When a female calf is born as a twin to a male calf, a sterile female is known as a _________________.

🔑Key Points
Free martinism is recognized as one of the most severe forms of sexual abnormality among cattle.
This condition causes infertility in the female cattle-born twin to a male.
When a heifer twin shares the uterus with a bull fetus, they also share the placental membranes connecting the fetuses with the dam.
When a set of twins is born and one is a bull calf and the other is a heifer calf, more than 90% of the time the female is infertile.
The infertile female twin is called a freemartin.
The hormones that the male fetus produces can cross to the female fetus and cause reproductive tract abnormalities.