Lameness is a pain-avoidance strategy adopted by horses, and is a common cause of poor athletic performance and compromised welfare.  Whatever the precise cause of pain (e.g. osteoarthritis,  tendon injury), that pain is caused by inflammation. 

Inflammation is the cascade of chemical and cellular events that occurs following any type of tissue damage. By causing pain it alerts the animal to rest the damaged area, thereby preventing further injury. Inflammation also acts as the initial stimulant of the healing or repair process, hence it is extremely important. However ongoing, uncontrolled inflammation causes chronic pain and can actually exacerbate the tissue damage. This is where veterinary intervention becomes necessary.

Conventional therapies aim to stop the inflammatory process, and these remain a vital, cost-effective component of orthopaedic disease treatment.  However, they do not influence the repair of tissue and can occasionally delay this important process. 

‘Regenerative therapies’ aim to optimise the repair of a structure by replacing damaged tissue with tissue of the same cell type and hope to minimise the formation of non-functional scar tissue, hence maintaining the original biomechanical properties of the structure. This increases the probability of return to previous athletic ability, and reduces the likelihood of ongoing lameness and/or reinjury. 

Research and clinical trials of regenerative therapies have been ongoing since 2003, but there are now several exciting options that have been scientifically proven to modify inflammation and reduce pain in clinical trials, all of which are available at Oakhill.

Stem cells are a type of cell which have the potential to develop into a variety of more specialist cell types dependant on the environmental signalling that they are subject to. An embryo begins as a ball of stem cells that go on to develop into every type of cell required to make a mature being! Stem cells continue to be present within the body after birth in reduced quantities.

It is not fully understood how stem cells behave when they are used as a medical treatment – whether they differentiate into the same cell type as the tissue they are introduced to, or if they modulate the inflammatory process. Either way, they have been found to decrease or eliminate lameness when used to treat joint disease, and have the potential to reduce the reinjury rate when used to treat tendon injuries!

Autologous stem cells are collected from the individual horse that requires treatment. Bone marrow is collected (most commonly from the sternum) under sedation and sent away for complex processing to provide a product containing millions of stem cells. 

These cells are injected into core (central) lesions within tendons and ligaments.

Allogenic stem cells are produced from the blood of donor horses (treated to prevent reaction when introduced into the horse requiring treatment). These are purified to get rid of other blood cells and then cultured to increase the number of cells into the millions. They are specifically stimulated to give the ability to differentiate into chondrocytes – the cell type present in cartilage.

Commercially this product is available as Arti-Cell. This has proven highly successful at reducing lameness in horses with degenerative joint disease.

Interleukin-1 Receptor Antagonist Protein, more commonly referred to as IRAP, is a protein synthesised by a variety of cells. It prevents the actions of Interleukin-1 – a substance which has an important role in the induction and maintenance of inflammation within diseased joints. Studies in humans and horses have proved that intra articular IRAP injections reduce synovial (joint lining) inflammation and lameness.

IRAP is produced by collection of blood (from the horse to be treated) in a special syringe.  This is then incubated overnight before filtration to produce concentrated and purified IRAP. This can be frozen to allow storage of the product until an appropriate time for medication of a joint. This product can be of benefit where steroid medication is not appropriate (e.g. competition horses where steroid medication is prohibited, horses at risk of lamintis) or where joint pain no longer responds to steroid medication. There is also some evidence that the effects of IRAP last for up to two years!  

Platelet Rich Plasma, or PRP is simply defined as plasma (the none cellular component of blood) which has been processed to have a high concentration of platelets. It is rich in growth factors – substances which stimulate cell multiplication and tissue repair, therefore it promotes a favourable environment for healing. Like IRAP, it is produced by the specialist collection and processing of blood (from the horse to be treated). This can be done immediately prior to injection of the PRP into the area of damage. 

PRP is most commonly used in the treatment of ligament injuries that are not healing as well as anticipated. It is also occasionally used in the treatment of joint disease that has not responded to steroid medication or IRAP.

Polyacrylamide hydrogel (marketed for use in horses as Aquamid) is unlike other regenerative therapies in that it is a synthetic compound. It is the same material used as a cosmetic filler in humans! When injected into joints, it becomes integrated into the synovial membrane (joint capsule) which decreases joint effusion (overproduction of poor quality joint fluid) and stiffness. 

