Endemic diseases and emerging threats

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1 Endemic diseases and emerging threats Dr Jane Nixon MRCVS, consultant equine vet and British Equestrian Federation Director of Equine Development The prevention of endemic diseases and the emergence of equine infectious disease is probably the most important subject I will talk about and, as a vet, the most important issue I will deal with. Unless we are vigilant, we may find ourselves in a dire situation. You only have to think of Ebola: it has been sorted in some parts of the world, but not in others. Why is it important? Endemic means diseases that are with us all the time, such as equine influenza and herpes. We can cope with this: we are learning how to deal with them. Emerging equine infectious diseases are something the BEF has as a top priority. If one of these arrives in our country, we could end up with no horses. They are of the greatest significance to our horses, our sports and our industry and we are talking about global, national and local repercussions. Flu is a virus, spread by viral droplets over a distance up to 20metres. The first sign is a rise in the horse s temperature. We must not underestimate it: in 2007, Australia experienced its first outbreak of equine influenza, brought in by an infected stallion. By the time it was recognised, it had started to spread, and 500,000 horses were infected during the outbreak. The direct cost was 100 million Australian dollars. The indirect cost was more than 1 billion Australian dollars. The Australian government imposed obligatory movement restrictions and obligatory vaccinations but it would have been so much better had it not happened in the first place. Since the turn of the millennium, the big problem has been biting insects carrying viral infections. Even more pertinent, we know there is global warming and we have floods, plus we also have changes in our flora and fauna. Mosquitoes/midges are changing their habitats and coming from Europe we only have to think of Bluetongue, which affects ruminants and camelids. So, how do midges get here? The most likely cause is that they are wind-borne, but other possibilities are that they could be brought in with cut flowers from Europe. We should be aware of two emerging diseases in particular, African Horse Sickness (AHS) and West Nile Virus (WNV). The average horse owner would not know how to deal with these, but they could come to our shores. AHS is a mosquito-borne disease that at present, is only in sub Saharan Africa and Spain. Sadly, 90 per cent of affected horses die within the first week through heart failure. Again, high temperature in the horse is the first sign. WNV is a mosquito-borne disease. Birds are the reservoir and horses and humans are incidental hosts. There is no treatment and no vaccination in Great Britain.

2 How do we reduce the likelihood of these diseases reaching our shores? Surveillance: the Animal Health Trust, Newmarket, is doing a fantastic job as a collation centre. For more information about the AHT, BEVA and DEFRA quarterly report, see Identification: as long as cases are identified, which is where we all have a role to play, we can do something about it by isolating, quarantining and treating. Both AHS and WNV are notifiable diseases and owners who are suspicious about their horses health MUST tell their vet. Any vet who suspects a case MUST report it. What can owners do? Biosecurity and good management are vital. A rise in a horse s temperature is an early warning, so good practice is: Take your horse s temperature twice a day at the same time and, if possible, in the same environment and time every day for five days. Most people find that 8am and 8pm are the most workable times. This will give you a baseline temperature for that horse. You should be concerned and ask your vet s advice if your horse s temperature rises by one degree or more. With the baseline established, take your horse s temperature two days before you take your horse to a competition or into an environment where you will be mixing with other horses. On the day you travel, take your horse s temperature before you load him and on arrival. Any rise in temperature by one degree or more should prompt you to isolate your horse and call your vet for advice. Vets would far rather you did this than risk an outbreak of disease! It is recommended that all equines, not just those who are out and about competing, are vaccinated against equine influenza and when appropriate - other diseases. Your vet will advise you. The importance of conformation Dr Jane Nixon MRCVS, consultant equine vet and British Equestrian Federation Director of Equine Development Evaluating the conformation, action and type of a show horse or pony is an essential part of the judging process. When evaluating conformation, look at the overall picture before homing in on different areas. Does a horse fill the eye on first appearance? Does he look balanced? Is he the one you would like to take home? Unbalanced conformation leads to under-performance and lameness and for the purchaser/producer/rider it leads to a waste of time, money and possibly heartbreak. Conformation is based on the underlying, genetically determined skeletal framework and is

