Coliform mastitis.

Many strains of E. coli, Klebsiella, and Enterobacter can cause udder infection in dairy cows. Although some cases are severe, and occasionally fatal, most cases are self-limiting and would be resolved without therapy. Chronic coliform infections also occur; these may be subclinical but typically elicit recurrent clinical episodes. Therapy of acute coliform infections should be directed at removal of and neutralization of the effects of endotoxin. In cases of endotoxic shock, electrolyte and fluid therapy are indicated. Selection of antibacterial drugs is made difficult by the variable susceptibility of the organisms and by the inavailability of effective drugs approved for use in dairy cows. The coliform-infection rate is not reduced by conventional mastitis-control schemes that employ germicidal teat dips and antibiotic therapy of dry cows. Germicidal teat dips are generally ineffective because coliform bacteria can reach the teat end at any time between milkings when the germicidal activity is gone. A teat dip providing a barrier film over the teat orifice between milkings has given promising results in reducing coliform infection in lactating cows. Bedding materials appear to be a major reservoir of coliform bacteria. Sawdust bedding can support high populations of coliform bacteria, especially Klebsiella. Treatment of sawdust with slaked lime can reduce coliform populations in sawdust bedding, but its effect on infection has not been determined. Other methods of control of coliform mastitis believed effective are the following: Careful premilking hygiene, including sparing use of water and careful drying of teats and udder before applying the milking machine. Maintenance of clean conditions for dry and calving cows; sawdust should be avoided as bedding for springing and newly calved cows.