EFFICACY OF BARRIER-TYPE POSTMILKING TEAT GERMICIDES AGAINST INTRAMAMMARY INFECTION

Two barrier tear dips were evaluated for efficacy in preventing new IM I by Staphylococcus aureus and Streptococcus agalactiae during experim ental exposure trials, and two barrier dips were evaluated during natu ral exposure trials. Dipping in an experimental product containing nic in as germicide using experimental exposure demonstrated no difference in rate of new Staph. aureus IMI (10.2%) compared with that of contro ls (7.1%) or in the rate of new Strep. agalactiae IMI (13.6%) compared with that of controls (11%). Testing of an experimental .55% chlorhex idine gluconate barrier dip using experimental exposure resulted in an increased rate of new Staph, aureus IMI compared with that of control s (4.8 vs. 1.7%, respectively), but no difference in the rate of new S trep. agalactiae IMI in dipped quarters (6.1%) compared with that of c ontrols (3.3%). Dipping with a commercial .3% iodine barrier dip durin g natural exposure increased the number of new coagulase-negative stap hylococcal and total IMI by 56.6 and 30.6%, respectively, compared wit h a 1% iodophor dip without barrier. Use of an experimental .3% iodine barrier dip during natural exposure demonstrated no difference in tot al rate of new IMI (18.4%) compared with that of controls (20.3%); how ever, after germicide concentration was increased to .5% iodine and fu rther tested, the reformulated product reduced new IMI by 43.1%. Under the conditions of these trials, the barrier teat dips tested were no more efficacious than no teat dip or using a nonbarrier product.