Ok I looked and there has been nothing since 2009 on this. Has anyone done this? I have one past the 54-70 day window and other will be in it in next few days. I heard you can do by transdermal after 100 days.
Would love to hear if anyone has done this in last few years!
There is a lady who sells in-utero foals that are sexed, every year.
Yes, you can check transabdominally between 120 and 150 days, but often it can be done transrectally, depending on the size of the mare’s uterus (easier on a maiden; tougher on a mare who’s had several foals).
I do my own repro work and have learned how do do it with much better accuracy at this later time in gestation than at the 60 day mark. This article, “Determination of Fetal Gender by Transrectal Ultrasound Examination: Field’s Experience” by Marco Livini, DVM, shows what to look for:
https://aaep.org/sites/default/files/issues/proceedings-10proceedings-z9100110000323.pdf