Equine Diseases

Colic What is it?

Colic is a relatively common disorder of the equine digestive system. But “colic” simply means “abdominal pain,” which can have a variety of causes and treatments. Colic also varies greatly in severity. All instances of colic in horses should be treated as a potential emergency. If you suspect that your horse is displaying colic symptoms, seek immediate veterinary assistance.

How does it happen? Colic can be caused by: • Gas - Excessive accumulation of gas stretches the intestines, causing pain. • Obstruction or impaction - Fecal material becomes hard and difficult to pass due to dehydration, the presence of large numbers of worms, ingestion of sand, etc. • Strangulation - The intestines rotate or become entrapped, which prevents the flow of food and feces and blocks blood flow. • Infarction - Poor blood supply to the intestine, which leads to tissue death. • Inflammatory - Infectious diseases or other conditions can cause gastroenteritis or colitis (inflammation of the gastrointestinal tract) or peritonitis (inflammation of the abdominal cavity). • Ulcers - Erosions of the lining of the gastrointestinal tract can lead to pain and poor gastrointestinal function.

Signs • Anxiety or depression • Pawing at the ground • Looking at their flank • Rolling or wanting to lie down • Lack of or infrequent defecation • Poor appetite and water intake • Excessive sweating • High heart rate (more than 50bpm) • Lack of normal gut noises • Stretching out as if to urinate

Treatment Depending on the type of colic a horse has, different forms of treatment will be necessary. Analgesics such as flunixin meglumine (Banamine) and detomidine or xylazine are used in almost every colic case to help control the abdominal pain that can be quite severe. A nasogastric tube may also be used to relieve pressure in the stomach, giving gas and fluids a way to exit since horses almost never vomit. IV fluids may be necessary if the horse is dehydrated or in shock.

If the horse is thought to be suffering from an impaction, the goal of treatment is to get faces moving again. Usually, mineral oil or another type of lubricant or laxative is given to help loosen and dislodge the impaction. The horse may be held off - feed until he has defecated, which indicates that normal gastrointestinal function is returning. Surgery is required in some cases of colic, such as when the veterinarian suspects there is a twist in a loop of bowel. The outcome of surgical colic cases is dependent on how long the colic has been going on, the condition of the horse, and the location of the problem within the digestive tract. Most colic cases can be resolved on the farm with medical intervention. Follow your vet’s recommendations with regards to medications, feeding and activity levels. After recovery, return your horse to work slowly and watch carefully for any reoccurring signs of abdominal pain.

Prevention Occasionally, a horse will colic for no apparent reason. In such cases, the best prevention is to know your horse’s habits so that you can quickly identify a colic episode in the future. Here are some preventative measures you can take: • Always make sure that your horse has access to fresh, clean water. In the winter, horses are more susceptible to impaction colic. They don’t like to drink ice cold water. In cold climates, regularly check to make sure there is no ice buildup in the water buckets, or install water heaters. • Ensure that your horse has enough access to roughage in his diet, such as pasture or hay. This part of a horse’s natural diet provides the bulk needed for proper gut motility. Limit feeding grain and/or pellets to the greatest extent possible. • Make sure your horse has regular dental checkups to ensure there are no sharp points or missing teeth that prevent him from grinding his food properly. • Talk to your veterinarian about the best way to control intestinal parasites. • In the spring, slowly introduce your horse to lush pasture. Do not let him out to graze full -time on new spring grass all at once.

Heaves What is it?

Although many horses breathe hard after running, you may notice your horse struggling to breathe after playing, walking, or while resting. It is usually an indication of a severe medical condition. The most common reason for a horse struggling to breathe is recurrent airway obstruction, also known as heaves. This condition usually affects horses over six years of age and is not contagious.

How does it happen? Exposure to environmental elements to which a horse is allergic is the main cause of the horse heaves. These elements may include dust and pollen in the air, poor quality feed, hay that may be dusty or contain mold or weeds, or an allergic reaction to weeds or grass in their pastures. The heaves are most often seen in older horses that are kept indoors, but it can also be found in horses kept in pastures throughout the year. When a horse breathes in the allergens, the cells in their lungs release chemicals that can cause air passages to swell, thicken and produce mucus. As the horse breaths, the swollen passages trap the air, and the horse needs to make an extra effort to expel air from his lungs. The more exposure a horse has to allergens, the more sensitive its lungs are to them. There is some indication that the heaves may be hereditary because of the link to allergies, but ponies are often fed poorer quality hay to prevent them from gaining weight. Sometimes, the heaves may be the result of a lung infection, but it and other factors are still being researched.

Signs If you have older horses, it is important to be able to recognize the symptoms of the heaves to get them help and to manage their condition. Usually, the first symptom is a mild cough after or during activity like playing or exercise. Sometimes when a horse coughs, there may be a white discharge, or mucus, that comes out of their nose. The nostrils will also tend to flare open as the horse tries to breathe and get more air into its lungs. Although it will be easier to hear with a stethoscope, you may be able to hear the horse breath from across the barn if they have the heaves. Their breathing may be noisy because their windpipe, or trachea, may be full of secretions. If a horse with heaves doesn’t receive treatment, the condition will worsen, and in a year or two, they may have difficulty breathing at rest. The condition will continue to deteriorate, and the horse will lose weight because he cannot breathe while eating. Muscular energy is also lost in the attempt to breathe. A horse with the heaves may develop what is known as a heave line. It is a visible line of abdominal muscles that develop as the horse tries to breathe and push air out of their lungs. The lines run diagonally across the abdomen and sometimes the chest. Some of the lines appear as are indentions that indicate the horse’s muscles are trying to push air from their lungs.

