A relatively frequent call I receive is from a horse owner with a horse that was fine yesterday evening but is toe touching lame this morning. The lameness is often described as seeming to originate from the shoulder or hip depending on whether a front or hind limb is involved. As with most lameness cases without an obvious cause, however, the best place to start is usually the foot.
A sole abscess is usually the result of some penetrating injury to the sole of the foot or the migration of bacteria and debris from some disruption near the white line. Under normal conditions, the sole is relatively hard and not very susceptible to this occurrance but wet conditions favor softening of the sole much like our fingernails soften after a long shower. These do seem to occur in waves on some farms following wet weather. Prevention of sole abscesses is in accordance with prevention of any disease of the foot and is primarily aimed at hygiene and providing a clean, dry environment and appropriate farriery.
The diagnosis is usually uncomplicated. Usually this presents as an acute, severe lameness of a single limb. The hoof wall is often warm compared to unaffected feet and digital pulses are often increased compared to unaffected feet. Hoof testers can be used to confirm the presence of a painful foot and to isolate the tender area. Depending on the horse’s temperament and pain tolerance, regional anesthesia is sometimes employed after applying the hoof testers to make the horse more comfortable and aid in treatment.
The treatment for this problem is all about establishing drainage. The pain from this condition results from pressure so it makes sense that relieving the pressure will relieve the pain. Usually this can be accomplished with a hoof knife or Dremmel tool if a tract can be identified. Foot soaks with betadine solution or Epson salt are frequently used to cleanse the foot or, some believe, to create an osmotic gradient to draw the exudate out of the abscess respectively. Currently, my favorite method after I have established drainage or for those that I cannot find a tract to establish drainage through, is to use an Animalintex poultice and a duct tape boot. This bandage is placed and left on for 24-48 hours. Most of the time the horse becomes sound during that time frame. If not, removing the bandage and re-examining the foot is necessary to rule out anything that might be complicating resolution or make another attempt at establishing drainage. The Animalintex poultice contains an exotic ingredient called tragacanth and boric acid. I will confess that I do not know what effect those ingredients are supposed to have other than softening the foot to facilitate drainage, but this method has proven so effective I have not felt it was necessary to soak a foot for an uncomplicated abscess in a while. Sometimes if there is an open solar defect we have to continue to bandage the foot and treat with topical medications as necessary.
I think it is also a good idea for these horses to receive a tetanus toxoid booster if it has been more than 6 months since their last dose.
Obviously, not every rapid-onset, severe lameness is an abscess, so it is always best to treat the situation with the enthusiasm it deserves and call your veterinarian to take a look. The good news is, if an abscess is diagnosed and an appropriate treatment plan instituted, there is usually an excellent prognosis and most horses will be back to work in short order. If you have a problem with a horse, lameness or otherwise, that you’d like some help with, please feel free to call or e-mail. We would love to help any way we can!
Sarcoids are an old, frustrating problem. They are rarely, if ever, life threatening but they are unsightly and disfiguring and they have a habit of occurring in places that make it necessary but difficult to treat them. The lack of any one good therapy to get rid of them has given them a well-earned reputation as a pesky problem to treat.
Appearance and Cause
Sarcoids are the most common type of neoplasia (cancer) in the horse. They do not tend to spread to distant sites (metastasize) but they can be quite locally aggressive, spreading like roots of a tree. Their appearance ranges from a slightly raised hairless region that can resemble ringworm to a large, raised, ulcerated and oozing mass. The appearance of the sarcoid is the basis for how they are classified—occult, verrucous, nodular, fibroblastic, malevolent and mixed. Classification is somewhat arbitrary and can change as the tumors behavior changes. The treatments available don’t really differ between the different classifications of sarcoids and it is unknown why some horses get a less aggressive classification and others get more aggressive forms.
The cause of sarcoids continues to be elusive but it seems we are getting closer to having some answers. As with many problems, there appear to be multiple factors involved. Sarcoids are frequently encountered in areas were a wound previously existed or areas where flies frequent. Bovine Papilloma Virus (BPV) has been known to be associated with equine sarcoids for some time and could reasonably be expected to be carried by a fly from its natural bovine host to a horse. The theory is that some horses are genetically predisposed to incorporation of an oncogene into their skin cells that they acquire from the virus. This gene causes the rapid and unorganized proliferation of cells that results in the visible tumor. However, there are some sarcoids from which the DNA of BPV cannot be detected and there certainly must be many horses that are exposed to BPV that do not get sarcoids so there is very likely more to this association than simple cause and effect.
