I have a beautiful 11yr old mare who I desperately want to get in foal. Tried to breed in hand for the past four years with no success. Been scanned and uterus seems 100%. Initially she seemed to have quite a long cycle +-7 days. Other than that everything looked 100% normal - no abnormalities. For the past two years she's been coming into heat at the beginning of the season and after being covered and ovulating, doesn't come into season for up to 3 to 4 months. Initially I assumed she was in foal. I live far from the vet, so regularly tracking her via ultrasound is out. Last season I got the vet to scan her and he found about 5 large follicles which hadn't ovulated. Because it was at the end of the season I tried giving her a course of ovarian steroids to cause her to cycle again normally but she switched off for winter. This spring, on time, she showed a good heat and she was covered by my stallion in hand, and once again didn't show a heat for 3 months +. Then last week she was interested in the stallion for 2 days. I covered her once in hand on the 3rd day. On the 4th day she and the stallion showed absolutely no interest in each other whatsover when teased or when left together in the paddock for the morning. When the vet scanned her two days ago, she had a very large 10cm flocculent follicle in the left ovary which showed no sign of ovulating. The vet wasn't sure if it was a follicle or a tumour. Also said she should be showing a heat. From the little bit of research I've done on the i'net it sounds more like a follicle as she doesn't (seem to) have any of the associated symptoms of a tumour. There was no fluid in the uterus and all seemed fine except for this huge follicle, which is a repeat performance of what happened last breeding season. Has anybody had a similar experience and have any idea what the cause could be? Also, has anyone experienced this and been able to correct the problem and successfully breed their mare? Thanks.
Based on what you are saying it sounds to me like she is like quite a few mares that I have dealt with that have a regular cycle... build a follicle and don't drop the follicle instead reabsorb it. I would be looking at injections for this mare to artificially bring her in and have her ovulate. This works 90% of the time if you have all timings right.
Thanks for your reply. At present, she has a 10cm follicle along with another 4cm follicle in the same (left) ovary. Had I given her Chorulon when the smaller follicle was still 3.5cm, would ovulation have occured on the smaller follicle within 48hrs regardless of the 10cm follicle? How long would it take for the 10cm follicle to be reabsorbed, and what is the cause of a follicle reaching this size without ovulating? Does such a large anovulatory follicle have any detrimental affect on attaining a pregnancy? Do you think that this is a hormonal problem and she needs hormone treatment? If she is hormonally deficient and she's given Chorulon to ovulate and subsequently gets} in foal, does it stand to reason that she will need prolonged hormone treatment to sustain the pregnancy i.e Regumate?
In my experience if we need to induce a mare into a heat cycle we have used lutalyse and to cause the mare to ovulate we have used HCG... Chorulon??? I am not familiar with. There are so many variables also with how long it takes to reabsorb... and as for the detrimental affect... I don't think so... Do you have a good repro vet?
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