The impact of chromogenic culture on clinical mastitis case duration and treatment success in dairy cows in an automatic milking system – a pilot study

Mastitis management in automatic milking systems (AMS) is challenging, as detection of clinical signs relies on sensors. Treatment recommendations for clinical mastitis (CM) advise conducting microbiological cultures of the infected quarter whenever possible to guide therapy. The objective of this study was to evaluate the association between the use of a rapid diagnostic mastitis pathogen chromogenic culture test on the CM case duration and the probability of more than one treatment before cure. A total of 106 CM cases from 65 dairy cows housed in a freestall AMS barn were retrospectively analysed: 25 treated according to chromogenic culture results and 81 without pathogen identification. All cases were pre-identified using AMS-derived milk parameters, confirmed through veterinary examination, and followed by weekly veterinary examinations until cure. Generalized mixed linear models were used to assess the association between chromogenic culture use and the outcomes, with confounders included as covariates. The use of a chromogenic culture reduced mastitis case duration by 2.78 ± 1.26 days compared to treatment without chromogenic culture. There was no effect on the likelihood of affected cows receiving more than one treatment for CM. The use of a chromogenic culture reduced CM time-to-cure in an AMS freestall dairy herd.