Cut the BS said:
mainegirl said:
I know that when a cow has twins- bull and heifer, the heifer is a free martin.
Not always... actually more like a 92% of not being good. Type in Chymera in google.. will help explain this better.
When a cow has triplets, 2 bulls and a heifer or 2 heifers and a bull, does this mean they are freemartins too?
Maybe, what causes the infertility-- has nothing really to do with the actual number of births- but has to do with egg splitting in half to form twins-- since most cattle won't drop 2 eggs. Somewhere along the lines- the heifer calf gets a shot of male DNA forcing her to be sterile. IF the triplets are from one egg- which I do not believe to be possible *unless the cow had quads and absorbed one* one should be different DNA-- or as my guess most of the time would be-- she dropped 3 eggs.
Now in sheep and goats, where dropping on more than one eggs is common- rarely are "free martins" ever seen.
That is how remember it....
Might have to politely disagree with you Jody. I was always taught that a freemartin was caused from the testosterone crossing the placental barrier while the gonads (sex organs) were forming early on, thus suppressing the growth of the female reproductive parts. If twins are the result of eggs splitting, they would be IDENTICAL, so same sex and no worry of freemartin. So, with triplets of different sex, I think you run into the same issues; if the testosterone crossed the placenta then the heifer will be sterile.
??? Am I correct??? I will have to look later, right now I am finishing up giving a quiz and packing up to head home to do chores.