Short communication: Efficacy of glycolic acid-based and iodine-based postmilking barrier teat disinfectants for prevention of new intramammary infections in dairy cattle

Abstract

A positive-control, natural exposure noninferiority field study was conducted to test the efficacy of a novel glycolic acid-based postmilking barrier teat disinfectant compared with a commercial iodine-based postmilking barrier teat disinfectant (positive control). Cows from 2 pens from a California Central Valley dairy farm were dipped after milking either with the positive-control product (PC) or the experimental product (EX) over 12 wk. New intramammary infections (NIMI) were determined by biweekly sampling of all quarters of study cows and classified as a NIMI based on somatic cell count and milk bacteriological culture results. The mean quarter-level incidence risks during a 2 wk study period were 3.50% (EX) and 4.28% (PC). The majority of NIMI were caused by coagulase-negative staphylococci, followed by non-agalactiae streptococci. The study results indicated that EX was noninferior to PC, with a 17% relative efficacy (improvement) in reducing NIMI compared with the PC group. Also, quarter somatic cell count was not affected by the postmilking teat disinfectant used. Finally, the EX product was safe in terms of teat conditioning: teat condition scores were not different between study groups. The study concluded that the glycolic acid-based experimental post-dip barrier was noninferior to the control, and could be considered a safe and effective postmilking teat disinfectant.

A review of test protocols for the evaluation of teat disinfectants

“…() had the highest number of cows enrolled in their study with 374 cows, followed by Lago et al . () and Godden et al . () with 299 and 317 cows, respectively.…”

“…() and Lago et al . () carried out their studies within a 10‐ to 12‐week period. The sample size and study length used in the studies gave adequate statistical power when analysing results.…”

“…() and Lago et al . () collected milk samples every 2 weeks with Foret et al . () collecting a monthly sample, whereas Ceballos‐Marquez et al .…”

“…() and Lago et al . () used SCC analysis to decide whether a sample should be cultured and considered samples from clinical cases as eligible for identifying new IMIs. Godden et al .…”

“…Cracked skin is more likely to harbour mastitis‐causing bacteria (Blowey and Edmondson ; Lago et al . ). Disinfectants must not leave any harmful residues in milk that could affect public health (Godden et al .…”