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Do I really need to worm my horse?

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Endoparasites;  the gut-wrenching villains that terrorise our horses from their tums to their bums, but how big an issue are they for the average horse? Which worms do we need to be aware of? Is wormer resistance really that big an issue? So many questions, so many drug names.

What is a worm?

A worm, or an endoparasite, is an organism that lives inside of your horse, to your horse's detriment. We have all seen the adverts for ‘good bacteria'; this is known as a synergistic relationship, where both host and occupier benefit. With parasites, only the parasite gains.

  1. Cyathostomes. Why did the cyathostome always get what he wanted? Because he was so encystant… Excuse my awful jokes; it’s been a long day. Cyathostomes are a type of nematode, or round worm, known as small encysted redworm.  The adults, when in the large intestine, produce eggs that the horse will excrete onto their pastures; the eggs then hatch, and the larvae are eaten by the horse. It is also the larvae that are capable of encysting (hiding) in the walls of the large intestine. So the saying really is true, don't eat where you… These nasty critters can encyst in the mucosal lining of the large intestine of horses; the larvae are capable of ‘hypobiosis’; they stay in a state of arrested development (a bit like hibernation).  It is when they emerge that they can cause potentially fatal damage and diarrhoea, known as larval cyathostomosis.
  2. Strongyles (large redworms). These nematodes are detrimental to your horse in a different way than their smaller namesakes. Eggs in the pasture have a moult phase, referred to as Larval stage 1, L1, and moult to form, logically, L2. The L3 are consumed by an unwitting grazer; it is the L4 stage that migrate from the gut to the arterial supply of the intestine (the cranial mesenteric artery if you are curious). This can cause a compromised blood supply to the large intestine with inflammation of the arteries known as verminous arteritis, and can cause the dreaded colic.
  3. Parascaris Equorum (ascarids); another nematode. Are you the owner of a young horse? This one is for you (sorry!).  Thankfully, our equid amigos develop a resistance to these worms; however, young-stock in the 6 month – 2-year old bracket are highly susceptible. The eggs are passed out in excrement, and moult to L1 and then L2; unlike large redworms, it is the second larval stage that is ingested. They, too, have a damaging migratory pathway; from the intestines, they migrate through the liver and moult to L3, before progressing to the lungs.  From here, they can be coughed up, swallowed, and moult to L4 and then adulthood in the small intestine before starting the whole cycle again. Liver and lungs may be damaged, but impacted colic from a heavy worm burden, along with ill-thrift and a pot-belly, are common signs.
  4. Dictyocaulus arnfieldi (lungworm) is another nematode. To my horror, it is donkeys that are particularly affected by lungworm, and carry it, as the life cycle is not actually completed in the horse.  These larvae are ingested, and burrow out of the intestinal wall into the bloodstream, where they penetrate the lungs. They will cause reactive changes in the respiratory system, such as coughing, increased mucus production and irritation of the bronchi. Chronic pneumonia, secondary infections and pulmonary oedema (fluid on the lungs) may be other features in heavy burdens.
  5. Anoplocephala (tapeworms); a cestode, not a nematode. It requires an intermediate host to develop to a larva from an egg, and it finds a host in the oribatid (harvest) mite. When the horse eats the mite with the parasite, the adult tapeworms can then settle in the caecum (the huge fermentation chamber of the horse gut) and small intestine. Tapeworms pose a real threat to your horse by associations with spasmodic colic; it can cause food impaction and intussusception, when the colon ‘telescopes’, folding in on itself. Inception may be about a dream within a dream, so think of intussusception as a colon within a colon.
Other parasites include Oxyurius equi (pinworms, causing itching and irritation around the anus) and Gasterophilus (bots; actually a fly larva, and not known to cause many problems despite settling in the stomach).

What can we do about worms?

