By Oliver Liyou BVSc (Hons) and Peter Graney (certified equine dental technician)
It is remarkable how often the comment is made, "I won't worry about her as she is only a broodmare" when it comes to getting dental work done. The broodmare all too often gets the raw end of the deal when it comes to preventative medicine. Just because she is not ridden, it doesn't mean she doesn't need to be taken care of.
Broodmares often have serious disease in their mouths due to the fact that regular maintenance is not routinely done on them. The problem with dental disease is that once it gets severe, it is often irreversible, and so the horse never regains its ability to chew properly and thus to be able to prepare the food for safe and e f f e c t i v e digestion. Not only can dental disease lead to poor conversion of feed to body condition (poor weight gains), but it can lead to many more serious conditions such as colic, choke, diarrhoea, etc. Simple dental pathology such as sharp enamel points on the teeth will lead to the cheek mucosa being cut on the sharp points during the mastication (chewing) process – as the mandible (lower jaw) is moved in a ovoid side to side pattern. These cheek ulcers are painful, and thus the horse may become motivated to move the jaw in an abnormal and awkward manner. Direct evidence of this abnormal chewing is the spilling of feed.
One problem with the change in chewing pattern is that it reduces the mouth's ability to "self clean" itself through normal chewing. Instead of the food particles moving in a smooth augerlike path through the mouth cavity whilst being chewed and prepared to be swallowed, they can become trapped and jammed in various parts of the mouth. Thus food gets stuck in small spaces for long periods of time. This leads to fermentation of the feed, and the production of acids. These acids are irritating to the gums and lead to gingivitis (inflamed gums). The gingivitis, if not arrested and corrected, will lead to the more severe condition called periodontal disease - which is painful and can progress to become irreversible.
Signs that your horse may have Periodontal Disease are bad breath (halitosis), drooling saliva when eating, slow eating, spilling feed and packing of feed inside their cheeks (quidding).
In humans, women with periodontal disease are 7 times more likely to either abort their pregnancy, or have a low birth weight child. Thus if this is to occur in horses, then this alone is a good reason to look after your broodmare's mouth. The suspected reason for the relationship between periodontal disease and poor fertility in humans, is the persistent "pumping" of bacteria from the infected gums into the blood stream (= production of bacteraemia) during the force of the chewing process. If large numbers of bacteria are floating around in the bloodstream, then some can lodge in the placenta and cause infection there. This is called placentitis, and can lead to a premature birth or a low birth weight due to the placenta not functioning properly in its role of delivering blood supply and nutrients to the developing foetus.
In mares, the warning signs of placentitis include the mare running milk down her legs before she is due to foal. In this situation the valuable colostrum may be lost from the udder even before the foal is born, and so the newborn foal doesn't get the essential antibody protection against infection that it needs for the first 2-3 months of life.
Please note that the most common entry of bacteria into the uterus is via the cervix. This occurs mainly in mares with poor vulval conformation whereby the vulva is sloping forward and not vertical as it should be. With an abnormally sloping vulva faeces can enter the vagina as the mare defecates, which can lead to infection entering the reproductive tract. Thus a Caslick's operation maybe indicated, to partially stitch up and so seal the vaginal opening.
Another reason for looking after the broodmare is for food conversion. Savings in feed of up to 20% may result from correcting dental problems in mares. Add to that, the fact that a lactating mare requires as much feeding as a horse in full work, makes you think that it pays to look after them.
One problem in performing dentals on broodmares is the fact that some of them are not very co-operative in having their teeth done. This may be due to the fact that the mare is in pain, or from memories of previous rough experiences in having dentistry performed on her. If a mare needs to be sedated for dentistry, it is recommended that HEAVY SEDATION NOT BE DONE in the first and last 6 weeks of pregnancy. It is fine to sedate mares in other times of the pregnancy, and The anti-anxiety effects of sedation can be very useful, as it is important to avoid stress in pregnant mares. Significant amounts of stress can contribute to abortion of the foal.
Sedation, of course, can only be legally administered by a registered veterinarian as part of their service - in all states of Australia. Reasons for this are many, and include the fact that adverse drug reactions can occur, and if a horse does react to the medication, then the back up expertise and treatment by a veterinary clinic will be required. Another issue is one of insurance. If any one of the horse, dentist or handler is injured during an illegal act (eg an equine dentist sedating a horse as part of their service), then insurance covers are likely to become null and void. This includes your property's public liability insurance cover. Sedated horses can behave in unusual ways, such as kicking and biting when not expected, so accidents can happen even though the sedated horse is standing still and appears to be quiet.
So in summing up, it is wise to check the oral and dental health of your broodmares on a yearly basis – for both immediate and long term prevention of disease. It is also wise to check your newborn foal for correct alignment of the jaw and teeth. Problems such as parrot mouth may be reversed if they are not too severe, through routine floating procedures if started early. A veterinary check of your newborn foal can also provide the opportunity to assess the foal for leg and foot conformation, tetanus status and administration of tetanus anti-toxin if the mare had not been vaccinated. The umbilical cord can be checked and prevention of retained meconium (constipation) through administration of an enema may be advisable (especially in colts) along with assessment of the foal's overall health. It also allows the opportunity for the mare's reproductive tract to be assessed and thus aid her in going back into foal as soon as possible.