Papillomatous
Digital Dermatitis (PDD)
Dr Darren Trott, School of Veterinary Science, University of Queensland is investigating PDD a chronic contagious disease that is the most common cause of lameness in dairy cattle in the USA and Europe.
PDD is endemic in these countries and is associated with the intensive housing and feeding of dairy cattle. In countries where dairy cattle predominantly graze pasture, PDD may occur sporadically but it is not considered to be a serous economic problem. One case of PDD was recently reported in Queensland, but there have been not other records of its occurrence in Australia.
Dr Trott is concerned that with the deregulation of the dairy industry in Australia, herd sizes will increase and conditions in dairies may become factorable for PDD to occur endemically providing the causative organisms are present in the herd.
A questionnaire has been designed to:
1. Determine what veterinarians consider are the most important causes of lameness in Australian dairy cattle;
2. Determine whether PDD lesions are widespread in Australian dairy cattle and whether dairy cattle veterinarians are familiar with the condition;
3. Identify potential herds with lesions that can be biopsied to confirm histopathological feature of PDD and attempt to grow the suspected aetiological agents.
PDD is a painful and contagious disease causing wart like lesions on the cattle’s feet. These lesions usually occur on the animal’s hind feet near the interdigital cleft or the bulb of the heel. Lesions however, do occur on the front feet and may also occur at the front of the foot near the dewclaws or in the interdigital cleft. Digital swelling is absent or only minor.
Cattle suffering from PDD suffer sever lameness with walking on toes and clubbing of hooves. Lameness does not occur in all cases of PDD, however, the onset of lameness may be sudden. Other clinical signs typical of PDD include decreased fertility, reduced milk production and weight loss.
The pathogenic agent responsible for PDD is unknown. There is strong evidence that bacteria are involved. PDD lesions are highly responsive to antibiotics and large numbers of invasive spirochaetes are found in 96% of lesions.
For further details contact: Gabriel Milinovich
Phone 04 1818 4653