Fight the Fat

Obesity can sometimes be a difficult area to discuss. No one likes to hear that the animal they care for is overweight or obese, and as I used to own a 43kg labrador I know how easy it is to not see! Part of the problem is that an overweight animal is not always easy to identify, horses and ponies especially are very good at storing their fat subtly, spreading it out across their ribs, crest, rump and shoulder. They don’t just end up with a ‘bread basket’.
A growing population?

So is the current situation something to be concerned about? Surely there can’t be that many horses falling into this category? Well recent studies have shown that almost half of all equines in the UK are overweight and around 33% are obese. These figures have been rising for some time and indeed correlate with the trend in human waistlines too! The groups most at risk come as little surprise; native breeds, cobs and ponies are overrepresented in these populations compared with breeds such as thoroughbreds. These ‘good doers’ generally need less energy dense feed, and any excess consumed will be deposited as fat stores.


But is it a problem if my pony is overweight?

In a word, yes. Obesity is a risk factor for a number of conditions and all of them can be very serious, compromising an animal’s well being and in some cases even resulting in euthanasia on welfare grounds.

The most widespread complication of being overweight is the development is insulin resistance. Insulin is a hormone released by the pancreas to stop glucose levels in the blood from rising too high, as this can have negative consequences. Horses with access to more simple sugars and starches in their diet need to produce more insulin as a response to this. High insulin levels are associated with laminitis, and in fact approximately 90% of cases of laminitis are due to endocrine diseases.Obesity also predisposes to developing hyperlipaema. This condition occurs when overweight animals go through a period of ‘negative energy balance’ i.e. they’re using more energy than they are consuming so must break down fat to meet the deficit. Examples of this are late pregnancy and anorexia due to unwellness. Increased body condition is associated with reduced fertility in mares and with dystocia at parturition which can have dire consequences for mare and foal. Also carrying all that excess weight puts greater forces through the joints and so contributes to the development of osteoarthritis (OA) and may exacerbate any existing OA.


So what can I do at home?

The best way to first identify whether your animal is overweight is to body condition score them. There are many different scales/methods for doing this, one of them is the Heneke scoring system. This method works for horses of any breed, sex or body type. It is based on a visual and hands-on assessment of various parts of your horse’s body. The table below contains detailed guidelines on how to interpret the findings:

Another less specific and more crude way of monitoring your horse’s weight is to use a weigh tape, or girth measurement. This is useful for monitoring any change in condition but it must be pointed out that here there is no distinction between fat and muscle.

thin but fat

Remember that it can be difficult to interpret the findings of a condition score and it is easy to be misled. The above horse has visible ribs so you may think it likely to have low body condition score. In fact it is clinically obese due to the fat pads above its tail head and shoulder and also its cresty neck. Horses with localised fat deposition such as this are likely to have an underlying endocrine issue.

In our next blog in this series we will post some videos on what to look out for when condition scoring your horse. If you feel your horse is either overweight or underweight, or would like any advice on their condition or nutrition then simply phone the practice on 01913859696.

Equine Arthritis

Arthritis in the horse can take on many names and forms. It is most often referred to as Osteoarthritis (OA) or Degenerative Joint Disease (DJD). It is often a chronic disease, with has been present for substantial period of time, and often gets worse as time goes along.

Arthritis is not only painful for the horse, but it also affects the way the horse moves.

OA and DJD can affect the joint itself, or the surroundings of the joint. There is cartilage within joints that provides cushioning support and a smooth surface allowing the joint to move in a fluid motion. DJD and such conditions wear away this cartilage, making the movement of the joint less fluid and more painful for the horse. There are also situations where the bone on either side of the joint develops “spurs” or “sharp edges” – these can pinch on the joint space or even rub on soft tissue structures (such as tendons) causing a lot of pain to the horse.

Commonly, OA or DJD are seen by owners in variable ways. It may be that your horse is less reluctant to go forward, or downhill. Maybe his gait has changed and he can no longer canter smoothly on one leg, or bring his hind legs up under him. You may even notice swelling on certain joints, or pain when you pick up his feet. Horses show pain and discomfort in many ways, and often changes to their behaviour or gait are best discussed with your veterinarian.

…..“Fez seems a bit stiff all over – it’s really noticeable when I ride her. It’s like she can’t move her legs properly, and seems really reluctant to move. I know she’s an older lady, but she is in good health and I want to keep her going. She used to love going for rides so much!”….

