Controlling Bots

 

Photo Credit: Lauren Langley

Have you ever noticed the tiny yellowish eggs that are laid usually on the inside of your horse’s front legs in late summer, early fall?  Bot flies (adults resemble bees) are responsible for laying those eggs on your horse.  Horses serve as a host for bot fly reproduction.  The bot flies can also lay eggs on the horse’s belly and jawline.  

You may be wondering, how are bot eggs a problem for my horse?  Once the flies start laying eggs on the horse, the horse becomes irritated and reacts by biting or kicking and as a result ingests the eggs.  Once the eggs are ingested, they attach to the stomach wall and develop into mature larvae.  Clinical signs that your horse is infested with bots: difficulty swallowing, ulcers, intestinal obstructions, and other digestive disorders.

Photo Credit: Lauren Langley

What can you do?  Remove the bot eggs if you can with a bot knife.  Be careful not to rub your eyes if you come in contact with the bot eggs which can infect human eyes.  You can also treat for bots after a killing freeze.  Most of the time, a killing freeze kills off the bot flies and that is an ideal time to treat for bots.  Make sure you are selecting a dewormer product that lists bots on the label.  Always consult with your veterinarian when selecting a dewormer product and for the best time to treat.

Fall Vaccinations

As temperatures begin to cool with the arrival of fall, now is a good time to schedule your horses for fall vaccines.  There are two categories of vaccines - core vaccinations and risk-based vaccinations.  Core vaccines include Eastern & Western Equine Encephalomyelitis (EEE and EWE), Tetanus and West Nile Virus and should be included in vaccination programs regardless of geographical locations. Risk-based vaccines such as Botulism, Potomac Horse Fever, Rhinopneumonitis (EHV-1 and EVH-4), and Equine Influenza should be given based on the risk of disease in a herd population or geographical area.  

In North Carolina, particularly in the eastern part of the state, it is highly recommended all horses regardless of age or travel status receive a fall booster of Eastern/Western Encephalomyelitis, a mosquito-born disease.  On September 16, 2021, a second and  third confirmed case of EEE was confirmed in eastern North Carolina for the year.  EEE has a high mortality rate in unvaccinated horses and treatment options are limited and often ineffective. Other fall boosters to consider include EHV-1 and EHV-4 and Influenza, particularly for horses in boarding operations of travel for shows and trail rides.  

Regardless of your location or the time of the year, any vaccination plan, should be developed with your veterinarian to ensure the best disease coverage is maintained for your horse.  The American Association of Equine Practitioners also has an very informative recommendation chart to study to become better more familiar with your options: https://aaep.org/sites/default/files/2021-05/Adult_Vaccinaton_Chart.pdf

Has Your Horse Been Vaccinated?

As we get into the summer months and see higher temperatures, it’s inevitable that insect pests, such as mosquitoes will be out looking to snack on the blood of horses, humans, and other animals alike. Mosquitoes should be a great concern to horse owners since these insects carry and transmit potentially lethal diseases such as EEE (Eastern Equine Encephalitis) and WNV (West Nile Virus). An unvaccinated horse can show signs of these diseases 5 to 15 days after being bitten by an infected mosquito. Symptoms of WNV include fever, weakness or paralysis of hind limbs, impaired vision, head pressing, seizures, and aimless wandering. Typical symptoms of EEE include: muscle spasms, difficulty swallowing, paralysis, staggering, aimless wandering, lack of coordination, and eventually death. Historically, most cases of WNV and EEE in NC occur in July and August. If you haven't already, now is the time to get your horses vaccinated. 

 

There is no cure for either of these diseases and mortality rates range from 30 percent for WNV and over 90 percent for EEE. Unfortunately, horses that contract EEE are often euthanized. This stresses the importance of having your horse vaccinated annually by a large animal veterinarian. Horse owners should talk with their veterinarians about establishing a vaccination schedule to protect horses from these mosquito-borne diseases as well as other diseases, such as rabies. Birds, equines, and humans can become infected from a bite by a mosquito carrying the diseases, but there is no evidence that horses can transmit the viruses to other horses, birds, or people through direct contact.