Despite their uncertain origins, sarcoids are usually not challenging to diagnose. Many can be diagnosed by visual examination alone. Biopsy and histopathology are the gold standard for diagnosis. Additionally, a PCR test is available for detection of BPV DNA in the tumor, which may be an aid in determining the treatment protocol.
There are numerous treatments for these tumors and, in some cases, some very strong opinions about what works the best. The medical literature at this point shows that just about all of the treatments work sometimes, some of the treatments (the better ones) work most of the time but none of the treatments work all of the time. Further confusing the matter of treatment is that reported success rates of the various treatments tend to vary widely from study to study (for example, reported resolution rates for intralesional cisplatin range from 33% to 96%). Regardless of the type of treatment, reported success rates never seem to get much above about 85%. This means that some sarcoids (the worst ones) are not so much cured as managed. The most aggressive types of sarcoids are typically more challenging to deal with and the longer a sarcoid has been present, in general, the more challenging it will be to completely resolve. Below are some of my preferred treatments for these lesions, which is by no means exhaustive of all the options available. Also, keep in mind that each case should be evaluated (and re-evaluated) individually.
Since there is no clear answer on what exactly causes these tumors it is hard to make a recommendation on how to prevent them. My best suggestion would be to have a thorough fly control program (including fly spray, premise treatment and manure management), good wound care practices and early intervention for suspicious skin lesions. If your horse has a sarcoid and you'd like us to take a look or if you are concerned about some other area of your horses health, we would love to help! Give us a call to schedule an appointment and find out what we can do for you!
Several times over the past few months the topic of rattlesnake bites has come up with clients. This post will take a closer look at the treatment and management of this emergency.
The Hill Country region of Texas is home to all 4 of the major groups of venomous snakes in North America (rattlesnakes, copperheads, water moccasins and coral snakes). Of these 4 groups, rattlesnakes and copperheads are the most common offenders probably due to their preferred habitat and behavior. Horses being the curious grazing creatures that they are, are usually bitten on the face and multiple bites are possible. Bites to the limbs occur but with much less frequency. The severity of a snake bite can range from mild local inflammation to death. Primarily due to size, and thus dilution of the venom, snakebites are not as commonly fatal in the horse as they are in smaller veterinary species like dogs. Much of the variability in severity can be attributed to the location of the bite wound, the type of snake and therefore toxins in the venom and the amount of venom injected by the snake. Snake venom is complex and unique to the species of snake. The venom of rattlesnakes contains numerous and variable enzymes that result in severe tissue damage at the site of the bite and can have systemic effects both due to the direct toxic effect of the venom and harmful side effects of the bodies response to the tissue damage caused by the bite.
The most common presentation for these cases is a horse with a severely swollen, edematous and painful nose and muzzle that may be breathing loudly. Respiratory rate and effort may be increased with even mild physical exertion due to the narrowing of the nasal passages caused by the swelling. There is usually a serous or serosanguinous nasal discharge (clear or blood tinged) initially that may become mucoid after time passes. Puncture wounds can often be identified, and are usually oozing, although the fang marks may be further apart than expected due to the swelling that occurs following the bite. The swelling is usually very warm to the touch and the horses are resentful to touching it because it, as you might imagine, is quite painful. Remarkably, even with what I regard to be significant discomfort and massive swelling, many will eat or attempt to eat through it all. Although acute cardiovascular effects of snakebites are only occasionally appreciated clinically in the horse, some recent research has indicated that ECG changes and cardiac troponin I (a protein specific for cardiac muscle injury) increases following envenomation are quite common and a risk factor for heart failure later in life.
