Abstract
We describe the successful surgical repair of third-degree perineal lacerations with rectovestibular fistulae in four cases using the single-stage modified Aanes method with purse-string suture of the vaginal vestibule and rectum. Fistulae formation and dehiscence of the repair were not observed after surgery. Two cows had five calves and one cow had four calves after surgery. The pregnant cows delivered normally. Additionally, there was no dehiscence of the suture line during the subsequent parturition. The breeding and fertility results obtained after the surgery are presented. According to the results of the present study, the modified Aanes method for the repair of third-degree perineal lacerations with rectovestibular fistulae appears to have a good prognosis for fertility following surgery in cows.