I have been on many yards with rigid worming routines as a means of prevention as much as treatment: this is called interval dosing. Is it necessary? If I had to fall in a strict ‘yes’ or ‘no’ camp, I would be in the latter. Wormers, known as "anthelmintics", are becoming less efficacious; that is to say, anthelminthic resistance is becoming a real problem. The more that worms are exposed to wormers, the more the wormer becomes a selection pressure; some worms will have innate features which allow them to survive despite these chemicals specifically designed to kill them – pesky mutants. The more that we use wormers when we may not need to, the stronger this selection pressure is; we kill the worms which are susceptible to the wormers, allowing the few worms which can survive to reproduce in an environment with less competition. Thus, new wormers need to be developed all the time; a laborious and long task. How can we slow or stop this resistance developing? By being responsible owners and avoiding ‘over-worming’ - saving our horses and wallets in the process! Moving away from wormers, we need to look to management. As we can see in the life-cycles, it is the output of eggs in faeces that are responsible for providing a suitable environment for parasites. Poo-picking fields is one of our biggest weapons in the battle of the bugs; deploy it often! Quarantining new horses prior to turn-out can help to minimise worms on a busy yard; moxidectin and praziquantel can be used 24 hours prior to turn-out. What wormers are available? There are macrocyclic lactones (ivermectin and moxidectin), tetrahydropyrimidines (pyrantel) and benzimidazoles (fenbendazoles) and pyrazinoisoquinolines (praziquantel). We must treat with what is most efficacious for the type of worm, and also only when it is needed. Faecal egg counts (FECs) give a picture of what worm eggs are being put out in your horse’s faeces; when the FEC exceeds 200 eggs per gram, it may be justification for worming. If that sounds a lot, we need to get our heads around the fact that horses will always have worms; whilst this is not a pleasant idea, unfortunately our horses will never have a totally worm-free body, and we shouldn’t strive for that in our worming regimes. Further to this, we want to keep a certain worm population ‘in refugia’; this means we want to keep some worms unexposed to wormers, because then we are not selecting for worms resistant to the wormers. It is only when worm burdens get too high and will damage our horses’ well-beings that we should use wormers. FECs can reduce the selection pressure that help those resistant worms to thrive, as well as being a cost-effective means of targeting the individual horses who need it most.

Is there an ideal worming regime?

Perhaps not. FECs will not give an accurate representation of encysted populations, and are not deemed specific enough for tapeworm counts. Fecal egg flotation or ELISA (enzyme-linked immunosorbent assay) blood tests can be used for tapeworms, but are more expensive. Furthermore, an ELISA detects the antigen (the immune response to a parasite) level, thus the burden may appear high as antibodies are still circulating against the old burden, even if the worms are now dead. However, there are means of interval dosing that do not require administration of a wormer, regardless of whether the horse needs it. We must focus on what burdens are of concern and when… SPRING: Performing a faecal egg count (FEC) for strongyles; ivermectin or single dose pyrantel can be utilised if there are over 200 eggs per gram. Stronglyes were previously a huge concern for causing colic, but thanks to ivermectin, they have become less of a menace, hence the need to protect the efficacy of this wormer by responsible use. Additionally, treatment for tapeworms in the form of praziquantel or double dose pyrantel may be used in spring. SUMMER: FEC for Strongyles and treatment when the FEC indicates, again with ivermectin or pyrantel. AUTUMN: we must treat for any encysted cyathostomes. Remember the larval cyathostomosis? Commonly these larvae will encyst, and emergence can occur in late winter/early spring. Treatment of a heavy burden is advisable; a five day course of fenbendazole, or a single dose of moxidectin are licensed for encysted cyathostomes. However, a large amount of dead worms and a huge inflammatory reaction can spell out a disaster in the form of colic, so if there's a heavy burden your vet may recommend using the older (and less potent) but "gentler" course of fenbendazole first, and then following up with moxidectin 4-6 weeks later to "mop up" any survivors. Tapeworms can be treated with praziquantel or double dose pyrantel again at this time of year. WINTER: The same treatment (or not!) for strongyles when indicated; if bot flies were a problem over the summer, ivermectin or moxidectin will kill the larvae in the stomach. From all of us here from VetHelpDirect, we hope your horses have a wonderfully worm-free year ahead! There is nothing so good for the inside of a man as the outside of a horse. ~John Lubbock
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Zoonotic diseases – what could you catch from your pet?

Zoonosis is any disease that can pass from animal to human. Although most are easily treated, some of them can be serious and even fatal. Below are several zoonotic diseases that can be passed from dogs and cats, sometimes via other organisms that use the dog and cat as their host.

Toxocariasis

These are the roundworms of the dog and cat (and other species). They can be transferred to humans via their eggs which are left in soil after infected animals have defecated. Children are more predisposed to ingesting the eggs as they might play in the soil and not wash their hands. Adults can also ingest the eggs from eating raw vegetables that have not been washed properly.