There is only one definitive treatment for venomous snakebites and that is antivenom. Antivenom contains antibodies of equine origin to rattlesnake venom that deactivate the enzymes in the venom thus reducing the venoms potency. It seems that many (not all) of these antibodies are cross protective to the different kinds of North American pit vipers. The earlier antivenom is administered the more helpful it will be. It probably exerts its greatest benefit if given within the first 6-8 hours following a bite but it may still be helpful much further out. It has shown effectiveness in decreasing mortality rates as well as decreasing pain and swelling which in turn decreases the duration and intensity of supportive care required. Additionally, since the toxins in the venom are being neutralized, it is currently hypothesized, though not proven, that there would be fewer chronic cardiac effects. It is currently believed that treatment may not only help the horse feel better sooner, but also help to prolong the athletic career or life of the horse by decreasing the cardiotoxic effects of the snake bite. The Rattler Antivenin product from Mg Biologics is approved for use in horses and none of the horses in the safety and efficacy studies had any reported adverse events associated with the product.
Supportive care measures for snakebites include:
The cost of antivenom therapy has historically been a significant barrier to its implementation. The good news is that it is now actually an affordable option for horses suffering from a snakebite and may significantly reduce the amount and cost of supportive care that follows. If you’ve made it this far—you’re a trooper! If you have questions or concerns about your horse’s (or cow’s or goat’s or sheep’s, you get the idea) health, feel free to give us a call to schedule an appointment. We would love to help any way we can!
Treating wounds is one of my favorite things to do as a veterinarian. It is often a very demonstrable way to appreciate the healing capacity of the body. Especially when we provide an optimal environment for healing to take place. If your horse has the misfortune to have a wound that needs attention there are a few points that are probably worthy of your consideration.
Location of the wound
This is probably the single most important consideration in determining how concerning any particular wound is. Wounds on or around joints or other synovial structures need to be thoroughly examined to make sure they do not involve the joint or synovial structure. Wounds, either from a puncture or laceration, are the most common cause of infected joints. For the uninitiated, infected joints are a very serious and potentially life threatening problem in a horse. These wounds always need to be evaluated by your veterinarian as quickly as possible because you really don’t want to wait around if there is a possibility of joint involvement. Lacerations around the eye or eyelid would be another area that should always be treated as an emergency.
In my opinion the severity of a wound is very closely tied to the location of the wound. A wound that may not require much or any treatment on a horse’s chest may be much more problematic and fraught with complications if it is over a canon bone or joint. Other things that determine the severity of a wound besides location are the degree of contamination, degree of tissue trauma and timing.
The decision on whether or not a wound can or should be closed with suture or staples is based on location and extent of the wound, the degree of contamination and the amount of time that has passed since the wound occurred. Generally, anything that has been open for greater than 12 hours will need to be treated as an open wound or additional steps and precautions will need to be made to optimize success of the closure. Primary closure of a wound, when possible, is ideal because it shortens the duration of time to resolution, results in less scarring and in general seems to be more comfortable for the horse.
Even if a wound will not need to be extensively treated, tetanus prophylaxis is a good reason to call your veterinarian. He or she can help you decide if your horse needs a toxoid booster or if he may need anti-toxin.
Bandaging is one of those skills that can only be mastered with practice (see below). The following are the 5 P’s of bandaging:
At the risk of opening myself up to scrutiny, many of the salves, creams and ointments marketed for wound care are unnecessary, ineffective or scientifically unverified. Some of them have merit and have been studied and can be used effectively for a specific purpose. However, in my opinion, there is no topical that is superior to good bandaging (if needed), cleanliness and fly control. I use many other topical on occasion but these are the ones that for one reason or another I seem to use most often:
Obviously, wound care is a broad topic and no two wounds are exactly the same. Treatments will vary and it is always a good idea to invite your veterinarian to examine the wound to initiate an appropriate treatment plan. If you have questions about wound care or how you can be prepared or if you find yourself in the unsavory position of having to deal with a wound on your horse give me a call and I would be happy to help you out!
