Mechanical nociceptive threshold testing in Bos indicus bull calves

Abstract

Pain assessment in cattle is difficult, but is essential to assess the effect of surgery 13 and analgesic drugs. Nociceptive threshold testing is an objective pain assessment 14 tool that has not been described in Bos indicus cattle. A technique for mechanical 15 nociceptive threshold testing was developed for use in Bos indicus cattle undergoing 16 surgical castration to evaluate post-operative pain. 17 Abstract. 18The aim of this prospective, controlled, randomised trial was to develop a technique 19 for mechanical nociceptive threshold testing ( and on days 1, 2, 6, 10 and 13 after surgery. A handheld manual pneumatic device 27 with a 1 mm (diameter) blunt pin was used to deliver a mechanical stimulus to a 28 maximum of 27 Newtons (N) either side of the most dorsal aspect of the sacrum. 29The most frequent responses to the mechanical stimulus were lifting or kicking of 30 the leg on the same side as the stimulus (31%) and stepping away from the stimulus 31 (24.9 %). Data were analysed with a mixed effect linear model with the nociceptive 32 threshold (NT) as the response variable and day and analgesic treatment as 33 predictors (p < 0.05 was considered significant). For all groups, there was a trend 34 toward decreasing NT over the study period but there were no significant 35 differences between groups.Step down model selection with day, batch and 36 treatment terms revealed a significant effect of day (p < 0.001) and batch (p = 37 0.007). Mechanical NTT for assessment of pain in Bos indicus bull calves requires 38 further refinement to determine if this is a useful method of pain assessment. 39

Pressure Algometry Validation and Determination of Efficacy of Articaine Hydrochloride Ring Block in Antler Removal in Red Deer (Cervus elaphus)

“…Some research studies investigating pain assessment showed a decrease in MNT when measured over consecutive days. Stubsjøen et al (2010) demonstrated a decrease in MNT in sheep over three consecutive days, and Musk et al (2017) found a decreased MNT in bull calves tested over six days [38]. In contrast, an increase in MNT measurements was observed in the current study.…”

Objective Measures for the Assessment of Post-Operative Pain in Bos indicus Bull Calves Following Castration

“…Objective assessments in this context are those that are measurable and consistent when different instruments are used to attain the measurement. For Bos indicus cattle undergoing castration, both objective and subjective assessments of pain and stress have been utilised [ 7 , 8 , 9 , 10 ]. Objective assessments of pain or inflammation include evaluation of changes in blood concentrations of circulating cortisol, haptoglobin, creatinine kinase, total protein, and packed cell volume, as well as nociceptive threshold testing, and changes in bodyweight and activity (using pedometry) [ 8 , 9 , 10 ].…”

“…For Bos indicus cattle undergoing castration, both objective and subjective assessments of pain and stress have been utilised [ 7 , 8 , 9 , 10 ]. Objective assessments of pain or inflammation include evaluation of changes in blood concentrations of circulating cortisol, haptoglobin, creatinine kinase, total protein, and packed cell volume, as well as nociceptive threshold testing, and changes in bodyweight and activity (using pedometry) [ 8 , 9 , 10 ]. Other assessments in Bos indicus cattle following castration are based almost exclusively on the observation and the interpretation of behaviour, which are more challenging and time consuming to quantify, but may more accurately capture the animals’ response to the environment [ 11 , 12 ].…”