Scratches

By: Katie Jones, CVT­­­

With the endless moisture this year, the horse-care watch list seems to grow; one of the items on this list should be scratches.

ScratchesSo what is scratches? From The Merck Veterinary Manual. “Scratches is a chronic, seborrheic (flaky skin) dermatitis characterized by hypertrophy (enlargement of the skin cells) and exudation (oozing) on the caudal (rear) surface of the pastern and fetlock. It often is associated with poor stable hygiene, but no specific cause is known. Heavy horses are particularly s­usceptible (potentially because their feathered legs trap dirt and moisture), and the hind limbs are affected more commonly.”   Scratches is a relatively common skin disease located on the horse’s heels and pastern. It can be caused by viral, bacterial, fungal, or parasitic infections. Although bacterial and fungal organisms are involved in the development of scratches, exposure to wet and dry conditions damages the skin allowing the infection to thrive. This damage causes an invasion of bacteria or fungi and the skin becomes red, swollen, or ulcerated.

Scratches1Mild cases usually respond to cleaning and topical medication treatments. If the leg becomes hot, swollen, or painful, the infection has become more severe and a veterinarian should be contacted. Regardless of the severity of the infection, horses should be removed from the wet environment. Any feathers or hair in the infected area should be clipped to prevent mud and moisture from lingering around the damaged area. Once the area has been cleaned and the hair removed, the area can be washed with an antibacterial soap such as a Betadine scrub. If scabs have developed, soaking the area to soften the scabs lessening the irritation of cleaning them off. It is best to clean the area only once a day to limit the amount of moisture the leg is exposed to. If an at-home cleaning doesn’t resolve the episode, a veterinarian can prescribe a topical cream containing an anti-fungal, a steroid, and antibiotics to promote healing. The area will be understandably sore, so use caution when cleaning.

Most cases of scratches will resolve with the above treatment course. To prevent a re-occurrence, try to keep horses out of muddy or wet pastures. During times of increased moisture, watch legs for any signs of redness or irritation and begin treatment at the first signs. If scratches becomes a chronic issue with your horse, contact a veterinarian for the best prevention and treatment course.

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Fall tune up for broodmares

082_anoka-equine_2012Is your mare expecting a foal next spring? If so, there are a few dates to remember. Vaccination against Rhinopneumonitis, a common cause for mid to late term abortions, should be administered at months 5, 7 and 9 of gestation.   This vaccine provides good protection against this cause of abortion, but the protection is short lived – hence the set of three vaccinations.  Administering prefoaling vaccinations  approximately a month prior to foaling will booster the mare’s immunity as she is making colostrum for the foal. This will elevate the necessary antibodies in the mare’s colostrum to help ensure the new foal is adequately protected against the most important diseases for the first few months of life.

Nutrition is an important element of a foal’s in utero development. An appropriately balanced diet is not difficult to provide, and the first part of that equation is to know what the nutritional value of the hay that you are feeding. Hay analysis is easily done by dropping off a hay sample at the clinic with your name and the ages and uses of the horses you are feeding. The cost is approximately $60, but is subject to change. Please call Anoka Equine for a current price.  From this initial information we can help you build an appropriate diet for your pregnant mare (and the rest of your equine population).

Physical signs to monitor during gestation: 1. Vulvar discharge: any appreciable discharge for a pregnant mare’s vulva has the possibility of being abnormal. 2. Premature udder development: most mares start to “bag up” approximately 4 – 5 weeks before foaling. Significant udder development prior to that time may indicate significant placental issues that could result in the loss of the foal if left untreated. 3. Weight: Run your hands over the fuzzy winter coat. You should not be able to easily tick ribs on your pregnant mare. This relates to the above paragraph. Any concerns related to these three items should be brought to your veterinarian’s attention.

If you were unsuccessful in your breeding attempt this year, remember to make sure your 006_anoka-equine_2012mare is ready to go for next breeding season by having a uterine culture and possibly a caslicks performed.

If your goal is to breed your mare early in next year’s breeding season there are a few things that need attention. Mares (the vast majority) cycle seasonally, and do not start to cycle regularly until mid to late March/early April in the upper Midwest. If you are planning on breeding your mare prior to that time she needs to be started under lights – a full 16 hours of light – the first part of December. The easiest method is to calculate the number of hours after natural daylight that will need to be added to total 16 hours and put a light (200 watt bulb) on a timer to make up the difference. There are studies that indicate “flash lighting” will also work. This is a short period of light “flashed” at the end of the 16 hour period instead of lights on the entire time. Most mares will respond to the flash lighting, but light for the entire 16 hour period gives a more consistent response. The other important aspect of this protocol is the need for either a heated barn or blankets and a hood. The “recipe” for fooling a mare into cycling early involves both light and heat. It takes a minimum of 60 days for a mare to respond to the early cycling protocol, and she should be in a normal cyclical pattern prior to breeding, so starting the protocol early December should provide a cycling mare by mid/late February.

 

Equine Osteochondrosis

Megan Slamka, DVM

What is Osteochondrosis?

Osteochondrosis (OC) is a common developmental bone abnormality that can result in lameness in horses. In a growing horse, the end of the long bones start as cartilage and then converts into bone as the horse grows. OCs occurs when there is a disruption in the cartilage converting into bone, (endochondral ossification) most commonly near a joint surface, see figure 1. The cause of OC is thought to be due to lack of nutrition to the developing bone. Initially, nutrients are brought to the developing cartilage through small vessels, however, as the cartilage begins to turn to born, vessels diminish and the joint synovial fluid becomes the sole source of nutrition to the cartilage. This can lead to areas of retained cartilage which then die and split off. The term osteochondritis dissecans (OCD) is used when a flap of cartilage or a joint mouse is present. Alternatively, Osteochondrosis(OC) is used when there is a defect in the cartilage, but there is no free edge. The most common joints affected are in the stifles, hocks, and the fetlocks.