Clinical trials have indicated a high success rate with this treatment, whether used as a primary treatment or in joints that have failed to respond to other treatments. 

Overall, this is an exciting time for the treatment of equine lameness. If you wish to discuss the potential benefits of regenerative therapy for your horse, we would be happy to do so.

Infundibular Caries is the name given to a condition affecting the upper molars of some horses. Horses have many adaptations in their teeth designed to help with the rough nature of their diet. One of these adaptations is the ‘infundibulum’.

This is simply an extra area of enamel, one of the hardest compounds found in the body, filled with a softer cementum. Having more of this hard enamel is therefore ideal for grinding down rough tree branches in the wild! Occasionally, the area within this extra enamel doesn’t develop as it should, for reasons that are not completely understood.

The horse is therefore left with a hole within the tooth which fills with food. Over time this food can cause the tooth to rot resulting in either infection of the tooth or catastrophic fracture. You will be pleased to hear that both of these outcomes are completely avoidable!!

Regular dental examinations using a mirror, or an oral camera, enables us to visualise the surface of the teeth and detect these small but significant defects. Once detected, they can be investigated by probing and/or x-ray to determine the depth of the hole and the requirement for filling.

These holes can easily be filled, much like if you or I went to the dentist! Under standing sedation at our clinic, these holes are thoroughly cleaned out of all the rotten food and filled using a material that binds to the tooth. Once the hole has been filled, food can no longer become trapped and the tooth is no longer at risk of becoming infected or fracturing.

If you have any concerns regarding your horses dental health, please phone our clinic and ask to speak to one of our friendly team who can point you in the right direction! 

Colic

• Colic is a collection of clinical signs shown by a horse that indicate abdominal discomfort.
• Changes in management, especially if not made gradually, can precipitate episodes of colic.
• At this time of year, horses undergo a significant management change, coming in from pasture to spend prolonged periods of time in their stable.
• Therefore, we frequently see an increased incidence of colic cases.
• Fortunately, the vast majority of cases can be managed medically and although arguably, spasmodic colic remains the most prevalent form of colic that we see, impaction colic occurs at an increased frequency.

Impactions

• Impactions generally occur following the accumulation of food material, which subsequently dehydrates (dries out), in a horse’s colon.
• The colon’s pelvic flexure is the most common site for this to occur. The pelvic flexure is a part of the large colon which turns 180 degrees on itself and naturally narrows. The reduced speed of food material passing through this area means it is more susceptible than other areas to blockage.
• Other risk factors for impaction development include reduced grazing and increased hay/haylage in the diet, reduced exercise due to increased time spend confined in the stable, reduced water intake during cold/frosty periods and straw ingestion (if bedded on straw) to name but a few.
• Clinical signs of impaction colic include passing reduced amounts of, drier than normal, faeces over the preceding 48-72 hours to eventually passing no droppings at all, reduced appetite and signs of colic which vary in severity but can be relatively mild.
• Veterinary examination may reveal a normal/mildly increased heart rate, dry gums and prolonged skin tent. Gut sounds are generally reduced. Impactions of the pelvic flexure are confirmed on rectal examination. They are usually ‘doughy’ in consistency and sit in the left, lower abdomen.
• Treatment, similar to other forms of colic, includes the administration of pain relief and smooth muscle relaxants. In addition, the blocked food material requires rehydration. The most effective way to achieve this is by regularly administering an electrolyte solution via stomach tube. The administered fluid stimulates colon contraction and the fluid passes through the gastrointestinal tract to rehydrate the impaction stimulating it’s passage through the remainder of the gastrointestinal tract prior to evacuation from the body. For the majority of patients, monitoring and treatment of the impaction is carried out most effectively at our equine clinic. Depending on severity, impactions can take varying periods of time to resolve from 24-48 hours to 5 days. Food is withheld until the impaction has cleared and is gradually reintroduced starting with walks to grass and ‘sloppy’ bucket feeds.

Tips for preventing impaction colic (and colic in general)!

• Make dietary changes slowly over a 2-week period of time.
• Avoid straw bedding if you are concerned your horse or pony eats it.
• Try to maintain exercise. A walk around the yard is better than standing still in a stable.
• Ensure a ready access to fresh water- break ice regularly when temperatures drop- a tennis ball/apple placed in water may help reduce freezing. 
• Ensure your horse is drinking. Water intake can be increased by adding water to your horse’s feeds. Providing a salt lick will also stimulate thirst.

