Emiliano

Spavin – fused hocks

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SPAVIN - FUSED HOCKS

“Spavin” is a lay term to describe arthritis of the lower hocks. This is a degenerative process that ultimately can progress to fusion of the hocks. However, this does not always predictably happen unless provoked by invasive procedures. 

Spavin can be painful and cause lameness to more or lesser degree. Once the hocks are fused, horses seem more comfortable. 

 How do they develop Spavin?

There could be many reasons why horses can develop spavin. From younger horses brought into work where there may be a developmental problem, to older horses for various reasons. 

We must not forget that conformation and concurrent problems (i.e. kissing spines) can play an important role (picture 1).

A healthy functional lower hock should look like the picture below.

Picture 1: Sickle hocks can predispose to spavin. Corrective shoeing can help to help prevent it.

The main mechanism is damage to the cartilage, which subsequently affects the bone underneath (subchondral bone) altering the architecture and impairing the anti-concussive properties. This is a cycle. Ultimately when cartilage disappears, both joint surfaces can become fused.

How long does it take to fuse?

Captura de pantalla 2022-02-18 a las 21.28.33

The timeline process of fusing as seen in the above x-rays is unpredictable. In most of the cases it either doesn’t quite happen, or is very slow in progress. 

When lameness occurs, pain would have to be managed. Generally the use of oral anti-inflammatories or intra-articular medication of long acting steroids would encourage progressive fusion of the joints. However on occasion, horses can become too sore to be ridden and they may need time off.

Regarding treatment there are other types of medications (aiming to regenerate rather than regenerate). The merits of these options should be discussed with your vet.

 

Can hocks can be fused with treatment or surgery?

When conservative treatment fails, there are options of provoking fusion to manage pain long term. This is not something to take lightly. It is invasive and there are important conditions to consider before deciding.

There are several methods:

1- Drilling across joint surfaces

2- Use of laser

3- Controlled injections of monoiodoacetate (MIA)

4- Injection of ethyl alcohol (or ethanol)

There are pros and cons for each technique. We want to achieve an optimal treatment with minimal pain, maximum effect arthrodesis, minimal side effects, short convalescence and cost effective. Ethyl alcohol would generally be a good choice. They tolerate this procedure better than MIA. The other procedures require general anaesthesia with the associated complications such as fracture in recovery which I personally experienced in one case.

Ethyl alcohol causes neurolysis and proteinolysis causing cell death and “cartilage damage”, precipitating joint fusion. It also affect nerves similar to a nerve block, which explains why horses had minimal to no lameness associated with the procedure. It has been used in humans for nerves medium to long term for pain blockade in cancer patients.

What can go wrong with ethyl alcohol fusion?

The hock has two main compartments that encompass the different joints. One in the lower hock connecting the less mobile joints and the other in the upper hock which communicates with the most mobile joints. The important point of this procedure is that it should be aimed to the lower tarsal joints only (turquoise colour on the right picture). If the alcohol reaches the more upper mobile joints (marked as red) it can cause severe arthritis and chronic lameness. 

It is of the upmost importance to ensure both lower joints and upper joints are not communicating which they can randomly be. A contrast injection should be performed prior to injection of alcohol. An x-ray should be taken (see picture below). If there is communication, the procedure should not be done. Also, the clinician should not apply overzealous pressure when injecting intra-articular as this could force alcohol to an unwanted place.

There may also be disadvantages where the alcohol may not reach the full joint surface and therefore achieving limited fusion.

Contrast x-rays: 

Left picture with normal communication of lower hock. 

Right picture shows communication with upper hock joints.

What does ethyl alcohol treatment involve?

The procedure is a simple intra-articular injection under x-ray guidance where firstly a contrast medium is injected, followed by ethyl alcohol. 

Horses generally display swelling over the next 24 hours which quickly improves by 2 weeks. There is a persistent swelling on the site of injection for a maximum of 4 months. 

