Pastern Dermatitis and other Summer-time skin blues

Pastern Dermatitis by Dr. Tena Boyd

Pastern dermatitis is a condition that can occur year round but is often worse during summer months.  This is a very common and inconvenient problem in our area and many remedies are marketed. 

• · The mild form (scratches, mud fever, mud rash is the mildest and most prevalent. This form is characterized by hair loss, dry scales, and crusts; may be “itchy” and/or painful.

                                           

• · The exudative form (grease heel, dew poisoning) is more serious characterized by very inflamed skin, hair loss, and heavier crusting. More aggressive treatment is required

• · The hind-limbs are affected more commonly than forelimbs and white or non-pigmented skin  more than dark skin

• · The affected skin is often suffering from a mixed infection of bacteria, fungal organisms, and possibly even insect or mite infestation

• · Photosensitization may be a cause or contributing factor in more severe conditions

• · The most common  agent we see is exposure to clover pasture;  affects both the muzzle and lower limbs

• · Other agents implicated are St. John’s Wart, buckwheat, and perennial rye grass

• · A veterinary examination can lead to the most targeted treatment.  Bacterial and/or fungal cultures, skin scrapings or biopsy may assist in diagnosis. Treatment:

· Wash off the offensive agents from the skin after contact, such as when brought in from turnout or from exercise where the lower limbs are in contact with grass

· Medicated shampoos that have a broad spectrum of activity are most effective but even a sudsing non-medicated shampoo is helpful

· Keeping the legs dry for several hours per day following elimination of the offensive agents is key

· Topical treatments that decrease the scales and help heal the skin

· Systemic antibiotics for stubborn infections or those that lead to cellulitis, fever, or lameness

· Recently we have seen a few products that act as “socks” for horses and have been very effective in assisting treatment. 

Another Summertime Blue, Sunburned Skin

Sunshine is often considered therapeutic for the body and spirit!  Some of our favorite equine friends may have a different view.   For those white-faced breeds with no pigment or pink skin, prolonged exposure to sun can create several uncomfortable conditions.  As the skin becomes inflamed from this delicate skin “burning”, it is very susceptible to changes that can lead to a skin cancer, Squamous Cell Carcinoma (SCC). 

To protect these horses, fly masks can be worn by these horses year-round whenever it is sunny out.  Those with nose shields will also protect the muzzle of these sensitive horses.  As discussed previously, agents that can cause photo-sensitivity such as clover pasture, can exacerbate this condition.  Another helpful protection, is to apply children’s waterproof sunscreen to the faces and around the eyes of these horses.  If your horse shows any of the conditions seen in these photographs, please call for an appointment.

Compounded Drugs, What Does this Mean?

Drug compounding is a process to "produce a medication by combining or altering ingredients for the special needs of a patient". As stated in the AAEP Horse Health Article of June 2009, Your Horse's Life is Not Worth the Risk: What every horse owner should know about drug compounding; "Because there is a scarcity of approved medications for use in horses, there is a legitimate need for compounding in equine veterinary medicine. Some examples of legitimate compounding would include crushing a tablet and creating a paste or gel to aid in the administration to the patient or mixing two anesthetics in the same syringe for use in your horse."

Further this article states the American Association of Equine Practitioners (AAEP) position statement on this topic. "The AAEP acknowledges that reputable pharmacies produce legitimate compounded drugs to improve the health of horses when an FDA-approved option doesn't exist. However, when inappropriately compounded and used, these drugs may pose a serious threat to the health of your horse. Knowing the facts about legitimate and illegitimate compounded drugs will help you and your veterinarian decide on the best treatment option for your horse." For the full article refer to the reprint in the OWEC Newsletter, July 2009 issue or search for it on www.aaep.org.

The topic of compounded drugs often sparks much debate. From near conspiracy-theorists who feel that all drug companies are bad and are out to gouge consumers for profit only, to those who are trying to find cheaper or more palatable or easily administered drug options for their horse and everything in between. Bottom line, our horses depend on us to make the safest and best choices for their health and welfare. If a cheaper alternative does not work or is unsafe, have we saved any money? Have we done our best or even an "OK" job by our horse?

