#09-251

Complete

Date Full Report Received

03/05/2013

Date Abstract Report Received

03/05/2013

Investigation

Institution:
Primary Investigator:

Lameness associated with painful joint lesions has been identified as a welfare challenge for confined sows. It has been ranked as the number 3 reason for culling sows; comprising 15% of the culls marketed in the U.S. Producers in the U.S. currently treat sow lameness using husbandry tools, for example housing sows individually to provide easy access to key resources and rubber mats. Currently, producers assess sow lameness using subjective scoring systems, which have been shown to be variable in their application. Objective tools to measure sow lameness on farm are required. The objective of this study was to validate a list of potential objective tools to determine which could discriminate between sows in a painful and non-painful lameness state. Cortisol was elevated on most lame days compared to sound and resolved days. For the Prototype Embedded Microcomputer-based force plate system weight placed on the injected hoof decreased on the most lame day. GAITFour ® pressure mat gait analysis walkway system; Stride Time increased on most lame day for all hooves. Stride Length decreased on most lame day compared to baseline levels. Maximum Pressure placed on the induced hoof decreased on the most lame day compared to baseline levels. Stance time increased for all sound hooves between sound and most lame day. Mechanical Nociception Threshold test pressure tolerated by the lame hoof decreased for every landmark when comparing sound and most lame days. The sound hoof tolerated more pressure on most lame and resolved than on baseline sound day. Thermal Nociception Threshold test tolerated by the sound hoof did not change over the 3 treatment days. However, the sows tolerated less heat stimulation on their lame hoof on most lame day compared to baseline levels. Therefore, in conclusion, the physiology, kinematics and pain sensitivity tests all detected changes when sows were sound and in acute lameness states and show promise for on farm application.