The Impact of Parlor Equipment and Milking Procedures on Milk Quality in the Southeast US

Milk quality has continued to improve over the last several decades in the US, but still remains to be a problem for dairy producers in the southeast (SE) US. The purpose of these analyses was to evaluate associations between parlor equipment function, milking procedures, and bulk tank somatic cell count (BTSCC) and bulk tank standard plate count (BTSPC) on SE US dairy farms. Data from dairies in Virginia (n = 96), Kentucky (n = 96), Tennessee (n = 84), and Mississippi (n = 7) were collected at a single visit for each farm. Monthly BTSCC and BTSPC data were retrieved from state regulatory offices for (n = 263) farms, and averaged over the 12 months prior to each farm visit and used as the dependent variables in each analysis in a backwards elimination regression model. Increased herd size was associated with lower BTSCS, but higher BTSPC. Utilization of an internal teat sealant was associated with lower BTSCS. Farms that housed cows exclusively on pasture had greater BTSCS than farms that keep lactating cows in confinement with no pasture access. Utilization of a freestall for lactating cow housing was associated with lower BTSCS. The likelihood of future dairy operation in 10 years as reported by the farm owner or manager influenced BTSPC. Beginning water temperature of the detergent wash cycle was found to influence BTSCS. These findings suggest that the most influential variables explaining milk quality are herd demographic information and farmer perceptions as well as a few management variables such as the use of an internal teat sealant and beginning water temperature of the detergent wash cycle. These findings suggest that farmer perceptions and attitudes may be influencing milk quality more than previously thought. Further research is needed to evaluate social factors that could be influencing milk quality. Milking equipment function has improved substantially over the last several decades and was not found to significantly influence milk quality among the evaluated SE US dairies in these analyses. Milking procedures such as pre- and post-milking teat disinfection are widely accepted by most dairies in the US. Minimal differences were found between milking procedures such as teat disinfectant active ingredient or using paper towels versus cloth towels suggesting that these factors may not be the most influential factors influencing milk quality.