Mill Creek Veterinary Service

» I don’t really need another horse, but I love my mare and it would be so fun to have a foal. I’m thinking about breeding my mare this spring. Is it really expensive to do artificial insemination?

That’s a really bad idea, not only because of cost. There are over 5000 unwanted horses in the state of Colorado alone, every year. If you don’t really need another horse please don’t produce any. Visit the Unwanted Horse Coalition website, the Colorado Unwanted Horse Alliance and see also the article, Abuse, Neglect and the Unwanted Horse Update 2010 in this website.

» I de-worm my horse four times a year and I rotate products. Is that ok?

No. Ivermectin dewormers (Zimectrin, ivermectin, bimectin, etc) only suppress the maturation of adult strongyle worms and egg production for 6-8 weeks. Anthelcide, Safeguard, and others probably only work for 4 weeks. Moxidectin (Quest) is the only dewormer that suppresses worms and egg production for 12-14 weeks, but your horse may or may not even have a significant worm load. Only a microscopic fecal flotation exam will tell for sure. With that, we can help you set up a rational management plan. Please see also Update on Deworming Your Horse. Remember that dewormers pass in the manure and may be toxic to dogs.

» Do horses get cavities?

A. Yes, they do -- two kinds.

Infundibular cavities are present in over 70% of horses over the age of fifteen. The infundibulae are cone shaped structures (cups) made from enamel infoldings and are found in all incisors and in the upper (maxillary) cheek teeth where there are two— front and back (mesial and distal)--infundibulae.

Prior to toth eruption, infundibulae are filled with a tissue called cementum from the chewing surface all the way to the root tip though some cells continue to fill the infundibulae as the root develops. Sometimes the infundibulae are irregularly shaped or are not completely filled and those in the first true molars commonly are not. Inadequate filling, called cemental hypoplasia, may occur during tooth development especially if the caps (baby teeth) are lost prematurely causing disruption of the blood supply to the infundibulum.

As cheek teeth wear, cavities in the infundibulae are exposed. Erosion of the surface of the cavity from carbohydrate fermentation and acids may lead to decalcification of cementum (stage 1 cavity). Further erosion may progress through the enamel cup (stage 2) and then into dentin and pulp horns (stage 3).

Deep infundibular cavities, especially those involving pulp horns, predispose the tooth to sagittal fracture, apical infection, and root abscess. See article on Little Bella in Dentistry Section

As for the second type, horses can also get infected cavities in the pulp horns, and though these aren't as common, they are certainly painful and can also lead to tooth loss or fracture.

» Do horses get painful periodontal disease?

Yes, they do -- two kinds.

Yes, they do. Periodontal disease occurs in 60% of horses over 15 years of age. It is commonly secondary to malocclusions, like waves, spaces between teeth (diastema), or anywhere food is trapped.

In young horses, periodontal disease occurs during eruption of permanent teeth—CHX rinse and time usually takes care of these.

Mild gingivitis is related to calculus on lower canines in geldings and stallions.—remove calculus periodically and rinse.

See article on Little Bella in dentistry section

» Why is dental work in horses called "floating"?

Floating in dentistry is a term that means to remove and smooth sharp edges and enamel points that develop on the outside of the upper cheek teeth and on the inside of the lower cheek teeth. "Floating" in general refers to smoothing or leveling a surface as in carpentry or concrete work. This term, for better or worse, was adopted by equine dentistry many years ago.

» How often should my horse have a dental exam?

A quick answer to this question is that a thorough exam should be done on a yearly basis. Generally if no unusual problems exist, checking the teeth and oral cavity yearly is quite sufficient to maintain good health. However, if on exam problems are noted, your veterinarian may have a different recommendation. For example, young horses going into training should have exams twice a year, and horses with significant overgrowths may need to be treated even more frequently. Finally, if your horse has a good record of dental health, stretching the examination interval may be possible.

» How do wild horses manage without an equine dentist?

Three things:

Feral horses eat a wide variety of vegetation including rough prairie grasses, leaves, small plants and shrubs and tree bark. This group is generally higher in silicates and is more abrasive and requires greater chewing action. Perhaps this is more healthy than the softer grasses, hay and concentrates that most personal horses are fed.
Examination of present day feral horse skulls and also prehistoric horse skulls, show a wide variety of dental abnormalities that we still see today. Some are minor, but some were likely health and maybe life limiting.
There is no real evidence that feral horses wouldn’t feel better and live longer if observed dental problems were addressed in a timely fashion.

» Will floating my horse’s teeth help him digest his food better?

