by Cindy Reich

My phone chimed and I glanced down to see a text from one of the mare caretakers. The text was alarming and the photo more so. The breeding crew had just gone down to the barn teasing mares for the morning and this mare started to urinate. However, the stream changed from urine to blood. The caretaker took a photo of the bloody pool in the stall and texted it to me.

I immediately went to the stall, whereupon inspection, there were several other bloody areas of bedding, some with large blood clots in them. My mind started whirling — what could have caused this? The mare had been bred 17 days previously, and had been scanned not in foal a few days previously. Could her bladder have been damaged in some way? She wasn’t showing any signs of colic or abdominal pain of any kind. Her temperature was normal and she was eating normally.

One of the possibilities could be bladder stones. Bladder stones in the horse are primarily made up of calcium. Horses that eat a lot of forage like alfalfa take in a lot of calcium. However, they also have a lot of mucus in their urine to help keep stones from forming. Nevertheless, some horses do form bladder stones and they have a rough surface. As the stones roll around in the bladder, they can rough up the lining of the bladder, causing bleeding that would be present when the horse urinates. However, would it be enough for the large clots we were seeing?

Other causes of blood in the urine may include bladder cancer, urinary tract infection, or reaction to some drugs.

The only way to diagnose the problem would be for an endoscopic examination of the bladder. This would give the veterinarian a chance to check for bladder stones and look at the lining of the bladder and the condition of the ureters. In the mare, the kidneys are connected to the bladder by the ureters — one for the right kidney and one for the left kidney. The urine exits the bladder via the urethra. Upon the endoscopic examination, there weren’t any bladder stones. However, there was something much more serious. There was blood at the entrance of the right ureter, and as the exam progressed, blood came flooding out of the ureter. This was the cause of the blood in the urine, but why?

Sometimes excessive exercise can cause a very minor amount of blood in the urine, due to the bouncing of the bladder against the pelvis during exercise. However, the amount of blood this mare had in her bladder was well in excess of what would occur from an abundance of work. Also, this mare lived in a small paddock and certainly didn’t qualify for “excessive” exercise. However, there is one condition that fit this mare’s symptoms perfectly.

Idiopathic renal hematuria (IRH) is characterized by a sudden onset of profuse bleeding and large blood clots in the urine. Upon examination, there may be no other abnormal signs, which is where the term idiopathic comes in — idiopathic means “no known cause.”

Interestingly, in the reported cases, IRH is most commonly reported in Arabian horses as opposed to any other breed. Treatment consisted of medication to slow down the bleeding to begin with. Initially the left ureter started to bleed as well. Apparently it is also more common in Arabian horses that if one ureter is affected, the other one will also ultimately become affected as well. If the bleeding becomes severe enough, a blood transfusion may be indicated. In this mare’s case, after several days of treatment, the amount of blood in the urine stopped. However, once the medical treatment was completed (ten days), the mare started urinating blood a few days later. There are some case histories of Arabians with this condition who received blood transfusions and treatment and went on to live a relatively normal life. However, there are also cases where the outcome was not as good.

With this mare, the prognosis is not good, considering that she started to bleed from the kidneys after the treatment was completed. She can go back on medical treatment and be managed for a time, but cannot stay on the medication indefinitely. Other than bleeding from the kidneys, her quality of life is fine. She eats well and does not show any signs of discomfort. At the moment, she will be maintained on medication. She has not lost enough blood for a transfusion and will be monitored daily for potential blood loss. We will follow up with her case in a future column.

The take home message with this mare is that when you think you have seen everything, you haven’t. IRH is most commonly found in Arabian horses yet this is the first one I have seen out of managing thousands of horses in my career. It is also important to always be observant and attentive to the daily habits of your horse. Although it was pretty hard to miss the large amounts of blood in this mare’s stall, if she were a pasture horse, for example, her condition may not have been noticed until it was at a critical point.

Common Foaling Questions

At this time of the year, I have seen the same questions on social media coming up time and time again as the foaling season progresses. I thought I would address some of the most common ones in hopes of helping a greater number of owners.

