There is also no doubt that mulesing is extremely painful. In addition to the scientific measurement of highly elevate cortisol levels in mulesed lambs, researchers have also measured behavioural indicators. When mulesed sheep were first released into a paddock they grazed and moved freely at first, suggesting some temporary pain relief from the endorphins. Soon, however, they showed abnormal behaviour which persisted to some degree for 72 hours and was described by Fell and Shutt (1989, p.2872) as follows: “Characteristically they stood with head down, nose almost touching the ground, back arched and body hunched and, maintaining this posture, they made sudden brief runs with a short, mincing gait quite unlike the steady walking of the controls.”
The mulesed lambs also showed strong avoidance of the person who mulesed them for 37 days. The work done by these researchers shows that lambs are in pain for at least 3 days following mulesing. The large scars left after mulesing take several weeks to heal and are susceptible to infection and flystrike.