As many will remember, in April of 2009, 21 polo ponies were the tragic victims of inappropriately compounded medication given to them by their trainers or caretakers that resulted in sudden death. Several horses in Louisiana in 2006 suffered a similar fate. These are very dramatic examples of the worst consequence. The problem is, when do we know when a compounded product we have ordered (and sent payment) from a source we thought to be reputable is unsafe or ineffective?

Whenever possible, if an FDA-approved drug is available for medicating our horses, our horses depend on us to use them. The FDA-approval process assures the product is safe and effective for its intended use, but also the methods, facilities and controls used for the production of the drug meet FDA Standards to preserve it's identity, strength, quality, purity, and consistency from batch to batch. The FDA-approval process is a very expensive one and those manufacturers who have complied with this process and been granted approval have invested much time and expense to provide the product. As well, if problems are noted we have someone to go to seek solutions or recompense when adverse effects are noted. Compounders' products are unregulated by the government and not subject to the same standards for consumer protection or accountability.

What's All the Fuss About Polyglan? by Dr. Laura Fontana

Polyglcan is a commercially available patented formulation that is labeled for post-surgical joint lavage and joint fluid replacement. This solution is comprised of 3 fractions: hyaluronic acid, sodium chondroitin sulfate, and N-acetyl-D-glucosamine. These 3 fractions are all naturally occurring components of synovia and are instrumental in maintaining joint health. Before discussing the efficacy of this compound, let's review the specific function and independent use of these 3 constituents. Hyaluronan (hyaluronic acid or HA) is a normal joint fluid and cartilage constituent with anti-inflammatory effects as well as joint lubrication and protection properties (1). In equine practice, intra-articular and intravenous administration of HA (Legend) is commonly employed for the treatment of synovitis and osteoarthritis, and intravenous Legend is also used prophylactically. In fact, Legend is the only FDA-approved joint therapy labeled for both intravenous and intra-articular treatment of non-infectious synovitis. Chondroitin sulfate belongs to a class known as polysulfated glycosaminoglycans (PSGAGs), which are an important element of the extracellular matrix of articular (joint) cartilage. Included in this class is Adequan, which is made from cow lung and trachea extracts primarily containing chondroitin sulfate. Adequan and other drugs in this class have been referred to as chondroprotective, or more recently, as slow-acting disease modifying osteoarthritic drugs (SAMOAD) intended to preclude, slow, or revers the cartilaginous lesion of OA (2). Adequan is used intramuscularly, and like HA (Legend), it is also used intra-articularly in equine practice. Glucosamine is a precursor to the disaccharides (sugars) found in aggregan, a molecule that comprises a substantial portion of the extracellular cartilage matrix. Many equine oral joint supplements contain glucosamine as well as chondroitin. The objective of combining hyaluronic acid, chondroitin sulfate, and glucosamine (as Polyglycan), all of which have long been administered independently by a variety of methods, is to create a safe and efficacious product for intravenous and intra-articular use in horse to promote joint health. But, is this combination effective? Frisbie et al (2009) (3) conducted a study to assess intravenous and intra-articular Polyglycan for the treatment of osteoarthritis in horses. The authors concluded that intra-articular Polyglycan (when given once every 7 days for a total of 4 treatments) significantly improved lameness and disease progression in horses, as evidenced by improved lameness scores, decreased radiographic evidence of osteoarthritis, and improved cartilage. In contrast, the intravenous Polyglycan treated horses (which received a dose every 5th day for a total of 14 treatments) showed no improvement in lameness scores and increased radiographic evidence of osteoarthritis. These findings do not support intravenous use of Polyglycan, and suggest that intravenous use may in fact be counterproductive. At this time, and until more studies are performed, continued use of FDA-approved products labeled for intravenous and intra-articular treatment of osteoarthritis is indicated. (1) Frisbie DD, Kawcak CE, McIlwraith CW, et al. Evaluation of polysulfated glycosaminoglycan or sodium hualuronan administered intra-articularly for treatment of horses with experimentally induced osteoarthritis. Am J Vet Res 2009; 70:203 - 209. (2) Section XII, Musculoskeletal System in Equine Surgery 3rd edition. 2005. Jorg Auer and John Stick eds. WB Saunders. Pp 1055 - 73. (3) Frisbie DD, Kawcak CE, McIlwraith CW, Werpy MW. Assessment of intravenous or intra-articular hyaluronic acid, condroitin sulfate and N-acetyl-D-glucosamine in treatment of osteoarthritis using an equine experimental model. Presented at : 55th Annual AAEP Convention; Decemeber 5 - 9: Las Vegas, NV.