1. What is the most effective foaling alert system to use on my mare? 

It depends on your situation and how your mare is housed. First of all, nothing should take the place of constant vigilance on the part of the mare owner. Having the mare in a stall or small enclosure with a camera is the most effective tool. The “foal alert” that is sutured on the vulva of the mare is the most reliable in my opinion. You will rarely miss a foal with this system. Regardless if the mare is down or standing, once the system is activated, it has the advantage of sounding an audible alarm for people working in the barn or sleeping in a bedroom. It can also be programmed to call up to three phone numbers and alert staff to the foaling. The disadvantage is that it is more expensive than other alert systems, but if it saves only one foal, it has paid for itself. The other disadvantage is that they can sometimes fail, and people who put all their reliance on this system as opposed to watching in addition to the alarm can be caught out on occasion.

2. How can I tell when my mare is close to foaling? 

The easiest method is to test the mare’s milk for calcium levels. There are several test strip methods and a titration method. I prefer the CHEMetrics water hardness titration kit. It is relatively inexpensive and gives a pretty clear test result. As the mare gets closer to foaling, the level of calcium goes up accordingly. When a certain calcium level is reached, a high percentage of mares will foal within either 24 or 48 hours. Again, nothing should take the place of careful observation (size of udder, placement of nipples, presence of wax, mare’s history, and so forth). However, this test can generally narrow the window of when the mare is going to foal quite effectively.

3. Can I check a foal’s IgG level myself or does it have to be done by a veterinarian? What test should I use?

All foals should have their IgG levels checked at 12 hours of age (preferably). IgG (immunoglobulin G) is a good indicator that the foal got the antibody protection from the mare’s colostrum to maintain its immune system until it develops its own immune system at five to six months of age. If foals fail to get immunity from the mare’s colostrum, they can die from a simple virus or bacterial infection. If they receive some protection from the mare’s colostrum, but at a low level, the foal can be prone to illness and may fail to thrive. The reason the test should be done at 12 hours is that if there was a FPT (failure of passive transfer), the foal can be given oral plasma to boost its immune status up to 24 hours of age. After 24 hours, if the foal needs plasma supplementation, it must be via intravenous transfusion.

The “foal check” Snap® test by IDEXX can be done with just a few drops of the foal’s blood and is very easy to do. It can be done at the barn and is the same test your veterinarian will do. However, it is not a bad idea to have your veterinarian do a well-foal check and do the IgG test at 12 hours if you only have a few foals. If you are foaling out a large number of foals, it may be more feasible to do your own.

The protocol that we use for all of our mares is that we do a milk calcium test every evening, all foaling mares are under cameras, and we use a foal alert on mares not under cameras or special cases like maiden mares or mares with a history of foaling without any signs. We do an IgG test on all foals at 12 hours of age and deworm the mare to prevent the spread of S. westeri through the milk. We also take a small sample of blood from the foal at birth and test it against the mare’s milk to test for NI (neonatal isoerythrolysis), a condition that will cause the mare’s colostrum to destroy the foal’s red blood cells. It is similar to RH factor in children.

As a result, so far, the foaling season has been a good one, and there are just a few more to go. There are still a majority of foals to be born on most farms in May and June, and soon foaling will start in the southern hemisphere.

Hotter weather is approaching, and with it, the risk of heat stress, dehydration, and fires. Make sure there is plenty of fresh, clean water for your horses. They should have some type of shelter or sunshade. If you live in fire prone areas, have a strategy for evacuation in case of fire.

It won’t be long until weaning starts and mares are being bred now for next year’s foals. It is a circular pattern that has played out for centuries. As each generation appears, we look forward to the next one. That is what keeps some breeders in this game for a lifetime. One never tires of waiting to see the next foal crop!


As I rose in the early dawn,

While stars were fading white,

I saw upon a grassy slope

A camp-fire burning bright;

With tent behind and blaze before

Three loggers in a row

Sang all together joyously —

Pull up the stakes and go!

As I rode on by Eagle Hawk,

The wide blue deep of air,

The wind among the glittering leaves,

The flowers so sweet and fair,

The thunder of the rude salt waves,

The creek’s soft overflow,

All joined in chorus to the words —

Pull up the stakes and go!

Now by the tent on forest skirt,

By odour of the earth,

By sight and scent of morning smoke,

By evening camp-fire’s mirth,

By deep-sea call and foaming green,

By new stars’ gleam and glow,

By summer trails in antique lands —

Pull up the stakes and go!

The world is wide and we are young,

The sounding marches beat,

And passion pipes her sweetest call

In lane and field and street;

So rouse the chorus, brothers all,

We’ll something have to show

When death comes round and strikes our tent–

Pull up the stakes and go!

 — James Hebblethwaite, The Oxford Book of Australasian Verse, London, New York: H. Milford, Oxford University Press, 1918.