3 unalterable after maturity. It can only be managed by breeding, so to facilitate good conformation, you need to breed sensibly; to review the foal from day one onwards; to maintain good management: foot balance, correct feeding, good ground surfaces. However, the latter does not mean that the horse should only be worked on artificial surfaces. We know that 65% horses never leave an arena, though I think a lot of that is due to Health and Safety legislation. Any horse with a rotational or angular limb deformity or deformities will, sadly, prove my 8/10 rule: by the time he is eight, he will be clinically lame; if you put him on a 20metre circle on a hard surface, he will be lame. By the time he is ten, he will overtly lame and have to be managed. Offset knees, etc. predispose to splints. Splints are not usually due to blows to the limb, but to poor conformation. The feet The hoof wall is modified skin (epidermis) thus it is constantly growing down from the coronary band The whole hoof as judged at weight bearing should be balanced front to back, side to side, to give level foot fall It should be trimmed to the conformation of the individual limb It is subject to distortion by torque from action due to poor conformation and/or foot balance Limb and feet abnormalities can be related. Slightly odd front feet should be caught from day one and are usually due to nutrition. Uneven heel depth is so important, because it means that the top of the shoulder blades will also be uneven. In turn, the back will be uneven and the saddle won t fit so a problem with the feet will lead to a problem with saddle fit. Weak conformation will cause feet imbalance that requires constant correction. Unless the hoof capsule is balanced, the hoof wall will revert towards imbalance within 20 minutes of trimming. Long hind toes cause more overall problems than front feet imbalance. This slows the breakover and the horse is less able to flex his hocks and stifle. The pelvis doesn t move properly, so there will be sacro iliac problems and the horse will develop problems in his back. Long toes coupled with upright pasterns predispose to ringbone (osteoarthritis of the pastern joints). Back at the knee is a fault which should not be ignored. It imposes a lot more stress on the pastern, hoof and fetlock and also on the back of the knee and check ligament. It is more serious in jumping horses than in dressage horses. The hindquarters

4 The flatter the pelvis, the more muscle there is, leading to greater strength and flexibility. The width of the quarters should be parallel with the thighs. A horse with straight hindlegs will find it more difficult to bring them underneath him. They also predispose to suspensory problems, as seen particularly in Andalusians and Paso Finos, and to upward fixation of the patella. The latter leads to changes in the gaskin muscles and an asymmetrical pelvis, causing pain and loss of impulsion. Cow hocks pre-dispose to pelvic fractures and sickle hocks predispose to curbs. Horses with sickle hocks are also les able to carry weight. The definition of a curb is: a complex of soft tissue injuries at the back of the hock joints. Until about five years ago, curbs were defined as true or false. Now, we know that both types cause problems. It s difficult if you have to assess a horse who is back at the knee next to a horse with a curb. I suggest you ask what the purpose of a horse is; if he s going to jump, it s not good if he s back at the knee. If he is going to do dressage, or will need to jump out of heavy going, a curb is a disaster. Over-extended fetlocks which have become colloquially known as soft fetlocks in the dressage world predispose to problems with the sesamoid bones and suspensory ligaments. With articular and non-articular windgalls, a small degree of change will not usually cause a problem. Balanced conformation is essential to prevent specific lesions. As judges, you should mark down odd front feet and outward rotation of the front or hind limbs/feet. To sum up, judges should look at the overall picture before concentrating on minutiae. You should avoid and mark down odd feet and outward rotating limbs and feet in front and behind before looking for specific lumps and bumps. Notes on hoof morphology by Mark Aikens DWCF Mark Aikens is founder of Anglia Equine, based in Norfolk, and specialises in shoeing event, dressage and endurance horses. He takes a proactive rather than reactive approach and uses the Equinalysis gait analysis system. As accredited technicians, Anglia Equine can liaise with leading UK specialists in veterinary science, equine sports, farriery and biomechanics. Hoof morphology the hoof changes shape because the hoof capsule changes shape through loading (the weight placed on it). Most of the time, it will return, but eventually it will not go back to its normal shape. This, from the farrier perspective, is when problems occur. The hoof capsule is elastic, dynamic and continually growing. It dissipates the concussion of the ground impact. Ground reaction force = the force exerted by the ground on the body in contact with it.

5 The average shoeing interval is six weeks. The hoof capsule grows continually and as the hoof grows, the capsule migrates forward. Why do we shoe? To give more grip To give support To increase or decrease traction For therapeutic applications A horse will usually be slightly more upright in the hoof/pastern axis in the hindlimbs than in the forelimbs. In most cases, horses work on several different surfaces. The foot and leg mimic the environment the horse works on, so if a horse is always worked on an artificial surface, the foot and leg won t strengthen. I am not in favour of horses being hammered on roads, but they need to work on different surfaces. If the toes are too long, the horse will need more effort to pick up his feet as he moves. A lot of movement in the horse is passive: it s as if they are being loaded to spring. When a horse moves on concrete, the foot lands horizontal and flat. On a surface, the toe tends to dig into the surface. The foot should be allowed a degree of slip. Be mindful of when and how you use studs. Many people talk about wild horses demonstrating the perfect model. However, the shape of a wild horse s foot depends on the horse s environment. That of a horse in the bush will be different from one in marshland.

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