Risk assessment and testing a key element in avoiding Johne's disease

Friday, May 6, 2011

In 2010, 70 per cent of Ontario dairy producers participated in a voluntary four-year prevention program and organizers are hoping to raise the tally to 100 per cent

by SUSAN MANN

Enniskillen-area dairy farmer Jim Millson always thought he did a great job with calf management. But now he knows for sure thanks to the Johne's Education and Management Assistance program.

Last November, Millson, the Dairy Farmers of Ontario board member representative on the program's working group, completed the on-farm risk assessment by his veterinarian and testing as part of the program. Millson's results revealed his herd was clean and he didn't have any high titre cows. He had 50 cows tested.

"The reason I wanted to test was to evaluate my calf-rearing program," he says.
On his farm, Millson says he separates the calves from the cows within 30 minutes of birth. "We always try to ensure the calf doesn't contact manure."

Millson uses several practices to ensure calves don't contact manure. First, he puts the cow due to give birth into a clean calving pen either the day before or the day she calves, and not weeks before. He also tries to be there during calving to offer assistance, ensure there aren't any problems and see that colostrum is fed to the calf within 30 minutes of birth.

The calf stays in a warming box for 24 hours and then is moved into a hutch. "The calves are raised in a separate facility until breeding age before being brought back to the main herd."

The risk assessment is designed to identify weaknesses in management that could lead to contamination. On Millson's farm, his veterinarian suggested he set aside a calving pen strictly for calving and not, for example, to temporarily house lame cows.

Farmers pay for the on-farm risk assessment administered by their veterinarian, but they can get reimbursed $8 per cow tested as part of the program. There is also a $500 reimbursement for culling high-titre cows. That compensation was retroactively increased this year to $500 from $250. Farmers must cull the identified high titre cow from the herd and the removal has to be confirmed before they get reimbursed for the testing, Millson says.

Prof. David Kelton of the University of Guelph says they're trying to convince not to put high titre cows into the food chain or sell them to other farms. The compensation for culled cows is a reasonable incentive to encourage people to cull rather than to totally reflect market value, he says.

Alain Lajeunesse, manager of market development and communications for Holstein Canada, says most farmers are culling their high titre cows.

Annual on-farm animal health inspections and veterinary drug use reviews by veterinarians will soon be mandatory on all dairy farms in Ontario. DFO has asked the Ontario Farm Products Marketing Commission to include the requirement in provincial Milk Act regulations, says George MacNaughton, production division director. Farmers doing the on-farm Johne's risk assessment would be fulfilling the requirement that all producers will have to meet likely starting in 2012. 

The voluntary four-year Johne's program is now in its second year. Industry and government contributed $2.5 million for the program. In 2010, 70 per cent of all Ontario dairy producers participated in their scheduled testing time slot. Of the 700 herds that took part, 46 herds identified 54 high titre cows, which are the ones shedding the mycobacterium paratuberculosis bacteria that causes Johne's disease. About one per cent of the 50,000 cows tested were positive and 10 per cent of the positive cows had a high titre.

Johne's is incurable but preventable. Cows infected by the disease produce less milk even if they don't show signs of sickness.

As for the infection rate, that was also in line with expectations. "We're a low-prevalence province and now is the time for producers to take management steps to maintain that status," MacNaughton explains.

Millson says he'd like to see 100 per cent of producers participating. But some farmers are afraid of discovering they have a high titre cow in their herd, a concern that stops them from taking part.

One of the strengths of the program is the education component outlining Johne's prevention strategies, Lajeunesse says. The risk assessment is a great tool to help farmers figure out what they can do to avoid the disease. "It can be completely avoided with management practices."

Will the program continue after four years? Program executive co-ordinator Nicole Perkins says that hasn't been decided yet. BF