How Much Does a Horse Need to Eat? - February 2005

Did you know that the average 150 lb. human needs approximately 1,500 to 2,000 calories per day and an average 1,000 lb. horse needs approximately 16,000 calories per day? So in calculation, a horse still needs approximately the same amount of calories per pound of body weight as we do. However, the big difference between horse and human is in the digestive tract. A horse has a cecum (carnivores do not) in which the microbes in the cecum can break down the fiber in the vegetables/hay to Volatile Fatty Acids and use them as an energy source. Dried hay has around 800-1,000 calories per pound, and fresh grass has around 400-500 calories per pound because of the higher water content in it. With dried hay, your average horse needs around 1-2% of their body weight in hay. If you take the middle amount, that would be 15 1bs. of dried hay per day! (15 lbs. of Alfalfa per day = approx.15,000 calories). So, a horse can maintain his weight on this amount. For fresh pasture, a horse has to eat about twice that amount (30 lbs.) because of the higher water content. This is why a horse on pasture grazes all day because they have to take in a higher volume of feed to meet their calorie needs. In addition, horses on pasture will walk around 5 to 10 miles per day because they have to search out their food. So, they also burn more calories per day. Horses in Arizona on dried hay only need about half of that plus, they don't burn the extra calories because they can just stand in one place and eat their whole meal. If we let them eat all day on the dried hay as they would in pasture, they would intake more calories than they need and would become overweight.

Herbs for skin care and wound management - November 2004

The information contained in this article was gathered from the Holistic Horse Magazine.

Is your horse's coat losing its shine in the winter cold and you're running out to buy skin products with unrecognizable ingredients? Well its important to know that what you put on your horse's skin can and usually will be absorbed into the body so you need to be careful! We've listed some herbs that are commonly used for skin care and wound management. And remember, you can use these herbs on you and your horse!

  • Arnica: Anti-inflammatory. Used for swelling, bruising, sprains, cartilage stress and arthritis. Do not ingest arnica -- for topical use only.
  • Aloe: Aloe promotes healing of burned and in the desert those white ponies probably need this on their more sensitive areas such as their nose. Aloe's active ingredient, Aloin, which consists of vitamins, minerals, enzymes and amino acids to help heal the skin.
  • Chickweed: The most common use of Chickweed is for topical care of cuts, wounds, and chronic itching caused by eczema and rashes. You can also add Chickweed to poultices to aid in pulling toxins from a wound.
  • Marigold: This is one of the most popular and effective herbs for treating skin problems. Also known as Calendula, it has been used for hundreds of years in ointments, infusions and tinctures to heal many skin problems including frostbite, burns, and boils. It has a strong antibiotic and anti-fungal effect. This can also be used to kill germs as a replacement for the harsher chemical of bleach and will not burn the skin.

Water Consumption - September 2004

Did you know the total amount of water within a horse's body is approximately 60% of their body weight? This means they need to drink an average of 10 to 15 gallons of water during the hot summer days in Arizona. This equals approximately 1-2 liters of water consumed per hour. Unfortunately, automatic watering systems just don't provide this type of flow rate for your horse to stay adequately hydrated. So be sure to provide a large bucket of water along with your watering system and your horse will stay hydrated and healthy!

What is a coffin bone?

The coffin bone is the wedge shaped bone in the horse's hoof. It's the main bone in the hoof that supports the horse's weight. Many lameness problems seen in horses can be attributed to problems with the coffin bone.

How does a horse fracture a coffin bone?

There are many things that can cause the coffin bone to break. A nail or other sharp penetrating wound through the hoof can cause a fracture in the coffin bone. Also, a concussion when violent enough can fracture the coffin bone which is how Chico's fractured. A sharp kick to a steel fence resulted in Chico's coffin bone fracture. But don't forget that in many instances coffin bone fractures can also be attributed to pathological conditions in the bone.

How do I know if my horse fractured his coffin bone?

Signs of a fracture vary depending on where the bone is fractured. When the break involves the joint surface there is sudden and severe lameness. Your horse may even tremble and sweat and an increase in pulse and heat in the foot region will be evident. Hoof testers will detect immediate pain over the sole.