Mud Fever

• Mud fever is an infection of the skin usually affecting the pastern.
• The bacteria implicated (Dermatophilus congolensis), gains entry to the skin most commonly, following prolonged periods of wetting/standing in mud.  
• The resulting dermatitis is characterised by hair loss and crusting. Hair comes away in tufts bound by a scab/crust (known as paint-brush lesions).
• Minor cases may present as just a few scabs; however, cellulitis (subcutaneous skin infection) can ensue.
• Treatment is based on removing your horse from the wet/muddy conditions. Mild cases can be managed topically using a combination of anti-bacterial and steroid based creams. The affected area may also be clipped and cleaned using a warm dilute chlorhexidine solution. Different vets vary in their recommendations as to frequency of cleaning so please follow your vet’s recommendations. In moderate to severe cases, sedation may be required to examine, clip and clean the area in the first instance. In cases with secondary cellulitis, antibiotics and anti-inflammatories are also required.

Rain scald

• Rain scald is similar to mud fever, in that it is caused by the same bacterium following prolonged skin wetting, but affects the horse’s topline.
• Treatment mirrors that of mud fever.

Are you organised following the new microchipping rules that came in on 1^st October 2020? Now all horses, irrespective of age should be microchipped and registered with the government central equine database. You can check if your horse is registered at www.equineregister.co.uk and follow our flowchart to check that you have satisfied the new guidelines.

If your horse needs a microchip, our equine vets can effortlessly insert one at our clinic or your yard for the price of £25 (plus VAT).

Microchips, does your horse need one?

Horse microchips or transponders are the size of a grain of rice, and are usually placed on the middle third of the crest of the neck. They contain a small computer, which transmits a 15-digit code to a reader when scanned. This code is unique, and can be used to identify an animal throughout their life.

Since July 2009, all horses must have a microchip when they are issued a new passport, however; for horses that had a passport issued before 2009, they may have a passport without a microchip. As of October 2020, by law, all horses must have a microchip, meaning that horses over 11 years of age which do not have a microchip, will need one inserting.

The change in rules has coincided with the creation of the central equine database, which is accessible at www.equineregister.co.uk. All UK passport-issuing organisations (PIOs) have provided this central database with the microchip numbers of horses that are registered with them. This is an important step aimed to centralise all of the collected microchip data. In the event of a lost or stolen horse (every owner’s worst nightmare, I think we will all agree), if a vet scanned a microchip, they would have to ring around each PIO to find which one held the owners details. As there are over 50 separate PIOs, this isn’t an easy task! Now a horse can be scanned, checked on the equine register, bringing up the details of which passport organisation has the owners details, therefore reuniting the animal with the owner without delay.

How do I comply?

First check if your horses has a microchip, this can be found in the passport, and is usually labelled transponder code, or on the markings page underneath a barcode. If you are unsure, one of our vets can scan your horse for a microchip.

If your horse has a microchip, then check it is registered at www.equineregister.co.uk . If it is, you are compliant with the law. If not, you may need to contact your passport agency to update them with the number.

If your horse doesn’t have a microchip, our equine vets can easily implant one by a quick injection. Only a vet is legally allowed to microchip a horse. Once inserted you will need to inform your passport agency of the microchip number (some require a form completing by the vet, some ask for the passport to be sent back for updating).

Private Microchip Databases

One final comment is about private databases such as PETtrac, Petlog or Identibase, which also record pet microchips. These link the microchip number to an owners phone number, and often have 24/7 phonelines, useful if your horse is lost out of hours! It is not a legal requirement however to be registered with these private databases. When we microchip you horse, we are able to register the chip number to the phone number on your account with PETtrac.

Magnetic Resonance Imaging (MRI) is an advanced imaging tool that is widely used in the veterinary and human healthcare fields. MRI has been developed for use on our equine patients and has been found to be invaluable in helping us to attain specific, accurate diagnoses for our patients. Did you know? Using MRI early on in a lameness case can actually reduce your overall spend by achieving a prompt diagnosis and treatment plan without trying numerous other approaches which are unlikely to help in the absence of a specific diagnosis. 

