Animal Care

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LITTLE CRITTERS

Mark Newton-Clarke MAVetMB PhD MRCVS, Newton Clarke Veterinary Surgeons

We all know there’s more to a cat than its coat and stroking the luxuriant fur of a puss-full of purr is one of the great pleasures of feline ownership. It’s not surprising then that when a bald patch appears, often with an open sore, owners seek our advice at an early stage. The first thing is a really good look for unwelcome visitors; harvest mites in autumn, fleas and ticks all the year round. Harvest mites are tiny, orange-red critters that collect in small colonies on ear tips and toes and can cause intense irritation. At least the nuisance is temporary as they are only parasitic in August and September, being free-living the rest of the time.

Fleas are the commonest cause of skin problems in cats, sometimes just by their presence but more often, by triggering an allergic reaction. The paradox here is a flea-allergic cat (or dog) rarely has a living flea on it to be found. The answer to this lies in the short lifespan of a flea on an allergic animal as it is often regularly treated with anti-flea products and the over-grooming response of the host keeps the numbers down. The problem here is the itchy allergic reaction continues after the culprit has been eliminated, so when we look for a living flea, we often don’t find one.

Cats do like to over-activate a particular sort of white blood cell (the eosinophil, pronounced ee-

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oh-sin-o-fil) that, when behaving itself, is a useful defence against parasites, particularly internal worms. For a proportion of cats, the eosinophils become far too enthusiastic and their capacity to produce excessive inflammation in the skin, the lung and the gastrointestinal tract are well-recognised. Obviously for the not-so-humble flea, the skin is the target tissue and the result of over-zealous eosinophil activity is often irritation enough for the sandpaper tongue of the cat to not only remove fur but layers of skin as well. This really can look quite shocking and the poor puss must be driven mad by the incessant itchiness. Luckily, improved flea control (paying particular attention to the home environment where flea eggs may be lurking) and our old friends, the steroids prednisolone and dexamethasone, often provide if not a cure, at least good management of a bad state of affairs.

Now, I mentioned that the Ying-Yang eosinophil is also involved in allergic reactions that can affect not only the skin but the lung and the gut as well. Cats, as you may well know, can suffer from asthma. Like humans, inhaling an allergen triggers an allergic response that causes airway inflammation and constriction, resulting in coughing and shortness of breath. Often affecting young to middle-aged cats (2-8 yrs) it is estimated that 1% of domestic moggies and up to 5% of oriental cats suffer from asthma to varying degrees. With a little coaxing and practice, cats can be successfully treated with an inhaler or a nebuliser but sometimes steroid tablets are needed.

We all know about the legendary ability of dogs to exhibit vomiting and diarrhoea as symptoms, usually due to eating something disgusting. But when a cat presents in a similar way, the cause is likely to be different, as fresh is best for the discerning feline. For kittens, a virus or a parasite is usually responsible. For older cats, although there are many things to consider, inflammatory bowel disease (IBD) caused by over-activated eosinophils (amongst others) in response to parasites or a food intolerance/allergy is always a consideration. Just to close the circle, cats that ingest fleas and excessive hair can then trigger a gut response not so different from what’s happening in the flea-allergic skin – the result, a very upset tummy that needs some investigation before the diagnosis can be confirmed.

But here’s the rub; ‘investigations’ are expensive! The trouble is, without them, we are in the dark and treatment becomes trial-and-error, which can waste time and money and cause frustration for owners, patients and vets. There is some good news, as the skin is nicely accessible to our probing and biopsies are quite easy, although a short anaesthetic is often needed. The same cannot be said for the gut and the lung but a blood test to count eosinophils in the circulation can help point us in the direction of an allergic/ inflammatory cause of the problem, be it respiratory or gastrointestinal. In general, whenever possible, we perform diagnostic tests step-by-step so that if the diagnosis is made early on in the process, treatment can start with minimal delay and expense.

LEARNING TO SPOT MINOR INJURIES ON YOUR HORSE’S FEET AND LEGS

Anthony Sargent, M.Phil., B.V.M.S., M.R.C.V.S., The Kingston Veterinary Group

Training my own endurance horse and being a vet carries advantages and disadvantages. I am of the firm opinion that rapid response to an injury, albeit sometimes minor, produces a rapid resolution of the problem. This is not to imply that you should call a vet out for every minor ailment, but rather that you learn to notice subtle changes in your horse’s legs and take the correct action. These are warning signs of micro-injury which may then progress to macroinjury if ignored, and will then necessitate a visit from the vet.

The disadvantage of being a rider and vet is that if my horse goes lame just before a competition then I must make sure that I take my rider hat off and put my vet hat on. This is not always easy when one sees one’s hopes dashed after weeks of training!

It should be noted that the following remarks apply to all ridden horses whatever discipline you are doing, and to whatever level.

I am going to deal with the subtle, or sometimes not so subtle, swellings and filling of the legs below the carpus (knees) and hocks as these are the two most common. The forelegs are more commonly affected as 60% of the horse’s weight is carried on these legs, owing to the weight of the head. I check my horse’s legs every day and it takes just a few seconds. Starting just below the carpus (knee) the tendons and ligaments when normal should feel tight and almost like steel cords. They tie in tight below the knees, the groove between the suspensory ligaments and the flexor tendons is clear and neat, and running down to the fetlock there should be no filling or doughiness at all. Now of course after a hard ride the day before all the legs may be equally, and a little to moderately, filled, but on palpation there is no tenderness and the horse is not lame. This is micro-injury and is a normal part of any horse training, which hardens and toughens the tendons and ligaments. This is why it is sensible after a period of more than two months’ rest to walk your horse for six weeks to strengthen the tendons and ligaments against possible injury later. In addition, but not visibly, bone density increases with steady training. The critical part of the statement above about filling in the legs is that there is equal swelling or at least both forelegs and both hind legs mimic each other. If however one limb, more commonly a forelimb, is more filled than the opposite side then this is a warning of what I would call an ‘overshoot’. The previous day’s training has been too intense and early macro-damage has been caused. The immediate response should be to back off for a few days, i.e. complete rest. If the swelling resolves steadily over the next two to three days, then the damage was not severe and rest alone will produce recovery. If however the tendon or ligament is at all painful after more than three days, then a veterinary visit is definitely advised. Further delay will simply increase the recovery time hugely.

At this point, I would like to bring in feet as a bruised sole is probably the commonest cause of injury. Yes, the tendon sheath will also fill with a bruised sole and we call this ‘teno-synovitis’ – this is inflammation of the sheath around the flexor tendon and is not the same as tendonitis or a tendon strain.

Interestingly, the feet have a physiological mechanism which perfuse the laminae with blood every hour or so, and in between times there are arterio-venous shunts which are open and shortcircuit the blood across the top of the hoof. This means that most of the time you would have noticed that all feet are cold to the touch, and then every so often you will feel four warm feet: this is completely normal. However if one foot is warm or even hot, and the others are cold then that foot is inflamed and your horse will almost certainly be lame. The best trot-up to assess the lameness is for someone else to do it for you on a hard grit track, concrete or tarmac. With forelimb lameness the head nods down on the sound limb.

The hind limb examination is the same: I start at the hock of which there should be no swelling at all, running down the back of the cannon bone the tendons and ligaments should feel tight and hard as in the forelimbs. However slight windgalls (windpuffs) on both hind fetlocks is quite common and acceptable in my opinion.

In summary: regularly feel your horse’s lower limbs and get to recognise those normal, very tight, cord-like tendons and ligaments. Feel the feet, check their temperature and notice if the shunts are open or closed. If symptoms are present and persist after the advised rest periods seek veterinary help.