This week Horse and Hound magazine wrote a number of ‘small articles’ on what is new in the equine veterinary world.
Air Quality Control
A high mucous or neutrophil count are linked to poor performance and are often interpreted as indicators of low-grade infection- the dreaded ‘virus’.
If a horse has a poor tracheal wash finding before racing, it will often be withdrawn from the race on veterinary grounds, rather than risk further exerting inflamed lungs. But vets in the American Midwest have recently thrown some doubt on the long-established interpretation of tracheal washes.
They monitored more than 100 racehorses from 3 training yards between July and September. When they performed endoscopic tracheal washes, they also sampled the air quality in the stable where each horse was kept. They used sophisticated equipment to measure the particulate matter in the air. These horses were all kept in American barn-type stables – large enclosed buildings with internal partitions.
When the results were analysed, there was a strong connection between indicators of inflammation and the amount of dust in the air. Both the mucous level and the neutrophil count were linked to the levels of dust in the atmosphere.
It was interesting that when larger diameter dust particles were floating about, the horses were likely to have greater amounts of mucus in their trachea. When the dust particles were smaller, it was the neutrophil cell count likely to be raised.
There is no doubt that poor tracheal wash findings are linked to poor performance. But this research suggests that trainers of horses with elevated mucus or neutrophil scores, and horses that perform below par, should not automatically assume that a virus is to blame. They should also consider whether the air in their stables is simply too dusty.
A horse might have its leg plastered for a fracture, after surgery, for a bad wound or to correct a joint or bone problem.
These days we tend to use a synthetic cast of fibreglass or resin-impregnated bandage. The cast is usually applied over a thin layer of padding so it is snug. It is often left in place for two or three weeks before it needs to be changed or replaced.
Casts have a history of causing second problems. Pressure sores broken or slipped casts and even further bone damage within the cast are all too common.
What causes these problems? Is it just the cast was not applied properly? Was there too much, or too little, padding?
In a study of almost 400 horses with limb casts in the USA, vets have tried to analyse whether there are factors that can predict the outcome of a period in a cast. Nearly 50% of horses with a cast developed complications and by far the most common was lameness associated with pressure sores – 45% of all casts resulted in such sores. The remaining 5% of complications were almost all caused by the cast breaking.
The position of the limb within the cast was significant. Far more horses cast with the leg flexed had complications than those immobilised with the leg in a normal, weight- bearing position. Interesting, geldings developed more problems than stallions or mares.
The conclusion is clear : putting a leg in a cast should not be undertaken lightly. Complications are common and there is no secret or expert method that can guarantee preventing them.
Your horse has a wound that isn’t healing- it keeps weeping, it won’t close up and it looks sore. When your vet suggests that maggots could help, you would be more than surprised! But research has proved the maggot’s worth.
Vets in France and Mali have recently reported their use to encourage healing in chronic wounds in 41 horses.
The maggots were specially bred for this medical purpose and were guaranteed to be sterile and free of infection. This is possible because the thick capsule of fly eggs is resistant to disinfectants and the eggs can be sterilised before the maggots hatch.
Ordinary green blowfly maggots are the best species to use. The sterile maggots were either placed in a net bag within the wound or put directly onto the affected area and kept in place with a covering. The maggots remained in the wound for three days. Sometimes a second three-day treatment was necessary.
The results were good. The maggots helped clean up dead and decaying tissue, secreted antiseptic enzymes and mopped up and killed bacteria. The can even fight off bugs like MRSA, which are resistant to antibiotics.
The French and Malinese vets concluded that maggot therapy for chronic or infected wounds is an excellent way of cleaning up the injuries and reducing bacterial infection.
Lens implants for horses?
The problem is that when a cataract is removed, the remaining lens of the eye is pretty useless at focusing. This causes a new problem for the patient – he becomes far-sighted. This is a problem recognised in humans – and we can be fitted with a synthetic lens to restore visual performance.
.As a result, equine ophthalmologists have pondered whether artificial lenses could be fitted to horses in the same way. Before this can become a known routine, vets need to know whether the magnifying strength of horses’ lenses is uniform across the board, or whether it is related to size, weight or age.
Vets at the University of Purdue in Indiana took 28 normal horses free of eye disease and measured their lenses using precise human equipment. They found a surprisingly wide range of lens strengths – from 15.4 to 30.1 diopter ( the unit of measurement of the optical power of a lens). There was no reliable correlation between the size or age of the horse and the performance of their lenses.
They even noted significant differences between the left lens and right lens in many animals.
The conclusion was that it would be impossible to predict what strength artificial lens a horse may need after cataract surgery. Every horse and every lens is different and each one must be individually measured and tailored for use – just like humans.
Pleasure or pain?
They asked the owners to give detailed information about the way they used and trained their horses and whether or not the animals had shown any of the behavioural problems listed. The survey was conducted over a whole year to avoid seasonal issues. The results proved interesting.
Some indicators of welfare were very high – 97% of owners said they had their horses’ teeth examined professionally at least once a year. But in contrast, only 60% had their saddles checked annually and 12% indicated that they didn’t think it was ever necessary to have their tack checked by a qualified saddler.
What surprised researchers the most was that behavioural problems were reported in more than 90% of the horses. The majority of these were annoying rather than dangerous, according to their owners – refusal to stand still when being mounted, or shying at strange objects. But as many as 7% were reported to rear or a regular basis.
As far as training went, most owners were using what were described as ‘traditional’ training methods, but over 50% also used so-called natural horsemanship, Parelli or clicker training.
This left the scientists speculating whether in the UK pleasure horse population, poor attention to saddle fitting and inappropriate use of training techniques or aids is contributing to the unexpectedly high level of ridden behavioural problems.
I thought these articles were particularly interesting as they are new ideas being developed in the veterinary equine world. I do not have such a strong opinion on these are they for the most part are not practised and reliable methods of treating a horse.
I hoped you enjoyed reading this article, more to come next Thursday!