A complete dental exam starts by taking a look at the face, looking for symmetry of the jaw muscles and face, normal function of the muscles of the jaw, face and tongue, or abnormal swellings. Then the incisors and canine teeth (if present), which are the 12 (up to 16 including canines) teeth in the front of the mouth, are examined looking for symmetry of the teeth, extra teeth and making sure there are no visible fractures and that the soft tissues appear healthy. Malocclusions are identified (if present) that may explain findings further back in the mouth. The speculum is then placed in the horses mouth and the interdental spaces (bars) are inspected. This is when wolf teeth are found (if they are present), the premolars and molars inspected, the cheek and tongue and the spaces between these teeth. A numbering system is used to identify the teeth called the Modified Triadan System. This system divides the mouth into 4 quadrants and numbers the teeth from the first incisor in each quadrant (ie: 101, 201, 301, 401) back to end with the last molar (ie: 111, 211, 311, 411). A thorough exam allows for the identification of many problems including tooth fracture, problems with occlusion (wave complexes, hooks, ramps, etc), periodontal disease and ulcers on the tongue or cheek just to name a few. The exam may also serve as an indicator that further diagnostics are necessary (usually radiographs but possibly CT scans) to determine the full extent of the problem and aid in treatment planning.
A horses dentition differs from ours in several important ways. Equine teeth are hypsidontal structures. Which means that they continue to erupt throughout the horse’s lifetime. This allows the horse to chew coarse roughage over the course of its life and not wear its teeth out prematurely. The surfaces of the teeth are also very different. Instead of being covered in enamel as our teeth are, the enamel is folded throughout the tooth with the bulk of the mass of the tooth being another dental substance called dentin and to a lesser degree cementum. The tooth root, or apex, of the cheek teeth contains a common pulp chamber that connects to 5-7 pulp cavities that extend towards the occlusal surface of the tooth. When a horse has a tooth root infection it is due to bacterial infection of these structures.
Due of the differences in width of the mandible and maxilla, the premolars and molars form sharp points typically on the buccal edges of the maxillary teeth (on the outside of the upper teeth) and the lingual edges of the mandibular teeth (the inside of the lower teeth). These sharp points are the object of the dental float. This procedure, as you may be aware, involves rasping away the sharp points that can form on the edges of the teeth as described above as well as any that may be present due to a malocclusion (ie: hooks and ramps). The points can cause significant damage to the cheeks and tongue that can interfere with riding and possibly cause weight loss sue to inefficient chewing or pain in more severe cases. I am of the opinion that every single horse benefits from having a dental exam (and a float if needed) performed every year.
These photos are of a tooth that was extracted from a three year-old quarter horse gelding that presented with a draining tract through his left mandible. Examination and radiographs confirmed that the 1st molar (tooth 309) had an apical infection. The tooth was removed orally and the mandible was cleaned up with curettage and antibiotic containing beads were placed. With about a week of anti-inflammatories and 2 weeks of antibiotics this horse was all fixed up. I’ll close here and offer a little commentary about one reason I think horses are pretty amazing. This horse had an infected hole in his jaw. He had an infection in the root of his tooth that was so bad and had been going on for so long that it had literally eaten a hole through his jaw. Think about that for a second. He never missed a meal or lost weight or did anything to act painful even though you know that had to hurt. This horse was so tough that his owners only realized there was a problem because of the discharge from his jaw and the terrible smell that went with it. In contrast, I bit my tongue last weekend and just about woke the dead. I am consistently impressed by my patients pain tolerance and stoicism.
If you know its time to have a dental exam and float performed on your horse or just want to know more about what we can do for your horse, feel free to shoot me an email or give me a call.
Below is a video that shows a clip from a gastroscopy and some bot larvae they found attached to the stomach. Watch for it to start moving at about the 0:10 mark. The video is not mine and was taken by a veterinarian in Norfolk, UK.
I remember several years ago sitting through a lecture on equine parasitology and realizing that I had really missed the boat on just how complex this area of equine medicine can be. Its easy enough to push a tube of dewormer in the horses mouth and forget about it but if you really start to dive into it, it can be a little overwhelming to digest the number of parasites that our equines are exposed to and must be protected from, each with their own lifecycle, anatomical preference, environmental considerations and drug susceptibility.
In my view, the most critical issue currently facing the equine industry in terms of parasites is the realization over the past several years that parasite resistance is real and quite widespread. This means that the dewormers we have counted on for years are not working the way they once did in many parts of the country. Also alarming is the fact that new dewormers are not hitting the market like they were 15-20 years ago leaving us with few options on farms where resistance has taken hold.
