RESEARCH
Massey University doctoral student Aaron Yang has been researching digital dermatitis in dairy herds for his studies. He visually assessed 59,849 cows in 127 herds.
Hoof disease reveals mysteries ANNE BOSWELL
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EW Zealand’s unique position with bovine digital dermatitis (DD) puts it in good stead to manage the disease in future, Massey University student Aaron Yang says. He gained many insights into the disease, which was previously thought to be absent or at least extremely rare here because of the unique pastoral dairy system, while doing his masters degree and doctorate. Studies have been done overseas but limited information was available on DD in NZ. DD is the most important infectious cause of cattle lameness in confined systems, particularly in the northern 52
hemisphere. Once in a herd DD typically becomes endemic and is eradicated from few herds. It can result in loss of production and increased animal health management time and cost. It also raises concerns of animal welfare because it causes varying levels of discomfort and pain. Yang’s interest was encouraged by hoof health expert Neil Chesterton. “Neil brought a project to Massey when I was doing my masters, which was a pilot study of DD in Taranaki,” he says. “I thought it was a very interesting study as no one else had really looked at this disease carefully in NZ. I took the project as my masters dissertation and then DD research became part of my life over the past five years.” He found the disease is rare, at least in Taranaki. Farms where more DD cases
were detected were generally related to loose biosecurity management. However, there was no information about it in the other parts of the country and he was to discover the mystery of DD in NZ where the dairy system is different to other major dairy production countries. Yang adopted novel methodological approaches and investigated the distribution, risk factors, climate effect and transmission dynamic of DD. He visually assessed 59,849 cows from 127 herds in Waikato, South Canterbury, West Coast and Manawatu. He chose those regions to provide a cross-section of farming systems: Waikato for its 3000-herds, South Canterbury to represent large herds and irrigated pastures, West Coast for its unique geography and predominantly self-
DAIRY FARMER
July 2020