At Oakhill, we have a standing low-field MRI scanner which means that horses are sedated and stood up for the whole procedure, no general anaesthetic is required, YIPPEEE! The use of the standing MRI scanner is now considered the optimum tool for diagnosing orthopaedic conditions in the horse. The MRI machine is a low field scanner and the strength of the magnet is 0.27Tesla, to put this in comparison to a high field scanner used in hospitals which is 1.5Tesla in strength. This is reflected in the size of the magnet, and the ‘U’ shaped standing magnet is much smaller than those in human hospitals. It’s U-shaped and not a cylindrical shape so that the horse can escape easily from the magnet without harm if they suddenly become anxious during the procedure. 

Usually a horse has been through a lameness investigation including nerve blocks prior to MRI. This may then be followed by radiography (X-rays) and an ultrasound scan, depending on the area to be imaged. If there is still no definitive diagnosis after these imaging modalities, then MRI is often advised. Nerve blocks are essential in determining exactly which site we need to scan. 

So, what will happen if your horse requires and MRI scan? Horses are often admitted as a day case. They will have their shoes removed and a catheter placed to allow small increments of sedation at short intervals to be given easily during the scan. A scan of both front feet typically takes 2-4 hours, but this hugely depends on how well the horse stands within the magnet. 

Our MRI machine is positioned within a specially insulated cabin (called a module!). These modules are made specifically for the MRI machine, to ensure control of temperature and signal interference. Occasionally a French radio wave of a certain frequency has been known to disrupt our scanning! The magnet works within a finely monitored temperature-controlled space and is quite sensitive to change. 

The foot is the most common site that we scan with the MRI machine due to the tough hoof capsule making imaging of the soft tissues difficult. We can assess the bones through radiography, however, MRI has a further advantage of being able to assess for fluid (inflammation) within a bone which no other imaging modality can visualise. Since MRI has been being used, ‘Navicular disease’ has become an outdated term, and we now know there are many different soft tissue and bone pathologies encompassing navicular syndrome, which can be individually assessed and a more accurate guidance on prognosis of the horse’s career given through the use of MRI. 

The magnet can also scan other aspects of the lower limb, up to and including the lower carpus (knee) and hock. This can be particularly useful in areas that can be difficult to fully assess with other imaging modalities such as the proximal suspensory ligament. MRI has revolutionised our ability to achieve a fast, accurate diagnosis and has dramatically enhanced our treatment capabilities of the lame horse. 

The liver has multiple responsibilities including nutrient and toxin absorption. It has a large ability to cope with insults however, clinical signs will become apparent when 60% of the liver is damaged. 

Signs can include jaundice (a yellowing of the gums or white of eyes), weight loss and in severe cases neurological signs such as head pressing and blindness. 

This pony was presented to vet Stuart after developing excessive sunburn. Unfortunately, a large proportion of his body was white haired so this sun burn covered his face, muzzle, his legs and around his eyes as seen in the pictures below. Blood evaluation showed an increase in liver enzymes (indicating liver damage) as well as bile acids, indicating impaired liver function.

A liver biopsy was performed with the pony under sedation and local anaesthetic. This ultrasound scan shows the appearance of the liver.

The results of the biopsy showed the pony to have severe fibrosis (scarring) of the liver, due to ragwort toxicity. However, the changes observed were deemed manageable. 

The pony was placed on steroids, to reduce liver inflammation, and antibiotics for the secondary skin infections. He has had regular antibacterial baths and creams applied to sooth his skin whilst avoiding sun contact. 

He has shown a great improvement whilst on medication and as you can see from the pictures his skin is less inflamed and has started growing hair again as seen in this picture.

His bloods will be monitored going forward. We will keep you updated on his progress.  Liver biopsies are simple to perform and gives a great deal more information on how to treat the liver disease affecting your horse or pony.

If you are concerned about anything discussed then please call us and speak to a vet on 01772 861 300 

Pinworm (Oxyuris equi) infection is manifest by affected horses itching their peri-anal and tailhead regions. Adult worms reside in the large intestine with the female worm travelling down the small colon to lay eggs on the skin surrounding the anus (often indicated by a yellow discharge as seen in photo one below). This usually causes intense irritation manifest by rubbing. Occasionally, mature worms are visible protruding from the anal sphincter which we can also see in this photo. 

