A powdered teat dip designed for winter usage was evaluated for bacteriological efficacy and teat conditioning qualities. A positive control, natural exposure field trial was conducted for 3 mo on 509 lactating cows. Two sets of cows, primiparous and multiparous, were used. The trial compared efficacy of a powdered teat dip with a teat dip of 1% iodine plus 10% glycerin. Bacteriological efficacy among primiparous cows was equivalent for all major mastitis pathogens, environmental pathogens, and streptococci other than Streptococcus agalactiae. Efficacy was not equivalent against coagulase-negative staphylococci and all mastitis pathogens. Results suggested that the positive control product was more efficacious. Among multiparous cows, efficacy was equivalent against environmental mastitis pathogens and bacteriologically negative, clinical mastitis. The products were not equivalent against Staphylococcus aureus, coagulase-negative staphylococci, or all major mastitis pathogens, once again suggesting that the positive control product was more efficacious. Data indicated that germicidal activity of the powdered dip was not sufficient to reduce the incidence of new IMI caused by contagious or minor pathogens normally associated with teat skin. Application of a powdered postmilking teat dip during 3 winter mo in Idaho resulted in improved teat end condition among primiparous and multiparous dairy cows. Teat skin condition improved among primiparous but not among multiparous cows.