Why do we do Coggins' tests each year?

As of March 2, 2011, an updated regulation will take effect regarding the Coggins' test for Equine Infectious Anemia in Virginia. The Virginia Department of Agriculture and Consumer Services (VDACS) has updated the regulation and specifies that "all horses assembled at a show, fair, race meet or other such function or participating in any activity on properties where horses belonging to different owners may come into contact with each other in Virginia must be accompanied by a report of an official negative test for Equine Infectious Anemia". This update further defines what "when horses are assembled" means. Assembly of horses for a trail ride on public property such as a state park is an example of an activity requiring horse owners to have a valid Coggins report with them.

Starting March 2, rangers in state and national parks may check for Coggins' papers and owners without valid test reports could be charged with a Class I Misdemeanor and asked to leave the park. As is currently the case under existing regulations, owners presenting fraudulent paperwork can be charged with civil penalties as well.

The Coggins' test is laboratory test for the disease Equine Infectious Anemia(EIA). EIA is a very contagious (infectious) and possibly fatal disease that affects any species of equines (horses, donkey, mules, etc). It is caused by a virus, a type classified as a retrovirus. There is no vaccine or treatment for the disease. EIA is a blood-borne infection and can be transmitted from horse to horse by large biting insects (horse flies, deer flies) or from blood-contaminated materials.

There are three clinical forms of the disease: Acute, Chronic, and Inapparent. In the Acute form, if a horse is exposed the the EIA virus, they can develop severe signs (fever) of the disease and die within 2 - 3 weeks. In more mildly affected horses, there may an initial fever that resolves and the horse recovers without further symptoms but if this horse is then interacting with other horses, it may act as a potential source of infection for any horse living in its vicinity. There may be no indication at all of the disease until picked up by a routine annual Coggins' test.

In the Chronic form, the horse survives the acute bout of the disease and may develop recurring bouts of illness. Symptoms of this illness may include moderate to high fevers (105 F), petechial hemorrhages (pin point blood spots on mucous membranes or gums), depression/lethargy, weight loss, edema in limbs or underbody surfaces such as the chest or belly, and anemia.

In the Inapparent form, the horse carries the disease with no signs or symptoms of illness. However, they serve as "resevoirs" of infection. The majority of horses positive for EIA are in this category. These horses are carriers for life and the infection may become chronic or acute when under stress from hard work, transportation stress, or when dealing with another illness. Inapparent carriers have lower concentrations of the EIA virus in the bloodstream than horses with active clinical signs of EIA. It is said that only 1 horse fly out of 6 million is likely to pick up and transmit the virus from such horses.

Prevention of EIA is centered around identifying carriers and affected individuals and removing them from contact with other horses. When an equine has a positive result on an official test for EIA, the animal is placed under quarantine. Confirmation testing is initiated and the quarantine from other horses is in order to prevent further exposure and possible transmission of the disease. All exposed horses within 200 yards of the location of the "positive horse" must also be placed under quarantine. The quarantined area and horses are monitored by federal or state regulatory personnel. For more information on EIA Uniform Methods and Rules to implement and conduct a national control program for EIA formulated by APHIS-VS, go to http://ww.aphis.usda.gov/vs/nahps/equine/eia or contact an area APHIS - VS office.

