Review Int/Adv Teeth

When is your horse said to have a full mouth? What does that mean?

How do deciduous teeth look different from permanent teeth?

When does Galvayne's Groove appear? Where does it appear?

What age do the middle permanent incisors come in?

How does the shape of the horse's teeth change over time?

When does the dental star first appear?
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Int./Adv Teeth

Don't look a gift horse in the mouth. But why? Well because you're likely evaluating it's age -- the ancient world's equivalent of checking the price tag of a gift you've received :)

But what would you be checking for? Well you know (since you either already know OR you read the beginner section :) that a horse's teeth never stop growing. So it stands to reason that they change shape over the years and with practice you can learn to judge the horse's age. Now this is unfortunately never really accurate beyond about age 7 -- but it can, at least, put you in the right ballpark. Why not accurate? Because as we know, wear changes based (among other things) on diet. So every horse's teeth will change at a slightly different rate.

So the very first thing to check -- does your horse still have baby teeth (if so, they're under the age of five). If they do, how many do they have?

Incisors

• Deciduous central incisors - come in at birth or within the first two weeks
  
• Deciduous middle incisors - come in at 4-6 weeks old
  
• Deciduous corner incisors - come in at 6-9 months
  
• Permanent central incisors - come in 2.5-3 years
  
• Permanent middle incisors - come in 3.5-4 years
  
• Permanent corner incisors - come in 4.5-5 years

Note, while it's a lot harder to check the molars, they also come in on schedule:

Premolars (the set at the front of the mouth, meets the bars)

• Wolf teeth (technically PM1) - no deciduous set, permanent ones at 5-6 months (if ever)
  
• All three other deciduous sets: come in at birth or within the first two weeks
  
• Permanent PM2 - 2.5 years
  
• Permanent PM3 - 3 years
  
• Permanent PM4 - 4 years

Molars (the set at the back of the mouth)

• There are no deciduous molars. The horse gets permanent ones as they get older.
  
• 1st - 9-12 months
  
• 2nd - 2 years
  
• 3rd - 3.5 years

Note for both molars and premolars the count goes from front to back. PM1, the wolf teeth, are closest to the incisors, PM2 the next tooth back, etc.

Your horse is said to have a "full mouth" about age 5 when all permanent incisors, premolars and molars are in. How to tell? Deciduous teeth tend to be smaller (I know, big surprise eh?), whiter, and have several grooves on the surface. If the teeth are big, yellow, and rectangular in shape, they're probably permanent. A good thing to do is find a horse who you know is 3 or 4 years of age and look at their teeth to see the difference between the baby teeth and the adult teeth. Ummmm find either a very patient horse or get somebody to help you do this the first time ;) Just a suggestion.

Note that if the gelding or stallion has canines it means they must be at least 4 years old (often these don't come in till 5).

After 5 things get a little trickier, but there are things you can specifically look for:

• The cups - in young horses you can see a cup in the incisors (essentially an oval shaped concave area that will eventually be worn away). By 9 the cups are gone (usually leave central incisors about 7, middle around 8, and corner around 9).
  
• The dental star - this appears at about 6 years of age (in the central incisor - other incisors to follow in the next year or two). If you look at the top of the incisor, you'll see a dark yellow/brown circular/star shape (technically what you're seeing is a dentin-filled pulp chamber -- don't you feel smarter now?). At this age it starts out as a narrow line and morphs into a rounder and bigger shape with age - most dramatic around age 10 (and then usually disappears entirely between 15 and 20). It's toward the front of the tooth.
  
• The hook - at about 7 years of age (and sometimes again at 9) a hook will appear on the upper corner incisor.
  
• Galvayne's Groove - a dark line that runs longitudinally on the upper corner incisor. This shows up about 10 years old, is half way down the tooth at 15, all the way down the tooth by 20, gone by 25. Useful if it's there but not all horses show this.

Then the other thing to evaluate (requires more practice) is the shape of the teeth:

• On a young horse the shape will be oval, then it will square off to become more rectangular. In old age the corners are worn and you end up with an almost triangular shape.
  
• Similarly the angle (when viewed from the side) at which the incisors meet changes. A young horse the teeth meet almost straight up and down like | (technically about 135deg for those who like those things - it's hard to show that accuracy in ascii art :). In an older horse though (age 20+), the angle has changed dramatically so that the incisors meet at almost 90deg (looks like < then).

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Review Beginner Teeth

Label the diagram. Which is the upper jaw? How do you know? Is this a mare or a gelding? How do you know?

What is floating the teeth?

What are four signs your horse may need his teeth floated?

Which teeth are usually pulled? Why?

How many teeth does your horse have?
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Beginner Teeth

So in the Intermediate section of Preventative Care, I promised more info about teeth. Without further ado, all you never wanted to know (and then some!)

So you know your horse has teeth. Big ones. Sharp ones. You may even have had the misfortune of having felt them before! Do you have any idea how many teeth your horse has? And did you realize that they are *always* growing?




So your horse likely has between 36 and 40 teeth depending on whether it's a mare or a gelding/stallion (mares usually don't have canine teeth) and whether or not the wolf teeth come in (wolf teeth, if they appear, are almost always pulled as they can be painful and may interfere with the bit).

