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Virginia Cooperative Extension - Knowledge for the CommonWealth

Anticipating higher somatic cell counts or greater clinical mastitis during the summer

Dairy Pipeline: April 2001

Gerald M. Jones
Professor & Extension Dairy Scientist,
Milk Quality & Milking Management
(540) 231-4764

Last summer, the average somatic cell count in herds enrolled in DHI increased from 311,000 during May to 390,000 in July and September and then declined to less than 300,000 in November and December. During those summer months, many milk producers have said that they had a greater number of clinical cases of mastitis. As far as we know, these higher cell counts and greater clinical mastitis resulted from mastitis infections, most likely caused by environmental streptococci and coliforms such as E. coli. In anticipation of similar occurrences this summer, review some of these management factors before cropping becomes intense and you won't have time later to consider them: 1. access to clean, dry, and comfortable shade, whether it be wooded areas, artificial shade, or housing; 2. good ventilation especially in barns, holding areas, and around feed bunks (which may require fans and other cooling aids in some or all of these areas), 3. clean and fresh water; 4. milking clean and dry teats which really begins with the environment where cows lie and be sure that predipping is a part of good milking practices; and 5. feed a ration which has been formulated to balance the nutritive contant of home grown feeds. In addition, to protein, energy, and fiber, attention should be given to providing adequate amounts of vitamins A, D, and E, as well as the major minerals calcium, phosphorus, magnesium, and especially potassium, and the trace minerals zinc, copper, and selenium. Injections of vitamin E and selenium to dry cows and bred heifers have been shown to reduce environmental mastitis when given at 2-3 weeks before calving. Your nutritionist may also wish to make sure that other minerals are balanced. Other vaccinations to consider include coliform and Staphylococcus aureus. Remember that cows also like to keep their cool and it's important where they do it.

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