In what month of pregnancy is a foal's sex determined?

I want to say that a vet is able to tell the gender at around 3-4 months of a fetus, I know it is hard to tell at that state of development, the ultrasound has to be positioned just right and if the little white speck looks like a diamond it's a girl, and if iit looks a square you've got a colt on your hands... I think - it's been a very very very long time since I've partaken in any reproductive ultrasounds.

I would just want to say that it would be eaisest later in the pregnancy - ask your repro vet - they would be able to tell you for sure.

I know nothing about at what point a mare's behaviour might change - I would just think that this depends on the mare - some might not change at all - some moody mares might mellow out during pregnancy and some might get defensive.

Good luck.

Gosh, about the time I know for sure she's pregnant, she's acting more aggressive with a colt. But, honestly...some mares are very mellow no matter what the fetus' sex is, others are crabs from the first day and have fillies. Only sure way to know is be there when it comes out.

I tried looking it up-but I don't know when.You can get it ultrasounded.And then they could tell you.Because when I looked it up all I got was that they could give an ultrasound to find out the gender.

The gender is determined at conception. Gender has nothing to do with your mare's attitude.