Does your horse cough at the beginning of an exercise session? Do you often find accumulations of mucus outside your horse’s stable door? These subtle signs can indicate lung inflammation.

Formerly known as COPD or RAO, Equine Asthma is commonly seen in equine practice. For the purpose of simplicity, two forms are recognised- Summer asthma and the more traditional dust-induced form.

Both forms of the disease occur when a susceptible horse inhales either an allergen, to which they are allergic, or dust into their airway. This results in the airway spasming and the production of increased amounts of both inflammatory cells and mucus within the airway.

Affected horses present with clinical signs of varying degrees of severity. Some horses present with the subtle signs mentioned above or with a history of poor performance, whereas others present in respiratory distress and struggling to breathe.

On examination affected horses will generally have an increased breathing rate and effort combined with nostril flare. Mucoid nasal discharge may also be present. More severely affected horses may cough, have abdominal effort to their breathing and may have a ‘heave-line.’ A horse’s history combined with clinical examination findings will point towards a diagnosis of asthma but for definitive confirmation, airway endoscopy, to visualise the airway and grade airway mucus combined with laboratory analysis of respiratory tract samples is required. This will also rule in/out secondary bacterial infection.

Treatment of asthma should be based on environmental modifications plus drug therapy on an as needed basis. Horses affected by dust-induced asthma should be turned out in so far as possible. The stable environment should be closely examined. Ideally, the stable will have an inlet and outlet for airflow. Forage should not be stored adjacent to the stable to minimise the dust to which the patient is exposed. Horses should be groomed outside of the stable and fresh bedding laid when your horse is not in the stable environment. If your horse’s stable is unsuitable, try find an alternate stable on your yard that has better airflow. If feeding hay or ‘dry’ haylage, steaming is optimal to reduce dust particles but if not available, soaking should be considered. Managing Summer asthma is more challenging, but the measures outlined above should be followed to ensure stable ‘air hygiene’ is a good as possible.

Drug therapy, when needed, is based on relieving airway spasm (bronchodilators) and reducing airway inflammation and mucus production (steroids and mucolytics). Drug therapy can be provided by the oral or inhalatory routes. Oral medication includes bronchodilators, steroids and mucolytics (which serve to break-up airway mucus). From an inhalatory medication perspective, three options are available- the Equihaler, MDIs and nebulisation. The Equihaler is a licensed, steroid based product which utilises a fine mist to deliver steroid directly to the lungs. The product is very safe as the steroid acts at the lung surface only. We have had some great success using this product in cases of severe asthma and in those that did not respond to other forms of medication. MDIs, human asthma inhalers administered via a baby asthma face mask, have been utilised in equine practice for many years. These are probably most useful in relatively mild cases. Drug delivery via a nebuliser is the third inhalatory option but arguably used less frequently these days.

If you have any questions regarding asthma or think your horse may be affected, please do not hesitate to contact the team for guidance.

Our standing MRI scanner can be used to assess injuries from the hoof, up to and including the hock and carpus (knee). The scanner is specifically designed to image the lower limb in the standing horse, as this is the most common site of lameness.  It has revolutionized our understanding of the structures of the hoof, and we can now differentiate between the multiple conditions that were encompassed as ‘navicular syndrome’.

Previously, a horse with forelimb lameness that was localized to the foot, was diagnosed with ‘navicular syndrome’.  However, a lot of the time, the severity of the lameness did not fit with the mild observations noted on radiographs (X-rays). We now know, through the use of MRI, that there are many other anatomical structures that could be injured and causing the lameness. With forelimb lameness being a common problem in horses, this diagnostic imaging tool means we can target rehabilitation, farriery, and treatment more specifically.

Injuries identifiable on MRI would include deep digital flexor tendon lesions within the hoof. Without the use of MRI this condition would have been misdiagnosed, leading to inaccurate management and unsoundness. MRI can also assess ligaments within the hoof capsule, such as the collateral ligaments of the coffin joint, which are often painful when horses are lunged in a circle. This amazing imaging modality also shows us the degree of inflammation within synovial structures such as the coffin joint and navicular bursa of the foot which cannot be visualized in any other way. Not only does MRI allow us to diagnose more accurately, but it allows us to monitor the progression of conditions and carefully assess the horse’s response to treatments.

