February 18, 2010
It has been suggested that studies of rectal prolapse are affected by confounding variables.8,9,10,11 A minimum length of tail to qualify for showing has been proposed11 and implemented in some states. The appropriate length for docking is variously expressed as exhibition of 0.7 inches of tail, docking at the third or fourth coccygeal vertebrae, or docking at the end of the caudal fold/hairless under-tail area.
Pain—Active behavioral responses indicating pain are restlessness, rolling, easing quarters (the hind quarters are moved slowly and alternately without locomotion), stamping, kicking, head turning and vocalization by the lamb. 2,3,11 High concentrations of cortisol in the blood are also associated with pain and distress. 2,3,12 Increased active behavior, as well as elevated peak blood cortisol concentrations are seen in lambs undergoing tail docking. 2,3,12
Hot blade—The hot blade method involves severing the tail and cauterizing it, using a heated anvil scissor docking iron. The cut end of the tail is held against the heated blade for approximately 1 second to improve hemostatis.3 Tail docking performed with a heated docking iron has been shown to produce levels of pain behavior and blood cortisol concentrations that are not significantly different from handled lambs whose tails are not docked.3
Rubber ring followed by crushing—A rubber ring may also be applied as described above followed by application of a bloodless castrator across the full width of the tail for approximately 10 seconds. 2,3 The rubber ring generally rolls into the groove made by the bloodless castrator.2 It has been shown that the application of a bloodless castrator in addition to rubber ring placement did reduce active behavioral pain responses (see section on pain above) and increases in blood cortisol concentrations associated with docking. 2
The Farm Animal Welfare Council (FAWC) recommends that docking should be avoided whenever possible.18 The FAWC also concluded that tail docking of lambs up to 7 days old is best done with a rubber ring; that lambs between the ages of 1 and 8 weeks old should be docked with a docking iron (hot blade) or a clamp; and that acute pain of tail docking can be alleviated using locally applied anesthetics.18
REFERENCES1 Webb Ware JK, Vizard AL and Lean GR. Effects of tail amputation and treatment with an albendazole controlled-release capsule on the health and productivity of prime lambs. Aust Vet J. 2000;78:838-842.2 Kent JE, Molony V and Graham MJ. Comparison of methods for the reduction of acute pain produced by rubber ring castration or tail docking of week-old lambs. Vet J. 1998;155:39-51.3 Graham MJ, Kent JE, and Molony V. Effects of four analgesic treatments on the behavioural and cortisol responses of 3-week-old lambs to tail docking. Vet J. 1997;153:87-97.4 Morris MC. Ethical issues associated with sheep fly strik research, prevention, and control. J Ag Envir Ethics. 2000;13:205-217.5 Graham MJ, Kent JE and Molony V. The influence of the site of application on the behavioural response of lambs to tail docking by rubber ring. Vet J 2002;164:240-243.6. Anderson DE and Miesner MD. Rectal prolapse. Veterinary Clinics of North America: Food Animal Practice 2008; 24: 403-408.7 Luther J. Causes, prevention and treatment of rectal prolapse in sheep. NDSU Extension Services September 2008. AS-1388.8 Thomas DL, Waldron DF, Lowe GD, Morrical DG, Meyer HH, High RA, Berger YM, Clevenger DD, Fogle GE, Gottfredson RG, Loerch SC, McClure KE, Willingham TD, Zartman DL and Zelinsky RD . Length of docked tail and the incidence of rectal prolapse in lambs. J Anim Sci 2003;81:2725-2732.9 Zanolini WF. The effects of dock length on the incidence of rectal prolapse in lambs. Master's Thesi, Texas Tech University. Available at: http://hdl.handle.net/2346/999 Accessed February 18, 2010.10 Windels H. Factors causing rectal prolapse in feedlot lambs. Proceeding 62nd annual sheep and lamb feeders day, University of Minnesota. 1990;10-13.11 Goodwin J, Murphy T and Jacobson R. A path to resolution regarding the show lamb taildocking controversy. J Extension 2007;45:Article 4FEA8.12 Molony V, Kent JE and McKendrick IJ. Validation of a method for assessment of an acute pain in lambs. Appl Anim Behav Sci 2002;76:215-238.13 Pollard JC, Roos V and Littlejohn RP. Effects of oral does of acetyl salicate at tail docking on the behavior of lambs aged three to six weeks. Appl Anim Behv Sci 2001;71:29-42.14 Mellor DJ and Murray L. Effects of tail docking and castration on behaviour and plasma cortisol concentrations in young lambs. Res Vet Sci 1989;46:387-391.15 Kent JE, Jackson RE, Molony V, and Hosie BD. Effects of acute pain reduction methods on the chronic inflammatory lesions and behavior of lambs castrated and tail docked with rubber rings at less than two days of age. Vet J 2000;160:33-41.16 Price J and Nolan AM. Analgesia of newborn lambs before castration and tail docking with rubber rings. Vet Rec. 2001;149:321-324.17 Scobie DR and O-Connell D. Genetic reduction of tail length in New Zealand sheep. Proceedings of the New Zealand Society of Animal Production 2002;62:195-198.18 Farm Animal Welfare Council. FAWC report on the implications of castration and tail docking for the welfare of lambs. FAWC, London, England. June 2008. Available at: http://www.fawc.org.uk/pdf/report-080630.pdf Accessed February 18, 2010.