  

There are also some cultural practices horse owners can also utilize to help curb mosquito populations. Mosquitoes can breed in any area of stagnant water that lasts for more than four days, so when possible, remove any source of standing water to minimize their breeding areas. This practice can decrease the chances of exposing animals to both EEE and WNV. Some other management practices such as keeping horses stalled at night, running barn fans, and turning off lights after dusk can also help reduce exposure to mosquitoes. Providing protective gear such as fly sheets and masks can also help deter mosquitoes and other insects from irritating horses, especially at night. Certain insect repellants, containing pyrethrins can be effective if used according to the manufacturer’s instructions. Many of these sprays only offer temporary relief so it is important that horse owners manage mosquitoes and other insects using an integrated approach.

Now is the time to get your horses vaccinated. Although there are few, most cases of EEE and WNV in North Carolina usually occur from June through August. If you think your horse or other equine animals may have contracted EEE or WNV contact your veterinarian immediately. 

Recurrent Airway Obstruction (RAO)

Recurrent Airway Obstruction (RAO), or heaves, the name which is more commonly known, is a chronic, non-infectious airway condition of horses. Symptoms of this disease are usually seen in horses six to 12 years old and is the result of an allergic reaction to inhaled particles (allergens), such as molds, organic dust, and endotoxins, present in hay and straw. Horses of both genders and all over the world can get heaves.

The allergic reaction that happens after the particles are inhaled causes the small airways in the lung tissue to narrow and become obstructed. A combination of three factors cause this obstruction: bronchiolitis (inflammation and thickening of the tissue lining of the airways), bronchospasm (constriction of the smooth muscles that surround the airways), and accumulation of mucous in the airways. Occasional coughing is one of the first noticeable signs. If the disease is not treated and progresses the coughing will become more frequent, the horse will have an increased respiratory rate even at rest, nasal discharge, wheezing, and can display exercise intolerance. A heave line may become apparent which is caused by the additional workload on the abdominal muscles during the late phase of exhalation. Weight loss and anorexia may be seen in severely affected horses. 

Heaves can be barn or pasture associated. It can also affect horses fed hay in round bales because of the high endotoxin and organic dust content in round bales. If a horse has barn-associated heaves try to maintain them on pasture full-time, while a horse with pasture-associated heaves should avoid access to pastures except during the winter months. Horses with heaves that are maintained in pastures should not have full access to round bales due to the potential cause of treatment failure. Horses with heaves that are kept in stalls should be maintained on low dust bedding. Straw is not recommended as bedding. Stalls should be well-ventilated and kept clean. Avoid storing hay above the stalls and sweeping the floor when affected horses are stalled. Soaking hay in water for approximately 10 minutes and then draining the water before feeding may alleviate the signs of heaves. Soaking grain can also help alleviate signs. Severely affected horses should have all hay removed from their diet and transitioned to a complete pelleted feed. It is very important to remember that although medications can help alleviate clinical signs of heaves, it is pivotal to recognize that without minimizing environmental allergens no long-term benefits will be seen. 

A veterinarian can help diagnose heaves based on the horse's history and clinical signs. They can evaluate the severity of the disease based on the presence and types of inflammatory cells, called neutrophils, in airway secretions. To determine this, fluid samples are taken from the lungs by bronchoalveolar lavage or BAL. The samples taken during a BAL are directly from the small airways, which is the affected part of the respiratory tract in a horse with heaves. Other tests that might be performed are an upper airway and tracheal endoscopy, lung function testing, thoracic radiographs, and ultrasound examination. 

