Version 1
: Received: 3 August 2020 / Approved: 4 August 2020 / Online: 4 August 2020 (11:13:41 CEST)
Version 2
: Received: 10 August 2020 / Approved: 11 August 2020 / Online: 11 August 2020 (10:10:24 CEST)
Sheil, M.; Polkinghorne, A. Optimal Methods of Documenting Analgesic Efficacy in Neonatal Piglets Undergoing Castration. Animals2020, 10, 1450.
Sheil, M.; Polkinghorne, A. Optimal Methods of Documenting Analgesic Efficacy in Neonatal Piglets Undergoing Castration. Animals 2020, 10, 1450.
Sheil, M.; Polkinghorne, A. Optimal Methods of Documenting Analgesic Efficacy in Neonatal Piglets Undergoing Castration. Animals2020, 10, 1450.
Sheil, M.; Polkinghorne, A. Optimal Methods of Documenting Analgesic Efficacy in Neonatal Piglets Undergoing Castration. Animals 2020, 10, 1450.
Abstract
Analgesic products for piglet castration are critically needed. This requires extensive animal experimentation such as to meet regulatory-required proof of efficacy. At present, there are no validated methods of assessing pain in neonatal piglets. This poses challenges for investigators to optimize trial design and to meet ethical obligations to minimize the number of animals needed. Pain in neonatal piglets may be subtle, transient and / or variably expressed and, in the absence of validated methods, investigators must rely on using a range of biochemical, physiological and behavioural variables, many of which appear to have very low (or unknown) sensitivity or specificity for documenting pain, or pain-relieving effects. A previous systematic review of this subject was hampered by the high degree of variability in the literature base both in terms of methods used to assess pain and pain mitigation, as well as in outcomes reported. In this setting we provide a narrative review, to assist in determining the optimal methods currently available to detect piglet pain during castration and methods to mitigate castration-induced pain. In overview, the optimal outcome variables identified are nociceptive motor and vocal response scores during castration, and quantitative sensory-threshold response testing and pain-associated behaviour scores following castration.
Copyright:
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Received:
11 August 2020
Commenter:
Meredith Sheil
Commenter's Conflict of Interests:
Author
Comment:
The review article has been revised following peer review, and contains additional / updated information regarding current analgesic/anaesthetic strategies in use and under investigation for piglet catration, progress and barriers to adoption, as well as reference to non-surgical options. These changes are principally in the introduction. Some rewording for clarity is also included in the body of the review, along with 2 new pertinent references (Yun et al., 2019 and Saller et al., 2020) which have been added to the tables. A number of additional references pertaining to mechanisms of pain, afferent nerve sensitisation and hyperalgesia have been included, along with references pertaining to opiate-induced sleep disruption.
Commenter: Meredith Sheil
Commenter's Conflict of Interests: Author