Thirty Ossimi lambs were used in an experiment to compare those whose tail was docked shortly after birth with controls. After weaning at 4 months of age the groups were further subdivided and two of the four groups closely shorn according to a 2 × 2 factorial design.
Male lambs at 20 kg were subjected to intensive finishing until the age of 50 weeks and nine were then slaughtered to determine carcass characteristics.
There was a trend for increased live-weight gain in the docked lambs in the preweaning stage (up to 16 weeks).
This trend was also present, although not statistically significant, in the final phase of intensive feeding from 20 kg weight to 50 weeks. Shearing significantly improved daily gain in this final period (P < 0·05). These increases in gain were also apparently associated with improvements in efficiency, as judged on a group basis.
Docking and shearing also tended to cause increases in body measurements: height, chest girth and abdomen girth in the case of docking (P < 0·05) and chest girth, chest depth and abdomen girth in the case of shearing (P < 0–05).
Carcass characteristics, measured on a relatively small sample, indicated several effects of docking and shearing on carcass traits although most of these were consistent with the expected differences stemming from the higher carcass weights acheived at 50 weeks of age by docked and sheared lambs.