If the infection is heavy or repeated, it can cause the disease ‘visceral larva migrans’. This is when the worm larvae move through the body and causing swelling to the major organs and affecting the central nervous system. High-temperature, coughing even pneumonia are various symptoms. The disease is also known to cause ‘ocular larva migrans’ when the worm larvae enter the eye causing inflammation and even blindness.

Once this disease has been diagnosed it is treatable by medication from a doctor.

Dermatophytosis

More commonly known as ringworm this highly infectious disease, affects cats and dogs, it is not a worm at all, but a fungal disease. It can be transferred from animals to humans by skin to skin contact. It can also be spread by contaminated clothing, grooming brushes and other items that have come into contact with the animal.

The disease is characterised in cats and dogs by circular, raised and dry lesions that are normally crusty and cause hair loss. The disease often starts on the head and feet areas, but can spread across the body if left untreated. In cats ringworm is often difficult to detect as it sometimes causes only very mild symptoms. In humans the infected areas are often red rings with scaly edges.

Ringworm can be treated both in animals and humans with the correct medication, however full recovery can be prolonged.

Sarcoptic mange

This is caused by a mite known as sarcoptes scabei canis and is found predominantly on dogs, a different, but closely related mite causes scabies in humans. A similar condition is caused in cats by the mite Notoedes cati. In animals sarcoptic mange causes fur loss and intense itching, where in extreme cases animals can bleed by prolonged scratching, the sarcoptic mange mite that infests dogs can infest humans, however in most cases the mite will quickly die off as they cannot complete their life cycle.

 Leptospirosis

This is a bacterial disease that is carried through the body of the infected animal (in companion animals this is normally dogs) and excreted in the urine. Dogs can pick up the disease by wading through, sniffing or drinking contaminated water where rats have been. Humans can contract this disease with direct contact of the animal’s infected urine.

In dogs the disease can cause vomiting, high-temperature, dehydration, shivering and muscle weakness. In advanced stages it can also cause chronic kidney failure, causing death.

In humans common symptoms are like influenza, however severely infected people can get intense headaches, muscle weakness, high-temperature, vomiting and diarrhoea and meningitis. The infection can go on to produce jaundice and kidney failure. In humans the condition is known as Weil’s disease.

Although there is a vaccine for dogs, there is no vaccine for humans. In some cases people are known to have come into contact with leptospirosis are put on antibiotics by their doctor as a precaution. Toxoplasmosis

This is a parasitic disease carried by cats. It can be transferred to humans by contaminated soil which carries the parasite after the cat has defecated in the area. The soil may be on poorly washed garden produce, much the same as Toxocariasis can be contracted. It can also be transferred to humans by poor hygiene after cleaning cat litter trays.

In cats there are very non-specific symptoms of toxoplasmosis, they might display a lack of appetite, vomiting or diarrhoea, high-temperature, lethargy and weight loss. These symptoms can be attributed to many other cat illnesses. In humans the symptoms are usually mild but people may display a prolonged high-temperature. The main issue with toxoplasmosis is for pregnant women. Should women that are carrying unborn children contract the condition, it can result in miscarriage or severe disease in the new-born child.

Rabies

Although this condition in the UK is very rare, it is not unknown. With the stringent guidelines of the pet passport scheme and quarantine, animals are highly unlikely to carry the disease in the UK.

The disease itself is an acute viral infection that affects the central nervous system. Affected animals normally show behavioural changes, in further stages they can start to drool, become excited then aggressive, attacking people and other animals. Convulsions and paralysis normally follow, before death.

If a human contracts the disease through a dog or cat bite, it is invariably fatal. After the initial bite, a high-temperature followed by headache and nausea are common. Mood changes such as apprehension or excitability come before paralysis, fear of water and delirium. A respiratory paralysis is often the final cause of death. Other Zoonoses Of course it is not just cats and dogs that carry diseases that can be passed to humans. Other species such as birds, goats and cattle can also carry diseases which can, if severe and left untreated, cause death. Reptiles and tropical fish are known to carry salmonella which can make humans very ill and even be fatal. Scientists are constantly monitoring infection and trying to develop treatments for new strains of zoonotic diseases for example avian bird flu, CJD and others. There are numerous zoonotic diseases in the UK (and there are more carried by cats and dogs than are listed above). Despite this, by the use of proper vaccination (in the case of leptospirosis, regular boosters as well), parasitic treatments, stringent hygiene and common sense, risks to human health from animals can be minimised.

