation of injury within the body. The image below illustrates a needle inserted in the tarsometatarsal joint for arthrocentesis or joint aspiration to remove fluid from the joint.


Joint injection in horses


References


  1. Colin, T. An Owner’s Guide to Joint Injections in Horses. Equitait Veterinary Practice.
  2. Epsy, B and J. Harper. Lameness & Joint Medications. AAEP.
  3. Hebner, Kelly. Joint Injections for Horses: How They Work & When to Use. Mad Barn


Photo Credits


  1. Gibbard, D. Diagnosis and Treatment of Equine Joint Disease. Community Horse Journals.
  2. Tatarniuk, D. So what exactly are joint injections in horses? Equine Sports Medicine and Surgery.