By: Rick S. Marion, D.V.M.
Hypercementosis is the name given to an emerging problem in older horses involving degeneration, and eventual loss of incisor teeth. The incisor teeth are the 12 teeth that sit in the front of the horse’s mouth, the ones seen when the lips are parted. They are used for biting and grabbing hay and grass but do almost no chewing, grinding, or processing of feed stuff. As we have all observed they sit perpendicular to the jaw in young horses and almost always become long and horizontal as the horse ages. The incisors can be severely affected by objectionable habits in the horse, such as cribbing or raking on solid objects.
Hypercementosis, more properly and recently renamed Equine Odontoclast Tooth Resorption and Hypercementosis (EOTRH) is a chronic degeneration of the incisor and canine roots. The degeneration of the root is accompanied by (or possibly caused by) inflammation of the periodontal membranes, loosening of the tooth, bacterial overgrowth, and gingivitis. The cause of this syndrome is not completely understood and it may be a combination of various syndromes with many causes alone or together, resulting in the same characteristic lesion.
The progression of the syndrome is inconsistent but typically begins with the corner incisor or canine teeth and progresses toward the center. As the teeth roots are variably reabsorbed and hypertrophied, the periodontal membrane becomes inflamed and infected, the gingival tissue also becomes infected, and the tooth loosens. Loose, inflamed teeth can be very painful but rarely will hinder the horse from eating.
Treatments vary tremendously, but as of now no treatment has been found to stop the degeneration and eventual loss of teeth. Antibiotics will partially control the gingiva and periodontal space infections. Anti-inflammatories, bute, banamine, aspirin, and steroids may help address the pain associated with the inflammation. Splints or braces may decrease the mobility of the teeth and also address some of the pain. All treatments will eventually end with tooth extractions. The incisors may be extracted one or two at a time as their roots fracture or the infection progresses enough to make removal necessary. However, they may all be extracted at one time to address their pain and to treat their condition as aggressively as possible.
Some veterinarians prefer to remove all the incisors at one time because they feel this more aggressive approach is the fastest and most complete way to resolve the pain, inflammation, and infection.
By: Katie Jones, CVT
Many of us are familiar with the yellow “seeds” that appear on our horses’ legs during summer months as bot eggs, but what exactly can we do to prevent these recurring parasites each year?
There are three different types of botflies. The first is considered the common horse bot (Gastrophilus intestinalis); they lay their eggs on the horse’s body and are ingested through self grooming. The second is the throat bot (Gastrophilus nasalis), they lay their eggs on the horse’s neck and beneath the jaw. The larvae from these eggs then travel from the neck to the mouth. The third and final type is the nose bot (Gastrophilus haemorrhoidalis). This type of bot is the rarest type and they lay their eggs around the lips. Once the bot larvae are in the horse’s mouth they remain there for around four weeks before traveling into the stomach. When the larvae enter the stomach they attach to the division between the glandular and non-glandular portions of the stomach (the Margo Plicatus). The larvae have hooks in their mouths that allow them to attach to this division for eight to ten months, or until mature. Once the larvae have reached this stage, they release themselves from the lining of the stomach and are passed in the horses feces. When they finally reach the environment, they burrow into the ground until they mature into adult flies. This lifecycle takes about a full calendar year; once the adult botfly emerges from the ground the cycle starts again.
There are several symptoms a horse possesses if they have been exposed to bots. Bot eggs on the body of the horse appear as clusters of orange and yellow dots on their head, belly, and legs. Due to these eggs a horse can be found licking at their stomach and legs, biting or rubbing their mouth (to try and relieve irritation), with ulcers in and around their mouth, or appear colicky. When the number of larvae in the stomach becomes overwhelmingly large a blockage can form, as well as, ulcers along the stomach lining. Visualization of the bot eggs and larvae is the main diagnosis. Once the bot larvae attach in the stomach they can be seen by gastroscopy.
To decrease a horse’s exposure, it is recommended to promptly remove any eggs found in the hair. This will minimize and even disrupt the bot’s life cycle. Using fly spray and fly control practices in barns during summer months will also help decrease chance of exposure. The best way to prevent bot larvae in the horse’s stomach is by practicing a good deworming schedule. The recommendation is to give a deworming product containing Ivermectin, preferably after the first frost in the fall.
Botflies are common in the Midwest but with good management, horses can be treated and the risk of exposure can be decreased. If you have concerns regarding bots, make sure to connect with your veterinarian to discuss what your horses’ risks are.
By: Katie Jones, CVT
Tetanus is a disease caused by the organism Clostridium tetani. It affects almost all animals; including humans. Horses are more susceptible to tetanus than any other domestic animal. This is due to their lower natural immunity and they live in environments with a high risk of tetanus.
- Not contagious.
- Anaerobic bacteria. Anaerobic organisms thrive in dark environments lacking in oxygen; however, their spores can survive in the environment for years.
- Disinfectants, heat, or drying can damage the integrity of the organism.
- High mortality rate.
Ideal environment: Deep puncture wound that includes tissue damage.
Process of Infection:
- The organism spores live in the soil and enter the body through wounds or incisions. The toxins produced begin to damage the tissue and decrease the blood supply to the infected area.
- The neurotoxins produced by the organism can enter the bloodstream from the infected site of the body.
- These neurotoxins tightly bind to specific areas of the spinal cord and brain, preventing the body’s ability to process brain signals. It causes the affected muscles to intensely and persistently contract. Once the neurotoxins attach to the spinal cord there is no medical treatment available to dislodge them and the effects must be allowed to slowly wear off.
Clinical Signs: Once the organism has entered the tissue and is producing toxins, the course of clinical signs can be very rapid.
- Beginning signs: Colic, vague stiffness, lameness (if the infected area is the limbs), retraction of the lips, flaring of the nostrils, development of a film over the third eye lid, and difficulty opening the jaw.
- After 24 hours of infection there is generalized spastic activity of the muscle groups that assist in standing.
- As the disease process continues the horse can develop labored breathing, stiffness in the front limbs, and the jaw can become locked preventing eating and drinking. These symptoms are characteristic of fatal tetanus; however, not all horses that are infected with tetanus progress to this state.
Treatment: Dependent on the severity of the disease.
- Early diagnosis is needed to prevent the progression of the disease with the use of a manufactured antitoxin.
- If the diagnosis isn’t made early, the wound will need to be surgically opened, effected tissue must be removed, and penicillin will be injected into the wound. The wound will ultimately be left open for continued drainage.
- The horse will remain on a course of penicillin.
- Supportive care is given to maintain nutrition and hydration.
- It can take weeks to see an improvement and clinical signs can last months.
Prevention: Tetanus is a nasty disease with an expensive treatment plan.
- Although the vaccine is not a 100% guaranteed, it has proven to be a successful way of preventing Tetanus. Check with a veterinarian regarding their specific vaccine protocols.
- Cleaning and bandaging wounds immediately will also help with preventing the development of tetanus.