Control of environmental mastitis remains a problem on many modern dairy farms. These infections are often transmitted between milkings, and milking hygiene will not prevent new infection. Consequently, the control of environmental mastitis has prompted dairy managers to develop new approaches that either limit bacterial contamination of teat ends between milkings or directly increase the cow's resistance to infection. Intervention strategies that may decrease the incidence of environmental mastitis include improved sanitation of housing areas, decreased water use in udder preparation, optimal dietary concentrations of vitamin E and selenium, and use of R-mutant vaccines (Smith et al. 1984, 1985; Weiss et al. 1990; Smith & Hogan, 1993; Tyler et al. 1993).
Dairy managers are encouraged to provide cows with clean, fresh, palatable feed immediately after milking. This practice is thought to provide cows with an incentive to remain standing for an extended interval, permit teat sphincters to close, and limit teat end contamination and new infections when cows lie down. In one recent study, cows that had access to feed remained standing for a significantly longer time than did cows that were denied access to feed (48 v. 21 min; Tyler et al. 1997). The purpose of the present study was to substantiate that feed availability could be used to extend postmilking standing time in a larger population of cows maintained under different management conditions.