Aetiopathogenesis and genomic architecture of resistance to claw horn disruption lesions in dairy cattle

Maintaining good foot health is one of the most critical challenges the dairy industry faces today. This is because poor foot health leads to reduced mobility of the animal and causes lameness. The latter is a debilitating and painful condition and is described as one of the clearest indicators of compromised welfare in dairy cattle and one of the most important factors for the involuntary replacement of animals. No other common condition is associated with such visible signs of pain and, as such, cow lameness damages the public's perception of the industry. Recent studies have suggested that nearly half the dairy cows in the UK face reduced mobility and lameness issues at some point in their life, costing the dairy sector approximately £250 million annually.

Painful foot lesions account for more than 90% of reduced cow mobility and lameness cases. These lesions broadly fall under two categories: infectious diseases such as digital dermatitis and interdigital phlegmon, and non-infectious claw horn disruption lesions (CHDL) such as sole haemorrhages, sole ulcers and white line disease. CHDL are the most prevalent conditions associated with impaired mobility and pain in dairy cattle in the UK and worldwide. In a recent study by our group, 44% of cows developed CHDL during 12 months of monitoring.

Despite the importance of CHDL, the reasons leading to their development have not yet been fully described. The anatomic structure of the foot, animal hormonal and immune profiles, inflammation around calving, animal metabolism, and management practices have been thought to contribute. There are also genetic differences between individual animal susceptibility to CHDL development. In this project, all these factors will be studied together using a large number of animals raised in commercial UK farms. As a result, the project will (i) determine and quantify the impact of different factors affecting the development of CHDL, and (ii) identify and quantify the genetic background of animal resistance to the development of CHDL. To achieve its objectives, the project will draw on complementary expertise in animal science, veterinary medicine, genetics, biotechnology, bioinformatics, molecular pathology, immunology, and epidemiology.