When the wings of the coffin bone are involved, lameness is not as noticeable when the horse is standing, however, it becomes more evident when the horse turns on the injured foot. The foot region will be warm and sensitive to pressure. You will still need to x-ray the hoof and have your veterinarian establish that a fracture has indeed occurred.

How is a coffin bone fracture treated?

The foot must be immobilized for the bone to heal which usually means 3 to 9 months of stall rest. Special shoeing is also needed which normally is a full bar shoe with clips behind the quarters. This type of shoe will prevent frog pressure and limit expansion of the foot. This is worn for 3 to 6 months and needs to be reset periodically.

Is the prognosis favorable?

The age of the horse and location of the fracture are major factors in how well the coffin bone fracture will heal. When the wings are fractured, the prognosis is good, and the chances of a complete recovery increase more if the horse is 3-years old or younger. However, if the fracture is in the joint surface the prognosis is much less favorable and the horse may suffer from chronic lameness.

by Julie Cary, DVM, MS

Diplomate, American College of Veterinary Surgeons
Associate, Cave Creek Equine Surgical Center

November 2004, Article #002

Navicular disease is a term that induces horror and panic in many horse owners. Fortunately, with advancing technology, the condition is not one that should be feared as much. Most veterinarians now refer to the condition as palmar or heel pain. This more accurately reflects the nature of the condition.

How is Navicular disease diagnosed?

Heel pain is defined as a lameness originating in the back half of the horse’s foot which blocks to a palmar digital nerve block. This is the area where the navicular bone resides, as well as several other soft tissue structures. There are certain types of hoof conformation or shoeing imbalances that can predispose an individual to developing pain in the back of the foot. The first line of diagnostics include taking radiographs of the foot. The classic navicular disease will have bone changes that can be seen on radiographs, such as bone spurs, holes in the marrow cavity, roughening of the flexor surface of the navicular bone, or thickening of the marrow cavity.

Unfortunately, radiographs do not reveal what is going on with the soft tissue structures. We now know that many times, the soft tissue injury precipitates the changes to the navicular bone. If we can see the soft tissue damage and manage it appropriately, we can better manage the horse and its lameness. Ultrasound can be used to image many of the structures within the foot including the deep digital flexor tendon, navicular bursa, and the small supporting structures of the navicular bone. The problem is that ultrasound of the foot can only be performed through a couple of windows (the frog and through the back of the heel bulbs) and requires considerable practice on the part of the veterinarian to diagnose the condition.

Recently, MRI has been used to document more conclusively the problems in the foot. Washington State University has been studying horses with palmar heel pain for the past seven years using MRI. Several practices have recently added MRI to their diagnostic capabilities. We have learned a wealth of knowledge from this modality. Interestingly, the majority of cases seen at one institution, which have been worked up by several veterinarians prior to referral, have turned out to be damage to the deep digital flexor tendon as it curves around the navicular bone and inserts on the coffin bone. These cases need to be rested and rehabilitated much the same was as a bowed tendon.

How is Navicular disease treated?

Treatment of heel pain includes corrective shoeing to ensure the foot is balanced and to minimize the stress on the soft tissue structures. Other treatments include pain modulation and anti-inflammatory medication, which is usually in the form of phenylbutazone. Isoxsuprine is a medication that is often used in cases of heel pain. The purpose of the medication is to help improve blood flow to the area. Also, treating the coffin joint or navicular bursa with hyaluronic acid with or without a cartilage friendly steroid can help with certain types of pathologic changes.

Some people advocate the use of “nerving” these horses. Nerving entails removing a chunk of nerve from the palmar digital nerve so that the horse can not feel the back 1/2 of the foot. This does not stop the disease process, and can contribute to its worsening in some circumstances. The nerve will eventually grow back in one to five years. It is the author’s opinion that nerving should only be performed on horses that do not respond to any other treatments and who have a finite career time required.

End stage navicular disease is a complex of problems associated with both the soft tissue and bone in the heel region of the foot. The most common is that the deep digital flexor tendon becomes stuck to the navicular bone which then interferes with the pulley function of the DDFT. Every time the horse steps it pulls on those soft tissue attachments. This is why many of the horses with this condition take extremely short steps with their front feet.

What is the prognosis for Navicular disease?

