240 Impact of structural traits on semen collection training and lesion characteristics in Duroc boars

Abstract

Abstract Rising incidence of lameness in boar stud contributes to increased morbidity and mortality, affecting longevity and likely semen output. Lameness is not unique to the boar and affects the swine industry as a whole, contributing to millions of dollars in losses every year. Hypothesized contributors to lameness incidence are body, feet, and leg structure. In the boar stud lameness affects the ability of the boar to mount the dummy and can cause pain-related stress which can impact reproductive function. Lameness is also often accompanied by skin lesions or wounds which can lead to infection and further semen production. Our objectives were to evaluate the relationship between boar structural traits and semen collection training traits and determine if structural traits influence presence and severity of skin lesions. Structural traits of developing Duroc boars (n = 82; 190 ± 10.3 d of age) were assessed at arrival to the stud and 6 wk later. Structural traits assessed included front and rear leg set, foot shape, chest width, and hip width (1 = poor; 5 = ideal). An overall structure score for each boar was determined by adding all structural trait scores. Lesions were assessed on a zero to three scale (0 = no lesions; 3 = severe lesions). Based on overall structure score, boars were categorized into one of three groups (poor, intermediate, or ideal) to determine if structural traits affected the presence and severity of lesions. All boars were subjected to semen collection training 1 wk after arriving at the stud and considered trained when successful mounting and ejaculation occurred. Pearson’s correlation coefficients were determined between total structure score, lesion severity, and semen collection training characteristics. The GLIMMIX procedure of SAS was used to assess lesion presence differences between structure groups. Structure score and lesion severity were not significantly correlated (-0.017; P = 0.91) with number of attempts to train, time to mount, or time to collection of ejaculates. Upon arrival at the stud, boars in the poor structure group displayed a greater (P < 0.01) incidence of lesions than intermediate and Ideal structure groups but did not have greater lesion severity (P = 0.74). After 6 wk in the boar stud, there were no differences (P = 0.83) in lesion presence or severity between structure groups, suggesting the lameness issues are more likely caused by housing environment or other factors than structural traits.