The main medical treatment of heaves is anti-inflammatory medicines, such as corticosteroids and bronchodilators. Generally, these drugs are administered orally or by injection and are usually used together because corticosteroids will decrease inflammation but will not provide immediate relief like bronchodilators. More recently, aerosolized corticosteroids and bronchodilators have become available for the treatment of heaves. Inhaled therapies are beneficial because they target inflammation directly in the lungs and have reduced side effects. Prolonged treatment with oral or injectable corticosteroids can cause laminitis. However, they do require an upfront financial investment to purchase the medications and mask required to administer the medication. 

Many horses affected by heaves are able to be excellent riding partners with a dedicated owner that understands this is a chronic condition that will require life-long management. The course of this disease is largely dependent on the effort put into improving the air quality and decreasing the amount of mold, endotoxins, and organic dust in the environment in which the horse is kept. While there is no permanent cure, complete or near complete recovery from clinical signs may be achieved with diligent management. 

Equine Protozoal Myeloencephalitis (EPM)

Equine Protozoal Myeloencephalitis, or EPM, is a serious disease that can be difficult to dignose because its signs and symptoms can mimic other health problems in horses and the signs can range in severity. More than 50 percent of all horses in the country may have been exposed to the causative organism so it is important to be aware of the signs and symptoms of this disease. 

The causative organism is a protozoa called Sarcocystis neurona, and is spread by opossums. Opossums are the definitive host which is an organism that supports the adult or reproductive form of a parasite. Opossums aquires the causative organism from cats, raccoons, skunks, and armadillos. The infective stage of the protozoa, the sporocysts) is passed in the opossum's feces and horses can come into contact with it while grazing or eating contaminated feed or drinking contaminated water. Once the sporocysts are ingested by the horse, the sporocysts will migrate from the intestinal tract into the bloodstream and will then cross the blood/brain barrier. Once this barrier is crossed, the horse's central nervous system begins to be attacked. Disease onset may be slow or sudden and if left undiagnosed and untreated, EPM can cause devastating and lasting neurological damage. 

The clinical signs and symptoms of EPM will vary and can be different in different horses. Clinical signs are usually asymmetrical, meaning not the same on both sides of the horse. Signs may include:

Ataxia (incoordination)

Spasticity (stiff movements)

Abnormal gait or lameness

Incoordination and weakness which worsens when going up or down slopes or when head is elevated

Muscle atrophy mostly along the topline or in large muscle groups like the hindquarters but can sometimes involved the muscles of the face or front limbs

Paralysis of muscles of the eyes, face, or mouth evident by drooping eyes, ears, or lips

Difficulty swallowing

Seizures or collapse

Abnormal sweating

Loss of sensation along the face, neck, or body

Head tilt with poor balance - horse may assume a splay-footed stance or lean against something for support

There are several factors that can influence the progression of the disease but these four things seem to play an important role:

The extent of the infection (number of organisms ingested)

How long the horse harbors the parasite prior to treatment

The point(s) in the brain or spinal cord where the organism localizes and damage occurs

Stressful events following infection or stressful events while infected

Almost every part of the country has reported cases of EPM, however there is a lower incidence of the disease in the western United States because of the smaller opossum population. About one percent of horses exposed to EPM will show clinical signs of the disease and due to the transport of horses and feedstuffs across the country, almost all horses are at risk to being exposed.

Diagnosing EPM can be difficult because there is no specific assay for this disease and it's clinical signs mimic other neurological diseases. A veterinarian will fist conduct a thorough physical exam to asses the horse's general health and identify any suspicious signs. One clue that can help lead to the correct diagnosis is that EMP tends to affect one side or part of the horse more than another. 

