Abstract

The rationale for the length at which lambs’ tails are docked was investigated by comparing lambs with No-tail, Short, Medium (covering the vulva in ewe lambs and at a similar length in males), Long, and Undocked tails. In Experiment 1, dagging and shearing required additional effort in Long and Undocked animals. There were no differences in average dag scores, but few lambs had dags. Shorter tail docking resulted in significantly (P<0.05) lighter recto-coccygeal muscles (from 8.9 ± 0.5g in Undocked to 6.6 ±0.4g in No-tail). The tail stumps of half of the No-tail, Short and Medium showed evidence of neuroma development and degenerative nerve changes compared with few of the Long and Undocked lambs. In Experiment 2, restlessness, an indicator of pain and distress in rubber ring docked lambs, tended to be more pronounced the shorter the tail was docked. Experiment 3 compared typical farm practices (Short), with the AWAC-recommended length (Medium). The slightly longer length was associated with (1) more lambs difficult to dag (11/44 Medium vs. 4/44 Short; P<0.001); and (2) no perceived benefits in increasing tail length. While the traditional Short and Medium tails appear to be the most appropriate, pain and distress, neuroma development and rectal muscle function may also be affected by tail length. It is yet to be determined if these additional factors justify a change to current practicesbut that possibility is considered unlikely.

MW, Fisher, and NG Gregory

Proceedings of the New Zealand Society of Animal Production, Volume 67, Wanaka, 32-38, 2007