Red Urine

We started see red urine in a new gelding. What is causing this? 

Horses often have quite a bit of sediment and occasionally some dark pigment in their urine. In addition, a dehydrated horse will produce very concentrated urine, resulting in a darker looking fluid (and often a stronger smell), a common situation in the wintertime due to reduce voluntary intake. Even perfectly normal, well-hydrated horses can produce very dark urine, particularly during the end of the stream when voiding the “dregs” at the bottom of the bladder.

This is usually not an indication of serious problems, but occasionally very dark urine can be a signal of health issues. Muscle damage, typically tying-up, releases pigment called myoglobin into the bloodstream that is subsequently filtered by the kidney and excreted in urine. Excessive levels of myoglobin will cause the urine to look like Coke and can cause serious damage to the kidney, which is why we will put a severely affected horse on IV fluids to help dilute and flush out this toxin. Blood in the urine, from trauma, infection, kidney/bladders stones, or invasive tumours can also appear quite dark. Even components of normal coloured urine will metabolize into a dark rusty coloured substance after voiding, which can look like blood when they pee on something light coloured like snow. This phenomenon causes lots of phone calls to the vet the day after a good snowfall.

If your horse seems healthy and normal otherwise, I would keep an eye on things but not worry too much. If you have any suspicion of a health problem, a physical exam with bloodwork and urinalysis can determine the source of the unusual colouring.

Melissa McKee DVM

Keeping Horses Cool in Hot Weather

Having just been to visit the barns at the Pan Am Games (congrats to all involved again!!) we noticed that when the temperatures spiked the grooms all ran out and purchased fans to hang around the stalls to cool the horses. We are wondering if this is necessary at a certain point? Or beneficial for competition horses over pleasure horses? As barn owners/managers, what is the best way to ensure the horses in our care stay cool during these heat waves?

Horses have a small surface area relative to their body mass so they tend to have more difficulty cooling off in hot humid weather, especially when exercising. Horses competing at the Pan Ams had to be in top physical condition and feel fresh and energetic on event day, so every precaution was taken to ensure their comfort. This included special misting/cooling fans, electrolytes, lots of cool baths, timing their workouts during cooler hours of the day when possible, and if necessary, intravenous fluids to replenish losses after extreme exertion.

Although horses under less demanding athletic conditions don’t necessarily require this level of preventative management, you can still take some simple measures to ensure their comfort during a heat wave. This includes:

  • Lots of fresh clean water available at all times. Dehydration is the most significant concern due to sweat losses, so it is important that they have water both in the stalls and on turnout.
  • Electrolyte supplementation- horses that are working in extreme heat will lose electrolytes in their sweat so replacement therapy is helpful.
  • Switching to overnight turnout keeps horses safe from direct sun and flies while allowing them to enjoy turnout in the cool hours overnight. Then they can loaf in a shady, well-ventilated stall during the day.
  • Placement of fans in doorways, windows, and in front of stalls will ensure good ventilation and help with cooling because air movement enhances the cooling effect of sweat through evaporation.
  • Alcohol or witch hazel baths are more cooling than a straight water bath.
  • Good fly control. Horses get very hot, cross, and fussy to work with if they have to spend the whole day stomping and swishing to dislodge flies. Not to mention the wear and tear on their legs from these activities.



How do you diagnose for PSSM? What are tell tale signs that I should be looking for that will tell me we need to start to treat and test?

PSSM is short for “polysaccharide storage disease”. It is a muscular condition that predominantly affects horses with draft or warmblood ancestry. Affected horses are unable to utilize dietary carbohydrates for energy to contract the skeletal muscles; they tend to store up large globules of carbohydrates in the muscle cells but cannot break them down for consumption- hence the name of the disease. Draft horses are the most severely affected by this condition and in some cases can die from it, while lighter breed horses have  milder and more nebulous symptoms. The usual complaint is that the horse is “stuck” or won’t go forward, has become grumpy and muscle sore, resents grooming, may show signs of shivers or muscle cramping, and lacks energy despite an increase in the grain rations. This is a separate syndrome from “tying up” seen in lighter breeds although the clinical signs and some of the bloodwork findings are similar. Quarter horses also have a cluster of breed-specific muscle disorders that are not exactly the same as PSSM. In fact, further research has shown that there are several variations of equine muscle storage disease that affect different breeds, and horses are so highly interbred that they can be affected by any of these conditions.