An important paradigm that I did not come up with, but have latched onto, is that due to differences in individual horses, about 20% of a herd will be responsible for 80% of the parasitism and parasite egg shedding. This means that when we treat based solely on a calendar that says its time to do it, we are likely overtreating many of the horses on the farm and possibly undertreating the horses that most need our attention. At this time, a fecal egg count test is the best tool available to find the horses that are most contributing to the overall parasite burden of the herd. The protocol is simple and requires a small fecal sample which is placed in a solution to separate parasite eggs from the organic material of the feces so they can be visualized under a microscope. The test is not perfect but is very helpful in directing treatment plans for the ranch and, through a modification of the test (fecal egg count reduction test), identifying which drugs are effective for that particular farm. I think it is important to note that the goal of deworming is not to eliminate all the parasites. The concept of parasite refugia has to do with maintaining a drug susceptible population of worms. In short, we want to keep the worm burden low enough that it has no impact on the horses health but not push so hard for a complete worm kill to select for resistance in that way.
When I set up a parasite control plan, several factors are important.
To varying extents, all of these factors have an effect on what parasites we need to be most concerned about. The worms that I feel have the strongest impact on the health of the horse in our area of Texas are small strongyles (cyathosomes), ascarids (round worms), possibly tapeworms and Draschia/Habronema (the cause of “summer sores”). The first three listed are probably the most important. Pinworms can be a great aggravation to the horse and deserve attention but are not a cause of illness in the same degree as those listed above. Bot larvae are undesirable and can look dramatic on an endoscopic exam of the stomach, but the adult flies seem to be a greater nuisance than the larvae themselves.
As a baseline, I am of the opinion that every adult horse that is in good body condition is going to likely benefit from being dewormed with a product labeled for encysted small strongyles and tapeworms once a year (Quest Plus) with minimal risk of resistance developing. The question that can be answered by fecal egg counts, fecal egg count reduction tests and an honest assessment of the properties grazing and manure management is which parasites seem to be causing a problem, which horse(s) need to be dewormed more than that and is the drug we have selected even effective. There is mixed opinion about the value of rotating dewormers. I am of the opinion that the most logical strategy is to maintain routine surveillance of the herd through fecal egg count tests and fecal egg count reduction tests and deworm with the most appropriate dewormer based on those findings.
I’ll close with a response to the most common question that comes up after I have a discussion about parasite control: How much is this going to cost? The answer to that question, quite frankly, is a lot less than if you develop a resistance problem in your herd. In reality, it does seem to be a little more expensive in the first year that the strategic program is implemented than the traditional deworming based on the calendar. In subsequent years, the cost is probably very comparable or less than traditional deworming protocols because many ranches will spend far less on drugs even with the additional costs of testing. But I must emphasize, resistance is a growing problem that will be expensive and very frustrating. I believe that it is in the best interest of the horse, firstly, and secondly, my clients finances to take this issue seriously and consider setting up a parasite surveillance and strategic deworming program.
If you made it this far, thanks for reading. If you have questions or want to develop a specific plan for your herd, feel free to call or shoot me an e-mail.
I walked out to the barn a few evenings ago and heard something that made me stop and listen. It could have been the whine of a distant train horn, but as I got closer to our stock tank and the three big live oak trees surrounding it, it dawned on me that I was hearing the collective hum of thousands of mosquitos looking for their next victim. I hate mosquitos and I would have sworn that they had not been there the day before. For some reason I have always gotten the feeling that those little devils like me just a little more than whoever I am with. As we have all been reminded in the news lately with information and warnings about the Zika virus, Mosquitos can be more than just a nuisance on a warm summer evening. According to the CDC, there is no known illness or disease transmission risk caused by the Zika virus in a horse (or any other domestic animal for that matter) but there are certainly many other mosquito borne diseases that can cause problems in horses in Texas. The risk is real especially with our unusually wet spring creating ideal mosquito conditions.
Several years ago the American Association of Equine Practitioners (AAEP) published vaccine recommendations for horses. The core vaccinations are the ones for which the risk of infection is universally great enough and the vaccines have been proven effective enough to recommend for every horse. The diseases that core vaccination helps to prevent, as you may know, are Eastern Equine Encephalitis (EEE), Western Equine Encephalitis (WEE), West Nile Virus (WNV), Tetanus and Rabies. The first three listed are transmitted by mosquitoes to horses. There are some great charts on the AAEP website (see link below) along with a thorough discussion of how the vaccines work, how they should be handled, some non-core/risk based vaccines available and descriptions of the diseases they help prevent so I won’t go into detail here but if you have questions about what your horse needs or just need to get it done feel free to give me a call.
