A cooperative project among Michigan dairy producers, educational institutions and government is providing practical lessons in controlling Johne’s disease.
The state recently released a report of the results in eight commercial dairy herds. Along with the cooperating herds, participants included: Michigan State University (MSU) and its College of Veterinary Medicine, MSU Cooperative Extension, the Michigan Department of Agriculture and USDA.
Here’s a summary of results from two of the farms:
Buning Dairy had a cull rate as high as 42% in the late 1990s. Once Johne’s disease was confirmed, the farm’s owners felt Johne’s was the likely cause of some of that high rate. "Looking back now, we assume that our infection rate was probably as high as 20% at that time," says Norm Buning.
The dairy milks 300 cows with a rolling herd average of 28,800 lb. of milk. The Bunings were housing young calves next to the maternity pen and other adult cattle. They suspect that’s where most of the new infections occurred. By maintaining a clean calving area and moving calves away from the area, they have lowered the Johne’s infection rate to less than 15% on culture tests and less than 10% on ELISA tests.
Brock Dairy culled 165 animals from a herd of 500 in 2006, with 50 of them showing clinical signs of Johne’s disease. MSU researchers found that the primary risk for Johne’s transmission on the farm was in the calving area. Consequently, the Brocks started using individual maternity pens during the winter and calving test-positive cows in a separate area.
Standing surface water in the heifer and dry cow pastures was also an area of disease transmission. That area has since been fenced off.
Colostrum is fed only from test-negative cows and a colostrum replacement is used when shortages exist. The share of ELISA positive cows has dropped from 13.5% in 2005 to 9.5% in 2009.