Diagnosis is based on a combination of history and physical exam, blood tests for muscle damage enzymes, muscle biopsy, and genetic testing. Horses affected with PSSM will often show a mild and persistent elevation in certain enzymes on blood tests, particularly after strenuous exercise. A muscle biopsy taken from the hindquarters can be examined for characteristic polysaccharide clumps in the muscle cells. Recently, a blood test for a particular gene associated with PSSM had been developed, but this will only detect one of several possible genes for the disease.

If PSSM is diagnosed, the treatment is to change the diet so that most of the energy is provided in a non-carbohydrate form. In most cases, this is the “high fat high fibre” ration that is becoming increasingly mainstream in the feed tubs. The fact is that many horses respond well to this diet, even those that suffer from other problems such as tying up or gastric ulcers.

If you suspect PSSM in your horse, you may wish to talk to your veterinarian about the various diagnostic options.

Dr Stephanie Valberg of the University of Minnesota specializes in neuromuscular disorders in horses, and has a very informative website. Here is a link to the PSSM page:

Subcutaneous Injection

Is it normal for a horse to get a lump after sub q injection?

A small lump equal to the volume of drug used is normal immediately following a subcutaneous injection. That will usually resolve within a few hours as the drug is absorbed. However, if the horse is sensitive to that medication or it is an irritating drug, they may develop an inflammatory reaction that results in a hard nodule at the injection site. These are usually permanent although they often diminish slowly over time to a very small palpable knot under the skin.

Melissa McKee DVM

Tail Troubles

I have a pony who lost a good portion of his tail (his turnout “friend” chewed it off). Are there any products/treatments that you would recommend that I can use to encourage it to grow back quickly? I know it won’t grow back overnight, but I am hoping I can help it along somehow.

Unfortunately they couldn’t even find a way to grow American Pharaoh’s tail back- he suffered the same fate as your pony when he was a yearling and still has a shorter tail now. Fortunately it didn’t stop him from winning the Triple Crown!

The best that you can do to encourage hair growth is to provide excellent nutrition so she is healthy and has all of the nutrients required to maintain a healthy skin and coat. If her skin is dry and flaky, there are oil-based supplements available that can improve skin quality and therefore hair quality, but nobody has been able to speed up actual growth so far.

Melissa McKee DVM

Girth Galls/Sores

My horse has recently presented with girth galls for the first time. What is the best way to treat them and then how do I prevent him from getting them again?

Girth sores typically result from a combination of sweat, dirt, and friction from the cinch or girth. They can also become infected, causing a secondary issue that occasionally requires more intensive treatment including antibiotics to get the situation resolved. The key to managing a new girth gall is to immediately remove the inciting factors. That includes gentle cleaning followed by application of an emollient dressing- I like derma gel and special formula for this because they are soothing to the tissues and provide some moisture and protection. The second key is to eliminate the source of chafing. In some cases this means you will have to forgo riding while the acute damage heals and develops some new epithelium. With less severe galls, adding a sheepskin or other form of padding is sufficient to eliminate the rub. Keep in mind that an excessively loose girth, and one tightened unevenly (elastic girths can create this kind of problem) can also cause galls To prevent future issues, careful choice of the shape and material of your girth is the most important strategy. The use of a shaped girth that is narrow behind the armpit but wide elsewhere to redistribute pressure, and the addition of a slipcover are usually sufficient. There are specialized girths that sit well back of the elbow area, which are worth investigating if the simpler strategies aren’t successful. I also like to dust the area with baby cornstarch or baby powder to help reduce friction and chafing.

Melissa McKee DVM

Blood Test for EPM

Is a blood test a good way to diagnose EPM?