X-ray imaging is used to assess bone pathology as an initial tool. However, it can take up to 2 weeks following injury before the bone pathology is noticeable on radiographs, and sometimes it is not visualized at all.  MRI is the only imaging modality that can assess inflammation within bones such as bone bruising or cysts. These can cause severe lameness and require long periods of rest but would not be diagnosed without the use of MRI.

As equine vets we are eternally grateful for these advancements in technology which have enabled us to achieve an accurate diagnosis much faster than ever before, and as we know, a faster diagnosis leads to more precise treatment and management protocols to get your horse feeling in tip-top shape again.

What is kissing spines and why has it suddenly become more common?

Kissing spines or more correctly termed ‘impinging dorsal spinous processes’ (IDSPs) is where there is over-crowding of the summits of the 18 spines that the horse has, usually in the saddle region of the spine. This leads to bone friction and pain which spreads along the muscles either side of the spine. In our years of experience of dealing with this disorder, by far the most common clinical signs are (in order):

1. Bucking
2. Being ‘Cold-backed’ on mounting
3. Hunching or arching of the spine
4. Sudden shooting/scurrying under saddle particularly on mounting
5. Bolting

Yes, some young (and old!) horses will buck when they are excited, these horses usually have their ears pricked and they are ready to go!! Horses who buck due to pain will have their ears pinned back and they are not ready to go, they just want to get rid of the pain (unfortunately that’s usually the rider on board!).

The problem we have in diagnosing this condition is that many horses will have kissing spines on X-rays of their spine, in fact up to 86% of thoroughbred horses will have x-rays consistent with IDSPs! That does not mean that they are all painful! To determine whether or not the x-ray findings are causing discomfort relies on 3 methods of diagnosis (in order of our preference!):

1. Medication of the spine with steroids (potent anti-inflammatory drugs) which lasts several weeks in this region in severe cases, so you can tell if your horse feels better over this prolonged period of time.
2. Infiltration of the spine with local anaesthetic and seeing if the clinical signs resolve when the horse is re-evaluated ridden.
3. A ‘bute’ trial, whereby we administer systemic anti-inflammatory drugs to see if the clinical signs improve.

Only then can we be sure if the X-ray findings are consistent with pain in the horse. So your horse is diagnosed with kissing spines, what can we do? Is it hopeless? NO, in fact, this condition can be treated fairly successfully in most cases either with conservative management and altered training techniques, including physiotherapy or with different surgical methods. If your horse is suffering with kissing spines, we are equipped to help you every step of the way with your journey back into the saddle.

And in answer to the original question, IDSPs is NOT more common than it was years ago…….we just have X-ray machines that are capable of seeing the spine now. We are also more aware than ever that our horses are generally not a naughty bunch, and are often just asking for our help because something hurts!

I have a 25-year-old gelding who struggles to eat hay in the winter, what can I do?

It is very important that our older horses and ponies have regular dental examinations, usually every 6 months. Older horses teeth can change very quickly and this can result in difficulty eating. Occasionally horses have loose teeth which can be removed and the horse then manages to eat hay again, however, many older horses have gaps between their teeth which need regular management by your vet/dentist. Additionally, dietary alterations can help for example maximising turnout where possible or feeding hay replacers instead of long hay.

My dentist has noticed that my horse has a lot of tooth decay, what can I do to help?

Some horses are more prone to tooth decay than others but it is certainly a condition we want to manage to prevent problems further down the line. One thing that can help reduce the decay is feeding less sugar. This includes apples and any treats that contain molasses or large amounts of sugar additives. If you are looking for a treat alternative, fibre cubes work very well! You can also help your horses decay but rinsing out their mouth of any sugary feed every day. Using a dental syringe works well but if you don’t have one of these, a hosepipe will do the job!

I have recently bought an 8-year-old horse and he has wolf teeth, what should I do?

Wolf teeth are very common, especially in geldings and rarely cause a problem! As long as the wolf teeth are in the correct location and are erupted from the gum they shouldn’t cause trouble. If your horse begins to show resentment to the bit it would be worth arranging an examination with us and we can discuss treatment options.

What are stem cells?

Stem cells are an undifferentiated cell of a multicellular organism which are capable of giving rise to indefinitely more cells of the same type. They are used in musculoskeletal injuries of the horse to improve the quality of repair tissue in injured tissue.