Treatment Once a diagnosis of the heaves has been made, including its severity, then the veterinarian can develop a treatment plan. For milder cases of the heaves, they may recommend treating it by: • Taking the horse outside more often to expose him to fresh air. • Stabling him in an area with good ventilation, such as an end stall. • Leaving the doors and windows open more often to increase exposure to fresh air. • Keeping the stall clean.Feeding him at chest level as feeding him on the ground or from a feed bag can increase their exposure to dust and hay particles. If your horse as a moderate case of the heaves, then the vet will prescribe medications for him, such as: • Oral corticosteroids like prednisone or dexamethasone to control the inflammation of the airways. These medications can help to reduce thickening of the airways and mucus production. • Oral bronchodilators like clenbuterol help to dilate and open airways to make it easier for the horse to breath. • Expectorants can break down mucus and make it thinner, so it is easier for the horse to expel from his lungs. Usually, an over - the - counter expectorant will work well, but a vet can prescribe potassium iodide if necessary. • Antibiotics may be necessary if bacteria are complicating the heaves. The bacteria will be found in the mucus sample taken from the horse during its examination.

For severe cases of the heaves, the vet may prescribe: • Inhaled corticosteroids to control inflammation of the airways. • Inhaled bronchodilators to open airways so the horse can breathe better. It should be noted that medications cannot “cure” the heaves, but only help to manage the disease. However, there are other things that owners can do to manage the disease as well.

Prevention Management is the key to preventing heaves in horses. Once a horse has had heaves, it will always be susceptible to developing the symptoms. Heaves must be managed through decreasing exposure to dusts known to make the horse’s disease worse. However, the longer the horse remains in clinical remission, the less likely it will develop another severe bout. It is not yet known if changes in the horse’s air passages that are consequences of inflammation can ever be truly reversed even with environmental management or long - term treatment with corticosteroids.

Laminitis What is it?

Laminitis (inflammation of the lamina of the hoof) is a common and potentially devastating foot problem that affects all members of the equine family. The disease process involves a breakdown of the bond between the hoof wall and the distal phalanx, commonly called the coffin bone, pedal bone, or third phalanx (P3).

How does it happen? • Grain overload • Ingestion of lush grass • Severe intestinal disease: Surgical colic or diarrhea • Sepsis (circulating bacteria in the blood stream) due to, but not limited to: o Pleuropneumonia o Uterine infection due to retained placenta in post foaling mares o Septic peritonitis (infection of the abdominal cavity). • Exposure to black walnut shavings used for bedding • Overweight bearing (ex: your horse steps on a nail on the left front limb & is unable to bear weight; if the problem in the left front limb is not resolved, the right forelimb is at a high risk for developing laminitis from bearing most of the weight = contralateral limb laminitis)

Signs Signs of laminitis vary with the severity of the damage to the lamella and whether the laminitis episode is acute (hours or days old) or chronic (lasting more than a week). The most common sign that you would see is lameness ranging in severity from a minor head nod, to non - weight bearing and inability of the horse to stand up, having the appearance of walking on eggshells or sawhorse stance. An increase in digital pulse pressure in the arteries that supply the affected foot referred to as "bounding digital pulse" and/or the hoof wall feels warm/hot to the touch can also be a common finding as well, although not specific for laminitis. Laminitis most commonly occurs in the forelimbs and both forelimbs but can also occur in all four hooves, especially with circulating systemic disease. Whatever the cause, if the lamella is sufficiently compromised, the coffin bone can: 1) Rotate downward within the hoof capsule, forcing the tip of the bone down onto the dermis of the sole and compromising the vasculature (blood vessels) in that area and /or 2) The entire boney column can drop or "sink" within the hoof capsule, causing severe pain and extensive vascular injury. Sinking can occur symmetrically or asymmetrically within the hoof capsule. The hoof has an abundant supply of sensory nerve endings, so laminitis is a very painful condition. In fact, it is the extreme and unmanageable pain experienced by horses with severe laminitis that most prompts humane euthanasia in these cases. Other sequelae of severe laminitis that may worsen the prognosis for a good recovery include:

• Extensive destruction of the blood supply within the hoof • Chronic bacterial infection within the hoof due to poor blood flow • Prolapse of the tip of the coffin bone through the sole of the hoof • Bone destruction at the tip of the coffin bone from abnormal mechanical loading

Treatment Laminitis is one of the most studied diseases of horses. Even so, there is still much we do not fully understand. Consequently, prevention and treatment of laminitis remain the challenge. Once the horse shows signs of laminitis, the destructive process is well under way and treatment becomes much more challenging with a variable outcome. Your primary care veterinarian may recommend the following treatment options: • Immediate medical and/or surgical management of the underlying primary cause • Intensive systemic anti - inflammatory and pain therapy • Cryotherapy • Meticulous nursing care as these horses may spend a major part of their time lying down which can cause additional problems such as: o Colic o Dehydration o Pneumonia o Bed sores o Muscle wasting • Focused hoof care once your horse is stable enough

Prevention Factors that seem to increase a horse's susceptibility to laminitis or incr ease the severity of the condition when it does occur include the following: • Heavy breeds, such as draft horses • Overweight body • High nutritional plane (feeding large amounts of carbohydrate - rich meals) • Ponies, Morgans, miniature horses and donkeys • Unrestricted grain binges, such as when a horse breaks into the feed room (if this happens, do not wait until symptoms develop to call your veterinarian -- call immediately so corrective action can be taken before tissue damage progresses) • Horses who have had previous episodes of laminitis • Older horses with Cushing's disease