Veterinary Medicine Extension, School of Veterinary Medicine
University of California Davis, Tulare

This past week rain, or at least a chance of rain, was predicted for the southern end of the Central Valley. It never happened, however, it reminded me that the warm, rainy season was not too far off. Warm, rainy weather means coliform mastitis for western dairymen, especially those with corrals. Here are some things to consider about coliform mastitis before the rain gets here.

Each case of coliform mastitis has an associated economic loss. Some coliform cases are non-clinical without obvious signs of mastitis. If the somatic cell count increases above 300,000 cells, there is a production loss associated with the case. The higher the SCC; the greater the production loss. When a quarter has visibly abnormal milk but the clinical signs are only seen in the mammary gland, a treatment cost of a few dollars occurs due to intramammary treatment with an infusion tube. There is also a milk discard cost that will easily exceed the cost of the mastitis tube. However, many cows with coliform infections are severely affected. These cows have abnormal milk and generalized signs of mastitis including depression, decreased appetite, and marked reduction in milk flow. Cow like this require aggressive treatment that may easily exceed $100. Rapid treatment response may be necessary to prevent permanent udder damage and to save the life of these cows. Perhaps 30% of the cows that recover from a severe coliform bout will be culled due to low production. Pregnant cows may also abort after coliform mastitis due to by-products on the infection such as prostaglandins. Clearly, coliform mastitis results in an economic loss no matter which form occurs.

To avoid the detrimental effects of coliform mastitis in the up-coming rainy season, begin to plan now. Consider the following steps to reduce the number of coliform cases and the impact of each case:

• Use a J-5-like vaccine to reduce the impact of the coliform cases. Be sure to follow the directions for the vaccine you use as they may vary between products. These vaccines will limited the clinical signs and reduce treatment costs, discard milk and production losses.

• Have appropriate medications on hand to treatment the clinical cases. Be sure the people who will be doing the treatments know how you expect them to handle the cases. Consult your veterinarian for tips of treatment practices.

• Check out the corrals for proper slope to provide adequate drainage. Remove excessive manure while the corrals are dry and manageable.

• Consult with your nutritionist to be sure adequate vitamin E and selenium is in the ration, as they are known to have a protective effect.

• Have fresh feed in the bunks when the cows return from the milking parlor. This will keep them on their feet allowing the teat sphincter to close before they lay down in the corrals or free stalls.

• Ensure that you have extra towels on hand to dry udders in the parlor before attaching the milking machine. Wet milking is a strong risk factor associated for coliform mastitis.

• Develop a written plan for maintenance of corrals and free stalls. Let every dairy worker know his part in the plan and what you expect him to do to prevent coliform mastitis. Daily maintenance of free stalls and weekly re-bedding is essential to maintain comfortable stalls.

• Check out the free stall to be sure that the stall dividers are in good shape and properly spaced. Too many cows lying in the alleys is a tip-off to check out the stalls.

• Plan ahead to have adequate dry, recycled manure on hand for free stall bedding.

• Have the milking equipment checked out for proper function. Be sure to change liners as recommended to prevent teat irritation and chapping.

While the rains did not come this past week, they will surely come! Be ready for them and control the economic impact of coliform mastitis.

9/19/2000