title: Pre-clinical and clinical walking kinematics in female breeding pigs with lameness: A nested case-control cohort study.
abstract: Gait profiles were investigated in a cohort of female pigs experiencing a lameness period prevalence of 29% over 17 months. Gait alterations before and during visually diagnosed lameness were evaluated to identify the best quantitative clinical lameness indicators and early predictors for lameness. Pre-breeding gilts (n= 84) were recruited to the study over a period of 6 months, underwent motion capture every 5 weeks and, depending on their age at entry to the study, were followed for up to three successive gestations. Animals were subject to motion capture in each parity at 8 weeks of gestation and on the day of weaning (28 days postpartum). During kinematic motion capture, the pigs walked on the same concrete walkway and an array of infra-red cameras was used to collect three dimensional coordinate data of reflective skin markers attached to the head, trunk and limb anatomical landmarks. Of 24 pigs diagnosed with lameness, 19 had preclinical gait records, whilst 18 had a motion capture while lame. Depending on availability, data from one or two preclinical motion capture 1-11 months prior to lameness and on the day of lameness were analysed. Lameness was best detected and evaluated using relative spatiotemporal gait parameters, especially vertical head displacement and asymmetric stride phase timing. Irregularity in the step-to-stride length ratio was elevated (deviation  ≥ 0.03) in young pigs which presented lameness in later life (odds ratio 7.2-10.8).
authors.affiliation: School of Agriculture, Food and Rural Development, Newcastle University, Newcastle upon Tyne NE1 7RU, UK; School of Mechanical and Systems Engineering, Newcastle University, Newcastle upon Tyne NE1 7RU, UK. Electronic address: Sophia.Stavrakakis@newcastle.ac.uk.
authors.forename: S
authors.initials: S
authors.lastname: Stavrakakis
authors.affiliation: School of Agriculture, Food and Rural Development, Newcastle University, Newcastle upon Tyne NE1 7RU, UK.
authors.forename: J H
authors.initials: JH
authors.lastname: Guy
authors.affiliation: School of Electrical and Electronic Engineering, Newcastle University, Newcastle upon Tyne NE1 7RU, UK.
authors.forename: I
authors.initials: I
authors.lastname: Syranidis
authors.affiliation: School of Mechanical and Systems Engineering, Newcastle University, Newcastle upon Tyne NE1 7RU, UK.
authors.forename: G R
authors.initials: GR
authors.lastname: Johnson
authors.affiliation: School of Agriculture, Food and Rural Development, Newcastle University, Newcastle upon Tyne NE1 7RU, UK.
authors.forename: S A
authors.initials: SA
authors.lastname: Edwards
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D001947:Breeding; D016022:Case-Control Studies; D015331:Cohort Studies; D005260:Female; D005684:Gait; D007794:Lameness, Animal / Q000175:diagnosis / Q000503:physiopathology*; D009040:Motion Pictures; D034421:Sus scrofa; D013552:Swine; D016138:Walking
keywords: Biomechanics; Lameness; Motion analysis; Prevention; Sow