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?

bot-eggsThere 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 botseggs 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.


Is Your Mare Driving You Crazy?

Tired of your mare cycling and dealing with the associated behavioral issues? Do you no longer wish to attempt to control her heat cycles with the use of hormones such as Regumate? Has she lost her marble!?!?!? If this applies to you and you have no intention of ever breeding the mare then there are options to permanently eliminate your mare’s obnoxious behavior.

A common procedure to deal with the issue is to “spay” the mare. This is not like spaying a dog – a procedure where both the dog’s ovaries and uterus are removed. In the mare the term “spay” means to remove just the ovaries. It is the equivalent of gelding a stallion. Usually this can be performed with the mare standing in a stocks, sedated with an epidural for anesthesia. There is no external incision so there is no scar visible. The mare is typically back riding 10 – 14 days after the surgery. Fall and winter are ideal times for the procedure to be performed – the mare cannot be in heat when the surgery is performed. Please contact Anoka Equine and speak to one of our veterinarians for more information.

Castrating Your Colt

Fall and early spring is a great time to consider gelding your colt or stallion. The more mild temperatures and virtual elimination of insects due to these colder temperatures results in a lower complication rate associated with infection.

We offer several different techniques for gelding. Many younger horses are done with a technique called an open castration. With this technique the incisions are left open to drain. The incisions will heal within 14—21 days. Regular turnout and exercise during this time is helpful for promoting drainage and decreasing the normal swelling that occurs with all castrations. This procedure can be performed either on your farm or at the clinic. Depending on the size and demeanor of the horse that is to be gelded, the procedure can either be done standing or down. The standing castrations are done with sedation that allows the horse to continue standing, and a local anesthetic is given at the site of the castration. In other cases, the horse is put under a short general anesthesia and then laid down in a clean, level area to perform the surgery. A recent tetanus vaccination (given within three months) is required. The veterinarian may also give antibiotics to the horse on the day of the surgery.

The other technique that can be used is performed under gas anesthesia at the clinic on the surgery table. This technique is called a closed castration. The difference is that the incisions are closed with absorbable sutures. As a result there are no open incisions to drain or heal. This type of procedure is often chosen for older mature stallions that would have a higher likelihood of post-surgical complications if the incisions were left open. The closed technique is also used for cryptorchid males. A cryptorchid is a stallion or colt that does not have both testicles descended into his scrotum. These horses have either one or both testicles still in their abdomen or inguinal ring. The testicles should drop into the scrotum within the first few months of life at the latest. Most newborn colts already have both testicles down in their scrotum.

Henderson Castration Instrument

By Dr. David Schwinghamer

Castration is the most common surgical procedure performed on the equine patient each year. A multitude of complications can occur with this procedure, the most common of which include hemorrhage and swelling. Other possible complications are intestinal evisceration, infection of the cord, fluid accumulation in the cord, and peritonitits (abdominal infection). The Henderson Castration Instrument was designed to help decrease some of the possible complications of equine castration. This method uses a rotary or spinning action of the instrument to ligate the vasculature of the testicular cord, thus decreasing bleeding after castration and reducing the degree of swelling. This method can be done as a sterile procedure so the skin incision can be sutured, thereby reducing the risk of ascending infection from environmental bacteria and flies. The horse is anesthetized which allows the practitioner better visualization and access to the surgery site. Post-operative management, including cold hosing and exercise, is dramatically reduced using this technique due to the decreased degree of swelling that is likely compared to using other common techniques. The Henderson Castration method is recommended for horses above one year of age. For younger horses, we still recommend either down closed castration or the standing emasculation castration. The Henderson Castration technique does not eliminate the risk factors of equine castration, but it does considerably reduce them. Therefore, we recommend considering this type of castration especially for the adult horse and for castrations done during the fly season.

If you have any questions regarding this or any other aspect of castrating your horse, please feel free to call the clinic or to schedule an appointment for your horse to be seen by one of our veterinarians.