AAEP Vaccination Guidelines (link)
Colic in horses can be a frightening and gut-wrenching ordeal (literally). If you have horses and have not already dealt with this emergency, eventually you likely will. Over the past couple of years I have encountered occasional misconceptions regarding colic that I think can be cleared up by getting a handle on what colic is and what is going to happen when you call your veterinarian to come examine your horse.
Colic is abdominal pain. The term by itself is simply descriptive of the collection signs you observe that indicate that the horse has a belly-ache (not eating, pawing, looking at its flank, laying down/rolling, yawning, sweating, etc.). Its causes are limited only by the horse’s anatomy and your imagination. The gastro-intestinal tract is the most common source of abdominal pain observed in horses but the liver, reproductive organs and kidneys can also have problems that may cause the horse to act colicky. Occasionally, even problems in the thorax or chest can cause discomfort that will look like colic.
When I look at a colicky horse in the field I am going to try to get several things done in a hurry. I have usually already started to ask questions and get an idea of how long the horse has been ill, normal diet, previous episodes of colic and other pertinent medical history while I start with the exam. This gives me a few minutes to observe the horse, get baseline vitals (temperature, pulse rate, respiration rate, gum color, gut sounds and jugular refill time) and decide if any immediate treatments are necessary or if immediate referral should be considered before proceeding.
If the horse is stable, I usually then perform a FLASH (Fast Localized Abdominal Sonogram of the Horse) abdominal ultrasound. This is a quick exam that is meant to identify significant problems of the small intestine, colon, kidneys, spleen, liver, abdominal fluid and thoracic fluid. If it can be done safely, the horse can then be palpated feeling for impactions, distension of small intestine or colon and proper positioning of the intestines. I will always pass a nasogastric tube at this point, if I have not already done so. This step can be helpful diagnostically and therapeutically. It is very uncommon for a horse to “throw up” so passing this tube through their nose, down the esophagus and into the stomach can relieve pressure if it exists (which can be a significant source of pain) by allowing undigested food, gas or reflux to exit the stomach. The presence of any of these may also give insight into the cause of the abdominal pain.
There are a couple of quick laboratory tests that are usually a good idea for colic patients . The PGVS mobile lab has the ability to get a packed cell volume, total protein and lactate reading from a small volume of blood. Abdominocentesis is another very helpful diagnostic tool that may be performed. This procedure involves the sterile preparation of the abdomen and collection of abdominal fluid for analysis (total protein and lactate). Analysis of abdominal fluid can be quite helpful in determining if some part of the intestine is experiencing circulatory compromise and may also be an aid in determining prognosis.
The goal of the exam and diagnostics is obviously to determine the specific cause of the colic. If that cannot be achieved we can usually at least categorize the colic. From a practical perspective being able to categorize the illness lets us answer the question of whether referral for surgery is necessary as quickly as possible. There are certain causes of colic that will need surgery every time (ie: Large Colon Volvulus). These cases are very time sensitive and outcomes are closely related to how quickly the condition is corrected with surgery. Other causes may not need surgery immediately but may progress to that point if medical interventions are unsuccessful (ie: Pelvic Flexure Impaction). Finally, there are several causes where surgery would be either contraindicated or unnecessary (ie: gastric ulcers). The take home message is that for horses that are surgical candidates, the question of whether surgery is necessary or not is the first, and arguably most important, question that must be answered.
That, in a nutshell, is my approach to a colicky horse. Hopefully it has shed some light on the medical decision-making that goes into evaluating a colicky horse and what you should expect to happen when you call your veterinarian out. Usually at this point there is enough information available to make a good decision about whether it would be best to refer the horse or treat at home.
So if you suspect your horse may be experiencing colic here is what I recommend you do:
If you made it this far, thanks for reading and feel free to call or e-mail to say hello or set up an appointment!
After about 6 weeks of planning, purchasing and preparing I am equipped and ready to start taking calls. I installed the rail boxes on the truck yesterday afternoon and they are now loaded down.
My intention is to use this part of the site to share interesting cases, topical information and maybe a funny story or picture every once in a while. Feel free to share it if you wish or make suggestions for a post.