A cooperative project among Michigan dairy producers, educational institutions and government is providing practical lesson in controlling Johne’s disease.
The state has just released a summary of the results in eight commercial dairy herds. Along with the cooperating herds, participants included: Michigan State University, the Michigan College of Veterinary Medicine, Michigan Cooperative Extension, the Michigan Department of Agriculture and USDA. Here’s a summary of results from several of the farms:
• Buning Dairy had a cull rate as high as 42% in the late 1990s. Once Johne’s Disease was confirmed, farm owners felt Johne’s was likely the cause of some of that high rate. “Looking back now we assume that our infection rate was probably as high as 20 percent 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, Johne’s infections rates have dropped below 15% on culture tests and below 10% on Eliza 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 determined the primary risk for Johne’s transmission on farm was in the calving area. Standing surface water that accumulated in the heifer and dry cow pastures was also an area of disease transmission. That area has since been fenced off. The Brocks also started using individual maternity pens in the barn during the winter and calving test-positive cows in a separate area. Colostrum is only fed from test-negative cows and a colostrum replacement is used when shortages of colostrum exist. The number of Eliza positive cows have dropped from 13.5% in 2005 to 9.5% in 2009.
• The Michigan State Dairy Cattle Teaching and Research Center has had a Johne’s infection rate of 2% or less between 2003 and 2007. “On this farm, a heifer doesn’t meet a cow until she is 22 months of age,” says Bob Kreft, farm manager. But in 2008, the Eliza positive rate jumped to 5%. While the 250-cow is aggressively managed to control Johne’s and all Johne’s positive animals culled, The Center is also open to hundreds of visitors annually. So the possibility of re-infection is always present. The lesson learned: Johne’s is difficult to eradicate and control programs must be consistently managed.
