Date of this Version
Hauxwell, K. Analysis of Bone Lesion Occurrence and Activity Measurement in Relation to Gilt Retention within Breeding Systems, Undergraduate Honors Thesis. University of Nebraska-Lincoln. 2022.
The swine and agriculture industries have consistently been searching for increased methods for improving efficiency. This study addressed this concern through measuring sow activity traits and lesions in order to identify associations with lameness and gilt retention. Culled females (n = 73) were removed from the operation due to witnessed structural unsoundness by a trained stockman. Control gilts (n = 132) in this study were those that exhibited appropriate conformation but failed to show estrus or were excessed due to limited space. All females had video collection using the NUtrack System for 7 days before replacement selection. The NUtrack System records active traits such as distance travelled (m), time standing (s), eating (s), and laying (s), angle rotated (degrees) and average speed (m/s). Gilts in this study were harvested by a USDA inspected abattoir. Joints on the humorous and femur head were evaluated for osteochondrosis or osteoarthritis lesions. These lesions were labeled as major or minor instances. Major was categorized with severe osteochondrosis lesions where the surface of the joint was necrotic or fractured in a space larger than 2 millimeters in diameter. Minor was defined with imperfections in the cartilage or discoloration associated with reduced blood flow within the bone tissue under the joint. Ninety-eight gilts exhibited major or minor lesions (28 cull and 70 control). Surprisingly, chi-square analysis identified control females with higher instances than cull gilts (p < 0.05). The study used logistic regression to analyze data (RStudio V1.2.5033) with the birth group included in the model. NUtrack traits did not predict joint lesions (P > 0.1). Yet, traits of time standing (P < 0.001) and average speed (P < 0.05) were significantly associated with breeding retention. This implies that trait analysis by the NUtrack system could amplify a stockman’s ability in accurately predicting longevity in gilt retention.