what is a freemartin heifer
A freemartin or free-martin (sometimes martin heifer) is an infertile female mammal with masculinized behavior and non-functioning ovaries.Genetically the animal is chimeric: Karyotyping of a sample of cells shows XX/XY chromosomes.The animal originates as a female (XX), but acquires the male (XY) component in utero by exchange of some cellular material from a male twin, via vascular connections between placentas.uring fetal development cells are exchanged between the fused circulations of the bovine twins. Up to 95% of the freemartin's blood cells can be derived from those of her twin brother. Male-derived cells and their progeny can be easily visualized in the freemartin tissues, as only they contain the male Y chromosome.