Detection and management of lameness in dairy cattle in New Zealand and Tanzania : a thesis submitted in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Veterinary Science at Massey University Te Kunenga Ki Pūrehuroa, University of New Zealand, School of Veterinary Science, Manawatu

Alongside mastitis and infertility, lameness is one of the key animal health challenges on dairy farms. Lameness is particularly challenging due to the complex nature of its aetiopathogenesis and its multiple risk factors. Early detection combined with effective treatment, management and prevention are integral approaches to reducing the impact of lameness on dairy farms, improving productivity, and enhancing animal health and welfare. This thesis focused on improving detection and improved management. Visual locomotion scoring (LS) is currently the most widely used system for detecting lameness worldwide but has attributes that limit its usefulness and application. The first part of this thesis presents three studies looking at alternatives to LS: infrared thermography (IRT) and in-parlour scoring (IPS). IRT was compared to LS in both New Zealand and Tanzania, while IPS was tested in New Zealand alone. Both IRT and IPS proved to be useful alternatives to LS, but further research on more farms across more countries is required before they can replace LS for lameness detection on dairy farms. The second part of the thesis evaluates the response to a three timepoint regime of prophylactic hoof trimming (dry-off, early lactation, and end of lactation) on; 1) lameness incidence and time from calving to increased locomotion score, and 2) the distance from the external claw sole surface to the distal phalanx (DDP), and how this relates to lameness risk. On the study farm, prophylactic hoof trimming did not decrease lameness incidence or time to clinical lameness (locomotion scores ≥2). However, it did increase the interval from calving to an observable change in gait (locomotion scores ≥1). In regard to DDP, the study showed that DDP was not affected by trimming and that changes in DDP did not affect the hazard of increased locomotion score, i.e. either locomotion scores ≥1 or locomotion scores ≥2. Keywords: lameness; locomotion scoring; infrared thermography; in-parlour