Dock Length Has No Effect on Rectal Prolapse

At Texas Tech, researchers investigated the effects of sex, breed, docked tail length, and the expression of the callipyge phenotype on the incidence of rectal prolapse in lambs.

To test whether these factors influence rectal prolapse in a controlled feedlot environment, lambs (n = 382) representing both sexes and four breed types were assigned randomly to one of three docking treatments. In short-docked lambs, the tail was removed as close to the body as possible. In medium-docked lambs, the tail was removed midway between the attachment of the tail to the body and the caudal folds to the tail. Long-docked lambs had their tails removed at the attachment of the caudal folds to the tail.

Incorporating the callipyge phenotype into the study design assessed the effect of enhanced muscle development on rectal prolapse. The overall incidence of rectal prolapse in the study was 2.1 percent. Ewe lambs were no more likely to experience prolapses than male lambs. Seven of the eight (87 percent) lambs that prolapsed were hair sheep. No lambs expressing the callipyge phenotype prolapsed. There was no difference in rectal prolapse occurrence among the three docking treatments.

In the study, sex, tail dock length, and muscling did not appear to contribute to rectal prolapse in lambs. However, there may be an over-looked genetic component that influences the occurrence of prolapses in response to the practice of docking.

Source: Sheep & Goat Research Journal, March 2014