77 Healing progression of tail docking and ear tag wound in lambs

Tail docking and ear tagging are common husbandry practices in lambs, but little is known about the healing process of the resulting wound. Additionally, evidence in other species shows that concurrent injurious procedures may delay wound healing. Thus, the objectives of this study were to 1) describe wound healing following tail docking and ear tagging, and 2) compare healing of ear tag wound in docked and undocked lambs. Within 28 Polypay female twin pairs, one lamb was docked by placing a constrictive rubber ring on the tail 24 to 48 h after birth and the tail of the other lamb was left intact (n = 28/treatment). Plastic-tipped ear tags were applied to both ears of all lambs immediately before tail docking. Wound photos of the ears and tail were taken twice weekly until weaning, resulting in 16 to 22 observations per lamb. Tail wound photos were analyzed to determine when the tail fell off and to score the presence of 6 tissue types: pus, serous exudate, sanguineous exudate, granulation, crust, and slough. A healed tail or ear wound was defined as one that was fully contracted, and no other tissue types were present. Tails took 19 ± 2 d to fall off (mean ± SD; range = 16 to 25 d) and their wound took 41 ± 8 d to heal completely (30 to 60 d). The prevalence of any of the 6 tissue types did not predict how long it took the tail wound to heal (F < 2.50, P > 0.13). Tissue types, indicative of possible infection, such as pus and slough, were present at least once in 89% and 93% of the docked lambs and in 8% and 10% of the total sampling periods, respectively. On average, pus and slough first appeared 12 ± 4 d (range = 5-22) and 11 ± 3 d (5-15) after docking, respectively. Of the 112 ear wounds, only 16% had healed by the time the lambs were weaned (55 to 74 d after tagging). Contrary to our predictions, there was a tendency for more docked lambs to have at least one healed ear wound by the end of the sampling period compared with undocked lambs (11 docked lambs vs 4 undocked lambs; X2 = 3.28, P = 0.07). This may be a result of an increased systemic inflammatory response and possible reduction in activity in the docked lambs. Overall, most ear tag wounds were still not healed after 2 mo, and tail wound took over 1 mo to heal. Further research is needed to determine the welfare implications of routine husbandry practices in sheep, including pain experienced during healing and how other factors may affect the healing process.