A study was done several years ago on a group of healthy mares. The particle size of feed found in the manure of each mare was evaluated before and after floating. Remember, floating means removing sharp enamel points on the cheek teeth. Results showed no significant difference in particle size. What was not reported, however, was if other dental abnormalities existed, such as sores on the cheeks, malocclusions or periodontal disease, these should also be identified and treated.

» My horse tosses his head when I ride him with a bit. Could this be a dental problem?

Yes. The whole oral cavity should be checked. Wounds to the palate, tongue or bars can be painful with a bit in place. If the horse wears a nose band there may be more cheek contact with sharp enamel points. Periodontal disease, infected or damaged teeth are also stressed more with a bridle on. A thorough exam with sedation, a full mouth speculum and a good light source may discover a correctable problem.

Of course, sometimes it is a training issue, but one should rule out oral pain before asking the horse to work through existing discomfort.

» Do horses have problems with their TMJ like people and dogs do?

Yes, horses do occasionally have TMJ disease, although not as commonly as may be suggested by some. For our purposes we will not discuss infection, cancer or fractures. TMJ pain may be one sided or two. Pain may result in chewing problems, swelling and tenderness over the joint(s), or precipitate training issues. Restricted jaw transit due to dental pain may result in TMJ pain or the opposite may be true.

If one TMJ is diseased, the jaw movement may be altered, resulting in abnormal tooth wear. Thorough palpation of the joints and jaw manipulation may rule in or rule out TMJ pain. Other more advanced diagnostic techniques are available such as joint blocks, x-rays, ultrasound or CT for a more complete investigation. Treatment often involves dental floating and equilibration along with joint injection if indicated.

» My veterinarian uses a power float when she works on my horse’s teeth. Are power floats dangerous?

No. Motorized dental floats are safe and effective for use in horses. Although traditional hand floats are still useful, power tools offer several advantages over manual floats. The rotating diamond impregnated discs of the more popular models can contour the teeth as desired without any axial (back and forth) stress in the teeth. This is an advantage particularly in geriatric patients where the teeth have much shorter roots. Secondly, the time to perform needed corrections is shorter which is beneficial to the horse. Third, the guarded disc, although good to remove enamel points, is very forgiving to the soft tissues of the mouth.

As with any instrument, proper training and careful application of the instrument is required. Prolonged grinding on one spot can cause thermal damage to a tooth resulting in pulp damage and possibly ultimate tooth loss. Research has shown that to avoid overheating, grinding on any individual tooth must be limited to no more than 15 seconds. Also the teeth should be irrigated with cool water frequently during the procedure or with a constant irrigation system.

» How much should I feed my horse, and how often?

How Much? Minimum forage for the horse is 1% of the body weight—10 pounds a day for a 1000 pound horse. Any horse in use, in stress, in cold, will need more, and the temperament and age of the horse will also determine the amount of feed. The average relaxed Quarter Horse weekend warrior can get by on about 1.2% of his body weight in feed—with 1/2 pound of that being a low carb concentrate like any senior feed, Ranchway’s Sound Starch, Nutrena’s Safe Choice, or other low carb feed, along with a measured amount of a balanced vitamin/mineral supplement (Ranch-O-Min 1011, Purina 12-12+, Moorman’s GrowStrong, etc. DO NOT count on mineral blocks designed for livestock. Pregnant mares, growing horses, old horses, and horses in considerable activity (2 hours daily with a mild sweat) need more concentrate, a higher quality and percent of protein and more hay per body weight. A nervous horse (TB) will require significantly more calories—2% body weight with greater carbohydrate load. The only way to really develop a ration is to have your hay analyzed (by Equi-Analytical Labs in New York, as they will determine all basic requirements as well as the carbohydrate levels significant to horse rations). Having a scale to weigh each feeding is critical.

How Often? The stomach of the horse produces acid around the clock and eating is a buffer to that acid. Horses were designed to eat 14 or more hours a day. It’s no wonder a high percentage of horses have stomach ulcers with our artificial feeding schedules. Our number one rule is: A HORSE SHOULD NEVER GO OVER 12 HOURS WITHOUT HAY. This means that in the winter, you need to be feeding a last meal after dark—if you feed at 7 am, you need to be feeding at 7 pm.

Ideally, spread the hay out into 4 feedings.

See article on Weight Management and Body Condition Scoring for more details.

» My horse is in his twenties, and this spring he came back from his winter home looking a little sick. I thought he was doing better this summer but every time I go see him this winter, he just looks thinner. Do you think he needs vitamins?

There is no reason that a senior horse should be underweight unless he has a physical problem—bad teeth, Equine Cushing’s Syndrome, some other illness. It’s all a matter of getting enough calories. Management is critical.

