Objective Measures for the Assessment of Post-Operative Pain in Bos indicus Bull Calves Following Castration
College of Veterinary Medicine, School of Veterinary and Life Sciences, Murdoch University, Murdoch, Western Australia 6150, Australia
Department of Large Animal Sciences, University of Copenhagen, DK-2630 Copenhagen, Denmark
School of Mathematics, University of Adelaide, Adelaide, South Australia 5005, Australia
Institute of Veterinary, Animal and Biomedical Sciences, Massey University, Palmerston North 4442, New Zealand
Author to whom correspondence should be addressed.
Received: 24 August 2017 / Revised: 25 September 2017 / Accepted: 25 September 2017 / Published: 28 September 2017
Surgical castration of cattle is a common husbandry procedure, and although this procedure is known to cause pain in cattle and other species, in some countries it is often performed without anaesthesia or analgesia. Society is increasingly aware of this animal welfare issue and it is creating pressure to drive research into animal welfare science with the aim of identifying practical and economical approaches to pain management in livestock. To effectively manage pain, a pain assessment must be performed. Pain assessment methods are often subjective and therefore influenced by the observer. Ideally, objective assessments that generate consistent and repeatable results between observers should be identified. Bos indicus bull calves were divided into four groups: no castration (NC, n = 6); castration with pre-operative local anaesthetic (CL n = 12); castration with pre-operative anti-inflammatory medication (CM, n = 12); and, castration without pain relief (C, n = 12). A range of objective assessments was performed: bodyweight measurements, activity, and rest levels, and four different compounds in the blood. The results of this study suggest that animals rest for longer periods after the pre-operative administration of anti-inflammatory medication. The other objective assessments measured in this study were not able to consistently differentiate between treatment groups. These findings emphasise the need for alternative quantifiable and objective indicators of pain in Bos indicus bull calves.