The key to palmar foot pain is early and accurate diagnosis. Lameness that has been noticed for a short period of time is much more likely to be resolved than lameness present for a long time. Getting an accurate diagnosis of the offending structure or structures helps more effectively treat the problem. Veterinarians with a special interest and understanding of feet are extremely helpful in diagnosing and treating these types of cases.

by Julie Cary, DVM, MS
Diplomate, American College of Veterinary Surgeons
Associate, Cave Creek Equine Surgical Center

November 2004, Article #001

One form of lameness associated with suspensory ligaments is Degenerative Suspensory Ligament Disease (DSLD) and is a point of frustration within the veterinary community, both because of lack of great treatment options and because very little is understood today about what triggers the process, or how to avoid or slow the degeneration. Interestingly, some horses degenerate with very little associated pain, while others will experience such pain that euthanasia will be considered as a reasonable option.

What is the Suspensory Ligament?

The suspensory ligament runs along the back of the cannon bone attaching the top of the cannon bone to the sesamoid bones at the fetlock joint. Along with the distal sesamoidean ligaments, the suspensory ligament forms the sling that supports the fetlock. The name of the ligament reflects the “suspension” of the fetlock. The anatomically correct name for the suspensory ligament is the third interosseous muscle, which reflects the presence of muscle fibers within the ligament.

What causes lameness in the Suspensory Ligament?

There are several types of injuries that can happen to the suspensory ligament. It is like any other tendon or ligament, which can get stretched beyond its capacity, causing tearing of the fibers, swelling within the structure, resulting in the classic “bow”. During times of overextension of the fetlock, small pieces of bone at the attachments of the suspensory ligament may be torn loose of the bone. These are known as avulsion fractures. There is also a class disease that results in the breakdown of the suspensory ligament without a traumatic or overuse origin including a condition known as degenerative suspensory ligament disease.

What is DSLD?

Degenerative suspensory ligament disease (DSLD) refers to cases that have seemingly spontaneous loss of the elastic property of the ligament. This loss of elasticity results in a gradual stretching of the ligament, which is seen as an increase in extension of the fetlock (it comes closer to the ground). The resulting conformation is a straight hock and fetlock that is at a more severe angle with times where the pastern bones are almost parallel with the ground. It is unknown if the conformation of the horse originally (ie, straight hocked) contributes to development of breakdown to the hindlimb suspensory. It is almost always seen in both hindlimbs, although one hindlimb may progress faster than the other.

There is some indication that this disease may follow family lines in certain breeds, such as Peruvian Pasos. Also, pregnant mares in the last part of their pregnancy seem to have an increased chance of having the painful form of this degeneration. It is suspected that this may be due to hormonal levels. These horses are often hospitalized and relatively heroic measures are taken in some cases to get the mare to term in order to save the foal.

How is DSLD diagnosed?

Diagnosis of DSLD can be challenging when the process is in the initial stages. Horses are often positive to both upper and lower limb flexion with fairly exaggerated lameness occurring. Clinical judgment combined with the results of the flexions, diagnostic nerve blocks and imaging such as radiographs and ultrasound generally lead the veterinarian to the diagnosis of degenerative suspensory ligament disease. Blocking the lameness can be frustrating, as it often requires a couple of different blocks to relieve the lameness entirely. Radiographs can reveal displacement of the sesamoid bones. Ultrasound can be an indicator of the amount of damage to the ligament. Ultrasound of the suspensory ligament of the hindlimbs can be challenging in some cases because the splint bones can interfere with the image. Use of the MRI in the future will help further characterize the damage to the ligament.

How is DSLD treated?

Treatment considerations include shoeing changes to decrease pressure on the suspensory ligament. Pain control if required may include herbal remedies, phenylbutazone, acupuncture, or more potent medications such as epidural morphine, depending on the level of discomfort. It is important to avoid excess body weight in these cases, as that causes more pressure on the suspensory ligament. Currently, many practitioners are included the use of Omega fatty acids in their treatment regimes to decrease inflammatory effects. Exceedingly painful cases, such as occurs with pregnant brood mares may require more heroic efforts such as body sling support and epidural medications. The ultimate goal, at this time, is to provide comfort for the horse and to slow the progression of the degeneration. With time and further research, veterinarians may ultimately learn to more effectively avoid and treat the condition.