David Kalcher RVN, DipCW(CTJT), A1

If you have any worries about your pet, please make an appointment with your vet, or try our Symptom Guide.

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June bugs – stopping parasites from bugging your pets!

Hurrah, it’s June!  Which means the weather is (hopefully) warming up and summer is just around the corner!  However, just as we enjoy the sunny conditions, so do the bugs and beasties that live on our pets.  A little forethought and treatment now, can save a whole lot of trouble (and maybe some vets bills!) in the future. Fleas These irritating little creatures are the ones everyone thinks about as the weather warms but here’s an interesting fact; actually the worst time of year for fleas is the Autumn.  Then the few fleas our pets have picked up over the summer move into our centrally heated houses and have a party.  However, what that means is by protecting our pets over the summer, we not only keep them from getting itchy bites now, we can stop a house infestation later! It can be surprisingly difficult to know if an animal has fleas, especially cats who are good at grooming out all the evidence, but you need to look for small black flecks of flea dirt in the coat, small red raised bites on the skin, excessive scratching and, of course, the insects themselves.  Rather than waiting for them to appear (especially as you will probably miss them anyway), treating against them preemptively is best.  There are various ways of doing this including spot-ons, tablets, sprays, injections and collars.  However, whichever you chose to use, make sure it comes from your vet, who will provide far more effective products (and better advice!) than pet shops. Scabies The more common name for Scabies is ‘Fox Mange’ and certainly most dogs (it is very rare in cats) who contract it are often those who enjoy rolling in fox poo (why DO they do that?!) or poking their heads down fox holes.  The Scabies mite is a burrowing kind; it digs through the skin causing a great deal damage.  The most commonly affected body areas are the head, ears, limbs and groin, where the skin will lose the hair, be very red and inflamed, is often extremely scabby and always very itchy.  It is easily treated, and prevented, using veterinary spot-on medications. Ticks Although these little blighters are most active in the Spring and Autumn, if the weather remains warm but wet (which pretty much describes our summers!), they can survive longer.  When they are attached, ticks look like small, grey beans stuck onto the skin.  They remain in place for a few days and get larger over this time as they gorge themselves on our pet’s blood.  Left untreated they will eventually drop off but while they are biting they can infect animals with some nasty diseases, are unsightly and can leave the skin very sore.  There are spot-ons which kill ticks but usually the best way to remove them is manually.  Tick pullers are cheap and easy to use, your vet can give you a demonstration! Worms Regularly worming your pets all year round is important, especially if you have young children, but it is particularly vital in the warmer months.  This is for several reasons; firstly, many of the worms that infect our pets are passed from prey animals, so hunters (and it is mainly cats but some dogs are very good rabbiters!) are more vulnerable when prey numbers are higher.  Secondly, worm eggs (which are microscopic & are passed in faeces in their millions) can survive in soil for a long time and although most pets get out and about all year round, most inevitably spend more time outside, and more time snuffling though flowerbeds and undergrowth, in the summer. Like fleas it can be very difficult to know if a pet has worms.  Many people know about signs like itchy bottoms & bloated tummies but, in fact, most infestations are symptom free, another reason why regular treatment is vital.  There are spot-ons, tablets and liquids available and, again, your vet is the best source for advice on which kind to pick. I hope I haven’t made your skin crawl too much thinking about all these little blighters!  Just remember, prevention is always better than cure and the best people to ask for advice on what is best for your pets is always your vet! Cat Henstridge BVSc MRCVS - Read more of her blogs at www.catthevet.com If you have any worries about your pet, please make an appointment with your vet, or try our Symptom Guide.
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Part 3: Surgical Colic

