HUMAN HEALTH RISKS ON YOUR DAIRY

Dr. Clell V. Bagley, D.V.M.
USU Extension Veterinarian
    There are some human health risks which come with living on, or even visiting, a dairy farm. Data are accumulating which better define and identify some of these risks. This information can enable you as a dairy owner / manager to make knowledge-based decisions in relation to procedures and policies on your dairy. It can also enable individuals with special health problems or conditions to better protect themselves.

    The chart below summarizes some of the microbiological (infectious) disease risks that are present on most dairies.

Agent	Typical Age of Cattle Shedding Agent	Prevalence
Cryptosporidia	7 - 21 days of age	On 90 % of dairies; 50 - 92% of calves in age group shed.
Giardia	Over 21 days of age	Common (most dairies). 100% of calves on some dairies.
Salmonella	Under 30 days of age	Common (most dairies). Level depends on sanitation and multiple other factors.
E. Coli O157	3 - 4 months age range (1 month post weaning)	Common; found on >75% of dairies; 5% of these calves shed in feces, dropping to 1% among older calves.
E. Coli O157, Salmonella, Listeria, Campylobacter, Yersinia, Staph aureus	Bulk tank (raw) milk	Over 33 % contain one or more pathogens. 60% of dairy families use milk that is un-pasteurized.

    The human groups that are at higher than normal risk include children (including those of farm families), the elderly, and those with reduced immune system function from a variety of causes. These individuals should be aware, or be made aware, of some of the special risks that may occur to them on a dairy farm.

    Some suggested precautions are listed below that can be taken to reduce human health risks on dairies.

Farm Family:

• Drink / use only pasteurized milk. To do otherwise is like eating uncooked hamburger.

Farm Children: (At increased risk from handling calves, especially those that are ill.)

• Adult workers should do most of the handling and moving of calves.
• Wear protective clothing; remove and wash it after use.
• Demonstrate, teach and insure proper hand washing after calf handling.

Farm Visitors: (School groups, etc.)

• Don’t provide raw milk samples. Use only commercial foods in individual packages. If visitors enter animal housing or touch (pet) animals (especially calves), there is increased risk involved.
• Provide protective clothing before they enter animal housing.
• Demonstrate and have them utilize proper hand washing afterwards.

    These risks are not overwhelming nor unique to dairies but they are real and should be recognized. Similar risks occur in other areas of life such as at Day Care Centers and community swimming pools, eating uncooked hamburger, or drinking unpasteurized apple cider. Recognition of the risks and planning allow us to minimize any real problems.