Bovine uterine torsion: 164 hospital referral cases.

Uterine torsion is more common in the cow than any other domestic species. The etiopathogenesis of the condition remains open to speculation. Available hospital referral records of bovine uterine torsions (n = 164) were collated, and additional comparisons for season, age and breed were made using the VDMP data base of 24 North American veterinary schools. There was no effect of season. Brown Swiss cows were at a significantly higher risk (P = 0.0001), while Hereford, Angus, and Jersey cows were at a lower risk for uterine torsion when compared with Holstein-Friesian cows, the largest breed population (P = 0.01). Most cows (81%) were at term. Clinical signs of torsion included fever (23%), tachycardia (93%), tachypnea (94%), straining (23%), anorexia (18%) and vaginal discharge (13%). In 34% of the cases the torsion was precervical, with no vaginal involvement being noted. The severity of the torsion was predominately 180 to 270 degrees (57%) and 271 to 360 degrees (22%). Counter-clockwise torsion was present in 63% of the cases. Vaginal delivery was possible after manual correction (20%) or rolling of the cow (18%). Cesarean section was performed immediately in 35% of the cases, after failed detorsion attempts in 7%, and due to failure of the cervix to dilate following successful correction of the torsion in 20%. Calf birth weights exceeded breed means in 89% of the cases, and a significantly greater proportion (63%) of the fetuses were male. Fetal survival rate was 24% (14% of dead fetuses were emphysematous), and the cow survival rate was 78% (10% were euthanized). The fetal membrane retention rate was 57%. It was found that large term fetuses appear to predispose a cow to uterine torsion.