Early diagnosis and treatment are key to increase the horse's chance at a full recovery. Sixty to 70 percent of EPM cases that are treated aggressively show significant or complete reversal of symptoms with many horses being able to return to normal activity. Although there are drug combinations available to treat EPM, there are propriety anti-protozoal drugs specifically labeled to treat the disease. Anti-inflammatory drugs may be prescribed to alleviate symptoms. Vitamin E, an antioxidant, supplementation aids in healing the nervous system tissue. Treatment duration generally lasts one month when using the proprietary products, but can be longer (up to six months) depending on which medication is used. Treatments for this disease can be expensive and may affect stallion fertility and may pose health risks for unborn foals. Despite the high success rates, not all horses respond positively to treatment, with approximately 10 to 20 percent of horses experiencing relapse. During treatment taking blood samples may be needed to monitor potential side effects sushc as anemia, low platelet count, and low white blood cell count. Horses undergoing treatment should be closely monitored for sings of improvement or decline and any changes should be reported to your veterinarian immediately. 

The best way to prevent this disease is good horse keeping practices that discourage opossums and other rodents from getting into and contaminating hay, grain, bedding, and water sources. Here are a few suggestions for how to do that.

Keep feed rooms and containers closed and sealed

Use feeders that minimize spillage and are difficult for wild animals to access

Clean up any dropped grain immediately to discourage scavengers

Feed heat-treated cereal grains and pelleted feeds sind these processes seem to kill the infective sporosysts

Keep water tanks clean and filled with fresh, clean water

Maximize your horse's health and fitness through proper nutrition, regular exercise, and routine vaccinations and vet visits

If you have more questions on the topic, please contact your local livestock Extension agent and your veterinarian. 

 

iPhone, iPad, iSperm?

 

Let’s face it, technology has become a necessary evil in almost every sector of agriculture including the reproduction of livestock. . .enter iSperm.  iSperm boasts being “the first mini/mobile computer-assisted sperm analyzer (mCASA)”.  Since it is mobile, it can help the user monitor semen quality almost anywhere, including in the middle of a field.  Test concentration, motility, mobility and sperm kinetics with a user friendly interface on an iPad Mini.  Quickly calculate total number of doses and amount of extender needed.  Results are archived in the cloud so you don’t even have to write anything down.  

Like most new technologies, there is an upfront cost associated with the purchase of the app, iPad Mini and a few pieces of collection equipment; however, this does make semen analysis access easier and more affordable plus iSperm has been validated by The Ohio State University School of Veterinary Medicine.  It has been used all over the world for research purposes and by many zoos to ensure the quality of their breeding programs for endangered animal recovery.  No more sending off samples for analysis, no more having to wait for results,  this portable semen analyzer gives you accurate results quickly.

More information about the iSperm system is available on their website: https://www.isperm.co/ or on the Breeder's Choice website.

Should I Feed My Horse Grain?

When it comes to developing a feeding program for your horse always keep in mind that high quality forage (pasture + hay) should always come first.  To answer the title to this blog post you first need to know the nutritional requirements of the horse in question.  Nutritional requirements are based on several factors including:

• Class of the horse
• Body weight
• Body condition
• Stage of production
• Age
• Activity level
• Growth

 For example, high quality forage alone should meet the nutritional requirements of horses in maintenance or light work.  In contrast, a horse that is in lactation or heavy work will almost always require supplementation in the form of grain to meet nutritional requirements.

How do you know if your forage is high quality and meeting your horse’s nutritional requirements?  The best way to know what you are feeding is through a forage test.  You can test fresh forage (pasture) and you can also test hay for nutritional value.  Then, you have a basis for your horse’s feeding program and can go from there if you need to supplement.  As you can see from the charts below, high quality forage can go a long way in meeting nutritional requirements:

Chart by: Dr. Paul Siciliano, NCSU

 

Chart by: Dr. Paul Siciliano, NCSU

Lastly, don’t forget the minerals!  All horse feeding programs need mineral supplementation year-round, especially trace minerals.

In summary, try to maximize high quality forages as much as possible to ensure a healthy gut and avoid unnecessary supplementation.  Not only will this save you time in feeding but also money!  Whenever forages do not meet nutritional requirements that is when you need to feed a supplement, usually in the form of grain.

For more information about feeding horses check out this article.