"Equine Infectious Anemia is a serious disease," said Dr. Richard Wilkes, VDACS State Veterinarian. "It affects all members of the equine species and is found in nearly every country of the world. All infected horses, even those that are asympotmatic, become carriers and are infectious for life. Infected animals must either be destroyed or remain permanently isolated from other equines to prevent transmission. The change in regulation is not drastic, but it is important and horse owners need to take seriously the need for a valid Coggins test each year prior to anny assemblage with other equines."

EPM Update: New Treatment and Prevention

New EPM medication and proposed prevention regime

A medication similar to Marquis (the only approved medication to treat EPM), but in a top dress pellet form will be introduced in early December. Both Marquis and this new medication(generic name diclazuril), prevent the EPM protozoa from growing and replicating. Neither actually seem to kill the EPM organism. However, the body’s own immune system can kill the protozoa once it stops multiplying. Dr. Tom Divers, of Cornell Veterinary School, presented the information at a recent seminar. Dr. Divers explained that diclazuril more easily crosses the blood brain barrier than ponazuril, the active ingredient in Marquis. Both medications have a wide margin of safety. Diclazuril has been used to treat coccidial infections in other animals. The other class of medication used to treat EPM is pyrimethamine which actually kills the EPM organism. However, there are cases where the horse gets worse when treated with the pryimethamine as the protozoa die off and there is an inflammatory response.

One of the proposals to prevent EPM disease in the horse is to kill the EPM protozoa after it enters the horse’s body but before it makes it’s way into the nervous system. It takes about 4 days from ingestion of the infective stage of EPM organism to the transformation to the stage that enters of spinal cord and brain. If treatment is given every 4 days then the organism shouldn’t be able to cause damage to the nervous system. Since the horse is a dead end host for the EPM organism (i.e. the horse can’t pass the disease on to any other animal) this treatment should not lead to resistance.

Trailering Tips

Below are 2 check lists. The first list is things to check before trailering, the second is a how to respond to an accident involving a horse trailer.

Before Trailering

· Wheel bearings serviced? (service every 12 mos./ 12,000 miles, carry spare bearing)
· Tires in good condition? (look for dry rot, replace every 3-5 years regardless of mileage)
· Check tire pressure (including spares and inside tire on dual wheels).
· Hitch locked on the ball? Correct size ball?
· Safety cables/chains connected?
· Plug and secure electrical connection.
· Connect emergency breakaway system.
· Emergency breakaway battery charged?
· Test trailer lighting (brakes, turn signals, running, perimeter).
· Check/test brake controller (calibrate/adjust per manufacturer’s directions).
· Adjust trailer brakes a few times a year. (You can find instructions for adjusting the brakes on the internet. http://ezinearticles.com/?How-to-Adjust-RV-Trailer-Brakes&id=450898. This needs to be done from under the trailer.)
· Be sure all the brakes are working. (With long periods of not being used one or more can easily rust in the free wheeling position.)
· Check trailer flooring for cracks, rot, rust, or damage, especially under mats.
· Prior to loading horse(s), check trailer for hazards (sharp edges, loose metal or wood, insect nests, etc.)
· Leg wraps, head bumper on horse(s)?
· If tying horse to trailer, include a breakaway link on trailer end (i.e., bailing twine).
· Secure and lock all trailer doors (use snap or carabineer to prevent accidental opening).
· Headlights on? For greater safety – get noticed.
· Drive safely – allow greater braking distance, and travel at generally slower speeds.

An accident happened
· Step 1.
Stay calm. If you are hauling horses and there is an accident, the first thing you must do is to remain calm. Whether it is just a minor fender-bender or a major accident that involves a flipped truck and trailer, you must take a deep breath and think clearly.
· Step 2
Call for help. If you are injured, you need someone to help you as well as anyone else in the vehicle. Take care of yourself and any others by calling 911. If someone is injured, begin emergency procedures by assessing their vital signs, injuries and securing them so there is no further damage. If you can, move accident victims away from the truck and horse trailer. Do not move anyone who might have spinal cord injuries unless there is risk of fire or explosion.

