Local Venoarterial Pathway for Uterine-Induced Luteolysis in Cows 1

Summary

The involvement of the main uterine vein and ovarian artery in the local pathway for uterine-induced luteolysis was studied in mature Holstein cows. At surgery on days 8-11 of diestrus, all cows were unilaterally hysterectomized and allocated to one of 4 groups: 1) controls with hysterectomy contralateral to CL, 2) controls with hysterectomy ipsilateral to CL, 3) hysterectomy ipsilateral to CL and surgical anastomosis of the main uterine vein from intact to hysterectomized side, and 4) hysterectomy ipsilateral to CL and surgical anastomosis of ovarian artery from intact to hysterectomized side. At necropsy on day 30, the surgical anastomosis was examined for patency and CL were weighed. Cows with an occluded venous anastomosis were reassigned to group 5. CL weights from 15 cows (3 per group) were analyzed. Mean weight of CL was less (P < 0.05) for group 1 controls (489 mg), group 3 with venous anastomosis (1920 mg), and group 4 with arterial anastomosis (708 mg), than for group 2 controls (4710 mg) or group 5 with occluded venous anastomosis (5142 mg). Mean weight of CL was not significantly different among groups 1,3, and 4 or between groups 2 and 5. Results indicate the involvement of a venoarterial pathway in the local uteroovarian luteolytic effect in cows. The main uterine vein serves as the proximal or uterine component and the ovarian artery serves as the distal or ovarian component of the pathway.