Scores of Namibian farmers are baffled by the presence of arthrosis in all breeds of cattle and it seems that the popular Brahman is affected the most by this non-infectious degenerative condition of especially hind leg joints.
The problem is so serious that it will be brought to the attention of the agricultural ministry as farmers regard it as being in the national interest. Even Dr Joggie Briedenhann, renowned globally for his Bonsmaras, says the disease occurs on his farm Hartebeestloop and all that seems clear is that arthrosis is caused by environmental factors and is not hereditary. The presence of the disease has resulted in almost daily discussions around de-bushing as it seems some bushes contains the vital vitamins and minerals cattle need to prevent the disease.
In 1982, cattle farmers and local veterinarians in the Vryburg area of the North West Province of South Africa noticed the then new disease. Affected cattle developed visible swelling of particularly the stifle joint (femoro-tibial joint), as a result of effusions into the joints. There was lameness and poor growth and production, which could eventually lead to the affected animal being slaughtered. Post-mortem examination revealed ulceration of the joint cartilage and collapse of underlying bone (osteochondrosis).
Arthrosis initially seemed to affect only a small number of show animals, but by the mid-1990s the problem became more widespread, affecting up to 40% of some herds.
All breeds, sexes and age groups are affected, in both commercial and communal herds. It was already then noted that the disease was also present in Namibian cattle. The incidence of affected animals per farm varies significantly but it is estimated to be 20-30%, and in some cases up to 80% of weaner calves have been affected.
It is recommended that farmers replace 10-15% of their female stock per annum.
But on some farms, and especially in communal areas, the owners could not replace even 10% of their breeding herd annually due to the high incidence of arthrosis. In these cases breeding stock had to be purchased to maintain herd numbers. The price of a breeder is estimated to be double the price of a commercial animal. The loss per breeding animal with arthrosis is estimated to be in the region of N$8,000 per animal.
Some farmers reported an incidence of up to 40% of arthrosis in their Phase D bulls, all of which had to be slaughtered.