Many dairy cows lumber along with chronic mammary gland infections that jack up the number of infection-fighting white blood cells in their milk--especially during the dog days of summer.
Milk quality is based on that cell count. And U.S. dairy producers get paid an extra 20 cents per 100 pounds for milk having a white blood cell count under a specified level. That level ranges from about 200,000 to 300,000 per milliliter, depending on which state testing is done in.
Producers can't sell milk with cell counts that exceed the legal limit. In the United States, that's 750,000 cells/ml. Canada and Europe have lower limits--500,000 and 400,000, respectively. "And there is a move afoot to lower the limit in this country," says ARS dairy scientist Max Paape, who is with the Immunology and Disease Resistance Laboratory in Beltsville, Maryland.
That's why Paape agreed to test bromelain supplied by Tokyo, Japan, manufacturer Ajinomoto Co., Inc., on cows with chronic mastitis.
A mix of enzymes extracted from the stems of pineapple plants, bromelain is sold in health foods stores under claims that it combats heart disease, arthritis, and many other maladies. In animals, it appears to reduce inflammation by interfering with the synthesis of prostaglandins and other inflammatory substances, says Paape.
He divided 10 cows into two groups having average cell counts a little over 300,000. For 4 weeks, group 1 got pellets containing 75 grams of bromelain in their feed; group 2 got no bromelain. A week after this first trial ended, Paape reversed the treatment, with only group 2 getting the bromelain.
Bromelain reduced cell counts by 100,000 on average during each trial, Paape says. Moreover, cell counts never surpassed the legal U.S. or Canadian limits when the cows got bromelain, as they did when left untreated.
"With bromelain, dairy producers will have more days with cell counts in the premium price range--under 300,000," says Paape.
Milk with a low white blood cell count has more milk protein, or casein. Cheesemakers prefer to buy high-casein milk because the protein allows the cheese to set properly.
Max J. Paape is at the USDA-ARS Immunology and Disease Resistance Laboratory, Bldg. 173, Room 103, 10300 Baltimore Ave., Beltsville, MD 20705-2350; phone (301) 504-8302, fax (301) 504-9498, e-mail email@example.com.
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