Often, if OA/DJD are suspected your veterinarian will recommend x-rays of one or more joints. This helps us develop a plan of the best way to treat the individual horse.
Each horse develops OA/DJD in slightly different ways, and we as veterinarians like to tailor a treatment plan specific for your horse. X-rays allow us to know how each joint is affected, and how badly, so we can tell you all your options and discuss your horses’ prognosis.

….”We have done Fez’s x-rays and found she has some significant arthritis in one of her hock joints, however there are minor changes through a lot of her other joints as well”….

Once OA/DJD has been diagnosed, the next step is management.
There is no cure for these conditions – the best chance for your horse is successful management.
The management of your horses arthritis depends on several factors;

– the extent of the disease – “which joints, how many joints, how badly…”

– the workload of the horse – “hacking, eventing or paddock companion…”

– any other compounding problems – “conformation, hooves, injuries in other areas…”

– the financial budget of the client

Once we know all these factors we can tailor a plan to suit your horse.

What are my options?

Joint Injections

If only one joint is affected, often times your veterinarian will recommend an injection into the joint.
This injection is often a steroid or steroid-combination. A steroid is a very potent anti-inflammatory drug, which helps to alleviate the pain associated with the arthritis in the effected joint.

By alleviating the pain, you aim to get the horse to use the joint as per normal.

….”We recommend doing a steroid injection into the hock joint that is worse affected on Fez”….

A joint injection is known as an aspectic procedure – that is that your veterinarian will aim to be as sterile as possible when performing the injection. This means your horses joint will be clipped, scrubbed and prepared much like a surgical site. Your veterinarian will be wearing gloves and be as clean as possible when injecting into the required joints.
Joint injections are not without risk, but your veterinarian will discuss the procedure with you in more detail at the time.

Some horses only require a one-off joint injection, some require it to be repeated down the track. This is very horse dependent, but often times owners see great improvement with joint injections.

Disease Modifying Osteoarthritis Drugs (DMOADs)

An example of this type of medication is Cartrophen.

These medications target the disease of OA/DJD on several different levels, aiming to alleviate the pain from the disease and minimise its progression. These medications aim to rebuild the cartilage within the affected joints and increase the amount of joint fluid, trying to recreate the fluid, pain-free motion of the joint.

The advantage to these types of medications is that it treats all the joints with one injection. The injections are administered into the muscle of the horse, and the drug localises in all the affected joints.

…”…as Fez seems a little stiff all over we suspect she will have arthritic changes in a few other joints. The best way to target these following her joint injection would be with a Cartrophen course. That way, we can treat multiple joints, get her out of pain, and hope to get her loving her rides again…”

The medication itself is a very effective anti-inflammatory, so it provides pain relief as well as improving the health of the joint. This means we hope to have your pain free and continuing with work, without other medications.

These injections are given as short courses (4 weeks) and repeated based on your horses condition.

Non-Steroidal Anti-inflammatories (NSAIDs)

The most common of this type of medication is Phenylbutazone (Bute).

These are anti-inflammatory medications, often given in the form of a powder.
They act by trying to relieve the pain and swelling caused by OA/DJD. They are much like a human taking Ibuprofen and such medication.

….”For the time being we can give her a course of Danilon and see how her lameness and stiffness improves. If she improves a lot, as we suspect she will, then we can move onto better long term management of her through joint injections and cartrophen”…

These types of medication often work very well to keep your horse comfortable and as mobile as possible. Although they are known to affect some organs of yours horses body, such as stomach, kidneys and liver with long-term use. It is also a controlled medication, meaning your veterinarian needs to be aware of the usage. This is the reason why your veterinarian will be required to do regular check-ups to ensure your horse or pony is managing well on these medications, especially if they intend to be on it for months or years.

Oral Joint Supplements

There are many joint supplements on the market targeted to help with arthritis.

Unfortunately, it can all be a bit “hit and miss” with effectiveness and you can often spend lots of money on these products, and get substandard results. This is often due to the products bio-availability. This refers to the “amount” of usable product the horses body can actually absorb. What this means is, just because your horse is eating it, doesn’t mean his body can use it. So worst case scenario he is just pooing or peeing out the supplement.

