Permanent implantation of a reinforced polytetrafluoroethylene vascular graft for treatment of artificial defects of the teat cistern mucosa in cows

Objective-To evaluate use of a reinforced polytetrafluoroethylene vascular graft for treatment of an artificial defect of mucosa of the leat cistern i n lactating cows. Design-Prospective study. Animals-9 clinically normal lactating dairy cows. Procedure-A 20-mm wide circumferential area of mucosa was sharply excised f rom the cistern of 1 teat on each cow 10 days after spontaneous calving, an d the lesion was covered by a graft. After 14 days of passive milk drainage , routine milking was resumed. Follow-up examinations were performed during the next 2 lactation periods and included evaluation of wound healing, loc ation and sonographic appearance of the implant, milk flow and yield, and s omatic cell counts. Cows were slaughtered, and teats and mammary glands wer e examined microscopically. Results-implants had partially to totally collapsed within 30 to 90 days. M ilk flow was significantly increased by day 15 of the first lactation, but decreased significantly by day 300 of lactation 1. At the end of lactation 1, milk flow had ceased in 3 out of 7 quarters. Only 3 of 9 quarters draine d through grafted teats were milkable at the end of the study. Somatic cell counts of these quarters were significantly increased in the first lactati on period. At necropsy, 2 grafts were in the tear cistern, but only 1 was i ncorporated into the mucosa by connective tissue. The mucosa was thickened in all teats with grafts, and there was epithelial metaplasia and granulati on tissue proliferation. Clinical Relevance-Use of a polytetrafluoroethylene graft can preserve pate ncy in the first lactation period. However, the graft may not be sufficient ly incorporated into the mucosa if routine machine milking is resumed 2 wee ks after implantation.