42 Activity and Bone Lesion Analysis on Gilt Retention to the Breeding Herd

Abstract

Abstract A consistent theme in swine production is to increase efficiency and reduce input costs. In this study, sow activity traits and lesions were analyzed to identify associations with lameness and gilt retention. Gilts (n = 73) were culled based on structural unsoundness as determined by an experienced herdsman. Females (n = 132) that had been retained for breeding, but either did not show estrus at an appropriate age or were excessed due to limited farrowing space were used as controls. Gilts were recorded with the NUtrack System for 1 week prior to selection. The NUtrack System records distance travelled (m), time standing (s), eating (s), and laying (s), angle rotated (degrees) and average speed (m/s). Animals were humanely harvested in a USDA inspected abattoir. Both ends of the humerus and the femur head were evaluated for osteochondrosis or osteoarthritis lesions. Joint lesions were categorized as Major or Minor lesions. Major lesions were severe osteochondrosis lesions where cartilage was severely fractured or cartilage exhibited a region of necrosis larger than 2 millimeters in diameter. Minor lesions were defined creases or indentations in the cartilage or where abnormal blood flow existed in bone tissue underneath cartilage. Ninety-eight animals were identified with minor or major lesions (28 cull and 70 control). Unexpectedly, chi-square analysis did identify control animals as having higher incidences of minor or major lesions than cull animals (p < 0.05). Data were analyzed using logistic regression (RStudio V1.2.5033) with farrowing group included in the model. No NUtrack trait was predictive of joint lesions (P > 0.1). However, time standing (P < 0.001) and average speed (P < 0.05) were significantly associated with being retained for breeding. These data suggest that animal behavior and movement, as analyzed by NUtrack, can enhance herdsman efforts in making culling decisions of breeding animals.