For example – some studies have shown that a horse is only able to absorb around 6% of the glucosamine that an oral joint supplement can provide.
There are many clinical studies being done on the effectiveness of joint supplements, so the news is ever changing!

There are joint supplements that have been manufactured in a way to ensure their product is effective and available to the horse. Unfortunately, there are so many products available on the shelf these days that the topic can be a bit of a mine field. Our best suggestion is to make sure you do your homework on a product, and consider bioavailabilty and the production of the product to ensure you are not wasting your precious dollars.

The vets here at Simply Horses

Of course there are certainly other options and areas to consider when it comes to owning a horse with arthritis. We have only touched on a few of the biggest options available to you as a horse owner.

Any of our veterinarians would be happy to discuss your horses case, and discuss in further detail which options would be best for you and your equine.

Vet view: spotlight on sarcoids

Sarcoids are like snowflakes, each one is different. So treatment is very varied too, as is the end result. Here, our vet Clara Sechi shares her experience of sarcoids.

“My horse, Lux, had four sarcoids. Three on his head and one on his left hind leg. The one on his leg was larger, but I was more concerned about the ones on his head, as they were growing quickly. I was studying to become a vet while this was going on, and so my Professor, E Sanna Passino, agreed to oversee Lux’s treatment.

We opted for a form of chemotherapy, since sarcoids are tumours. Medication was injected into the sarcoids on his face and leg over a period of five months, before we removed them by operation. The sarcoid that was very close to his eye was not injected, due to the risk, but was removed by surgery.

The results were excellent and we were very pleased with the outcome, with no regrowth over the next two years. Sadly, I lost Lux to a severe disease that was unrelated to his sarcoids and their treatment, but the experience gave me a valuable insight into dealing with sarcoids.”

Sarcoids are common, and used to be called warts, whereas they are actually a type of skin tumour. They are not usually painful, but they are problematic, as they can grow quickly and interfere with the eyes and joints of a horse; as well as areas where tack should fit.

There is very strong evidence that sarcoids are caused by a virus closely related or identical to the BPV (Bovine Papilloma Virus), found in cattle.

Some sarcoids regress of their own accord, and some reoccur. It is important for your vet to have a look, as what you think is a sarcoid may be something else entirely, and need a different approach.

There are multiple treatments available, from topical creams to lazer therapy.

To discuss options for your horse, call Simply Horses on 0191 385 9696

Vet view: considering insurance

By Clara Sechi DVM MRCVS

For many of us equestrians, our horse is one of our most valuable treasures. Firstly in initial cost, then in ongoing expense and last but certainly not least, in emotional terms.

Which is why we vets often find treating an insured horse is a much-less fraught experience for everyone involved. When a horse is covered by a good policy, we can get down to treatment and recovery. But when there is no insurance as back-up, and an owner has no savings, it is so difficult.

There are many insurance policies available and it is worthwhile taking time to find out what is on offer. Buying the cheapest does not always mean you have got the best value, or the right insurance for your needs.

Illness, injury, theft or an accident can happen at any time and may result in unexpected bills.

It is always a good idea to get a horse vetted so that you are aware of its condition – warts and all!

The horse may be lame, have an eye or heart condition, or a sarcoid. The vet can then advise on the implications of the conditions found and the suitability of the horse for you.

For example, a small sarcoid may seem like a trivial reason to turn down the perfect horse, but sarcoids can be very tricky and are extremely unpredictable in how they will develop or plateau, so a conversation with your vet could save heartache and expense down the line.

Even if you did decide to buy a horse with one or two issues, a vetting can at least prepare you for what might happen.

Remember though, insurance is for unexpected problems, so if your horse already has pre-existing conditions, the insurance company may reject claims relating to this, or build an exclusion into your policy.

Cover will vary, so shop around and ask questions. When you decide who you want to insure with, generally immediate cover will be available for accidental injuries, with illness cover being provided after a short time (often 14 days), which may also be dependent on you providing any necessary veterinary reports or other information, for example the passport or evidence of value.

Read the small print. If you do decide to insure – know exactly what you are getting for your money. A surprising number of people are unaware of what their horse is actually covered for, and may be in for a nasty surprise when they find out. Equally, you can’t claim for something you don’t know you’re entitled to – so it works both ways. Some, though not all, insurance companies will pay for alternative therapy or supplements.