Diagnosis is confirmed through microscopic examination of a sellotape impression taken from the peri-anal skin or yellow discharge (if present) which will reveal the pinworm eggs (seen in photo two below). 

Most commonly used wormers are effective for pinworm (ivermectin, avermectin or pyrantel based wormers) and should be administered to clinical cases. The peri-anal region and underside of the dock should also be washed using dilute hibiscrub to remove the eggs. We generally recommend cleaning for three to five consecutive days. The stable should also be thoroughly cleaned and disinfected to endeavour to remove environmental eggs.

Pinworm infection should always be considered in cases of tailhead itching but it is also important to consider other potential causes including sweet itch, other allergies, mites and lice. It is also important to remember that pinworm infection is generally not indicated on faecal worm egg counts as the eggs are deposited on the skin surrounding the anus. Therefore, horses with negative faecal worm egg counts may still succumb to pinworm infection.

As always, should you have any questions, please do not hesitate to contact the equine team. 

Colic is the term used to describe abdominal pain. This is usually from the gastrointestinal tract but can be from any abdominal organ (e.g. the ovaries). Colic signs include curling of the top lip, pawing the ground, flank watching, rolling, increased recumbency (lying down) and change in the amount and/or consistency of droppings. Most cases require a veterinary examination to determine the cause and instigate treatment, from pain relief through to life-saving surgery. 

Initially the vet will observe the horse to see how severe the signs are. The cardiovascular system is then assessed. The mucous membranes (gums or inner eyelids) are examined to establish how well the blood is circulating round the body. The membranes should be salmon pink, and when blanched this colour should return within two seconds (the capillary refill time or CRT). Any discoloration of these membranes, with or without increased CRT, are a sign of poor circulation. Dry mucous membranes are a sign of dehydration. 

A heart rate will then be taken. Slight increases in heart rate can often be attributed to increased stress levels in the horse, but a very high rate is generally an indication of dehydration and disrupted circulation. The digital pulses (at the level of the fetlock) may also be felt – a lack of indicating poor circulation, and an increase potentially indicating toxic laminitis (caused by gut toxin leakage into the circulation). 

Poor circulation results from the leakage of toxins from damaged gut into the circulation. The gut becomes damaged when it gets twisted or stuck, cutting off the blood supply that keeps it alive and functional. Mild dehydration can arise from reduced water intake or sweating. Severe dehydration normally occurs when the damaged gut is no longer capable of absorbing fluid into the body. 

Following cardiovascular assessment, a respiratory rate is obtained. An increased rate can be due to the horse being in pain and using more energy whilst colicking. It can also be due to chemical changes in the blood caused by toxin release. Rarely, an increased respiratory rate can be caused by something in the abdomen pressing on the lungs e.g. a stomach impaction (where food fails to leave the stomach causing expansion and discomfort). 

Next the vet will listen with a stethoscope at four points on the abdomen. A moderate amount of noise should be heard, as gas and food move through the guts (borborygmi). Increased noise is generally an indication of spasmodic movement of the guts. Decrease in, or absence of noise usually indicates that gut movement has stopped or that the portion of gut that is normally positioned in this area has been displaced, which can indicate a more serious problem. 

The horse’s temperature is then taken. A low temperature can indicate poor circulation, and a high temperature generally indicates infection. 

If the vet is now satisfied that the horse merely has some spasmodic gut pain, the colic examination is complete and appropriate medication can be administered. However, if a more serious cause of colic is suspected, a rectal examination will occur. A lubricated, gloved arm is inserted into the horse’s rectum so the vet can feel deeper into the abdomen. The size, position and content of different portions of the gut (and other structures e.g ovaries, tumours) can be assessed allowing an accurate diagnosis of which part of the gut (or otherwise) is affected. Rectal examination has huge benefits but also carries a small risk of tearing the lining, hence it will not be carried out if deemed unnecessary. 

Horses are unable to vomit, so if your vet is suspicious that the passage of food and liquid through the stomach is obstructed, they will pass a tube via the nostril to aspirate excessive fluid build-up. Without the ability to vomit or the act of stomach tubing, a horse’s stomach can eventually rupture. Once your vet is confident that no excess ingesta is present in the stomach, they may use it as a route of treatment for dehydration, administering fluid and electrolytes. 

