2017 ACVIM Forum Research Abstract Program

Udder-half level milk samples were aseptically collected for bacterial culture, somatic cell count (SCC), and milk components (% fat and % protein) determination from all lactating goats (n = 909) on a commercial goat dairy. Aerobic bacterial culture was performed on Columbia blood agar for 24 h at 37°C. Goats with at least one udder-half yielding a single colony morphology of CNS were enrolled for two additional once monthly udder-half level milk samplings. Staphylococcal isolates were identified to the species-level using matrix assisted laser desorption/ionization time of flight (MALDI-ToF) mass spectrometry or PCR amplification and sequencing of the tuf gene when MALDI-ToF yielded an indeterminate result. Intramammary infection status was defined based on the presence of the same species of CNS in 1, 2, or 3 of the samples from each udder half. Differences in prevalence of chronic IMI (CNS-CNS-0, CNS-0-CNS or CNS-CNS-CNS) versus only an IMI on the first sample (CNS-0-0) were assessed within species using the Chi-square test or Fisher's Exact test as applicable (Table 1) . Significance was declared at P < 0.05. For species with ≤ 3 IMI within species, data were combined into a single category (Other CNS) for analysis.