The fusion of the joints are visible on x-rays at about 1 month’s time and achieve fusion at around 4 months. Following treatment horses are on box rest and walk in-hand for 1-2 weeks, followed by paddock rest for 6 weeks, and then they can start walk and trot for another 6 weeks if they continue to improve.

 

What is the success rate?

In a published study of 24 horses from different clinics in the UK, it was found that 52% improved the degree of lameness, 19% deteriorated and 8% developed serious complications

Adding to that study, I have compiled 20 cases. Of those 25% improved to allow previous level of performance, 15% partly improved but not fully (so 40% go better one way or another), 30% did not improve longterm and 10% were found to have other concurrent problems that were more relevant. I couldn’t follow 20% of those cases which may have improved the statistic. I haven’t experienced any serious complications.

The keys to make this treatment a more successful choice are:

1- They have to have a clear response to nerve block. Many of the cases that weren’t successful didn’t in general have a clear response to analgesia initially.

2- Take in consideration conformation or concurrent problems as they can affect the outcome. Therefore it is important to reach a clear diagnosis.

 

Please get in touch with us if you want to know more about this procedure.

Lameness and poor performance

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Poor performance is described as the “inability of the horse to exercise or perform at a level previously observed (or to be expected) based on its training, level of fitness, and physical characteristics”. This may manifest physically as exercise intolerance, stiffness, resistance on one rein, or difficulty executing a specific movement. It can also present through abnormal behavioural issues, for example napping, rearing or bucking. It can even be non-specific; just a feeling that the horse is “not quite right in itself”.

What causes poor performance in horses?

There are many factors that can contribute to poor performance. To successfully diagnose, treat or manage these cases, its important to have an in-depth understanding of the demands of each sport and the potential ways in which an injury can occur or present itself. Pain can influence a horse’s attitude and vice versa, so while some exceptional horses may be able to tolerate working at a high level quite happily with moderate pathological issues, others may exhibit reluctance to perform even at a low level. This is also why we should look at each horse’s individual nature.

What are the next steps?

Lameness cases often require specialist investigation, as the problems can be multi-faceted and quite complex. Whether the issue is suspected to be musculoskeletal, gastro-intestinal, respiratory, cardiopulmonary or hormonal, there are many areas to be considered. Lameness, the most common cause, can be insidious and at first may not be recognised as the cause of the poor performance. Sudden onset lameness is often easier to recognise initially but may still require in-depth investigation to determine the root cause of the problem.

I also believe that it is important not only to manage and treat any poor performance issues, but to look at ways of preventing them from arising in the first place. As a member of the International Society of Equine Locomotor Pathology, I keep up to date with the latest advances in the cause and treatment of performance issues. I enjoy sharing this knowledge with horse owners, with my regular updates on Facebook and quarterly newsletter.

Equine worming

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A parasite prevention plan cannot rely on dosing of wormers alone! Pasture management is a more effective way of keeping low infestation, as unnecessary drug dosing can lead to worm resistance.
Worming regimes should be individually tailored and faecal examination enables us to identify most types of egg-laying parasites present in the intestinal tract at the time of testing. However this means migrating or immature parasites and encysted worms could well be missed. So a zero egg worm count doesn’t rule out the presence of parasites!

Pasture management tips:

  • Avoid overstocking of horses. Ideally rotate (or share) fields with cattle or sheep.
  • Remove droppings from field (at least twice a week) and avoid harrowing/spreading (infesting areas with fresh manure).
  • Horses that are lower in the pecking order will be forced onto poorer grazing (may have higher worm burden).
  • Worm new arrivals with Eqvalan or give 5 day course of Panacur equine guard, then double dose of pyrantel on the sixth day. Keep new horses in for 48 hours before mixing to allow ovicidal effects time to take place.
  • Worm horses 48 hours before moving to new pastures.
  • If possible, rest pasture for 12 months (or from autumn until mid-summer the following year). For mares with foals, weanlings and yearlings, rest pasture for at least five months from February onwards (most winter larvae will have died by June).

