As the title says…
I have an older mare that is giving me fits! She’s basically been a career broodie and in the past was an easy breeder. In 2011 she foaled late June, we bred her on 30 day heat with frozen semen. I have a great therio doing my work, timing was excellent, semen quality was great, she looked good post breeding, was started on Regumate at 5 days post ov but she did not settle. After that breeding she quit cycling. We checked and rechecked to see if we missed a pregnancy and finally we lutalysed…and nothing. We cultured, ran blood, etc. Thyroid was low so we started Thyro-L, retested and her levels are right where they should be. We put her under lights in December to get an early start.
Fast forward to late January. We checked her to see where she was at and she’d already had an ovulation. We followed her through another cycle, vaccinated her, did her teeth, cultured her again and got set to breed her in mid-late March. March 3rd (third cycle of the year) she had a beautiful 45mm follicle and was teasing like crazy but I had just finished her vaccines the day before so we decided to wait until the next cycle. Well, we are still waiting…We’ve checked her every 5-10 days since then, pulled blood and ran Progesterone just in case she popped a small follicle we missed (though she’s not had anything bigger than a 25mm), we lutalysed and nothing. She seems to have completely shut down.
It is very early in the season here in NY but the weather has been warm and she’s been under lights since the beginning of December and my other mares have started cycling.
Anybody ever have a mare do anything like this? Any suggestions? I know my therio is racking her brain (and calling colleagues) too but I’m getting ready to start pulling my hair out!
How old is she and how many foals has she had?
How old is older? What is her Biopsy score?
A lot of old mares who have had a lot of foals develop a lot of fibrosis and scarring in the uterus and that does not bode well for holding a pregnancy. Especially since she has now had a year off. For whatever reason, these older mares if you can keep them pregnant year after year, they get pregnant and stay pregnant. But, once they have a year off, a lot of times it is VERY difficult to get them pregnant again… if at all.
I would strongly suggest you start completely from scratch and get a full biopsy, culture and sensitivity done and if she has been on a lot of antibiotics recently, your vet might want to test for yeast in addition to bacteria culture. If her biopsy score is really terrible, then you may want to consider a DMSO/Betadine flush as a last resort. Sometimes, although not always, this can refresh the uterus just enough to get another pregnancy from her.
A mare’s most fertile months are late April, May, June and July. Most mares are quite transitional in the early spring and having her under lights is no guarantee that you can skip that transitional period.
You could start her on some additional Vitamin E (without selenium as selenium toxicity is easy to achieve). Vitamin E seems to aid in fertility.
Thyroid is tricky and treatment for it must be most strictly adhered to. Any fluctuations and it will spell doom and gloom for pregnancy.
Metabolic syndrome can also wreak havoc on maintaining a pregnancy so you might want to check for that too.
You could also try Immunall - some breeders swear by it. Contact Rainbow Equus Meadows for this.
Those are my thoughts. Perhaps another breeder, Kathy or Jos, or an attending vet can add further thoughts.
There is a hormone treatment made by Bet Pharm who’s purpose is to “jump start” mares that have appeared to go transitional, despite it being breeding season. I highly recommend you call them and ask about it!! I had a mare do this last year, and I was about to start treatment when she came back into heat on her own.
Lutalyse will not work if she is not cycling.
We sometimes have luck using a 10 day course of progesterone (usually Regumate) on these mares, and then using a prostaglandin on day 11. This will usually bring them into heat, especially if you have verified an ovulation already this season.
I didn’t mention a hem. follicle, b/c it should have been apparent on ultrasound. However, it is a good thought.
My other question is that you mention the mare was started under lights in December. Has she always been under lights in the winter, or is this the first time? We sometimes see mares (and other show horses) that are kept under lights for several years in a row that have either shut down (or in the case of geldings) grown a winter coat at an inappropriate time of the year. If the body is not allowed a winter period (in terms of lighting) it will eventually do so on its own, but sometimes it can take years of artificial lights to do so. And generally these are horses that are kept under lights year round, year in-and-year-out for showing purposes. In these cases you can still try the regumate/prostaglandin protocol, but generally only tincture of time works.
You don’t mention exactly how old this mare is, but I’m assuming she is a teen-ager? My mare was doing as you describe, having a heat, not ovulating, not growing a normal follicle. She was in the early stages of cushings.
