Dairy: Dairy industry working group proposes help in fighting Johne's disease
Sunday, January 4, 2009
The 12-year management assistance program, which is expected to cost $24 million, will provide advice on farm prevention practices for every dairy farmer in Ontario
by SUSAN MANN
A dairy industry working group has proposed a province-wide management assistance program, where every dairy farmer across Ontario would discuss farm prevention practices against Johne's disease with a trained veterinarian.
The proposal, being developed by the Johne's Industry Working Group, should be launched sometime in 2009, says George MacNaughton, production and regulatory compliance director with Dairy Farmers of Ontario. He's a member of the working group, which includes representatives from government, breed associations, dairy veterinarians and other industry organizations.
The group is looking for funding from the federal Growing Forward initiative for its 12-year program, which is expected to cost $24 million.
Johne's is a disease which reduces milk production in cattle. Most antibiotics don't work against the bacterial infection and the ones that may be effective can't be used in food animals.
Both MacNaughton and Dr. Ann Godkin, an Ontario agriculture ministry veterinarian, believe that there is strong interest from farmers in the proposed program. During the 2005-2007 pilot Johne's Prevention Project, almost 500 herds were signed up for the second year even though farmers had to pay some of the costs, such as testing fees.
"That shows the high level of interest producers and veterinarians have in finding ways to prevent this disease and having a program to do that,"
Dr. Godkin says.
Johne's develops slowly and an infected animal can pass it to a new generation of heifers before she tests positive or shows any symptoms. The best way to prevent very young calves from being exposed is to ensure that they don't get manure from infected cows in their mouths, Dr. Godkin says.
Young calves can ingest the bacteria that cause Johne's from bedding in a maternity pen, from milk or colostrum from infected and shedding cows, or just by general environmental contact. "Calves need to be out of contact with cows and their manure," Dr. Godkin.
If the Johne's infection starts in milk-fed calves, it will last for the animal's lifetime. While it's not impossible, current research shows that most animals older than one year don't become infected, Dr. Godkin says.
About five per cent of animals become outwardly sick and develop persistent or recurrent diarrhea without fever or signs of other aliments. But it's a hard disease to identify, because other illnesses may have similar symptoms.
"Farmers who have this problem in their herds do learn to recognize these cows," she notes. "But a single cow with diarrhea isn't proof that you have Johne's."
Current research in Ontario shows that even cows which don't have signs of sickness but test positive for Johne's, using the milk ELISA test, produce about three kilograms of milk per day less than herd mates which test negative.
The milk ELISA test doesn't detect all infected cows. But it's good for detecting animals in the advanced stages of the disease when they are shedding the organism. Shedding animals will pass the disease on to young cattle.
In Ontario, it's estimated that 30 to 50 per cent of dairy herds have one infected cow. In most herds, the infection rate is low, Dr. Godkin says. But there are some herds with higher infection rates. BF