title: Correlation between standard plate count and somatic cell count milk quality results for Wisconsin dairy producers.
abstract: The objective of this study was to determine if a correlation exists between standard plate count (SPC) and somatic cell count (SCC) monthly reported results for Wisconsin dairy producers. Such a correlation may indicate that Wisconsin producers effectively controlling sanitation and milk temperature (reflected in low SPC) also have implemented good herd health management practices (reflected in low SCC). The SPC and SCC results for all grade A and B dairy producers who submitted results to the Wisconsin Department of Agriculture, Trade, and Consumer Protection, in each month of 2012 were analyzed. Grade A producer SPC results were less dispersed than grade B producer SPC results. Regression analysis showed a highly significant correlation between SPC and SCC, but the R(2) value was very small (0.02-0.03), suggesting that many other factors, besides SCC, influence SPC. Average SCC (across 12 mo) for grade A and B producers decreased with an increase in the number of monthly SPC results (out of 12) that were ≤ 25,000 cfu/mL. A chi-squared test of independence showed that the proportion of monthly SCC results >250,000 cells/mL varied significantly depending on whether the corresponding SPC result was ≤ 25,000 or >25,000 cfu/mL. This significant difference occurred in all months of 2012 for grade A and B producers. The results suggest that a generally consistent level of skill exists across dairy production practices affecting SPC and SCC.
authors.affiliation: Department of Food Science, University of Wisconsin-Madison, 1605 Linden Drive, Madison 53706-1565.
authors.forename: Darand L
authors.initials: DL
authors.lastname: Borneman
authors.affiliation: Wisconsin Department of Agriculture, Trade, and Consumer Protection, Division of Food Safety, PO Box 8911, Madison 53708-8911. Electronic address: Steve.Ingham@wisconsin.gov.
authors.forename: Steve
authors.initials: S
authors.lastname: Ingham
mesh_terms: D000818:Animals; D002417:Cattle; D002452:Cell Count / Q000379:methods / Q000662:veterinary*; D003612:Dairying / Q000379:methods* / Q000706:statistics & numerical data; D005260:Female; D063427:Food Quality; D008892:Milk / Q000166:cytology* / Q000382:microbiology; D012044:Regression Analysis; D012621:Seasons; D013696:Temperature; D014481:United States; D014922:Wisconsin
keywords: milk; milk quality; somatic cell count; standard plate count