"Lameness is one of the most serious health and welfare disorders in the dairy industry. Research into the detection of, causes of, and treatments for lameness have focused on gait scoring and environmental effects on hoof disorders. However these methods have limited usefulness when it comes to early lameness detection. Gait scoring methodologies are subjective and have low repeatability, and hoof injuries only become visible 2 to 3 months after the initial insult to the hoof. Early and accurate lameness detection means overall prognosis and the welfare of cows is improved. Previous studies that have used a molecular approach to identifying biomarkers of lameness were confounded because the researchers did not differentiate between different types of hoof disorder, which have various aetiologies. Moreover, the studies did not attempt to determine whether any potential biomarkers would be useful for early identification of cows at risk of lameness. The degree to which lameness affects animal health may be influenced to a large part by leukocytes of the immune system. Neutrophils are phagocytic granulocytes of the innate immune system, are plentiful in bovine blood, and provide a crucial first-line defense against invading pathogens. Gene expression profiles in these cells are affected by stress (e.g. transportation stress). Cows display a physiological stress and sickness response to lameness, and thus investigation into the usefulness of changes in neutrophil gene expression as objective measures of lameness onset is warranted. Initially we will investigate changes in the physiological stress response and gene expression profiles in neutrophils of cows that have lameness caused by claw horn disorders. We will then investigate levels of expression of identified biomarkers in cows with various lameness severity. Finally we aim to investigate whether identified biomarkers could be used as early indicators of claw horn disorder development."