New surgical technique to correct urovagina improves the fertility of dairy cows

摘要

Several surgical techniques have been proposed for the treatment of urovagina as a major cause of infertility in cows. However, so far no technique seems to be successful in all cases. Given that an incompetent or damaged constrictor vestibuli muscle is a feature of cows with urovagina, we hypothesized that surgical correction of urovagina by cerclage of the vestibulovaginal junction under the vaginal wall cranial to the urethral opening would prevent cranial flow of urine and improve fertility. Our study was performed on 39 non-pregnant lactating Holstein-Friesian cows suffering urovagina, with a vaginal content of urine exceeding 100mL and with evident incompetence of the constrictor vestibuli muscle. Cows were randomly assigned to a Control (untreated cows, n =20) or Experimental (n =19) group. An encircling polydioxanone suture was placed in the vaginal wall at the vestibulovaginal junction to create a vestibulovaginal cerclage in the Experimental cows. Surgery was observed to resolve urovagina in 17 (89.5%) of the 19 treated cows. Pregnancy was recorded in 7/20 (35%) and 14/19 (74%) cows in the Control and Experimental groups, respectively. Using logistic regression procedures and based on the odds ratio, we determined that cows undergoing surgical correction of urovagina were 5.2 times more likely to become pregnant than untreated cows (P =0.015). Our results suggest that vestibulovaginal junction cerclage prevents the cranial flow of urine and improves the function of the constrictor vestibuli muscle in cows suffering urovagina. They also indicate that, under these conditions, urovagina correction may dramatically increase fertility.