vet focus


Seven equine only vets led by Andrew McDiarmid BVM&S Cert ES (Orth) MRCVS New Lanark Market, Hyndford Road, Lanark, Ml11 9SZ Tel: 01555 660000 www.clydevetgroup.co.uk


Fax 01555 667290


Diastemata; just a pain in the mouth by Will Marshall BVMS MRCVS


Bent Limbs in Foals


A diastema is a variable sized gap between a horse’s teeth. When they occur in the molar cheek teeth of horse, they can be a major cause of oral discomfort, quidding and weight loss, in any age of horse. Diastemata, which is the pleural of diastema, are being seen more frequently in recent years perhaps due to better understanding of the condition and the feeding of more preserved forage feeds such as haylage.


by Susan Donaldson BVMS MRCVS


Foals can either be born with bent limbs or these may develop over the first few months of life, often being caused by other developmental problems. In this article, we will look at the significance of these bent limbs, what kinds of deformities occur and how these can be treated.


Diastemata cause pain when food becomes trapped and packed in the space that opens up between teeth. This food material starts to rot, causing infection and tissue destruction. Inflammation then spreads to adjacent teeth, causing the erosion of their attachments to the gum and surrounding tissues and eventually to their loss. These processes are intensely uncomfortable and painful. The molar cheek teeth of horses are normally kept close together by the way in which teeth erupt through life. The front and back teeth are aligned with their tops tilted towards one another, and


tendons which run down the back of the limb are too tight meaning the limb cannot be


straightened. Forelimbs are most commonly affected. If the foal is able to move and feed from the mare, then mild cases often simply require careful


monitoring and no specific treatment. In severe cases, treatment includes intravenous injections of


oxytetracycline; which is an antibiotic but has the useful side effect of relaxing tendons and ligaments; and


bandaging and splinting of the limbs to attempt to straighten the leg, allowing the foal to move around and the tendons stretch. In older foals, tendons


may become contracted after a period of rapid


Why are bent limbs a problem? Any deviation from a straight leg can alter the foal's foot placement and therefore lead to uneven pressure being placed on the joints. Once the foal has stopped growing, any bend in the limb will be permanent and the uneven strain on joints can influence future soundness for athletic performance.


Bent limbs can be divided into angular deformities and flexural deformities.


Flexural deformities are identified by assessing the foal's limbs from the side. The most common of these is 'contracted tendons' where the


it is this angle of eruption that compresses the surfaces of the teeth together and prevents gaps from forming. As horses become older progressively less tooth remains under the gum, therefore the teeth’s ability to maintain a tight grouping is lost. Diastemata can also develop when one of the cheek teeth becomes displaced or drifts out of its normal position, either towards the tongue or the cheek. Dental overgrowths or the retention of deciduous (‘baby teeth’) add to the pressure put on these teeth during chewing, leading to their displacement. Diastemata can also occur in young horses as the result of abnormal conformation of their jaws. Horses spend over 18 hours of each day vigorously chewing. This means that some food fibres are inevitably forced into any spaces that form between teeth. If the gap is wide, then the food may simply fall out once it has decayed through the activity of saliva in the mouth. However, if the gap is too narrow, then food enters under the pressure of chewing but does not leave. It is


Examination of a horse’s mouth using a dental gag and source of light


Foal with severe flexural deformity of forelimbs. Photo by Luanne Hunt. to stretch and by use of anti-


inflammatory drugs. If the tendons do not relax, the foal's foot will begin to take on a 'boxy' or 'club foot' appearance. In such cases, surgical intervention may be indicated. Where surgery is performed, normally the accessory ligament of the deep digital flexor tendon (ALDDFT) or 'inferior check ligament'


joint, most commonly the knee (carpus), but the fetlock, hock or even a


Using a probe to check the spaces between teeth can help to diagnose diastemata


which attaches the deep We can divide ALD into problems which digital flexor tendon to the back of the knee is cut.


The other kind of flexural deformity which is seen in young foals is laxity of the tendons. Hindlimbs and specifically hind fetlocks are most


commonly affected, with foals often being


described as being 'down' on their fetlocks. In general, affected foals require little or no


treatment, unless the deformity is so severe that the heels and


fetlocks make contact with the ground and therefore require


protection by bandaging. Glue-on shoes can also be used.


Carpal Valgus. Photo by Luanne Hunt.


growth and initially these foals can be treated by restricting their exercise, trimming of the heels to help the tendons


Angular limb deformities (ALD) can be defined as a deviation of the leg


from a straight line when the limb is looked at from the front or back. The


deviation can be centred over one specific X-rays of a bent leg will allow the


these so-called valve diastemata that result in discomfort and damage to adjacent structures. Ongoing accumulation of food material in a diastema is followed by compression down into the gum causing inflammation and destruction. The pain is seen during chewing, causing horses to ‘quid’ or to drop food. In addition to quidding, symptoms include halitosis (very bad/rotten breath) and swelling of the cheek (due to packed food). Many horses will favour one side of the mouth when chewing, avoiding the affected side. Some horses will lose weight through not ingesting adequate food. Choke and impaction colic can also occur because forage is inadequately chewed. Signs are usually more noticeable when long fibre feeds such as hay and haylage are fed, as opposed to short fibre chopped feeds like chaff and grass. Diagnosis of diastemata requires careful and complete examination of the mouth. This is achieved using a speculum or gag in the horses mouth and an appropriate source of light, such as a head torch. Diastemata are more common on the lower jaw and can be very difficult to visualise when they affect the rear most teeth. They are most often picked up by


Equine Page 20


combination of joints can be affected. We can also describe the direction the leg is deviated in: deviation to the outside (laterally) is described as valgus, whilst deviation to the inside (medially) is described as varus.


the foal is born with and those which occur during growth, usually in the first six months of life. Those noticed at birth or soon after are perinatal deformities and those developing during growth are acquired deformities. It is very common for foals to be born with a mild carpal valgus where both forelegs are slightly deviated to the outside from the knee and a slight toed-out conformation; as these foals grow and their chests widen these problems often self-correct. In premature foals, the small bones in the knee and hock may not have calcified properly and therefore are softer meaning that they can be 'crushed' when the foal is moving, leading to bent legs and in time, if untreated, arthritis in the affected joints. These bones are best assessed by x-rays. If the foal is only mildly affected, bandaging or splinting and box rest can be used while the bones become more calcified.


Acquired ALD is likely to have a number of contributing factors, including injury, overfeeding or nutritional imbalances, and inflammation of the growth plate in the cannon (physitis).


So how can ALD be treated?


feel or with the use of a dental mirror. Alternatively a special oral endoscope can be used for direct inspection.


Long food fibres are found between the affected teeth and there may well be a variable depth crater-like depression in the associated gum margin. Due to the associated pain, touching or pressing the affected area is usually deeply resented. When food material is then washed out or removed with a dental pick, it is often bloodstained and rotten in appearance and smell. Diastemata are often seen at multiple sites in any one horse, making it essential to examine the entire mouth. Occasionally x-rays may be taken in order to more accurately assess location and severity, as well as to help identify any other contributing factors or secondary complications such as sinusitis or bony infections. Initial treatment involves thoroughly cleaning out ALL of the food material from the gap(s) using a combination of high-pressure water jets and special grabbing/picking instrumentation followed by further flushing. This is often combined with packing of a special antimicrobial gel/ putty into the gap to try and encourage healing of the sensitive damaged gum margins


www.theequinesite.co.uk


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56