• The incisors (officially I1, I2, I3 from the middle out) are the central incisor (1), the middle incisor (2), and the corner incisor (3). Creative eh? These are used for biting the food -- just like yours!
  
• Then there is a gap, technically the "interdental space" but more commonly known as the bars, this is where the bit rests.
  
• At the far back, again as in your mouth, are the molars (6). These are the chewing teeth, used to grind the food for digestion. The three molars closest to the front are referred to as the premolars.
  
• Wolf teeth (5), if they appear, are found right in front of the molars and tend to be short and pointy. They provide no real benefit to the current domestic horse. These usually only come in on the upper jaw.
  
• Canine teeth (4), aka Tushes, in the boys, are in the space between the incisors and the molars (called the.... ??? that'd be the bars -- look up a couple points!). They usually don't exactly line up with each other -- the lower jaw canines are closer to the incisors than the upper jaw. These tend to be super sharp. You do very occasionally see them in mares, but usually they're unerrupted (a bump under the gums) or tiny.

By 9 months a foal will have a full set of 24 baby teeth (called deciduous teeth - like deciduous trees, they shed). These will eventually be replaced by permanent teeth -- usually by the age of 5. They will also pick up 12 new molars, possibly wolf teeth, and for geldings and stallions the canine teeth (four).

Got all that?

Ok so now you know how many teeth your horse has and where they go, but what about the idea that they're always growing? This is why somebody who's really old might be said to be "long in the tooth". They also form a much sharper angle as they get older (young teeth, the top incisor meet the bottom like | Old teeth the top incisors meet the bottom like < -- in a horse looking left that is Gotta love ascii illustration!). Now while they are always growing, they are also always wearing down; and in a perfect scenario, at about the same rate. It's that whole "perfect scenario" thing that causes problems.

Your horse's top jaw is wider than the bottom. When he grazes in the wild his jaw moves from side-to-side as he munches - for up to 18h a day! What a life :) This helps keep the wear on the teeth even. But when the horse eats hard feed (ie pellets, grain, etc) the jaw moves much less, which means the teeth do not wear evenly. The stabled horse is also far less likely to spend all day grazing. This combination of less grazing and less jaw movement causes very sharp points appear on the outside of the upper molars and the inside of the lower ones. To help with this we "float" or rasp the teeth -- usually needs to be done about once/year, but they should be checked every six months, just in case. This basically files the sharp points off so your horse can be comfortable.



Some signs that your horse may need his teeth done include:

• Head shaking or tossing, esp when riding.
  
• Feed packing (you may see bumps on the outsides of the molars because of accumulation of feed)
  
• Quidding (opposite of feed packing, the food basically drools out as he eats)
  
• Bitting problems
  
• Reluctant to eat
  
• Pulling/tilting the head to one side when being ridden
  
• You might find large particles of straw and oats in the manure
  
• Colics and impactions of the throat.
  
• Losing weight and condition, dull coat
  
• Frothing and excessive salivation (again, esp with the bit in)

Copious amounts of information today. Did you get it all?


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Int/Adv Preventative Care

Preventative care includes the things we do to avoid the horse getting sick in the first place. There are four important preventative care considerations: parasite control, vaccinations, teeth, and introducing new horses.

Parasite Control:

All horses have parasites. Let me repeat that: All horses have parasites. Since most cause problems and we do everything we can to eradicate them. There are a few things you can do to help control parasites:

• De-worm your horse (more on this next paragraph :)
  
• Avoid overgrazing pasture
  
• Avoid keeping too many horses in one pasture
  
• Rotate pastures (horse parasites won't live in cattle and vise versa)
  
• Keep hay and grain away from manure
  

So deworming -- horses should be dewormed every 8-12 weeks (most people seem to do once/season). Different dewormers kill off different parasites in different phases of their life-cycles. It is important to rotate dewormers so as to eliminate a wide variety and to help prevent any of the worms developing an immunity to the dewormer. Some of the common worms include:

• Large Strongyles: these can cause serious damage. A blocked mesenteric artery (which supplies the intestine) can lead to severe colic, or a blocked iliac artery (which supplies the hind legs) can cause lameness or paralysis.
  
• Small Strongyles: also cause serious damage. Signs include weight loss, loss of appetite, diarrhea, and colic.
  
• Ascarids: most common in foals. These are disgustingly large worms. Signs include: poor coat, coughing, diarrhea, lack of appetite, pot belly, apathetic behaviour, and stunted growth.
  
• Bots: these are less harmful and among the easier to avoid. They lay their eggs on the horse's legs, chest, etc where they get licked off and swallowed. They look like little yellow dots, and if you make a point of removing them when they appear you'll help cut down significantly on the bot population. They can cause sores in the mouth, and sometimes stomach ulcers.
  
• Pinworms: not overly harmful in itself, but a sign that your strongyles dewormer probably isn't working overly well since they're killed off by the same thing. Pinworms lead to the horse rubbing its tail and sometimes you can see gray or yellow eggs around the anus. Pinworms are very rare in horses that live outdoors 24/7.