As we saw in the previous part of this series, Medical colics are those which can be managed medically, usually on the yard. However, about 1 in 10 cases of colic require emergency referral to an equine hospital for surgery. This is what most horse owners are terrified of. The general indicators that a horse has a surgical colic are: 1) Heart rate over 60 that isn't relieved by injectable painkillers. 2) Dilated loops of small intestine on rectal exam. 3) Positive stomach reflux from the stomach tube. 4) A definite rectal diagnosis of a surgical problem. 5) "Toxic rings" - dark red or purple gums, that indicate that the horse is going into toxic shock. Of course, it varies between horses, and the vet has to make a judgment call based on all the evidence available. We also have to talk to the (by now usually frantic) owners about costs. Colic surgery usually costs between £4000 and £5000, but can easily be a lot more. Even if the horse is insured, it is important to check how much the insurance company will cover - there are a couple of companies out there who will only cover part of the costs of emergency surgery. If in doubt, always call your insurer's helpline. However, colic surgery is one of the most genuine emergency operations there is - and it can be truly life-saving. So, what causes a surgical colic? Probably the most common are: 1) Twisted bowel. If a length of bowel twists around itself, it can cut off the circulation. At this point, the gut begins to die, and unless it can be removed by surgery, and quickly, the horse will go into toxic shock and die. This commonly happens in the small intestine or occasionally the colon, but there's also a condition where the caecum gets turned partially inside out (an intussusception). 2) Small intestinal blockages. Horses rarely eat things that get stuck in the small intestine (although it can happen). More commonly, a really heavy worm burden can simply block up the bowel; with the bowel overfull, the blood supply starts to fail, and the gut, again, can die. I once had a patient who was a little foal with a severe colic; we removed two gallons of worms from her small intestine! 3) Strangulating Lipomas. These are really common in older horses and ponies. A small, benign, fatty tumour forms somewhere in the abdomen, causing no harm at all. However, it grows on a stalk, and eventually, the stalk gets wrapped around a length of gut, cutting off the blood supply... This results in the bowel dying, as if it had twisted. Fortunately, these are usually really simple surgical procedures; unfortunately, older horses and ponies are less likely to be insured for surgery. There are also a number of medical conditions that can mimic those requiring surgery - particularly peritonitis and anterior (or proximal) enteritis. Horses with these conditions are often referred for possible surgery because it's very hard for the vet in the field or on the yard to be 100% certain they're not surgical. I think that most of us would say it makes a lot more sense to have the horse at the hospital, with a surgeon on call, to make the definitive diagnosis, rather than waste time in the stable, and risk having to then decide it needs surgery when it's still an hour or more away in travelling time from the hospital! So, what happens when the vet decides that a colic case isn't suitable for medical management? Firstly, they'll talk to you about the options. If a horse isn't insured, or there's no money for treatment, it is a perfectly respectable and responsible decision to decide, sadly, to put the horse to sleep rather than prolong its suffering. Hopefully, of course, that won't be the case. Once you and the vet have decided that referral is the way forward, your vet will get in contact with a referral hospital. If you're very lucky, it will be one run by your vet's practice, but in most cases, it will be a specialist referral hospital. I must say here that not every centre with surgical facilities is able to cope with emergency colic surgery - they need not only to have the facilities (knock-down box, operating theatre, recovery box etc), but also the staff (not only a surgeon, but also enough vets and nurses to take care of your horse in the vital recovery period). Your vet will have a list of suitable referral hospitals - generally, its best to send the horse to the closest one with the shortest transport time, but your vet will be able to advise you. Making an emergency referral is simple - but only your vet can do it. A referral hospital will not accept referrals from the horse's owner! Once you've made the decision to refer, your vet will call them and speak to the veterinary team on call, who will be available 24/7/365 (when I was part of one such team, we ALWAYS seemed to get our referrals at about 10pm!). They'll let him or her know what they want done during transport - generally, they'll describe what painkillers they want given, and what samples they want taken (don't be surprised if your vet gives you a couple of blood tubes to take up and give to the referral team). In addition, they'll sometimes ask the vet to put in a stomach tube and tie it in for the journey - this is to prevent the stomach from getting over-full and bursting if there's an obstruction in the small intestine. Don't forget your horse's passport - legally, they do need it even when being rushed to emergency surgery. Your vet will generally give you directions and a contact number for the hospital, and send you on your way. Remember, they can't normally go with you, because your horse's colic, while devastating, is probably only one of several cases they'll have to deal with. If there's a problem (e.g. your horse getting distressed) in transit, call your vet or the referral number you were given - but if at all possible don't stop unless they tell you to! Remember, you're on your way to the best equipped help available. On arrival at the hospital, you can expect to be met by the veterinary and nursing team. Your horse will be rushed to an assessment area, and you'll probably be given a lot of scary-looking paperwork to sign. Generally, this comes into 2 parts - firstly, you're signing to give consent for whatever they need to do (and remember, a lot of drugs aren't technically licensed for use in horses, because the manufacturers haven't