A study of 55 field cases of uterine torsion in dairy cattle.

Two-hundred and seventy-three animals were enrolled in a case-case comparison of uterine torsions and other dystocias. The purpose of the study was to describe field cases of uterine torsion and their clinical management, compare them with other types of dystocia attended by field veterinarians, and evaluate the effect of season and housing on the incidence of torsions. Fifty-five cases of uterine torsions representing 20% of the dystocias were diagnosed. Most cases of uterine torsion were successfully corrected and followed by the vaginal delivery of a live calf. When compared with other types of dystocia, cows were at greater risk for uterine torsion than were heifers (OR = 5.2; P < 0.0001), while animals suffering from fetopelvic disproportion or carrying twins were at a lesser risk (OR = 0.05; P < 0.0001 and OR = 0.09; P = 0.007, respectively). Heifers had a lower risk when calving alone in a pen versus a tie-stall (OR = 0.2, P = 0.04). There was no significant effect of season on the risk of uterine torsion.