Effects of local anesthetic or systemic analgesia on pain associated with cautery disbudding in calves: A systematic review and meta-analysis

Abstract

Disbudding is a common management procedure performed on dairy farms and, when done without pain mitigation, is viewed as a key welfare issue. Use of pain control has increased in recent years, but full adoption of anesthesia and analgesia by veterinarians or dairy producers has not been achieved. This may in part be due to the lack of a consistent recommendations of treatment protocols between studies examining pain control methods for disbudding. The objective of this systematic review was to examine the effects of these pain control practices for the most common method of disbudding, cautery, on outcomes associated with disbudding pain in calves. The outcomes were plasma cortisol concentrations, pressure sensitivity of the horn bud area, and validated pain behaviors (ear flick, head shake, head rub, foot stamp, and vocalization). Intervention studies describing cautery disbudding in calves 12 wk of age or younger were eligible, provided they compared local anesthesia, nonsteroidal anti-inflammatory drug (NSAID), or local anesthesia and NSAID to 1 or more of local anesthesia, NSAID, or no pain control. The search strategy used the Agricola, Medline (via OvidSP), and Web of Science databases, as well as the Searchable Proceedings of Animal Conferences (S-PAC), ProQuest Dissertations and Theses Database, and Open Access Theses and Dissertations. Meta-analysis was performed for all outcomes measured at similar time points with more than 2 studies. Local anesthetic was associated with reduced plasma cortisol until 2 h postdisbudding; however, a rise in cortisol was observed in the meta-analysis of studies reporting at 4 h postdisbudding. Heterogeneity was present in several of the analyses for this comparison. The addition of NSAID to local anesthetic showed reduction in plasma cortisol at 4 h, and a reduction in pressure sensitivity and pain behaviors in some analyses between 3 and 6 h postdisbudding. Heterogeneity was present in some meta-analyses, including several using pain behavior outcomes. This may reflect the variation in measurement time periods for behavioral measures between studies, as well as differences among NSAID treatments. Overall, a protective effect of local anesthetic was seen for the acute pain of cautery disbudding, and the delayed rise in cortisol was mitigated by the addition of an NSAID, which also reduced other signs of pain, including pressure sensitivity and pain behaviors. Based on these findings, we recommend use of local anesthetic and an NSAID as best practices for pain mitigation for cautery disbudding of calves 12 wk of age or less. The magnitude and duration of the effect of NSAID treatment was not possible to deduce from the literature because wide variation existed between studies. We recommend consideration of more standardized outcome measurements, especially for pain behaviors. Adherence to reporting guidelines by authors would help ensure more transparent and complete information is available to end users.

Symposium review: Scientific assessment of affective states in dairy cattle

“…Wound-directed behaviors do allow inferences about the where of the affective experience, even if details about the what are less clear. For example, in the hours following hot-iron disbudding, calves show increased attention toward the injured area, including an increased frequency of ear flicks and head shakes (McMeekan et al, 1999;Sylvester et al, 2004;Winder et al, 2018). However, some variation in results might be explained by changes in behaviors less likely to be useful, such as changes in activity.…”

Invited review: Completeness of reporting of experiments: REFLECTing on a year of animal trials in the Journal of Dairy Science

“…Incomplete reporting in primary studies is a common finding in systematic reviews in animal health research (Dzikamunkenga et al, 2014;Baltzell et al, 2015), and limits the ability to answer relevant questions (Winder et al, 2018;Ali Naqvi et al, 2018). A lack of detail in reporting results in studies with suitable intervention groups and outcomes being excluded from meta-analysis (Rodney et al, 2105;Haimerl et al, 2017), thus reducing the utility and impact of these individual studies.…”

Organic Dairy Cattle: Do European Union Regulations Promote Animal Welfare?

“…Disbudding is acutely painful and induces strong behavioral and physiological responses in absence of pain mitigation [ 29 ]. There is a growing body of evidence indicating that the intra-operative pain can be controlled by using general anesthesia, local anesthesia or a combination of both [ 30 , 31 ]. However, effects of these drugs are limited to approximately 2 hours and, therefore, fail to mitigate the post-operative pain [ 28 , 31 , 32 ].…”

“…There is a growing body of evidence indicating that the intra-operative pain can be controlled by using general anesthesia, local anesthesia or a combination of both [ 30 , 31 ]. However, effects of these drugs are limited to approximately 2 hours and, therefore, fail to mitigate the post-operative pain [ 28 , 31 , 32 ]. Evidence of post-operative pain begins when the effects of the drugs wane as shown by behavioral and physiological changes [ 31 ].…”