paid for an official license for that drug in horses. It doesn't mean a drug is dangerous or experimental, it's probably used on a daily basis by the hospital. You'll have to sign consent to use unlicensed medication - it's absolutely routine, and nothing to worry about). Most hospitals will also ask to see your passport - if you haven't got it, or it isn't signed to mark the horse as "not intended for human consumption", legally the hospital can refuse treatment (although they rarely do). The second set of paperwork you'll sign is a bit more pedestrian - you'll be signing to say that you will pay for any treatment! While you're contemplating the paperwork, your horse will be undergoing another examination by the veterinary team. This is to establish what's going on, and what's changed since your vet examined him back on the yard. They may well repeat some tests - most colic conditions are dynamic (i.e. constantly changing), and sometimes the change is more useful in working out what's going on than a one-off test. Other tests they may wheel out include ultrasound - the powerful ultrasound systems available in a hospital environment can give the vets a lot more information about what's going on. The vets will then make a decision about what to do - don't be disappointed or worried if they don't rush immediately to surgery! They may decide to try a course of medical treatment first (remember, they don't have to rush as much as your vet does - if your horse's situation deteriorates, they can operate at a moment's notice). In many cases, however, they will decide to take the horse straight to theatre. If so, you normally won't be able to follow, so I'm going to describe what happens once you've been gently steered in the direction of a waiting room. To begin with, the horse will have an intravenous catheter fitted, to allow easy access for fluids and drugs. A horse with colic is systemically weakened, so will almost invariably be given intravenous fluids during surgery. He'll then be given a premed - this is a sedative, designed to make induction into anaesthesia gentler. It will usually contain the drug acepromazine, because the use of this before surgery has been demonstrated to reduce the risks of anaesthetics. He'll then be led into a knock-down box: this is a special padded room, designed to make induction of anaesthesia safer. Then he'll be anaesthetised with an injection containing (usually) a mixture of 2 anaesthetic agents, ketamine (no, it's not a tranquilizer, it's an anaesthetic) and diazepam or a similar drug. Shortly after the injection, he'll go wobbly, and then quickly lie down. Once he's asleep, the team will swing into action: a tube will be passed down his throat to help him breathe and he'll be moved into the operating theatre. While this was going on, the surgeon(s) will have been scrubbing up, ready to start. Once he's in theatre and safely ensconced on a well cushioned table (to prevent pressure sores etc), he'll be put onto anaesthetic gas to keep him asleep. Colic3 - SurgeryThe surgery involves a long incision down the midline of the belly. The surgeons can then have a good look through all the intestines, to find the problem. This is the exciting, sexy bit, but it's actually pretty simple in principle: "if in doubt, cut it out". In other words, removing devitalized (dead) bowel, emptying out anything in the bowel that shouldn't be there (e.g. a caecal impaction), replacing anything that's got stuck in the wrong place (e.g. an entrapment) and untwisting anything that's tied up. There are usually at least 2 surgeons, because one person is needed to hold loops of intestines (and they don't stay still - sometimes they wriggle around in your arms)! Meanwhile, the anaesthetist will be carefully monitoring all sorts of parameters (heart rate, blood pressure, ECG, reflexes, breathing and blood gasses can all be monitored at many hospitals) and adjusting the anaesthetic and any other drugs to give the safest and most effective anaesthetic. Once whatever the problem was has been found and (hopefully) sorted out, your horse will be returned to the recovery room. In many ways, this is the most dangerous part of the procedure. Horses are very prone to breaking things when they wake up, so everything is done to keep it as calm and quiet as possible. Sometimes, the veterinary team will help the horse to rise, using hoists and lifts; other times, it works out better to let him get up in his own time. In either case, he will be moved into a padded room, and left in dim light, as quietly as possible, so he wakes up slowly. Once awake, and steady on his feet, he'll be moved to an intensive care box; he'll almost certainly be on a drip to keep him hydrated. At regular intervals through the next 24 hours (or longer) he'll be checked by vets and nurses. In some cases, the guts don't start working properly on their own, and medication may be needed to encourage motility (e.g. a lidocaine drip). Although everyone gets excited about the surgery, it is this recovery period that is in many ways the most important in getting a good long-term prognosis. As time goes on, the vets and nurses will try and tempt the horse to eat - normally, we'll try and get him eating fresh grass as soon as possible. As soon as he is stable enough and eating on his own, he'll be sent home - most horses do better in their own home environment, so as soon as they no longer require advanced medical intervention, they can go home. Once home, it's important that the discharge instructions from the hospital are followed - it can be tempting to try and speed things up, but don't rush it! Major abdominal surgery takes time to recover from. Colic is a worrying condition to have to deal with as an owner, especially as it often seems to come out of the blue. However, if you ever have to go through it, I hope that having read these blogs, you'll have some idea of what's being done, and why. Remember, our aim as vets is to help your horse and, if at all possible, send him home to you fit and well. If you are worried your horse or pony may be suffering from colic, talk to your vet, or check the symptoms using our Interactive Equine Symptom Guide to help assess how urgent the problem may be.
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Looking after the Older Horse

