[Seein'Spots]

when is a mare most fertile? it has been 19 days since her last cover and I just started to tease again, she is really ****** ,squirting and winking. I'm not sure if she's peeing or ? I covered her alot last heat. could she be dislaying this anry behavior if she is pregnant? or just wait it out a few more days to see if she comes into a standing heat?

I know , I know, I need to ulrasound her.

[Lopinslow]

yes, you need to ultra sound. we don't usually wait until they come into heat, we US them about 14 days after the last breeding date to check, and then if there is twins, you can pinch one.
i used to board/help out at a breeding farm, and during breeding season the vet was out every monday, wed and Friday to check mares. As soon as they came in to heat, we would check to see what size she was at. then, she would get checked again in 2 days. even with live cover, we didn't breed until they were large and soft, which obviously getting close to when they will ovulate. so, most mares were only covered once or twice.
AI is a different story of course, with as much as it costs for collection and shipping, you want to time it as close to ovulation as possible. when they get close, we'll give them HCG that morning, and get a shipment in for AI that night. if the stallion owner sends a second dose, we'll AI that one the next day.

[Seein'Spots]

I know the 14 day rule but what is that latest a twin could be destroyed?

Ohh I hate even typing that..

[RiddleMeThis]

Originally Posted by Seein'Spots

I know the 14 day rule but what is that latest a twin could be destroyed?

Ohh I hate even typing that..

Not sure, but why would you want to risk waiting?

[DancerLover08]

Originally Posted by Seein'Spots

I know the 14 day rule but what is that latest a twin could be destroyed?

Ohh I hate even typing that..

I believe 21 days is the last date a twin can be pinched...

[Haas Horse Farm]

Sounds like you need to have the vet do a check on the mare. Unfortunately ovulation and heat do not always go hand in hand so ultrasound is the only way to know where your mare is in her cycle.

[Equine Repro]

Originally Posted by Seein'Spots

when is a mare most fertile? it has been 19 days since her last cover and I just started to tease again, she is really ****** ,squirting and winking. I'm not sure if she's peeing or ? I covered her alot last heat. could she be dislaying this anry behavior if she is pregnant? or just wait it out a few more days to see if she comes into a standing heat?

I know , I know, I need to ulrasound her.

Mares can and do display estrus even when pregnant - up to 20% of mares will! Secondly, breeding repeatedly throughout a mare's estrus cycle can have a negative impact on pregnancy. If the stallion is fertile and has decent sperm numbers, by repeatedly breeding the mare you are literally just dumping stuff into her uterus that she must deal with. Semen is irritating to the mare's uterus, so by repeatedly breeding her, you are actually creating a hostile environment for semen. Every other day is MORE than adequate - you just don't increase your chances of success by breeding more often.

With regards to when is a mare most fertile - most mares ovulate approximately 24 hours prior to cessation of estrus display.

A twin can be pinched up to about day 32 of pregnancy. After that, the formation of the endometrial cups begins and if you can't reduce one of the twins and have to terminate the pregancy, your mare may not return to estrus for 60 to 90 days. The endometrial cups are part of the hormone cascade and are what are essential for pregnancy maintenance and providing sufficient progesterone levels. Once they form, it takes 60 to 90 days for them to regress and they will continue releasing progesterone during that period.

With all of that said, checking for twins prior to day 16 of pregancy, it is MUCH easier to reduce one of the pregnancies as the concpetus are still mobile within theuterus. After day 16, if the twins fixate adjacent to each other, it can be MUCH more difficult to reduce one without negatively impacting the other.

Hope that helps!

Kathy St.Martin
Equine Reproduction Short Courses
http://www.equine-reproduction.com