Date Full Report Received02/28/2011
Date Abstract Report Received02/28/2011
Funded ByIowa Pork Producers Association
Objectives of this study were to evaluate pressure algometry and thermal sensitivity as methods of pain assessment and to assess sodium salicylate and flunixin meglumine (BanamineÒ) for pain mitigation in sows with lameness. Twelve clinically normal sows were temporarily made lame on one hind limb, and were randomly assigned to one of two analgesic treatment groups or a control treatment. This arrangement was repeated 3 times so that all sows received each non-steroidal anti-inflammatory drugs (NSAID) treatment and served as an untreated control over the three repetitions with a two-week recovery and drug wash-out period between each repetition. Forty eight hours after they were made lame, NSAID treatments were initiated and were given daily for four consecutive days. Pain assessment tests were conducted on the day before the animals were made lame (when they should have been clinically sound), the day after they were made lame (when they should have been most lame), and the day after the treatment regimen (when they should have the most benefit from the treatment). Pressure algometry is a non-invasive tool used to determine the sensitivity to pressure threshold of the sow by gradually increasing the amount of pressure over time on the hind feet until a withdrawal (leg-lift response) was seen. The thermal sensitivity test measured the time required for a sow to withdraw in response to precise, focused heat stimulation. All measurements occurred on rear legs. There was no difference between the sound and lame rear legs for pressure algometry on the day before lameness was initiated. There was a significant difference between legs on the day that they were expected to be most lame proving that pressure algometry is capable of objectively detecting pain. The thermal sensitivity test was not able to detect differences in pain. These results support pressure algometry as an objective, noninvasive method for measuring pain sensitivity in sows induced with transient lameness. Thermal sensitivity is not a valid pain assessment tool for this induced sow lameness model. Neither pain tests were able to measure a significant positive effect of either sodium salicylate nor flunixin meglumine after treatment for four days. During implementation of the research protocol, extensive high definition video (~150 hours) was collected to create a library for training and comparing lameness scoring systems. This video allows visual comparison of the same sow when she is both lame and sound. An advantage of this comparison is that basic lameness evaluation can be taught without the complication of individual sow gait variation. Questions about the trial, conclusions, or the video library can be addressed to Dr. Locke Karriker using email: firstname.lastname@example.org or by phone: 515-294-2283.