Title: Changes in tail length between docking and weaning of lambs Author
Submitted to: Sheep and Goat Research Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 1, 2013
Publication Date: September 1, 2013
Citation: Lewis, G.S. 2013. Changes in tail length between docking and weaning of lambs. Sheep and Goat Research Journal. 28:6-9. Interpretive Summary: Tail length consistently increased between docking and weaning. Docked tail length was closely related to bodyweight, and a simple regression equation was adequate for using bodyweight to predict docked tail length. Such an equation, after derivation and validation for the subpopulation of interest, would be useful for predicting tail length at weaning if lambs had been docked according to a defined protocol.
Technical Abstract: This study was conducted with crossbred lambs (n = 109 female and 120 male) to quantify tail length at docking and weaning. Lambs were born in April of one year and weaned at ˜ 125 d of age. Within 24 h after birth, lambs were weighed and ear tagged, and rubber rings were applied to dock tails. Rings were applied just past the distal end of the caudal folds of the tail, at a point just beyond where the folds attached to the tail. Time of rubber ring application was considered time of docking. Using a specially designed device, dock lengths were measured immediately after rubber ring application and at weaning. Lambs were weighed at weaning. Time of measurement (i.e., docking vs. weaning; P < 0.0001), gender (P < 0.003), gender × breed type (P < 0.002), and the covariate BW (P < 0.0001) were significant for tail length. Tail length adjusted for BW was greater (P < 0.0001) at weaning than at docking (6.4 vs. 5.1 cm). An equation was derived to use weaning BW to predict length of docked tails at weaning; difference between actual and predicted tail length was 0.04 cm. In conclusion, tail length consistently increased between docking and weaning and was closely related to BW. Bodyweight can be used to predict dock length at weaning.