OC Image 1

Figure 1: Disruption in endochondral ossification due to poor blood supply leads to defects in the subchondral bone and retention of cartilage. Adams Lameness 2011, pg 2633.

 What factors contribute?

Many factors contribute to the cause of OC. Although, the exact inciting factor is unknown; genetics, rapid growth, conformation, trauma and dietary imbalances have all been implicated. Studies have shown animals fed a high energy diet and diets low in copper or high in phosphorus may predispose horses to development of OC. Thoroughbreds and Quarter Horses are overrepresented in breed prevalence; however, a variety of breeds can be affected. Horses tend to be around one year of age when clinical signs manifest, but OCs can manifest later in slow growing breeds such as Warmbloods.

Diagnosis

Diagnosis is mostly based on presenting clinical signs, signalment and radiographic evidence. Presenting clinical signs often include acute onset of joint swelling that may correlate with a recent increase in level of exercise. Horses tend to have a very stiff gait which is exacerbated by flexion tests. Diagnosis can be confounded in that horses may show both radiographic and clinical signs, clinical signs without radiographic abnormalities (but arthroscopic abnormalities), and radiographic abnormalities with no clinical signs. Radiographic signs include areas in the bone that appear dark or borders that are irregular.

OC image 2

Treatment

In mild cases, such as small lesions in very young horses, a more conservative approach can be taken. A reduction in feed intake is recommended to slow growth rate along with rest. Intra-articular corticosteroids and hyaluronic acid may be helpful as well in reducing swelling and associated synovitis. More often, surgical intervention via arthroscopy (see figure 3) is needed when lameness is a factor and the horse is over 8 months of age. The arthroscope is inserted into the joint and the cartilage flap or the bone fragment is removed. The bone underlying the defect is smoothed out to reveal healthy bone to ensure optimal healing.

OC Image 3

Prognosis

Overall, the prognosis for a return athletic function is good post surgery, with more severe lesions and those in the shoulder joint having a worse prognosis. Success rates have ranged from 75 to 90% depending on the affected site.

 

Cellulitis

By: Katie Jones, CVT

Many riders have had the experience of walking out to the barn only to find one or more of their horse’s legs are swollen.   There are a few different possibilities to why the localized swelling in the legs has started. The most common reason is seen with horses on prolonged stall rest; they commonly can develop “stocked up” legs when they are unable to leave their stall. “Stocking up” usually doesn’t cause lameness and the swelling typically diminishes once the horse moves. Another cause, and the one we’ll be discussing today, is the development of cellulites. Compared to “stocking up”, cellulitis is slightly more complicated and many times requires treatment for it to resolve.

Cellulitus 1The initial cause of cellulitis can’t always be identified. It is commonly caused by a wound which allows bacteria to get beneath the skin and spread to deeper tissue. The wound can range widely in size and depth depending on the cut, scrape, bruise, or insect bite. When wounds are exposed to deep mud, sand, or any moist environment, bacteria can enter under the compromised skin. The most common species of bacteria which cause cellulitis are: Staphylococcus aureus, Streptococcus species, E. Coli, and Pseudomonas.

Cellulitis is characterized by warm, painful tissue which can swell within a couple hours. Cellulitis most commonly occurs in the hind legs with potential swelling reaching 2-3 times the legs’ normal size.   (The horse may also develop a fever and increased heart rate.) When blood work is done by the veterinarian, it will often reveal an increased white blood cell count and fibrinogen.  All of these factors will confirm a cellulitis diagnosis. With the swelling and pain associated with cellulitis, secondary complications may develop over the treatment time. Some complications associated with cellulitis are: thrombosis (or hardening) of the blood vessels in the affected limb, extensive tissue necrosis due to the swelling which can also cause the loss of skin and/or hair, or potentially the development of laminitis in the opposite limb.

Treatment for cellulitis is focused on using broad-spectrum antimicrobials as well as non-steroidal anti-inflammatory agents (Bute or Banamine®); hydrotherapy, compression wraps, and hand-walking can also aid the reduction of swelling. If feathers (long hair) are present on the affected leg, the hair should be clipped to help kept it clean and dry while it heals.

In horses who do recover, scar tissue can form in the affected leg; this decreases the body’s ability to drain fluid from the area which then prevents the leg from regaining its original contour. In addition, if the skin was damaged, its natural defenses are weakened allowing cellulitis to redevelop or become chronic.   Some pointers to prevent cellulitis from developing are:

  1. Maintain an exercise program for your horse. Movement improves fluid drainage from the leg through the lymphatic system.
  2. Keep your horse’s legs clean and dry as much as possible. Don’t leave horses out in deep standing water or mud.
  3. Monitor their legs for heat or swelling if environmental conditions are not ideal.
  4. Call your veterinarian with any concerns in order to start treatment early.

Cellulitis can be managed with proper care and monitoring.   Once the cellulitis has been cleared, it is critical to continue monitoring the leg and environment the horse is kept in to reduce the chance of reoccurrence. If there are any signs that cause concern, early communication with a veterinarian will diminish the risk of permanent damage to the leg.