Comparison of Duplicate and Single Quarter Milk Samples for the Identification of Intramammary Infections

Abstract Results of bacteriological culture of 5426 pairs of duplicate quarter milk samples collected were analyzed for agreement. Overall, the percentage of agreeing pairs was 98.1%. The percentage agreement by infection type was greater for the contagious pathogens, Streptococcus agalactiae (96.4%) and Staphylococcus aureus (94.2%), than for other Streptococcus spp. (81.6%) and coliform organisms (55.6%). Single quarter samples 5 be adequate for determining status of quarter infection with Strep. agalactiae and Staph. aureus .