You'll notice the signs for most of these are similar. In general, any combination of inexplicable weight loss, poor coat condition, rubbing the tail, lethargy, and constipation or diarrhea should have you de-worming your horse or at very least having a fecal test done. Colic is also a sign of parasites gone horribly wrong (really you should catch it before then), but since it can be caused by so many other things may not be a sign in itself.

In areas with winter, the only things you'll really be able to kill after the frost are small strongyles -- so a Moxidectin based dewormer is best used in the winter months. This should be followed with an Invermectin based wormer in the spring to kill off any adult strongyles that survived the winter. Through spring/summer/fall you can alternate between Ivermectin-based and Pyrantel-based. There are multiple brands and types of each of these. Twice a year a Praziquiantel (which is a relatively new super-wormer) is a good idea.

So just for the curious, here's a sched for one horse as an example for the year. This is a 5yo TB mare in good health who lives in Ontario and will be competing from May though Sept. Keep in mind this is just a sample -- your plan should be created in consultation with your vet.



Vaccinations

Like people, horses can be vaccinated against common diseases. Most vaccinations need to be boosted -- some annually, some more often. What you vaccinate against will depend, among other things, where you live and how much contact your horse has with outside horses. If you have a private farm with two back-yard ponies who never go anywhere, they're far less likely to catch something than a competitive horse at a large boarding barn where they get shipped to multiple shows, all obviously with other horses, AND all the ones they live with at home are doing the same thing. Anybody could bring something home and spread it.

Some of the common ones include:

• Tetanus -- aka Lockjaw. Just as with people, this disease affects the nervous system. Usually caused by a dirty would, signs include stiffness of the head, neck and hind end, muscle spasms of the jaw, and the appearance of a third eyelid. There is an 80% mortality rate. Annual boosters are required. If you are working on a farm you would be smart to make sure YOUR tetanus vaccination is also up-to-date (although requires far less often booster).
  
• Rabies -- affects attitude and behaviour. Rabid horses will become violent -- biting, striking and rolling. It is almost always caused by a bite from an infected animal. This is also one of the few diseases that is transmissible to humans. Usually fatal.
  
• Encecphalitis (Eastern: EEE, Western: WEE, Venezuelan: VEE) -- a viral disease often transmitted by mosquitoes. 50-90% mortality rate. Booster shots annually if you have winter, every 6 mths if not.
  
• Influenza -- same concept as with people. Highly contagious but rarely fatal viral disease characterized by a high fever, cough, nasal discharge, depression and loss of appetite. Bi-annual vaccine, usually given spring and fall.
  Rhinopneumonia -- a highly contagious viral infection with signs much like flu. This is most common in young horses.
  
• Potomac Horse Fever -- believed to be carried by ticks (uncommon in this area). Signs include depression, loss of appetite, profuse watery diarrhea, distended abdomen, severe colic and sometimes laminitis. May be fatal. Annual vaccination.
  
• Strangles -- highly infections viral infection which affects the lymph nodes in the upper respiratory and cheek mucous membranes. This has been going around Ontario for the last few years, so be very aware if you're in this area and showing at all, you might want to consider this vaccination seriously. Signs are inflammation of the throat and cheeks, a fever of 39.5-41C (103-106F), reluctance to eat, and a moist cough. Annual Vaccination.
  
• West Nile -- a mosquito-spread neurological infection. Symptoms include listlessness, muscle twitching, weakness or paralysis in limbs, sometimes a fever. Can be fatal or have permanent complications. Annual booster.
  
• Equine Infections Anemia (EIA) -- aka Swamp Fever. Very serious, and any horse who survives it could become a carrier (who looks and acts normal while infecting the rest of the barn). Highly contagious, signs include a really high fever (40.5-41.2C, 105-106F0, rapid weight loss, anemia and hemorrhages of the mucous membranes. There is no cure, and most provinces require any horse that tests positive for EIA to be humanely destroyed. Most farms require proof that a horse is EIA negative before allowing any horse on the property. This proof is in the form of a Coggins test -- a simple blood test done by your vet. An annual coggins test is required for horses showing on most recognized circuits. There is no vaccination or cure for this disease.

As always, check with your vet about what they would recommend in your area.

Teeth:

Horses teeth continually grow. A horse's upper-jaw is wider than his lower-jaw. When they graze, the jaw moves in a side-to-side motion, and the molars wear out unevenly causing sharp points ("hooks") to appear on them. These can hurt. So every six months they should be checked and the sharp points need to be "floated" or filed. This is not a painful procedure but it is awkward and some horses really don't like the noise.



If a horse's mouth seems sore (particularly evident when the previously accepting horse starts flipping their head with any bit contact), or if they start quidding (which is when food dribbles out the side of their mouth as they're eating) they should absolutely be checked.

More on teeth another Thursday :)

New Horses:

When a new horse comes to a facility, proof of negative coggins should always be required. They should also be quarantined until their health is assured and introduced to the other horses slowly. Similarly, when bringing your horse away (ie to a show) it is important to keep them from the other horses. No rubbing noses, no sharing water buckets, food, or brushes. Little things that will keep your horse much healthier in the long run!

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