Time spent in postures with full extension of the hind limbs in the 90 minutes after different rubber ring castration treatments of lambs less than a week of age
CTD - Bilateral castration and docking
C2 - Bilateral castration
C1 - Unilateral castration
C0 - Short scrotum castration
LA - Short scrotum castration with local anaesthetic
H - Handled control lambs
TD - Tail docked only
V4 - lying ventral / sternal posture with full extension of the hind limbs
LL - lying in a lateral posture with full extesion of the hind limbs
Lambs fully castrated and tail docked spent 50 minutes (out of a possible 90 minutes) lying with full extension of the hind limbs. This compares with 45 min for those bilaterally castrated, 17 minutes for unilaterally castrated lambs and 5 minutes when castrated by the short scrotum technique. When local anaesthetic was used with short scrotum castration the time spent with full extension of the hind limbs reduced to less than a minute, close to the value in handled lambs, when the posture was never seen during this experiment. Tail docked lambs spent less than two minutes in this posture.
Lying with full extension of the hind limbs is a useful posture to measure when assessing severe pain but less useful for mild to moderate pain, when abnormal standing and lying with partial extension of the hind limbs becomes more important. This statement is particularly true if the effectiveness of an analgesic is being tested; it is difficult to show a reduction in a parameter that is only rarely shown.
