The strangest chapter yet.

I’ve arrived at one of the most unusual chapters of my history with Limerick.

Sometime in March, in the middle of Lim’s intense case of the spring crazies, as I groomed her I noticed her udder was a bit puffy. Since the swelling was mild and uniform, and Limerick is the type of mare that will kick your head off if you casually reach down and manhandle her udder, I decided to just keep an eye on it.

Over the next several months the swelling held steady. It intensified in late May but I was not ready to call the vet…yet. Lim was showing no signs of illness or soreness and the swelling continued to be uniform. No alarm bells were going off in my head.

Then one day in early June I noticed the udder was more swollen than ever. Now I was starting to worry a bit.

I asked a fellow boarder about it and she said it was odd. I even peeked at the udders of a couple other mares to make sure I wasn’t just “seeing” things with Lim’s udder. The teats of these mares were so tiny I could hardly find them. The vet that gave vaccinations at the barn happened to be there and I asked him to take a look at Limerick’s udder.

Several violent kicks and one very angry mare later, the vet showed me his hand—it was covered in clear liquid.

I made an appointment with my own vet. In the meantime, not being one to sit on my hands, I began Googling and looking up past articles on The Horse about mammary swelling in non-pregnant mares. According to my research, the most common cause of such swelling was an infection. However, an infection often included lopsided swelling, fever, pus or gray/chunky discharge, and lameness. Lim had none of these symptoms.

I asked a vet friend what it could be and she gave me some possibilities. I also asked a woman with more mare udder experience than I could ever have in a hundred lifetimes about what it could be. She said that sometimes infections have no clear symptoms other than swelling.

I ran through a list of possible causes.

Infection? See above.

Ovarian cysts or tumors? Ehh…these will make a mare extremely irritable or even aggressive, and Lim had been unusually sweet in the past months. In fact she was so sweet that she let me hug and cuddle her much more than she typically allowed—and she always liked it!

Allergy or trauma to the area? Due to the very slow growth of the swelling and lack of hives or lameness or other more obvious symptoms, this was seriously doubtful.

Mammary tumor? This one scared me. From what I read, while very rare, mammary tumors were almost always fatal. Symptoms were often confused with those of an infection early on, and included swelling and clear discharge.

The fact that Lim had not gone into heat since April also came to mind, as well as the knowledge that Lim’s “boyfriend” Nick mounted her in the early spring. He was busted doing this to other mares so of course he’d do it to his top girl!

During the vet visit, my vet was not in the least concerned which reassured me…a bit. Like me, she was doubtful that Limerick had an infection. She thought it could be “some kind of hormone issue” and injected Lim with progesterone and estrogen. She was also doubtful that the udder was due to an allergy but since the start of the swelling was around the time the barn switched from shavings to corn cob stall bedding, she gave me a bottle of hydroxyzine capsules to give Lim.

Two weeks later there was no change, other than Lim displaying very brief and weak heat symptoms a couple days after the injections (I would later learn this was from the estrogen injection).

I asked that she get a culture of the discharge so we could see what exactly was in there. She also drew blood to make sure everything was okay with that. The blood came back fine and the culture wasn’t bad, although it had a small population of bacteria that could be causing a problem. My vet prescribed Lim SMZ’s for an undetermined time—10 tablets twice a day.

Two weeks later they had done absolutely nil—in fact, her udder seemed a tad more swollen. I felt it was time for another opinion. My farrier recommended an equine reproductive specialist and I made an appointment with him.

This is where it gets interesting….

Lim was sedated and I positioned her for a transrectal examination and ultrasound (non-horse people: a mare’s reproductive organs are best felt through her butt. Fortunately the same doesn’t apply for humans…). The vet had his arm in there for some time. Finally, he pulled his arm out and said, “Something isn’t right.”

Now, I would usually freak out if a vet says “something isn’t right” but you know what? I got the impression that nothing was bad, just unusual. So, my curiosity at levels greater than ever, I waited.

The vet passed the ultrasound wand over Lim’s ovaries. The left one was just sitting there, doing nothing special. The right one had a white mass over it. The vet did not comment (but I would later find out that this was a corpus luteum). He passed the ultrasound wand over Lim’s uterus. Or at least, where it should be.

After a couple silent minutes he withdrew the wand. “I can’t find her uterus,” he said. “Are there any stallions on the property? It is possible she is pregnant.” What?! He explained that her uterus may be forward and down, in the pregnancy position. He said that the uterus is usually positioned in a semi-circle behind the ovaries and feels like a tubular muscle much like your forearm. Yet he did not feel or see this.

He applied more lube to the long plastic glove covering his hand and arm, and put his arm back in Lim’s butt.

Finally, he found her uterus. It was where it was supposed to be, by the ovaries, but rather than feeling like a muscle, it was thin and papery. He retrieved the ultrasound wand and passed it over her uterus again. This time he found it. The ultrasound confirmed the texture of the uterus and also revealed two harmless (and common) cysts in it.

After some discussion with the vet it was decided that since Limerick appeared to be displaying signs of false pregnancy (swollen udder, stretched-out, flaccid uterus, corpus luteum, lack of heat cycles), he would give her a shot of Estrumate, which jump-starts the mare’s hormonal cycle.

He also reviewed the results of the blood and culture tests my usual vet ran and noted that the small population of bacteria that could be causing issues was resistant to SMZs. But you know what? My vet did not clean Lim’s udder before collecting the discharge for culture, while the reproductive specialist took care to clean her udder very well before collecting discharge for his own viewing purposes. So the results of the culture could be meaningless, after all.

I was shocked, relieved, and fascinated beyond belief. I started this appointment expectant with the unknown (would he find a tumor? Confirm the infection? What?) and walked away with a tentative, rare diagnosis.

How Lim reacted to the Estrumate injection—and a follow-up visit—would confirm the diagnosis. Did I want the specialist to come back? You bet!

Two days after the Estrumate injection, as I groomed Limerick, I noticed drops of pure white liquid coming out of her udder. Wow! The stuff wasn’t clearish-white, or whitish-clear—it was definitely white. I emailed the specialist about this and he said the Estrumate would force her body into a “labor/delivery” stage, and lactation occurs when a mare (any mammal, really) delivers a baby. So the white stuff was witch’s milk.

Exactly one week after the Estrumate injection, the specialist was back to being shoulder-deep in a sedated Lim’s butt. The examination revealed her uterus had sprung back to normal, which the ultrasound confirmed. The ultrasound also showed that in place of the corpus luteum on her right ovary was a 40mm follicle—she was ovulating (but I didn’t need an ultrasound to tell me that, oh no…). The uterine cysts were still there but unchanged.

The diagnosis of false pregnancy was confirmed!

I asked the vet why this had occurred. I knew from my recent research that this typically only happens when a pregnant mare loses her embryo and the brain does not receive notification of the loss. He said maybe, just maybe, her body mis-interpreted the uterine cysts as an embryo. Personally I also think the extreme swing of her hormones in early spring, along with her boyfriend mounting her, contributed to the whole thing.

I’ve always thought Lim was special, in so many ways….now she’s practically a textbook miracle!

Now I just need to watch and see if she comes back into heat in a couple weeks. As for her udder…it is expected to remain swollen for some months, but will go down eventually.