This Seminar, held in the fine new Centaur building at Cheltenham Racecourse, lived up to expectations and attracted nearly 500 delegates, many of whom stayed overnight for the Countryside Raceday.First on was Dr Wayne McIlwraith from Colorado, and he began with the results of a large project designed to look into changes in conformation in young horses by photographing them from 3 angles and logging the images onto a computer. Following individuals through from foals to 3 year olds revealed the changes in shape that take place, particularly from “back at the knee”, and more importantly, improving naturally from being “knock-kneed”[ which many foals are born with]. He admitted that many knee “strip” operations are probably unnecessary as natural correction often is sufficient. This is a view that some English Vets have long believed, especially in Newmarket.
The second part of the study involved relating the Race performances to the adult conformation of these Horses. This involved a huge amount of work but was well worth it. He showed that a mild degree of carpal valgus [knock-kneed] was beneficial to soundness, and that back-at –the knee was, as expected definitely deleterious. Offset knees also increased the risk of fracture together with long pasterns. Unsurprisingly, carpal varus [ bandy-kneed] also led to problems and is something that needs to be minimised as soon as it appears in young horses.
Secondly, we heard from Dr McIlwraith the effect of training on bone and cartilage using a treadmill over 6 months. Pathological investigation showed that bone and cartilage damage occurs in the fetlocks and knees, causing lameness and preceding fractures. This may not seem all that surprising, but further work is looking at the practise of controlled exercise [ie cantering foals loose on an oval track behind a quad bike]. It is likely that an ideal regime will emerge to promote healthy development of bone and cartilage, not to mention the rest of the body. N.B. The exercise must not be overdone! The take home message was that exercise helps the foal and that time spent in the stable is not helpful.
Dr Roger Smith from London spoke next on the effects of training on tendons and he also showed that recent work reinforces the theory of beneficial effect of pasture exercise to foals together with carefully controlled exercise to help development. Training at adult level does not appear to help tendons as much, but obviously is needed for the bone, muscles and cardiovascular systems. An interesting finding was the fact that tendon tissue gets very hot during vigorous exercise – is this harmful? and are boots/leg bandages a good idea? It seems that tendon cells can survive these temperatures in cell cultures so the truth remains unclear at present.
Dr McIlwraith then presented the results of a study that recorded the lesions found on 1200 yearlings’ pre sale X-Rays in USA and then their Race performances. Rather as expected, fetlock lamenesses were commonest, front legs more than hind. Various radiographic abnormalities were associated with an increased incidence of surgery, but mostly had little effect on performance. Changes seen on knee radiographs [intercarpal joint] would often lead to lameness as would sesamoidean damage. One aspect of the study was that 26% of yearlings with radiographic changes were lost to follow up, suggesting that they may have been more unsound. There will be more of these studies and they will greatly increase knowledge to us as Vets to interpret their importance.
Dr Sandy Love from Glasgow gave the Peter Calver Memorial Lecture, collating the well respected late Vet’s observations on 3,400 yearlings conformation at Sales with their race performances. Significantly, the “toe-in” and “straight front leg” defects had a negative effect on performance, as did yearlings with more than one defect. No effect was seen in individuals with off-set knees, tied-in, base narrow, weak hocks and surprisingly back at the knee but there was a positive effect with toeing out. We have to remember that these yearlings were “selected for vetting” and therefore many of the worst ones must have been excluded.
Dr Jenny Mumford from the AHT gave us an update on the situation regarding influenza and the work going on to harmonise different vaccines and study the outbreaks where there is vaccine failure.
We were then given a presentation on the new Intervet StranglesVaccine which has just been launched. It shows some protection to challenged horses and may be useful in the event of a protracted outbreak when other measures need help.
Dr Nick Davis-Pointer, also from the AHT, described how recent work looking at genetic markers may help scientists decide if an Equine Herpes Virus outbreak is likely to develop into the dangerous paralytic form as a single gene has been strongly linked. Dr Richard Newton described the West Nile Fever that has been rapidly spread in the USA, and also been diagnosed in France and Italy. Birds have shown serological evidence of disease in the UK, but no disease itself has been seen. There is no doubt that the vectors [some birds and mosquitoes] are present in the UK to spread the disease if it arrived and the American vaccine has been licensed for use here. The horse is an “end host” and cannot give the disease to man.
All in all, it was an excellent day and I hope that the organisers can produce another of similar quality next year.
J.S.C. |