Separate your underweight horse from more dominant, healthy individuals. Even on the hay stubble in Arboles, the dominant horses get the best grazing, and in the last few years the snow has been too deep for most horses to get much to eat. Begin feeding grass hay in small amounts several times daily.
This old horse has very little padding to keep him warm. He needs shelter, and he may need a blanket at night if he is shivering. An extra meal of grass hay after 8 pm will help him maintain body temperature during the night.
Special senior concentrates are indicated for an underweight older horse or any horse with missing or diseased teeth. Start with 1 pound twice daily and increase by 1/2 pound each feeding every week to a maximum of 5 pounds per feeding. If he needs more than that (which he might if he can’t eat hay or grass) then we may suggest adding canola oil or soaked alfalfa pellets, or giving a third feeding of senior feed in the middle of the day.
Yes, a balanced vitamin/mineral supplement should be given (Ranch0Min, GrowStrong, Purina 12-12+) daily.
Use a weight tape every two weeks, and keep a chart.

A full physical exam, a fecal examination for parasites, a complete dental exam, and lab work are indicated. In horses with weight loss due to dental problems we often find gingivitis and periodontal disease. These oral infections are exacerbated by the decreased immune status of an underweight horse. Other infections also tend to become more serious.

See also, Weight Management article to learn about Body Condition Scores and proper use of the Weight Tape. See Dentistry in the Geriatric Horse, and the article on Equine Cushing’s Syndrome if indicated.

» I use fly spray every 3 days like the bottle says and my horse still is covered with flies. Why doesn’t this stuff work?

A: There are several important factors to fly control, only one of which is using fly spray.

Flies lay eggs in manure and then the thousands of larvae hatch to become adults. Removal of manure from stalls and paddocks at least twice daily will greatly decrease the fly population. Haul the manure well away from the horses. It can be composted or placed in a dumpster.
There are dozens of fly sprays available everywhere. Some kill flies, some repel flies and some do neither very well. One should buy a product that will both repel and kill. This generally means a product with permethrin or derivatives like cypermethrin to repel. Secondly, pyrethrin will kill the flies, but only once they feed on the horse. The names are similar, but very different in action. Some of the so called “Natural” sprays may have some beneficial action, but have been consistently shown to be inferior in protecting the horse.
Fly predators are tiny insects that feed on fly larvae in manure. They are a good addition to any fly mitigation program, but will not act alone to control flies in the presence of too much manure.
Some horses have sensitive eyes that benefit from masks. Some get hive reactions and may benefit from fly sheets. If either of these conditions get out of hand ophthalmic washes or ointments, antihistamines or corticosteroids can bring great relief in many instances.
Horses seek shade to get away from flies. Provide a shelter and keep it clean.
We are not big fans of feed through insecticides which reportedly kill fly larvae in manure, although new products are being developed that may be safe.

» My five year old mare has some little, ugly white bumps inside her ears. Right now they aren’t bothering her (it is winter) but during the summer she rubs her ears on anything she can find and shakes her head. If I try to look at her ears or wipe them, she dodges away and she is sensitive if I bump her ears putting on her headstall. I use a fly mask with “ears” and I use roll on fly wipes. I hate looking at these ugly things on my pretty mare. What are they and what can I do??

The little pale raised bumps in your mare’s ears are called Aural Plaques and in the winter they are just an unsightly blemish. But once warm weather comes, the black gnat, Simulium, will return to bite the inside of your mare’s ears, releasing a toxin and causing a tiny bleeding sore. At the same time, that gnat may deposit a Papilloma Virus (PV), though the DNA from the virus is not always found in Aural Plaques. The Papilloma Virus is not equine in origin, and research has not documented a clear association with the Bovine PV that causes Equine Sarcoids. However, the microscopic examination of Aural Plaques sure looks similar.

Once the gnats have attacked, the crusty, bleeding sores cause extreme itching and sensitivity. By that time, you may need help with a mild sedative to get the ears clean and disinfected and treated topically to control the pain and itch. Once that is accomplished, most horses really learn to appreciate a gentle cleaning and application of an antibiotic/steroid cream to quiet things down. After that, it is a matter of preventing further irritation by preventing the gnat bites.

Fly sprays and lotions containing Permethrin and cypermethrin are about the only ones that truly repel flies, mosquitoes, and gnats. Products containing pyrethrins kill flies but do not effectively repel. So read the labels. You can make a protective layer by mixing permethrin and Vaseline or bag balm. And then, go ahead and use those fly masks with ears.