· Step 3
Take the truck keys. Never leave the truck keys in the ignition. As soon as you exit the vehicle, take the keys with you and keep them in your pocket.
· Step 4
Check the horses. If it is a minor accident and the trailer is secured to the truck, you can easily assess the horses. More than likely they are alright, but very frightened. If the trailer is viable and the horses are not injured, leave them in the trailer. Offer hay and open all windows so they have fresh air. This is the safest thing to do until help arrives.
· Step 5
Call a veterinarian. If a horse is injured, wedged in the trailer or somehow stuck, call a vet for help. Do not attempt to unload the horse until medical help arrives, as this may exacerbate the horse's injuries. Only attempt to unload the horse if you can do so safely and there is immediate danger of fire or other unusual harm.
· Step 6
Work with authorities. As police and emergency personnel come to your aid, work with them for the best possible outcome. If they ask you to do something, do your best to comply. You can tell them about a horse's personality or give your judgment, but in the end, it is up to the authorities to take care of the situation. They are there to help, so work with them and do as they say.
· Step 7
Unload the horses. Remove the horses from the trailer to a safe area where they can graze, if possible. Now each horse can receive a medical evaluation and treatment, if necessary.

Tendonitis by Nicole R. Eads, DVM

Pal is a 16 year old Quarter Horse gelding

History: For 10 years, Pal was the Pony Club mount for a young rider. Pal excelled at cross country events, and even took his rider to her B rating. During this time, he maintained excellent health, and never had any lameness issues. For the past 2 years, however, Pal has mostly been a pasture potato as his partner has gone away to college. He does give the neighbor children a jumping lesson once a week and goes on the occasional trail ride. Recently, both neighbors got to ride Pal in a lesson on a local cross country course. The next morning, Pal was acutely lame, and his left front leg was hot and swollen.




Veterinary Examination: Pal was mildly overweight. Otherwise, his physical examination was unremarkable except for his left front leg. The left front leg had an obvious area of swelling midway down the back of the cannon. The swelling was warm and painful to palpation. Pal was considered to be Grade 3 out of 5 lame, meaning he appeared sound at the walk, but was obviously lame when trotted in a straight line. Applying pressure to the swollen area increased Pal’s lameness dramatically.

Ultrasonography: Due to the presence of obvious swelling in the region of the flexor tendons, ultrasound was used for further investigation. A lesion was identified in the superficial digital flexor tendon (SDFT).



The image is a transverse view of the flexor tendons. The SDFT is the bright circular area at the top of the screen, and the lesion is the distinct black circle within the SDFT. The lesion is black due to tendon fiber disruption and the presence of blood or serum.

Diagnosis: Superficial Digital Tendonitis of the Left Forelimb

Discussion: Tendonitis, or a tendon “bow,” is inflammation of the tendon due to strain or disruption of the fibers. It is caused by excessive loading or overstretching of the tendon. There are several factors which predisposed Pal to an injury of this nature:
-Inadequate conditioning
-Obesity
-Uneven footing
-Muscle Fatigue

Treatment and Physical Therapy: For the 1st 48 hours, Pal was confined to a stall. He received 1g of Bute twice per day. The leg was cold hosed for 10-15 minutes three times daily and kept in a bandage with a mixture of DMSO and poultice. Starting on the 3rd day, Pal was handwalked for 10 minutes in an indoor arena with good footing. At this time, his Bute was decreased to 1g once per day. Hydrotherapy and bandaging were continued for two weeks. Over the next month, the length of time Pal spent handwalking was increased gradually, until he was walking for about 30 minutes per day.




Pal spent the 2nd month walking in the arena with a rider on his back until he had worked up to one hour per day. At the end of this time, a follow-up ultrasound was performed. Pal’s tendon healing was progressing well, so some jogging was added into his walking regimen. The amount of time spent jogging was increased gradually over the next several months. Five months after his injury, due to another good ultrasound, Pal was permitted to start adding cantering segments and integrating trot poles. He continued to heal well, and now, 8 months later, he has begun jumping small cross rails. Prognosis for full recovery is good.