One more thing to consider. If you do decide that insurance is not for you, it is well worth putting a monthly amount to one side in case of emergency. A nest egg can truly save the day when it comes to your treasured horse.

Be wise, and don’t think accidents and injury won’t happen to you – few of us are that lucky and we all know that things rarely go to plan with horses!

Simply Horses New Vets and Pony Games. Exciting times

Hello. We would all like to introduce our new vet Sabine and her partner Paul together with their hobby Mounted Games. Fast and Furious may be the buzzword and even more impressive, Paul was representing Australia!

“Hi, my name is Paul and I am Sabine’s partner. I’m from Australia and I have just recently arrived in the UK as Sabine is an equine vet now working at Simply Horses Vet Clinic, in Fencehouses.

On my way here I stayed in America for six weeks in preparation for the International Mounted Games World Team Championship. I competed on the Australian team with four other Auzzies (as the Americans would say). For those that don’t know what mounted games is, Google it. I would try to explain it but I wouldn’t be able to give it the justice it deserves. What you do need to know and what I can explain is that it’s the best kind of equine sport out there for competitive, adrenaline seeking riders. It requires hand-to-eye and horsemanship skills, a good attitude and an amazing pony. Well that’s to play at a international level.

So you need a good pony.

Competing at pony games games2 games1
All but the American and Canadian Teams had their own ponies, the rest of the 13 teams had to source or get their ponies from the pool of ponies, it is a long way to take a pony after all. Us, Aussies, and the Northern Irish were the only ones to source our ponies for the competition while the rest relied on the pool. We met our ponies a couple of days before the competition.  I travelled with mine from Pennsylvania down to Virginia for some training with the team, then we made our way to Kentucky. Everyone else, excluding the Americans, Canadians, us and half the Northern Irish, had 3 days to get to know their ponies. Some changed ponies through the competition. So this kind of competition require a very confident and skilled rider.

The competition had four sets of ten races, with each race contributing to a total score. Then the top 8 scoring countries when into a two part final of 24 races, the next 6 had final to. We had a good set of ponies, though they were not as fast as some of the others in the pool. We made our way through the sets with 2 set seconds and a win. Our last set wasn’t so great, but we were saving the ponies for the finals. We started off the final with a few crackers and held the lead early. However we lost momentum in the middle and tried to keep our heads and finish as well as possible for part A. The Irish had a formidable lead on the rest for part B of the final and we didn’t have the speed to win so we were going for accuracy. The states had a smashing set, putting to sleep any doubts. The Irish lost their nerves and the States caught them making every race count till the last. The Canadians played well throughout, leaving them in front of us in the end. The Kiwis once again beat us, the development and competitiveness of the grass roots shining through on a world stage.

We had a rough trot in the final I think. We were down a rider due to injury, leaving me with two challenging but great horse as options for each race. For me it’s a case as always of could of, would of, should of. One of our ponies also lost all his speed and was a challenge on the way home in the final. The odds stacked against us, and we lost the moment and rhythm we had in the heats. It was a tough final and we did well to finish in the top five. The four other members of our team rode fantastic over the week riding with serious precision and team work, injury and all. 5th in the world is more than I ever expected. The Americans had a well deserved win, the Irish losing their lead in the second part of the final.

The final scores for the A final:

144 USA

141 Ireland

124 Canada

113 New Zealand

102 Australia

90 Wales

83 Northern Ireland

66 Switzerland
I have moved over to the UK for a while now to get more exposure to the sport, as it’s so big and competitive here compared to back home. World individuals is starting on the 28th of July and I’ll be there having a go.

Test That Crest

Until October of this year Boehringer in conjunction with Liphook are offering free blood tests for equine Cushing’s desease. Because of this we thought it would be a good idea to provide some information on this condition!

Equine Cushing’s typically affects older horses and ponies, usually over the age of 15 or so but there are examples of individuals as young as 8 suffering from the disease. Animals present with a curly, shaggy coat and commonly have excessive fat pads on their rumps, crests and above their eyes.

Overweight and Cresty neck

Overweight and Cresty neck

Despite these, animals can look thin as they also lose muscle and so may have a poor topline or poor muscle mass in general. Other signs include increased thirst and urination, having poor wound healing and suffering from recurrent foot abscesses.

