Economic impact of trichomoniasis on reproductive health: A worldwide concern for bovine veterinarians and their clients

Bovine trichomonosis (BT) is a sexually transmitted disease that is prevalent in extensive beef production systems where natural breeding is widely practiced. Effective control of BT has been achieved in many areas of Europe, but the disease is still reported sporadically. In recent years, the Spanish beef cattle population managed in extensive outdoor grazing systems has increased significantly. The concomitant increase in the use of natural mating and shared grazing in these systems, combined with the absence of effective control measures, has led to the re-emergence of BT in some areas of Spain. We demonstrated the presence of Tritrichomonas foetus in 32% of bulls from one representative Spanish beef cattle breed reared in traditional mountain systems. In other areas, the infection is also detected in breed bulls routinely tested for BT in our laboratory (SALUVET, Veterinary Faculty, Madrid, Spain). BT is considered a cause of early reproductive failure in cattle; thus, the presence of T. foetus means that infection could have a significant deleterious effect on reproductive efficiency and sustainability of suckler beef herds. An economic analysis showed that BT could reduce income by 68.7% in Spanish infected herds, primarily as a result of prolonged calving intervals and calf crop reduction. On average, the infected herds required 79 days longer to engender a live calf. Elongation of the calving interval translates into an excess of days open, which causes losses from the cost of maintaining open cows. Overall, calf production was reduced by 17.7% by failure or delay in conception. Considering the consequences of infection, we also study the effect of a ‘test and cull’ control plan in infected herds. Following elimination of the infected bulls, an improvement in reproductive performance was observed. However, complete elimination of T. foetus using the ‘test and cull’ approach without substantial changes in management in Spanish suckler beef herds seems unlikely because putative risk factors associated with BT are present. In view of these results, more studies should be accomplished to presence of BT in areas where natural breeding of beef cattle is common.