New Research Journal Article Posted
July 25, 2014

A new Sheep and Goat Research Journal article -- Effects of Sex, Breed, Callipyge Phenotype and Docked Tail Length on Rectal Prolapse in Lambs, authored by B. Zanolini, A.M. Oberbauer, S.D. Prien, M.L. Galyean and S.P. Jackson -- is now available at by clicking on Research and Education and then Sheep and Goat Research Journal.

The objective of this study was to investigate 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 representing both sexes and four breed types were assigned randomly to one of three docking treatments: 1) tail removed as close to the body as possible; 2) tail removed midway between the attachment of the tail to the body and the caudal folds to the tail; and 3) tail 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 this study was 2.1 percent. Ewe lambs were no more likely to experience prolapses than male lambs. Seven of the eight 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 this 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.