Slow shedding coat and quite thin

Slow shedding coat and quite thin

One of the most concerning things about Equine Cushing’s (and other endocrine diseases such as EMS) is that it predisposes horses and ponies to developing laminitis, which can have devastating consequences if not treated promptly.

The blood test looks for a hormone called ACTH, which is usually elevated in cases of Cushing’s. This hormone encourages the production of steroids within the body, which account for the clinical signs seen. The treatment of Cushing’s aims to decrease the production of ACTH.

If your horse or pony shows any of the signs above then we recommend they have a health check and blood sample to determine the underlying cause.

Please note that charges for taking of the blood sample, postage and any necessary health checks and visit fees will still apply. please ring the Simply Horses Vet Clinic to make an appointment or with any queries

Why we all need to vaccinate

This article from Horse and Hound highlights all too clearly why vaccinations need to be a priority for horse owners.

Key points:

  • Less than half the equine population is currently vaccinated against flu
  • An outbreak brought Australia to a standstill in 2007
  • Flu doesn’t kill many horses, but it does kill events – putting venues and associated businesses in a perilous financial position.

Click here to read more.

Laminitis – Prevention Is Better than cure!

The Laminitis cases are coming in now thick and fast, here at Simply Horses here are a few tips from the Laminitis Trust to try and avoid this painful condition

You can prevent laminitis by avoiding high risk situations. The following is a list of “causes” or circumstances  which we know commonly precede the onset of laminitis.

Overeating on foods rich in carbohydrate or rapidly fermentable fibre i.e. cereals, coarse mixes, rapidly growing or fertilised grass
Any illness which involves a toxaemia. This may be a bacterial infection or following the ingestion of plant or chemical toxins.
Cushing’s Disease. This is a condition which follows an abnormality affecting the pituitary gland in the horse’s head. It results in the horse failing to shed its winter coat. The coat becomes long and matted and eventually curly. The horse drinks and eats increased amounts of food while sweating excessively and losing weight. All Cushing’s cases suffer laminitis.
Weight-bearing laminitis. When the horse is severely lame on one leg and has to put all his weight on the contra-lateral limb they often suffer from founder in the weightbearing limb. This is particularly common in hind feet.
Concussive laminitis (road founder). When horses are subjected to fast or prolonged work on hard surfaces they may develop laminitis as a result of trauma to the laminae, particularly if their horn quality is poor.
Hormonal problems. Animals which are “good doers” may be hypothyroid or have an abnormal peripheral cortisol enzyme system. The latter condition, recently described has been called obesity related laminitis or peripheral Cushing’s disease. Others develop laminitis when they are in season.
Cold weather. A few horses show laminitis during cold weather, fitting warm leg wraps during cold snaps prevents the problem in most cases.
Stress. Worming, vaccination, traveling or separation from a “friend” can trigger an attack of laminitis.
Drug induced laminitis. Although some wormers can precipitate laminitis, the most common group of drugs which cause laminitis are the corticosteroids. Even injecting short acting corticosteroids into joints can cause severe laminitis.
Overeating / Obesity are the most common high risk situations which lead to laminitis. The secret to avoiding laminitis in this situation is not to turn the horse out whilst he is fatter than condition score 3. This means he should not have a fat depot along his crest or at the tail head, around the sheath or udder or over the loins. You should be able to feel his ribs easily by running your hand along his side yet you should not be able to see his ribs.

Limiting the grass intake can be accomplished by using a grazing mask or muzzle or by restricting the area available for grazing.

Podgy horses grazing lush grass -bad combination

Podgy horses grazing lush grass -bad combination

A Foal is a fragile thing

Although the weather feels like it is still winter, we are actually in the middle of the foaling season! The past couple of weeks we have seen many happy, healthy foals for mare and foal checks, the best part of this job! However, we have also seen some foals with health problems, some very serious. It’s important to remember a foal is programmed not to show any signs of illness or weakness, so it doesn’t attract the attention of predators.
This makes it difficult to spot signs that your foal is ill. Important signs to look out for are;

1) Changes in behavior of the foal

2) Not getting up when stimulated

3) Not drinking regularly

4) Showing signs of colic

5) Not following the mare around

you can look at the mare’s udder to see if the foal has been drinking recently. In the very early stages of a foals life it is vital to recognize that the foal is ill as soon as possible, as they are born without any energy reserves and will deteriorate very very quickly if they stop drinking from the mare.