Types of stem cells

Traditionally we obtained cells via a large bore needle placed into the sternum of the horse and extracted bone marrow. Stem cells from the bone marrow were cultured in a laboratory over 30 days and were re-implanted into the injured region of the horse. These cells then differentiated into the environment they were placed in, for example tendon tissue in the case of a tendon injury.

Now, we have the option of commercially available stem cells, thereby avoiding having to harvest the cells from the horse, we can simply buy them in small vials…..amazing!!! There are two types available, one derived from donor horse’s blood, which is treated to make the cells transform into a cartilage type of cell, this is useful in cases of osteoarthritis, whereby the cartilage layer of the joint is damaged.

The other type is humanely and ethically harvested from umbilical cord blood, which is wonderful as these cells can transform into any cell type! They can be implanted into joints, tendons and ligaments and will transform according to the environment in which they are implanted which is particularly helpful!

The clinical use of stem cells

Stem cell treatment is not a magical cure for these musculoskeletal injuries, but they do improve the quality of healing and prevent the likelihood of reinjury most importantly. We used the cartilage cells in a lovely horse called Rosie a while back who had a severe cartilage injury in her fetlock joint diagnosed on MRI and she is now back as a sound ridden horse! We have also recently implanted the umbilical cord type cell into a soft tissue injury of an event horse, who is still undergoing intensive rehabilitation, we will keep you posted!

Many of you may have noticed the characteristic helicopter seeds present on sycamore trees as of late so we thought it would be a good idea to remind you about sycamore poisoning. But what exactly do we mean by the term sycamore poisoning? Keep reading to find out more!

Sycamore poisoning, also known as atypical myopathy, is a devastating, highly fatal muscle disorder that occurs following the ingestion of hypoglycin A toxin. The toxin is found in a number of plant species, the most common in the UK being the leaves, seeds and seedlings of sycamore trees hence the term sycamore poisoning.

There is sadly a 75% fatality rate with most non-survivors succumbing within 72 hours of the development of clinical signs.

Cause

The disease occurs following the ingestion of sycamore seeds or leaves in Autumn or seedlings in Spring that contain the hypoglycin A toxin. It should be noted that the toxin is not present in all sycamores. There is also speculation that toxin levels may differ at different times of year and under different climatic conditions. Cases often follow an adverse change in weather conditions such as frost or rain.

Clinical Signs

Affected horses show clinical signs of weakness, stiffness, muscle tremors, a fast (sometimes irregular) heartbeat, difficulties in breathing and dark red/brown coloured urine. Other clinical signs include depression and signs of colic. Severely affected horses become recumbent and others may be found already deceased.

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Diagnosis

Diagnosis of atypical myopathy is based on the presence of compatible clinical signs, a history of grazing pasture containing sycamore trees and physical examination and blood work findings.

Supportive blood work includes evidence of dehydration and an exponential increase in muscle enzyme values with or without increased kidney enzyme values. We are capable of running this blood work  in-house with a rapid turn-around time on results.

For the definitive diagnosis, blood, with or without a urine sample, are submitted to the Royal Veterinary College for analysis. Results take a number of days to return and therefore, if a diagnosis of atypical myopathy is suspected, then the affected patient should be treated as such. Time is of the essence and rapid initiation of treatment is essential to improve prognosis.

Treatment

Suspected cases are generally hospitalised to facilitate intensive medical management. Treatment is predominantly based on supportive care including administration of large volumes of intravenous fluid therapy. As affected patients are generally quite painful, the provision of adequate pain relief is vitally important. One study has also shown the administration of vitamins to be advantageous.

Prevention

Prevention is based on preventing exposure to sycamore seedlings in Spring and seeds and leaves in Autumn. The area surrounding sycamore trees should be fenced off and the seeds and leaves collected. It is important to remember that the helicopter seeds may travel up to 200 yards. Therefore, pasture beyond the sycamore tree should be searched for seeds.

Remember not all sycamores contain the hypoglycin A toxin but prevention is better than cure.

The Royal Veterinary College (RVC) offer testing to identify plants containing the toxin. You may submit seeds, leaves and seedling directly to the RVC Comparative Neuromuscular Laboratory to determine if plants on your property contain the toxin. Test results are generally available within 2-3 weeks but can be available within 72 hours for an additional fee. If interested, please consult your veterinary surgeon for further information.