Drug treatment:

  • Perform an egg worm count twice a year (a 4g faecal sample is required).
  • Tapeworm, encysted small red worm and bots cannot be detected by a faecal worm egg count, so it is still necessary to worm your horse for these parasites.
  • Do not aim for a zero count – frequent dosing stops young horses developing natural functional immunity and also encourages drug resistance in worms!
  • Use a weigh tape or weighbridge to ensure your horse is getting an effective dose.
  • Use the maximum interval if grazing is kept clean – use the minimum interval for crowded conditions, sick horses etc.
  • Some worms are targeted strategically at specific times of the year. If there is no resistance, ivermectin, pyrantel, benzimidazoles and moxidectin can be used the rest of the year.
  • Rotate wormers not by brand name but by drug class to help prevent resistance.
  • If resistance is suspected you should ask your vet to carry out a faecal egg count before and after treatment to check its effectiveness (7 day interval between samples for pyrantel, 10-14 day interval for fenbendazole and 21 day interval for ivermectin) in a representative number/age range of animals with at least 200 eggs per gram on first sample – less than 80% reduction would be suggestive of resistance.

Wormers

Although there is a great variety of commercial brands there are actually only a limited amount of chemical compounds (active ingredients). This means we need to be careful; only judicious use will prevent us from facing a generation of resistant superworms in the future!

Please ask for more advice on a tailored worming plan to suit your situation!
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What worm where? Know the parasites that threaten your horse.

Equine Regenerative Medicine

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?Exciting news! ?

Emiliano is pleased to be able to provide regenerative medicine services – a wide range of biological treatments for horses suffering with lameness or poor performance issues.

Biological Treatments – What we offer

Regenerative medicine encompasses treatments that aim to repair, generate or replace tissues, cells and organs in the horse’s own body, in order to restore normal function. Historically, these treatments often used to require hospital visits and take a long period of time to perform. However, modern advances mean that many procedures can now be done at your yard!

The most vital step is first to obtain a diagnosis, as this allows for a comprehensive plan to be formed. In many cases, any biological treatment will go hand in hand with a rehabilitation programme such as corrective shoeing, physiotherapy and management changes, which could potentially make a huge difference by themselves.

If it is decided that regenerative medicine could be a suitable option, then it is important to discuss with Emiliano which one is best for your horse’s specific situation.

And remember that if you are experiencing problems with your horse, it is always helpful to have a chat with the vet to ensure that there are no other underlying issues that may need investigating beforehand!

Espinar Equine – Regenerative Medicine; Biological Treatments for horses.

Equine Herpesvirus (EHV)

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EHV (Equine Herpesvirus) is a ‘special’ virus because it is endemic (everywhere!) Generally it causes mild respiratory symptoms, but it can turn occasionally nasty invading deeper into the neurological system (hence neurological effects). As many people have asked, vaccination does decrease the risk of EHV as it reduces the risk of viral shedding, improving herd immunity and meaning that there will be less chance of it being spread around between horses. The vaccine is truly effective for a short period of time however; if you want general cover then you can do an annual vaccination, however better protection will be provided by vaccinating every 6 months and if you are at high risk then you can do every 4 months. Pregnant mares should be vaccinated during the 5th, 7th and 9th month of pregnancy.

We advise our clients (especially those who are planning on competing, or who have breeding horses for example), to vaccinate. The primary vaccination can be given to any horse over 5 months old, and a second should be given 4-6 weeks later, followed by the booster every 4-6 months.

You can read more about the EHV outbreak earlier this year from the Animal Health Trust, along with some advice on monitoring horses that may be at risk.

What age should I castrate my horse?

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We are often asked what is the best age to castrate colts.
Providing both testicles have descended, colts can normally be castrated anywhere from 5 months – 2 years old. Any younger and the testicles may not have descended or be developed enough to remove, and any older than that and the risk of complications from bleeding can be higher (although of course, horses can still be castrated at any age).