This is routinely the end of an ‘on-yard’ colic examination. If your horse needs to be admitted to a clinic, further examinations may take place. These include abdominal ultrasound, blood sampling and peritoneal fluid (the fluid lubricating the abdominal organs) sampling. These samples can be looked at with the naked eye or machine analysed to provide information about how the rest of the body is coping with the problem causing the colic signs. 

Ultimately, the vet will be able to make an accurate diagnosis and appreciate how sick the horse is. Appropriate treatment can be advised with the vet able to predict the horse is well enough to recover after treatment, or if (on some sad occasions) euthanasia needs to be considered. 

Approximately 90% of colic are diagnosed as medical. Of these, only a very small proportion will require more than one treatment. The sooner the horse arrives at a surgical facility, the better the prognosis. In all cases, this detailed examination will limit any period of discomfort and distress for both you and your horse. 

There are many different causes of skin disease in horses and ponies, with the most common being associated with parasites and insects. However, occasionally immune mediated skin conditions can occur spontaneously or as a reaction to a drug or stressful situation. Below is a picture of a horse presented to us for excess scabs which had originally started on the lower leg but had progressed rapidly and was now affecting the belly and flanks (see picture on the left).

Skin biopsies are required to diagnose immune mediated conditions and the process is well tolerated by horses. Local anaesthetic and a punch biopsy tool (like a small apple core) are used in several areas to obtain samples which are then sent to the lab. The lab can then determine based on the cells present which condition is causing the skins appearance. 

In this case pemphigus foliaceous was diagnosed. In this disease the body directs antibodies against the cells on the skin surface and in doing so causes blister and excessive crust formation. The mainstay of treatment for autoimmune conditions is immunosuppression using corticosteroids. Autoimmune conditions carry a good to guarded prognosis depending upon how well the immunosuppressive therapy works. However, we are pleased to report that in this case the corticosteroids have worked wonders. The pony is back in full work and as you can see the skin appears completely normal (like in the picture at the top). The pony will be closely monitored to detect any future recurrence. If you have any queries about your horse/ ponies’ skin then please call us to speak to one of our vets on 01772 861 300.

Summer time is hopefully a period that we are blessed with good weather and sunshine and while this is inevitably good for the soul, the sunshine and resulting UV, sadly can have negative implications for our equine patients namely in the form of sunburn and photosensitization. 

The first, simple sunburn, occurs when light- coloured skin, including flesh marks, becomes red and scaly following excessive exposure to UV light. Similar to humans, the severity of the damage depends on the strength of the radiation and the individual’s skin sensitivity. Light-coloured skin is predisposed due to a lack of melanin pigment which absorbs UV light and scatters the radiation. Hairless skin is also more severely affected. The most common affected area is arguably the muzzle.

Mild cases generally self-resolve provided further exposure to UV light is prevented and the skin is given a chance to heal. More severely affected patients require veterinary attention and topical medications are frequently indicated (usually steroid-based creams).

Prevention is based on avoiding exposure to intense sunlight by stabling at periods of intensity, use of water-repellent sunblock and if the muzzle is an ‘at risk’ area, use of a face shade mask (which includes a shade to cover the muzzle area).

Ragwort 

· Whilst intact, ragwort is generally quite unpalatable and horses don’t tend to eat it unless no alternate forage is available. Ragwort becomes much more palatable for horses when it is treated using a herbicide but hasn’t yet fully decomposed or when it is cut down and subsequently dries out. Therefore, one of the main sources of exposure to our horses is when it is inadvertently incorporated into hay or haylage. 

· The toxin in ragwort, pyrrolizidine alkaloid, is generally a cumulative toxin. While a toxic dose may be consumed on one occasion, it is much more common for a patient to consume the toxic dose over a longer period of time i.e. years. 

· The toxin causes irreparable damage to the patient’s liver which can lead to liver failure which is fatal. Clinical signs of liver failure are often only apparent when greater than 75% of a patient’s liver is affected. Clinical signs include depression/abnormal demeanor, reduced appetite, weight loss, jaundice, diarrhoea and photosensitisation to name but a few. 

· Diagnosis is based on the presence of compatible clinical signs, with/without a history of grazing ragwort-infested pasture, blood work and ideally, a liver biopsy. 

· Treatment is generally of a palliative nature.