Uterine segmental aplasia in sheep

Résumé

The complete absence of one of the uterine horns, named segmental uterine aplasia or unicorn uterus, occurs due to deficiency in the development of segments of the paramesonephric or Mullerian ducts. It is a congenital or hereditary anomaly of the female reproductive tract caused by recessive genes, which occurrence is unusual. In cows, this malformation was initially called “white heifer disease”, comprising an alteration in the Mullerian ducts in association with the white skin gene that causes aplasia of the uterus, cervix and vagina. Two pieces of sheep reproductive system from a slaughterhouse under federal inspection in the state of Bahia, Brazil, were received for pathological diagnosis. The collection, dissection and macroscopic analysis were carried out. In the macroscopic evaluation, uterine segmental aplasia was identified in both cases, with complete absence of the left uterine horns. Both had agenesis of the uterine tubes associated with the absence of internal bifurcation of the uterine horns. Animals that have a unicorn uterus often have reduced fertility which consequently leads to losses to sheep farming.