In general, castrations can be performed in the field (meaning we can do the procedure at your yard). Both testicles are removed using an instrument called an emasculator. After the horse has recovered from anaesthesia, they are often better being able to move about, which reduces post-surgical swelling. Therefore the best time for doing the procedure is in late autumn or winter, as there will be fewer flies present, enabling the incisions to heal faster. If you want to know more about what is involved in the castration procedure, we have a helpful video here: https://youtu.be/mH0HrHFb590

Rainscald

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Rainscald is common during the winter months with persistent rain – did you know it can be caused by the same bacteria as mud fever?

Rain scald causes dermatitis and is usually present along the horse’s topline (especially the loins) with the hair on affected areas resembling little paintbrushes. Scabs cause tufts of hair to become matted together, and when removed, they reveal sore skin underneath. Further secondary infection may result as the skin is weakened.

Affected areas need to be cleaned with Malaseb, diluted hibiscrub or similar and horses should be kept dry and free from mud and application of topical antibacterial will speed recovery. Remember that infection can be spread through contaminated grooming kits, so keep any brushes used for the affected horse separate. In severe cases a course of antibiotics may also be required.

Rainscald can sometimes be confused with ringworm (which is a fungal infection) so it is worth getting a proper diagnosis from your vet to ensure that your horse can be made comfortable, and so that you don’t waste time or money on the wrong treatment.

Tetanus

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Tetanus, a bacterial disease that affect horses and also humans, is an often fatal bacterial toxin that affects the nervous system, causing progressively worsening muscle contractions. Usually associated with the spasms of the jaw and neck (hence its common name of “lockjaw”), the horse will be unable to eat or drink. But it is important to remember that all muscles can be affected; including those that control breathing. This is why death can occur due to respiratory failure (leading to cardiac arrest).

The bacteria are present in soil and droppings, therefore tetanus can be easily picked up from puncture wounds, open cuts, or the umbilici of foals. However, it can be easily prevented with a vaccine! This is why it should form part of your horse’s core vaccination schedule. Tetanus can be treated but reports state that 80% of horses die once recumbent, so if your horse is unvaccinated, prompt veterinary attention can mean the difference between life and death.

Strangles

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Strangles is endemic in the UK. It is an infectious bacterial disease that affects the upper respiratory tract. It usually causes:

  • high temperature
  • inappetance
  • nasal discharge
  • swollen glands and lymph nodes
  • abscesses, typically under the jaw.

It can be overlooked as ‘a bit of a cold’ but in time, infected horses can develop painful lymph node abscesses that often rupture. This makes it difficult for them to breath and swallow.
Another serious complication known as ‘bastard strangles’ can occur when the bacteria spreads and causes abscesses in other parts of the body (difficult to treat, this can often be fatal). Diagnosis is usually easy; blood tests can detect antibodies to strangles, and are useful for horses moving to a new yard, whereas guttural pouch lavage using an endoscope can be a quicker and more accurate test for most cases. At present, strangles vaccines have had limited success and high rates of vaccine reactions, so the best way to prevent the spread of strangles is good biosecurity measures.

Spring grass – how do we manage intake?

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While “Dr Green” can be the best medicine in some cases, for others, it can cause problems.

Grass contains simple sugars (that are produced in daylight hours via photosynthesis) and fructan, (sugar in its storage form). Known as WSC or “water soluble carbohydrates”, high intakes can lead to laminitis, insulin dysregulation, and weight gain. WSC levels can vary depending on temperature, soil fertility and moisture, so it is often hard to determine the best time for turnout.

Also, it may not be the grass itself that is the issue. Sometimes, simply the change of routine (going from being stabled on dry hay or sparse pasture to being turned out on grass) is enough to trigger a bout of colic. Your horse’s digestive system will be unused to the non-structural carbohydrates in grass and this can cause digestive upsets and therefore colic.

Grazing muzzles, strip grazing and timed turnout amongst other options can be used to help control your horse’s intake of grass. However, when managing weight, care must be taken not to restrict fibre intake too much as gastric ulcers may result. If you’d like advice regarding spring grass, associated issues and how best to manage your horse’s weight or diet, do speak to us!