Unexpected open or short-bred cows are often an unfortunate sign of a Trichomoniasis, or trich, problem. It is a reproductive disease caused by a protozoan called Tritrichomonas foetus. Bulls are asymptomatic carriers of the disease, writes Rosslyn Biggs, DVM, but play the major role in trichomoniasis transmission.
Positive bulls must be removed from the herd and either castrated or sent to slaughter as there is no treatment for the disease.”
Source: BEEF, May 2021. Link. The first step in prevention is to conduct annual trichomoniasis tests as part of a breeding soundness exam. Infection in cows and heifers results in infertility and abortions, typically within the first four months of pregnancy. Although females can maintain long term infection, most clear the infection in four to five months.