When I was training as a vet, a 20 year old horse was considered really quite old. Now, however, I regularly find myself working with healthy horses in their late twenties and thirties - even a few that go on into their forties! That said, horses don't age uniformly - one may be sprightly and fit at 30, while her paddock mate is really feeling his age at 20, so there's a lot of variation. The challenge is maintaining them at the best quality of life for as long as possible. To do so, we need to consider three things: • Work and exercise • Preventative health (worming, dental care etc) • Disease management and medication I'll deal with these in sequence, although really they are of course all interconnected. Work and Exercise PerryI'd like to introduce Perry, a horse I've known for many, many years. Born in 1986, by 2002 Perry was a successful Eventer, competing on the Affiliated circuit, and usually well up in the places. However, by then he was starting to slow up a bit, and his then-owner decided it was time to reduce his workload. He was struggling in particular with the dressage and show jumping, so they sold him on to a friend of mine as a Pony Club horse for Tetrathlon. All he had to do was carry his (fairly novice) rider round a cross country course - the phase he enjoyed the most anyway. Relieved of the need to work in an outline, or in collection, he flourished at Tetrathlon, going on to compete at the National Championships. Of course, in time, his low-grade arthritis (which I'll talk about more later) meant that he was struggling with the cross country requirements, and he moved into a semi-retirement as a hack. He'd seen it all, done it all, and was as close to 100% in traffic, tractors and low flying aircraft as any horse could be. For most horses, as long as they can work, they want to - generally (and there are always exceptions!), it isn't in a horse's best interests to take him out of work one day and retire him to a field. A gradual wind-down over several years is kinder, and helps to keep him interested and alert. So, by changing career, Perry had an extra five years of competition, and then many more years of useful work - simply because his various owners were wise enough not to over face him, but to play to his strengths. Preventative Health I've talked before about the importance of regular dental work - in the older horse, it is doubly important. As the horse ages, his teeth undergo a number of changes. Although it appears that teeth grow constantly, that is in fact an illusion - the adult teeth are pretty much a fixed length, but most of the tooth is hidden away within the gums (the reserve crown). As the tooth is worn down by chewing, more of this reserve is extruded (which is, by the way, the basis of ageing horses by dentition). However, sooner or later, this reserve is expended, and the teeth "cup out", becoming small, loosely held, concave structures, of limited use for chewing. Good, regular dental care can help delay the onset, and can help the horse to manage as the teeth cup out. Remember, as long as there are a few pairs of teeth in occlusion (i.e. Facing each other), the horse can still chew, he'll just be very slow about it! In my experience, teeth generally start to cup out about 30-35 years of age, but it depends on their dental history - more use and wear and tear means the teeth are ground down faster. Worming is also inceasingly important in the older horse, simply because although they may have higher immunity to worms (this is still debated, but does seem likely), they also have less reserves to cope if they have a heavy infestation. The spring is a particularly risky time, as sometimes large numbers of small redworms can emerge all at once, causing massive gut wall damage. It is important to make sure that at some point over the winter, you use a wormer that is active against hibernating (hypobiotic) worm larvae - currently, the only wormers on the market that have this activity are a full 5 day course of Panacur, and (reportedly) Equest. Foot care is always important, as older horses can suffer some terrible hoof capsule problems if left untreated. I always recommend that people keep up vaccinating their horses, even if they're not competing or going out. Equine influenza probably isn't essential in a stay-at-home horse or pony (although they can still contract it if they're in contact with a younger friend who does go out and do), but Tetanus vaccination is essential. Just because a horse is old doesn't mean you can stop vaccinating, because tetanus kills horses of any age just as easily. It's also a really useful opportunity to have a general "MOT" and get your vet to check the horse over thoroughly, to detect and problems before they become too serious. Disease Management Although many horses lead a long and healthy life, the probability is that as they enter old