Freemartin

Freemartin is an infertile female with a modified genital tract born cotwin, or in greater multiples, with a bull with which it has exchanged whole blood.

The freemartin is one of two dizygotic individuals that are of different sexes and do not resemble each other.

Clinical Signs of Freemartinism in Cattle

• Ovaries usually fail to develop and remain small, about the size of a flattened barley grain, and undifferentiated.
• In rare cases some differentiation toward the female or male gonad may occur.
• The genital tract, especially the portion arising from the paramesonephric duct, is markedly arrested in development.
• Often in the region of the cervix, two tubular structures or remnants of the mesonephric duct resembling seminal vesicles are present.
• The vagina is undeveloped.
• The vulva is fairly normal, except for the occasional presence of a prominent clitoris and a large tuft of vulvar hair.
• In the yearling animal, failure of oestrous cycle; the udder and teats remain very small and the external characteristics resemble a steer.

Diagnosis

Fincher’s Test Tube Test

Insert a test tube or glass speculum of 3/8 to 1/2 inch with lubrication into the vulva of the suspected heifer.

In freemartin cow

• Tube will go no further than the hymen, or the caudal portion of the vagina or about 7.5 to 10 cm, 3 to 4 inches, in a young calf, as there is no normal vagina.
• Use of a light will reveal the no vaginal opening anterior to the urethral opening on the floor of the vulva.

In normal cow

• Some resistance may be encountered when the test tube passes through the vulvovaginal region but it then will pass 12 to 18 cm, 5 to 7 inches into a freely dilatable vagina.

Use of a light will reveal a normal small cervix.