Some may ask if their horse has grazed for many years on pasture containing sycamore trees without any issues, if their horse is at risk? The answer is yes. Risk is reduced by following the steps outlined above in addition to considering laboratory analysis of the sycamores for the presence of the hypoglycin A toxin.

At birth, foals are immuno-naive meaning that they are born without any protective antibodies (immunoglobulins/IgG) against common ‘bugs’ in their environment.

In order to gain protection, foals need to ingest a sufficient quantity of good quality colostrum (first milk containing high levels of antibodies) within the first 12 hours of life.

It is during this time that foals have maximal absorption of ingested IgG. After this time, absorption rapidly decreases.

Adequate IgG levels are crucial to protect foals from developing infections (namely sepsis). Inadequate levels result from failure to ingest sufficient quantities of colostrum or poor quality colostrum (e.g. when the mare runs milk before birth and loses IgG).

To determine that foals have adequate IgG levels, we recommend measuring IgG using a simple blood test, generally 18-24 hours following birth.

If levels are inadequate then a hyperimmune plasma transfusion is recommended to provide the foal with IgG and in turn protect the foal from developing life threatening infections.

 

Image source: foalpatrol.com

 

Pre-Breeding Testing

Taking your mare to stud? Depending on which stud you are going to, you may be asked to test for a variety of diseases.

The most common disease is contagious equine metritis (CEM). This is a bacterial uterine infection caused by T. equigenitalis, K. pneumoniae or P. aeruginosa. Testing involves takes a swab – either clitoral or endometrial (if the mare is in season) – which is then cultured (grown) for at least 7 days, or tested by PCR which gives a result in 1-2 days. The PCR option is slightly more expensive.  

Next is EVA or Equine Viral Arteritis. This disease can cause a variety of signs including fever, lethargy, and swelling of eyes, limbs, scrotum and mammary glands. In rare cases it can be fatal. It is spread by both the respiratory (droplets in the air) and venereal (mating) routes. If stallions are infected, they can become chronically infected for years, spreading it to many mares via infected semen. Testing is performed by blood sampling.

Then, there is also Equine Infectious Anaemia (EIA). Horses with EIA are often extremely sick, as the disease damages their red blood cells causing an anaemia. It is spread by the transfer of infected blood, colostrum and semen. Again, this is checked for via a blood sample.

CEM, EVA and EIA are all notifiable disease. The last reported case of CEM in the UK was in February 2022, while the last reported EVA was 2019 and EIA was 2012.

Finally, it is worth mentioning strangles. Whilst this isn’t necessarily related to breeding outbreaks can occur when horses from different sources meet at stud farms. Therefore, some studs require testing, in the form of a blood test, prior to arrival at stud.

As different studs have different test requirements, we recommend that you check your stud’s requirements prior to your veterinary appointment for testing.

Twins

Twins are a problem in horses. This is because only in exceptional cases can a mare give birth to two healthy foals. Should a twin pregnancy continue, sadly most mares will lose both pregnancies mid-late gestation due to lack of space and nutrition for both foetuses.

We can minimise the risk of this by ultrasound scanning mares after covering/insemination. We would usually scan mares between 14-20 days to look for twins. At this stage it is easier to identify them and manage them. If detected, we will try to abort one of the embryos then recheck a week later to see if the remaining embryo is still healthy.

Artificial Insemination Options

Fresh semen – This is used within 3 hours of being collected. It is the most successful option, as the semen will live for up to 3 days in the mare, meaning the timing of insemination is less critical. However, it is limited to local stallions reducing the options available.

Chilled semen – This needs to be inseminated within 48hrs. It is usually collected and then posted overnight to the mare in a special container. This limits it to stallions within the UK and Europe.

Frozen Semen – After collection, the semen is frozen in liquid nitrogen at -196°C. It can be stored for years after collection, and hence can be shipped around the world. It also means the stallion does not need to be at stud when you’re breeding. However, fertility rates are lower, and the semen only survives in the mare for 6hrs so the timing of insemination with ovulation is crucial.

Along with different semen options, there are some considerations as to its place of origin.

UK semen – With UK semen, there tends to be less postage delays and no issues with regards to customs. If semen is required urgently, then it can be collected in person.

Foreign semen – With semen originating abroad, there is a higher risk of delivery delays meaning missed cycles. Since Brexit there has been an increase in problems with health paperwork and customs delays. However, semen from a much larger range of stallions is available giving you more choice regarding how to produce your perfect foal!