Testing mature bulls for trich - what's important? Bovine trichomoniasis “trich” testing – what is it? Once infected, bulls remain infected for life. Additionally, movement of mature (greater than 18 months of age in most cases) and/or non-virgin breeding bulls across state lines will require trich testing to document negative status. Producers should expect trich testing to be on the agenda when they book breeding soundness exams of their mature bull batteries.