|STOJKOV, JANE - University Of British Columbia|
|VON KEYSERLINGK, MARINA - University Of British Columbia|
|WEARY, DANIEL - University Of British Columbia|
Submitted to: Physiology & Behavior
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/19/2015
Publication Date: 7/16/2015
Citation: Stojkov, J., Von Keyserlingk, M.A., Marchant Forde, J.N., Weary, D.M. 2015. Assessment of visceral pain associated with metritis in dairy cows. Physiology and Behavior. DOI:10.3168/jds.2014-9296.
Interpretive Summary: Inflammation of the wall of the uterus, known as metritis, is common in dairy cattle. It is assumed to be painful, but there are no known studies that have tried to quantify this pain. The aim of this study was determine the visceral pain responses of healthy and metritic cows during rectal and uterine palpation, using a combination of pain behavior and heart rate variability - a statistical method of identifying the cyclical changes in heart rate that can be indicatative of stress and pain. A total of 24 metritic cows and 39 healthy cows were monitored during rectal and uterine palpation. Arching of the back was greater during palpation for metritic cows versus health cows and greater during uterine palpation than during rectal palpation. Heart rate variability analysis also showed differences in measures that indicated increased pain both between metritic and healthy cows and between rectal and uterine palpation. Together, these results indicate that the inflammation associated with metritis is painful, and that the pain response can be detected during rectal and uterine palpation. Uterine palpation appears to be more aversive than rectal palpation, suggesting that the former should be avoided whenever possible.
Technical Abstract: Metritis is a common disease in dairy cattle but to our knowledge no work has assessed pain associated with this disease. Tissue palpation is commonly used to assess pain in human and veterinary medicine. The objective of this study was to evaluate visceral pain responses during rectal and uterine palpation in healthy cows and in cows diagnosed with clinical signs of metritis. A total of 73 Holstein dairy cows (mean±SD parity = 3±1.8) were subjected to systematic health checks starting 3d after parturition and continuing every 3d for 21d. Cows were scored for vaginal discharge (0 to 4); 24 cows showed a discharge score = 2 during at least one health check and were classified as metritic and 39 cows were classified as ‘healthy’ all showing no sign of any other disease (including mastitis and lameness). Back arch and heart rate variability (HRV) before examination and during palpation were recorded using video and heart rate monitors. Back arch (cm²) on the day of diagnosis was higher in metritic versus healthy cows (32±2.2cm²vs. 19±1.5cm²), and greater during uterine versus rectal palpation (27±1.4cm² vs. 24±1.4cm²). Heart rate frequency analysis showed that low frequency portion (LF%) was higher in cows with metritis versus healthy cows (16.3±1.22 vs. 12.8±1.10). The SD between normal to normal inter beat intervals and the root mean square of successive differences both decreased during uterine versus rectal palpation (1.9±0.14 vs. 1.9±0.14 and 1.3±0.14 vs. 1.7±0.10, respectively). Together, these results indicate that the inflammation associated with metritis is painful, and that the pain response can be detected during rectal and uterine palpation. Uterine palpation appears to be more aversive than rectal palpation, suggesting that the former should be avoided whenever possible.