age, they will suffer from one or more "chronic diseases". These are generally low-level conditions, and in the older horse are usually manageable rather than curable. Probably the most common are arthritis and Cushing's disease, but malabsorbtion diseases and some tumours aren't that uncommon either. The key factor is managing the disease in such a way that the horse doesn't suffer from the symptoms, and is able to keep up as much work as possible, for as long as possible. Arthritis is perhaps the commonest condition of older horses, and those that aren't so old. In most cases, it is due to simple wear and tear on the joint surfaces. The harder a horse has worked, the more rapid the onset of arthritic changes. It's often the case that, initially, a horse will have trouble working in an outline, and perhaps with show jumps, but hacking and cross country, with it's more open jumping style, is less of a problem. This of course was exactly the case with Perry. Managing arthritis is a lot more than just monitoring exercise, however - nowadays, we no longer need to just accept "a bit of stiffness" in the older horse. It's often best to use several different strategies. I generally recommend a combination of joint supplementation (feed supplements such as Cosequin and Newmarket Joint Supplement are the most popular, while injectables like Adequan are more expensive but possibly more effective) with analgesics (bute and/or Danilon, usually) as required. Although painkillers like bute don't address the underlying disease, they reduce the inflammation and associated pain. Although there can be side effects, it really isn't fair to put a horse through the pain and discomfort of arthritis without some pain relief; if side effects are a particular concern, Danilon has a much lower risk, although it seems to be a little less effective. Its usually best to start out using bute only as required, and then build up the dose as necessary. Perry, for example, started using bute about 10 years ago, but just a sachet or so immediately after a competition. As he's got older, he uses more, and at the moment he's on an average of 4-5 sachets a week - enough to keep him comfortable (and galloping round his paddock like a yearling!). Cushing's disease (hyperadrenocorticism) is most common in older horses, and is caused by a micro-tumour in the pituitary gland. This results in an excess of circulating cortisol (a stress hormone), that causes the characteristic symptoms of abnormal fat pads (typically over the eyes and as saddle-packs), excessive drinking and urination, and increasing susceptibility to minor infections and laminitis. Ironically, the "classic" shaggy coat of the Cushingoid horse isn't entirely due to cortisol - the presence of a tumour in the pituitary causes a malfunction in the part of the brain that controls body temperature, causing retention of a winter coat for longer. Cushing's isn't curable in horses, but symptoms can be partially controlled by management (regular clipping, diet and exercise control and remedial shoeing), or largely eliminated with some medications - Cyproheptadine (Periactin) may be of some use; however, Pergolide (Prascend) is highly effective, and is licensed for the treatment of Cushing's. Gut problems of one sort or another are also more common in older horses - these may be malabsorbtion issues, caused by thickening of the gut wall, or an increased susceptibility to colic. This may be due to a diffuse Lymphoma (a cancer of the white blood cells) which is the commonest tumour of older horses. In these cases, the key is to feed a highly digestible, high feed value ration, possibly with a probiotic to enhance digestion. Tooth loss is also a problem in the older horse - as I discussed earlier, eventually the teeth "cup out", at which point there's little more that can be done, dentally. The next phase is that the tooth falls out, leaving naked gums. I remember once doing a regular tooth rasping on a 38 year old mare - I put a hand in to have a feel around, and four teeth fell out in my palm... (she actually did better once the teeth were out than she had in months!). An edentulous (toothless) horse needs a soft, ultra-high fibre diet; typically a mash made from fibre pellets or pencils. Horses can live healthily for quite some time on such a diet - however, once your horse has reached this stage, it is probably time to consider how long you can fairly keep him going. If you can stay on top of all these points, you have every chance of keeping your older horse going for a long, healthy life - as Perry has had, and indeed continues to have. If you are worried about any symptoms your horse or pony is showing, please talk to your vet or check how urgent the problem may be by using our Interactive Equine Symptom Guide written by expert equine vets.
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