If you provide us with more details as to what your boss is considering to be "metabolic syndrome", plus some other details of your mare's fertility issue (I'm sorry - I don't remember what it was), we can take a look and see if there is something.
As a general rule though, extrapolating problems from other species into the equine is a risky thing to do when reproduction is concerned, as the mare has a moderately unique reproductive process.
Well her basic fertility issue is that all of the testing we have done on her indicates that she should be able to get pregnant, but hasn't in two years.
We had an early issue with her holding fluid, but finally got that cleaned up (culture and cytology is clear now) and the oxytocin protocol has kept her 'dry' and clean.
Now we seem to be having problems with EED.
She is a very easy keeper. Not cresty at all, but has a large belly considering the amount of excercise and food she provided with. (Yes fecal is done, she is in good shape that way.)
She has significant mood shifts when she is in heat. And has always tested low for Progesterone 1.4-1.7.
He walked me through the history of the treatment of PCOD (poly cyctic ovary disease). It turns out that PCOD isn't really the problem--it's the 'Metabolic Syndrome' that leads to the PCOD that needs to be fixed.
High Estrogen, low progesterone. Storage of fat in the central body. Aggressive behavior. Sometimes diabetes or Insulin Resistance (IR) is involved, but not always. These can point to Metabolic Syndrome.
Basically then you treat them for IR and increase their exercise and a lot of the time the fertility comes back to normal.
Well... as I said, it is always risky extrapolating problems from other species (especially humans) into the equine...
The first thing to consider in the attempted extrapolation is that the human and equine reproductive cycles are completely different. Mares should have high elevations of estrogen when they are in estrus - that's what makes them receptive to the stallion's advances. It is also what stimulates the uterine immune response that is so essential for preventing infection at the time of breeding. Remember the cervix is open in the mare for 5-7 days - a very different situation from the human, and one that requires an increased immune response. Come to that, the cervix is relaxed as a result of the elevated estrogen levels. So... high estrogen is not an issue in the equine in the same way that it is in the human.
The progesterone levels you indicate are possibly a little lower than one would expect, but there are a couple of important points/questions there too... What unit of measurement is being used? When were the samples taken? How often were samples taken? There is an explanation of the importance of those points to be found in the article about Regumate use.
The low progesterone may however be a pointer to another problem - which can also result in EED - which is referenced in that above article. You know you have an issue with delayed uterine clearance, so it is quite possible that there is still a low grade endometritis which is not being resolved following breeding that is resulting in interference with the function of the CL and progesterone secretion levels.
What sort of mood swings, and how are you evaluating them? Changes in response to external stimuli from estrus to diestrus is completely normal in the mare. They do not suffer from PMS because mares do not menstruate. The hormonal profiles are completely different between the species.
Cysts on the ovaries are extremely rare in the equine, and you would (should) have easily identified them in the event that they were present when the mare was ultrasounded, so I'm afraid I'm pretty skeptical there too, although you've pretty much ruled that out apparently yourself...
My money is still on issues related to the delayed uterine clearance. Successful management of these mares to achieve and maintain pregnancies can be very intense. Have you considered using her as a donor mare for ET? It may in the long run be cheaper!
Just adding my two cents. I have a mare that responded to breeding much as yours did. She went open almost 2 years. She was low thyroid which she is being treated for (not convinced it was a factor), never tested low Progesterone but was having EED issues. We used the oxytocine protocal that Jos talks about as well as on the last breeding we decided to use Regumate. After losing two to EED the last resort was oxytocine and Regumate which we kept her on for 150 days. She is now in her 6th month. (I know Jos, you are not a fan of Regumate use!) I can't say wether or not the Regumate or the Oxytocine did the trick, but I have a mare in foal. With her it was patience, persistance and LOTS of money. If you choose to use Regumate it costs about $250 for a 1000 liter bottle (I think I used 1 and a half bottles). This is one expensive baby! You seem to be evaluating your options...if I were you I would stick with the Oxytocine, without it I didn't even have an embryo
Interesting...What are you treating her with? I wonder if this is similar to my mares troubles. I still have her on 1/2 scoop of Thyro-L just for $hits and Giggles. Vet and I figure it can't hurt and she is on the same food rations as last year and her weight even for being pregnant is very good. Is this a natural treatment with vitamins or meds? You should post a picture of your mare I would like to see her.
The supplement is Chasteberry. You can not give it past the first trimester because is suppresses Prolactin production.
It is most often used in horses to treat Cushings, but can also help infertility due to luteal insufficiency. One of the by products is that it helps IR and has adaptogenic properties on the estrogen/progesterone balance.
Some new research has been released that does point to the possibility of Equine Metabolic Syndrome. I'm not particularly seeing a link with the mare cited above though. This is a synopsis of a report from the AAEP meeting, provided by The Horse Magazine:
Equine metabolic syndrome typically affects horses aged 8 to 18-years-old. Pony breeds, domesticated Spanish Mustangs, Peruvian Pasos, Paso Finos, and some Warmblood breeds appear especially prone. A preliminary diagnosis is based on obesity, insulin resistance and insidious onset of laminitis. EMS horses typically have fat deposits in the crest of the neck, over the tail head, above the eyes, behind the shoulders, and in the sheath of male horses. Diagnosis is confirmed by measuring insulin and glucose levels in the blood. Unfortunately, there are no medications to treat EMS. At this time, experts recommend a low sugar/starch diet, exercise, and antioxidants such as Vitamin E to help manage the oxidative stress that comes with the syndrome.
It will be interesting to watch the next couple of years to see if they find a link between Metabolic Syndrome in horses and decreased mare fertility.
The interesting thing about the Syndrome in humans is that is presents in many different ways. There are 6 major indicators, and the patient must have 2 out of the six to be diagnosed. According to my boss about half of the people diagnosed have normal insulin and glucose levels--so I'm not sure about using that in horses.
I have changed her diet to a low starch/sugar (and upping her protein a bit), antioxidants, and and continuing with the supplement. She continues to look better.
We are giving the 'traditional' route one more try. She is due to be checked out by the vet in a couple of weeks, hopefully we will still be clean and 'dry'.
I'll let you know how it turns out! Thanks for following up.
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