So what about the ugly white bumps that never seem to go away even if you prevent more gnat bites? The most recent research describes using Aldara (5% imiquimod) crème twice weekly for 8-24 weeks. Imiquimod is an immunomodulator that has antiviral and antitumor activity used in human herpes induced warts. Eventually the white lumps will become inflamed and sensitive and then greatly reduce or disappear in about 75% of cases.

Your mare will greatly appreciate your preventing further gnat bites and the stimulation of more aural plaques. But I’m not sure she’d really want you to get rid of the ones she already has.

» How often should my horse be trimmed (or shod)?

Most horses grow enough foot that they need to be trimmed or re-shod every 6 weeks. See Hoof Care Check List for Horse Owners for more details.

Q:Does my horse have to wear shoes?
Potentially not. Some horses can adapt to the surfaces that they walk on every day. But in this area, most mountain trails have significant gravel and rock, and many horses are quickly lame when taken on a ride. Additionally, the average horse needs to have a fairly thick sole to be comfortable on hard surfaces, and in this day and age, many do not.

There are a number of boots that can be used for trail riding, but fit is critical.

A horse is most sensitive when his shoes are pulled at the end of the riding season. Be sure to have boots available for the first few weeks in the fall after shoe removal.

» Why does my horse's urine turn red when it hits the snow in winter time?

We get occasional calls about “blood in the urine” in the winter. While if true, this would be a serious problem, with further questioning, it usually becomes apparent that what the owner is observing is red or orange colored urine spots in the snow. Some horse urine will change color from yellow to an orange-red after cooling in the snow at certain temperatures for some time. A similar thing occurs if urine is refrigerated. The color change is a chemical reaction of components in the urine activated by cold. So when the horse is actually observed urinating and the urine is normal, no worries unless the urine is red when it comes out of the horse.

» What is your opinion and advice for wood chewing horses? I've been applying chew-stop almost daily this winter to the outside of the barn, plus they all have wood pieces in their stalls, and they have access to the natural wood in the pasture. Is this the best preventative? Why do they do this? Boredom? Or are they missing something in their diet?

Good question. Horses are designed to eat 14 hours a day. Otherwise, their constantly produced stomach acid builds up. So the instinct to forage is pretty strong. Are your horses going out every day into the pasture on paths that they have made in the snow, I assume? What kind of wood pieces do they have in their stalls? We find that they will preferentially gnaw aspen bark, then pine bark. They also really like willow, but not sure how much they should have. And yes, oak bark. Keep in mind that the local mustangs subsist almost entirely on oak and aspen bark and willow twigs all winter. Pretty natural. One of our favorite winter additives is a lesser quality hay (low protein and low carb grass) fed at night because you can feed a lot and they don't get fatter, the metabolism of this hay creates heat, and reduces their need to chew so much on alternative sources.

Yes, boredom is a part of the picture. Horses can walk and trot on most plowed gravel roads without shoes or boots around here. Get out your hand and toe warmers and start conditioning for spring. Ride one and pony one if you have a pair. Just watch for icy spots. And once the snow melts and gravel is visible, you may need those protective rubber boots until it is time to put shoes back on. So--aspen logs and pine logs, low carb grass hay, and more exercise.

To protect the barn, consider installing Propanel metal siding for the horse side of the barn come summer. It'll save you a lot of damage every year.

» When should I use a blanket on my horse?

The 2007 edition of the National Research Council’s Nutrient Requirements of horses states that the lower critical temperature for mature horses is 5 degrees Fahrenheit. Below that, horses require additional grass hay to increase metabolism and body core temperature. However, that lower critical temp must be evaluated in light of age, body condition, and adaptation of the individual horse. Also consider the significance of wind chill factor and humidity adding to the bone chilling cold.

Our general recommendation is to not blanket horses unless they are underweight, have insufficient winter hair coats, and are unprotected. Blankets should be dry and waterproof, and should be removed for several hours every day. Horses that are well adapted with long hair coats, have protection from the wind and rain at night, and are on grass hay which produces the most heat from metabolism, probably will not need a blanket. That said, if you find your horse shivering, take a rectal temperature and plan to blanket the horse if the temp is below 98.

We advise owners to feed two extra pounds of grass hay late in the evening per animal when temps are forecast to be below 5 degrees and in general advise feeding 4 meals a day in winter. Each animal should be evaluated for body condition and for dental issues that may preclude adequate chewing of hay. Older individuals may need senior feeds which are complete feeds and not considered grains, to balance their intake if teeth are in poor shape. All of your animals should be getting a balanced vitamin/mineral supplement designed only for horses and a salt block.

Breeding