Relationship of observed parlor practices and producer attitudes with bulk tank somatic cell counts in the Southeast USA

Inflammation of the mammary gland is indicated by a rise in somatic cell count (SCC) and impacts milk quality. The Southeast (SE) USA has a higher proportion of herds with elevated SCC compared to other USA regions. The SE also has the least information available about parlor procedures. The goals of this thesis are to explore the level of implementation of parlor procedures, determine which practices promote low SCC in Southeast USA dairy herds and investigate the association of attitude towards parlor management methods with BTSCC.

In chapter I, researchers performed on-farm assessments in Kentucky, Mississippi, Tennessee, and Virginia. The evaluations included a management survey and observation of milking procedures. In chapter II, dairy producers in Georgia, Mississippi, Kentucky, North Carolina, South Carolina, Tennessee, and Virginia were mailed a survey to gather information about producers’ attitudes regarding mastitis management. The reported level of effectiveness and practicality of each parlor management practice was summed, and were used to create a Practicality and Effectiveness Index, or PEI.

To understand the level of implementation, frequencies for observed practices were developed. Next, the GLMselect procedure which performs a stepwise selection of terms that best fit the general linear model identified a) practices strongly associated with BTSCC, and b) association between the PEI of parlor management practices and BTSCC.

A higher percentage of operations (88%) use gloves compared to a national survey (55%). When evaluating towel use, a majority (66%) of operations used single service towels: less so than nationally (77%). Practices associated with BTSCC were: post-milking disinfectant active ingredient, interaction of pre-milking disinfection removal method and post-milking disinfectant active ingredient.

Responses by producers to the mail survey indicated three parlor management practices were significantly associated with BTSCC: 1) disinfecting teats of all cows before milking (pre-milking disinfectant; p=0.01), 2) training employees in milking procedures to reduce BTSCC (p=0.03), 3) having and implementing a mastitis management plan (p=0.02). The strongest association (p=0.01) was between PEI for pre-milking disinfectant and BTSCC.

Overall, implementation of practices in the dairy parlor and a producer’s attitude toward its effectiveness and practicality are associated with the BTSCC of their herd.