PART 1: COMMON VETERINARY

ISSUES IN RACEHORSES

The Larynx and Airways

“WIND” problems in horses are widely documented, and involve conditions of the upper airway and larynx that reduce airflow to the lungs and hinder performance.

This airflow impairment can be heard as a noise (whistle or gurgle) when listening to a horse at exercise. Any abnormalities can be visualised using an overground endoscope placed in the horse’s airway while cantering, a practice routinely carried out at Mark Johnston Racing on horses heard to make a noise.

Many of these problems get better with fitness and conditioning, but a small number may require surgery to attempt to maintain better airflow to the lungs. Exercise Induced Pulmonary Haemorrhage is bleeding from very small blood vessels in the lungs after strenuous exercise. It is characterised by blood appearing in the airways and occasionally at the nostrils. A horse may also cough as the blood irritates the airway. There is sadly no guaranteed preventative treatment and cases are treated with rest and anti-inflammatory drugs, antibiotics. Turning out can often improve the health of the airways.

Mild and passive infections of the upper respiratory tract are very common and have many similarities with colds in humans. They are often viral in origin but may have a bacterial component. They are characterised by nasal discharge, coughing and the horse being slightly dull. These infections often resolve on their own but clinical signs can be reduced with antibiotics and anti-inflammatory drugs if required.

Foot

“No foot, no horse” is a commonly heard phrase in the equine world. It emphasises the importance of looking after a horse’s feet to maintain soundness and athletic performance.

As far as numbers are concerned, lameness associated with the foot is the most common form of lameness we encounter here at Mark Johnston Racing. Such lameness usually has characteristic features: the horse does not want to put the foot on the floor and bear weight on it; the foot is often warm and has an increased pulse; and pain can be observed when light pressure is applied with hoof testers.

Abscesses are infections of the foot caused by bacteria which enter the foot via small cracks in the white line (a region which forms the border between the sole and hoof wall) or sole. These bacteria then multiply and damage the tissues of the foot causing a build-up of pus.

It is the pressure of the pus within the abscess in the foot that causes the pain and lameness commonly found when a horse has a foot abscess. Foot abscesses are treated by locating the abscess with hoof testers and opening the abscess with a special hoof knife, allowing it to drain. A hot poultice is often applied to soften the foot and encourage drainage. The foot can also be bruised by stones on uneven ground. These bruises usually resolve with rest and treatment to harden the sole of the foot. More rarely, the pedal bone within the hoof can be fractured, either by the horse kicking out at a structure, such as a wall, or while cantering. Most of these fractures heal quite quickly with rest as the hoof and a specially made shoe can stabilise the pedal bone while it heals.

Pastern

Pastern fractures in racehorses are relatively common. They tend to occur in a longitudinal fashion, straight down the middle of the pastern from the fetlock joint down. The prospects of a full, successful recovery are fairly good. Often specialist surgery is carried out to screw the pastern back together. Horses often return to racing after these injuries.

Skin

Skin wounds and infectious disease of the skin are extremely common. Ringworm and infected spots are frequently seen, especially in younger horses. They tend to get better without intervention, but, if they affect the tack positioning, the horse may require a short period without being ridden.

Pelvis

The pelvis in a horse is best thought of as a large bone frame upon which the strong muscles of propulsion attach and exert their forces on the limb. Due to the large forces placed on the bones of the pelvis, fractures can sometimes occur. The severity and consequences of these injuries, like any fracture I have mentioned, vary massively depending on their position and any displacement of the fracture.

Horses are placed on box rest until sound after a pelvic fracture to prevent any chance of displacing the fracture during the early stages of healing. They then go through a gradual return to exercise, spending four-six weeks on the walker and equal time walking and trotting before a return to cantering.

CanNon

The cannon bone is the long bone above the fetlock joint. The condyles of the cannon bone articulate with the pastern at the fetlock joint. Occasionally, horses may fracture the condyles of the cannon bone. Many stress fractures of the condyles heal with rest and conservative management, but some require surgical screw placement to aid healing of the fracture. The good news is that a very large proportion of these horses return to full training and racing after these injuries.

Sore shins are a condition of pain associated with the remodelling of the cannon bone as a horse’s exercise is increased. Treatment involves a short period of anti-inflammatory and cold therapy, with controlled exercise before returning to normal training.

The splint bones are two long, thin bones which run down either side of the cannon bone. As with sore shins, the splint bones are prone to becoming reactive, forming “splints” (small lumps of callous) after being knocked or when the horse’s exercise is increased as they get fit. Splints are treated in the same way as sore shins and represent only a minor setback.

This article is an overview of the anatomy of the horse and our graphic shows some common sites of problems that may require veterinary intervention. The word “fracture” of course strikes fear into anyone involved in racehorses. But many horses with fractures return to normal training relatively quickly nowadays and fatalities associated with fractures are thankfully rare.

At Mark Johnston Racing, fatalities associated with fractures stand at fewer than 1% of all the horses we have in training throughout the year. The onsite veterinary facilities allow immediate investigation and treatment of any horses with ailments.

Neil Mechie is a graduate of the University of London and is in practice in Mark Johnston Racing. This article first appeared in the Kingsley Klarion.