mare and foal

Not a happy foal

I was called out by a concerned recently, the foal had been suckling and her behavior had been normal at first, but a couple of hours after the birth the foal started to lose interest in the mare and was very lethargic. This alert owner had spotted the difference in the foals behavior and called us out for an examination. After my clinical
exam I decided the foal was suffering from perinatal asphyxia syndrome, meaning it had been deprived of oxygen during the birth. It is typical for these foals that they look fine initially, but then slowly deteriorate to the point where they are not suckling anymore and
become very ill. This specific foal was very precious to the owner, so we decided to refer it to a large hospital so it could be monitored 24/7 and they could give it a permanent feeding tube, as the foal had stopped drinking. Thanks to the quick response of the owner
and the intensive therapy it received the foal is now back home and doing really well. We all love a happy ending!

This case also illustrates the importance of having the vet out after the foal is born for a mare and foal check, as subtle signs of illness will be picked up during the clinical exam of the foal. A lot of conditions in foals can be treated on the yard with good result, but the sooner treatment can be started the better!

PS if your mare is expecting a foal and you want some help and advice about the birth, here at Simply Horses we have a very useful foal package, consisting of detailed information about the birth process,
tips on what to do and what not to do, a discount voucher for a mare and foal check by one of our vets and lots of other goodies!

Well adjusted healthy foal

Well adjusted healthy foal

Advances in preventing Strangles

Great article written by Stacey Oke DVM MSc, first published here

If you live in an area where equine strangles runs rampant, then you’re probably aware that vaccines against this infectious disease are less than perfect. This leaves many horses unprotected from the disease and/or at risk for developing vaccine reactions, including abscesses or purpura hemorrhagica (damaged, leaky blood vessels resulting in swelling).

There are currently two strangles vaccines available in the United States: one injectable and one intranasal. Unfortunately, despite aggressive efforts, neither can protect a horse against the disease 100% of the time. This leaves even vaccinated horses at risk, which can be problematic as strangles, caused by the bacteriumStreptococcus equi subspecies equi, is one of the most frequently diagnosed equine infectious diseases worldwide.

“There is an urgent need to develop new preventative vaccines against strangles and, to date, our success in doing so has been limited,” said Andrew Waller, BSc, PhD, from the Animal Health Trust, in Newmarket, U.K.

Waller and colleagues set out to develop a strangles vaccine veterinarians could administer intramuscularly without abscesses developing at the injection site (a common problem).

“The other goal was to produce a vaccine that, after administration, allows veterinarians to differentiate between vaccinated horses and those that are actually infected,” Waller said. “This would facilitate movement of vaccinated horses between premises and permit identification of vaccinated horses that were later exposed to S. equi without developing clinical signs of the disease.”

Well-aware that S. equi has an arsenal of tricks up its microscopic sleeve to evade and “confound” a horse’s immune system, Waller and colleagues modified a strain of S. equi by deleting six genes from the bacterium’s DNA to create a new strain. They anticipated that this novel strain of S. equi (used in a live vaccine) would prime a vaccinated horse’s immune response so that if the horse was subsequently exposed to natural strains of S. equi, the immune system would be ready and better able to fight off infection.

Waller and colleagues administered two intramuscular doses of their new vaccine several weeks apart to nine ponies and found that:

  • After the first injection, four ponies developed slow-growing abscesses at the injection site; two of those four were removed from the study after the first vaccine due to humane reasons related to the abscesses;
  • One pony developed a slow-growing abscess after the second vaccine administration;
  • All of the vaccinated ponies, but none of the control ponies they were housed with, developed immune responses against S. equi (meaning the vaccinated ponies did not shed S. equi); and
  • Eleven days after challenge, 100% of the vaccinated ponies remained disease-free whereas six of the nine unvaccinated ponies developed clinical signs of strangles.

“This information will help us continue to build better vaccines against strangles, by directing improvements to the safety of new live vaccines and the effectiveness of recombinant subunit vaccines that have fewer S. equi targets, but benefit from an excellent safety profile,” Waller concluded. “Even with better vaccines, the requirements of good biosecurity in the prevention and management of strangles outbreaks cannot be emphasized enough.”

The study, “Vaccination with a live multi-gene deletion strain protects horses against virulent challenge with Streptococcus equi,” was published in Vaccine.