Tell me about your hormonal mares

[leheath]

My horse had serious hormone problems and they caused her a lot of pain. Spring and fall were the worse (which is when their heat cycles can be strongest). She is a super friendly, social, cuddly horse, but there were times she would just stand in her stall pinning her ears and looking angry/unhappy/miserable for no apparent reason. She was also dangerous to ride - she’d go from hopping around Training level eventing courses like they were nothing, to rearing and refusing to move or go over a cross rail in the space of a few days. We tried regumate and, for the first year, it worked perfectly - she was happy, comfortable, and consistent in her behavior. Then it stopped working in the spring of the second year. Had her ultrasounded the day after a particularly bad riding incident and she had literally dozens of follicles on both ovaries, some as large as 2cm…while on regumate…she shouldn’t have had any! We tried upping the regumate but she still had multiple follicles on both ovaries at the next US and the cost of regumate was killing me. I had her spayed and she has been very happy ever since! Random other observation - she has had enlarged areas just in front on her udder since these problems started. No idea if they are related or not, but find it interesting since you mention your horse’s udder.

I should note I’ve had mare for 30+ years and never had one need regumate, or have any real hormone issues, or behavioral problems related to heat cycles, until this one.

[goodhors]

Out in left field, but while you are getting blood checked, do a Selenium test too. In Michigan, most areas are Selenium deficient, so horses do not get enough grazing or fed locally harvested hay. A mineral block and most feed supplements do not provide enough Selenium (which needs to be fed with Vit E to be absorbed) to the horse. If horse sweats often, they use up their Selenium even faster.

Lack of Selenium will affect muscles, reproduction in mares, along with other issues. Amazing how many things are affected by Selenium!

We had mare issues, sore back, super ovulating, eggs staying stuck in groups, not moving thru the reproductive system. Consistant tiredness, though horse SHOULD have been getting fitter on her conditioning program. Selenium test showed her at extremely low levels, which had Vet make a special trip to give her Selenium shots right away! He thought she might die! She WAS getting supplemented, we just were doing it incorrectly, not enough, no Vit E included. Changed that, got her into the normal range and she was a changed horse!!

Getting her tested will at least rule out low Selenium as a problem. We now feed Selenium and Vit E as one supplement, not included in other feeds or vitamins. This ensures each horse gets their proper amount DAILY. They get worked hard and sweat most days in work, so they use up Selenium in their body quickly. Body does not store it up like fat, have reserves on hand. Amounts fed are low, about a level 1/8th teaspoon per horse, once daily. We test a couple horses a year, the hardest sweating horses, to see Selenium levels are not low or high.

[greywithchrome]

This is interesting, and I am glad you figured it out for your horse! Did your horse have any issues moving around without a rider? Like could you lunge her without problems?

[awaywego]

The bloodwork revealed normal hormone levels so I guess we are going to try increasing the Regu-mate to see if that changes anything. This time of year is so tricky because if I do see any improvement, will it be because we increased the Regumate or is it because we’re well into fall now and her cycles will be slowing down.

You couldn’t pay me to take another mare right about now

ETA: interesting thought about the selenium. I think she gets selenium with her Vit E but I will check!

[leheath]

@greywithchrome

This is interesting, and I am glad you figured it out for your horse! Did your horse have any issues moving around without a rider? Like could you lunge her without problems?

No, not really. Generally speaking she was fine on the lunge. Stress seemed to exacerbate the pain (or perhaps just lower her tolerance of it), so she was always worse at shows, clinics, etc away from home. I rarely lunge at shows or clinics so not sure how she’d have been but she was always pretty good to lunge regardless. However, she would look miserable and grumpy in her stall when she was in pain (home or away), which was very out of character for her (normally she’s happy and social when stabled).

[leheath]

@awaywego

The bloodwork revealed normal hormone levels so I guess we are going to try increasing the Regu-mate to see if that changes anything.

My mare’s hormone levels were “normal” too - she just produced too many follicles. I’m sorry you’re having so much trouble and I sure how you get things figured out, but know that significant hormone issues are actually fairly uncommon in mares in my experience (30+ years of owning and knowing multiple mares!).