In the opinion of livestock farmers, signs of pain in calves less than 1-week old are generally
weak and thus in their view castration is usually considered a painless procedure that does not
require pain control (Boesch et al., 2006). The farmers’ practical experience contrasts to recent scientific evidence that very young human beings and animals can feel pain as older animals do (Mellor and Stafford, 2004; Baccei and Fitzgerald, 2006; Qiu, 2006; Mellor and Gregory, 2003), even the behavioural responses to pain might be less expressive. Robertson et al. (1994) reported that there was usually less struggling and shorter periods of abnormal postures associated with castration in 6-day-old calves compared with 21- and 42-day-old calves; this made themconclude that the procedure caused less pain in the younger calves.