The blood test for EPM detects circulating antibodies to the parasite. A positive can occur if the horse has ever been exposed to the disease and has mounted an immune response. For example, if you have ever had chicken pox, you will have antibodies to that virus in your bloodstream but that doesn’t mean that you still have chicken pox years later. Horses have varying levels of susceptibility to EPM so exposure does not necessarily mean that they will develop any clinical signs. Therefore, the blood test is a better tool for ruling out the diagnosis of EPM rather than confirming that neurologic signs are a result of infection. Having said that, we know that there is more than one organism that can cause the signs of EPM. While sarcocystis neurona is the parasite that we traditionally identify, there are other organisms that affect the nervous system in a similar fashion that may not show up on blood tests. The good news is that most of the treatments for the disease are sufficiently broad-spectrum that they seem to cover most of these bugs. In conclusion, the likelihood of infection in the face of a negative blood test is very small but not impossible.

Melissa McKee DVM

Bladder Stones

Are bladder stones common in horses?

Bladder stones in horses are not as common as they are in dogs, but they do occur. We normally diagnose a few cases each year. Horses naturally secrete a lot of mucus and mineral crystals in their urine, which is why it often looks cloudy. The first sign of trouble is often a little blood at the end of the urine stream as the bottom of the bladder is voided. This is from local irritation of the bladder wall by the rough edges of the stones. Occasionally we will have an emergency situation where a horse is trying to urinate, but can only dribble small amounts because the bladder outlet (called the urethra) is blocked. They are very uncomfortable and this is an emergency because the bladder can rupture and kidney damage can occur from the extreme pressure. Anybody who has been to the vet with a “blocked” cat knows just how miserable they feel! Sometimes we can relieve the obstruction by passing a catheter through the urethra into the bladder, otherwise the horse will need surgery to bypass the blockage. This is much more common in geldings than mares because the male urethra is so long and narrow. Fortunately, the surgical procedure can often be performed in a standing horse with epidural anesthesia. A small incision into the urethra just below the anus can provide adequate bladder access in most cases. The prognosis then depends on the amount of bladder and kidney damage that has occurred. The occurrence of stones in any particular horse is difficult to predict and prevent. We can attempt to acidify the urine with certain feed additives, which can prevent crystals from precipitating in the urine and congealing into stones. Unfortunately, the fact is that it takes several pounds of supplement to lower the pH of the urine even slightly, and it is nearly impossible to convince a horse to eat it. In conclusion, there is little to be done to prevent stones, so take comfort that they are relatively rare and stay alert for the subtle signs before an emergency develops.

Melissa McKee DVM

Bald Spot on Nose

My pony has had a spot on her nose that hasn’t be able to grow back for 10 years now. We’ve tried everything from different products to removing her halter that was rubbing her nose when she gets turned out. Do you know if there are any products that will grow back the follicles? I am going to keep trying Vitamin E but if that doesn’t work, is there anything else I can use?

Unfortunately, I don’t think that anything is going to bring back the hair follicles on your pony’s nose after ten years. The problem is that there probably aren’t any follicles left, dead or alive, in that scar tissue. Since scar tissue also lacks normal sebaceous (oil) glands, it tends to get dry and flaky so I still think that she will still appreciate your efforts with the vitamin E cream because it will keep the skin soft and supple. Occasionally, the prescription topical product rogaine, which is marketed for male pattern baldness, will rescue dormant follicles in recently bald skin but it is rather expensive and a pretty long shot under the best of circumstances. Should she have to wear a halter for any length of time, might I suggest a nice sheepskin fuzzy?

Melissa McKee DVM


Ace for Trailering

I am trailering my horse this week and am considering giving him some Ace to help calm his this time. His last trailer experience (when I got him) was not good and he ended up rearing up multiple times which resulted in a big gash that needed stitches on his head. Is giving Ace a good idea? If so, how much should I give? He’s a 16’1 thoroughbred gelding (5 years old). Also keep in mind his manners still aren’t the greatest yet and can be very pushy.

A small dose of acepromazine can significantly reduce anxiety in a horse without making them too drowsy to ship safely. I work with a lot of young racehorses and the handlers often give them a shot about 45 minutes before loading them up. Not only are they quieter and less reactive to startling events, I can give them a much lower dose of other tranquilizers if we need to perform a procedure. The appropriate dose for your horse will depend on whether you will giving it orally or injecting it in the vein or muscle. Acepromazine is a prescription drug so I have to recommend you speak to your regular veterinarian about how much to give him. Hopefully the memory of his bad experience will fade and he can get over his anxiety about shipping soon.


Melissa McKee DVM