Assessing experimental visceral pain in dairy cattle: A pilot, prospective, blinded, randomized, and controlled study focusing on spinal pain proteomics.

Few studies have verified the validity of behavioral and physiological methods of pain assessment in cattle. This prospective, blinded, randomized controlled experimental study aimed to validate different methods of pain assessment during acute and chronic (up to 21 d postintervention) conditions in dairy cattle, in response to 3 analgesic treatments for traumatic reticuloperitonitis. Cerebrospinal fluid (CSF) biomarkers and mechanical sensitization were measured as indicators of centralized pain. Proteomics in the CSF were examined to detect specific (to pain intensity) and sensitive (responsive to analgesia) markers. Recordings of spontaneous behavior with video analysis, telemetered motor activity, pain scales, electrodermal activity, and plasma cortisol concentration were quantified at regular intervals. Cows were assigned to group 1 (n=4, standard control receiving aspirin), group 2 (n=5, test group receiving preemptive tolfenamic acid), or group 3 (n=3, positive control receiving preemptive multimodal analgesia composed of epidural morphine, plus tolfenamic acid and butorphanol). Rescue analgesia was administered as needed. Generalized estimating equations tested group differences and the influence of rescue analgesia on the measurements. All 3 groups demonstrated a long-term decrease in a CSF protein identified as transthyretin. The decrease in transthyretin expression inversely correlated with the expected level of analgesia (group 1<2<3). Moreover, in group 1, CSF noradrenaline decreased long term, cows were hypersensitive to mechanical stimulation, and they demonstrated signs of discomfort with higher motor activity and "agitation while lying" recorded from video analysis. Decreased "feeding behavior," observer-reported pain scales, electrodermal activity, and plasma cortisol concentration were inconsistent to differentiate pain intensity between groups. In summary, changes in CSF biomarkers and mechanical sensitization reflected modulation of central pain in dairy cows. The spontaneous behavior "agitation while lying" was the only behavioral outcome validated for assessing acute and chronic pain in this visceral pain model.

Pain induced by a minor medical procedure (bone marrow aspiration) in dogs: comparison of pain scales in a pilot study.

BACKGROUND: Bone marrow aspiration (BMA) is a clinical procedure frequently performed in dogs. OBJECTIVE: To compare levels of pain intensity induced by 3 different BMA procedures using several pain scoring instruments. ANIMALS: Sixteen healthy Beagles. METHODS: A prospective experimental pilot study was conducted using blinded observers. Dogs were randomized into 3 groups: iliac BMA under sedation (Iliac-Sed, n = 4), sternum BMA under sedation (Stern-Sed, n = 4), and sternum BMA on conscious dogs without sedation (Stern-No-Sed, n = 8). RESULTS: Using the SF-Glasgow pain scale, the overall pain score in the Stern-No-Sed group was lower than that in the Stern-Sed group (P = 0.04). Using the 4A-VET pain scale, the effects of procedures over time on pain scores did not differ between and within groups. An inactivity index indicated that the overall score for the Stern-No-Sed group was significantly lower than the scores for the Stern-Sed and Iliac-Sed groups (P ≤ 0.01). There was a significant association in pain assessment using the SF-Glasgow and 4A-VET pain scales (P = 0.0004). When comparing the SF-Glasgowscale to the 4A-VET pain scale, the scores for the Stern-No-Sed group were lower compared to those of the Stern-Sed scores (P = 0.03). Based on telemetered motor activity, the Iliac-Sed group may have experienced more discomfort during the post-procedural period. CONCLUSIONS AND CLINICAL IMPORTANCE: Dogs may experience mild to moderate pain after BMA procedures, and the sternal site should be preferred. The SF-Glasgow pain scale showed better interobserver reliability, but the 4A-VET scale was less biased by sedation.