Hygiene in the Prevention of Udder Infections. IV. Evaluation of Teat Dips with Excised Cows’ Teats

Abstract

Suspensions of Staphylococcus aureus, Streptococcus agalactiae, Escherichia coli, and Pseudomonas aeruginosa were used to contaminate teats excised from cows. Commercially available teat dips were applied for evaluation of comparative germicidal activity. Iodophors, sodium hypochlorite, and sodium dichloro-s-triazenetrione were highly effective against all four test organisms. Quarternary ammonium, chlorhexidine, and cetylpyridinium chloride were effective against Staphylococcus aureus, and Streptococcus agalactiae but not Escherichia coli and Pseudomonas aeruginosa. Bronopol and 8-hydroxyquinoline sulfate were marginally effective on the two Gram positive organisms and ineffective on the two Gram negatives. Three of the dips were ineffective against all four pathogens; two were in nonaqueous bases, and the other was a blend of pine oil and antibodies with udder origin. In other trials, iodophor at .3% titratable iodine was highly effective against Staphylococcus aureus and Streptococcus agalactiae. Products containing .5 and 1% iodophor maintained effectiveness after each was used to dip 140 teats under conditions of commercial dairying. Logarithmic reduction in the geometric mean number of organisms recovered from teats was more meaningful for evaluating data than percent reduction.

A review of test protocols for the evaluation of teat disinfectants

“…The excised teat protocol could potentially give a better indication of efficacy when compared to other laboratory methods as they lack the characteristics of bovine teat skin (Philpot et al . ). The use of negative control teats allows for a comparison with the number of bacteria removed from the treated teats.…”

“…(), both used the excised protocol as previously described by Philpot et al . (). Thus, this protocol has changed very little over the last 30 years which suggests that the protocol is a very effective measure of efficacy; however, few studies have used this method over the years.…”

“…To be accurate and reproducible, teat skin condition must be recorded and the teat prepared by trimming excess skin, washing in warm detergent, rinsed in sterile water, dried (Philpot et al . ; Schmidt et al . ; Boddie et al .…”

“…Similarly, Philpot et al . () carried out an evaluation of 13 teat disinfectants. Results show that the iodophors, sodium hypochlorite and sodium dichloro‐s‐triazinetrione were effective against a number of strains ( Staph .…”

“…To be accurate and reproducible, teat skin condition must be recorded and the teat prepared by trimming excess skin, washing in warm detergent, rinsed in sterile water, dried (Philpot et al 1978;Schmidt et al 1984;Boddie et al 2002;Enger et al 2015) and disinfected in 70% w/v ethyl alcohol (Boddie et al 2002), 70% w/v isopropyl alcohol (Enger et al 2015) or 70% w/v alcohol (type not stated) (Philpot et al 1978;Schmidt et al 1984). Teats can be placed in plastic bags in a glycerine and water solution and frozen at À20°C until further use (Boddie et al 2002;Enger et al 2015).…”