January 2015

Angus preg check

A veterinarian doing the first pregnancy check of the season on a small beef ranch (20 cows/heifers, 1 bull) finds a high number of open cows. One cow is noted to have a small amount of muco-purulent vaginal discharge. Also, the rancher mentions that he found an aborted calf last week. The rancher recently purchased a new bull, and a breeding soundness exam was performed on the bull prior to purchase, and he has observed the bull mating, but due to the number of open cows, he would like further testing to confirm the bull is fertile. A preputial wash and culture is performed, and after 48 hours, a sample is spotted onto a slide and fixed/stained. The parasite below is observed under the microscope:

What is your diagnosis?

Answer

These are trophozoites of Tritrichomonas foetus, which is a sexually transmitted parasite that causes early embyonic death and abortions between 2-4 months of gestation. The main clinical signs in cows include infertility, pyometra, abortion, vaginitis, cervicitis, endometritis, and salpingitis. Bulls most commonly display no clinical signs. There is no approved FDA treatment for infection with this parasite. Recommendations are to test bulls for infection prior to introduction onto a farm, cull those identified as infected, and allow infected cows to have at least four months of breed rest to clear the infection.