Healing of experimentally induced wounds of mammary papilla (teat) of the cow: comparison of closure with tissue adhesive versus nonsutured wounds.

Lacerations were surgically produced on the mammary papillae (teats) in 11 healthy dairy cows (10 Holstein and 1 Guernsey). Chemical restraint and local anesthesia were used before the lacerations were done. Twenty-one lacerations (10 front and 11 rear papillae) were apposed with synthetic adhesives. Eight lacerated papillae (6 front and 2 rear) were allowed to heal without tissue apposition. Healing was evaluated daily by palpation and visual inspection. Histologic and subgross photomycrographies were done at the time of slaughter (13 to 20 days). Of the 21 lacerated wounds apposed with adhesive materials, 17 healed by primary intention (81%). One papillary laceration dehisced on the second day and developed a milk fistula. The remaining 3 wounds which were initially repaired with adhesives were injured during the cows' anesthetic recovery and were reapposed with adhesives. The latter healed, but not as well as did the 17. Clinically, there was no detectable differences between adhesives as concerns healing. Of the 8 controls (papillary lacerations that were not apposed), 3 healed by 1st intention (37.5%). The remaining five (62.6%) healed by 2nd and 3rd intention with fistula formation. When evaluated by subgross photomycrography, 20 wounds (18 glued; 2 controls) were bridged by connective tissue and showed no change in wall thickness. Three papillary lacerations (2 glued; 1 control) showed different stages of bridging with connective tissue and wall thickness. Histopathologic evaluation revealed a marked foreign body response evidenced by giant cell and epithelial macrophages adjacent to all lacerations apposed with adhesives. Tissue alteration varied widely depending on the method of tissue apposition and the tissue adhesive used.