The status of milk quality at the start of the Southeast Quality Milk Initiative
The quality of milk produced in the Southeast (SE), based on somatic cell count (SCC) and standard plate count (SPC), is consistently lower than the rest of the US. Reduced milk quality increases costs while decreasing revenues and efficiency. The combined effect of these factors contributes to the declining dairy industry in the SE. Understanding factors that have the greatest impact on milk quality will provide a background for programs aimed at helping producers improve their operations and was the underlying basis for the establishment of the Southeast Quality Milk Initiative (SQMI). Our overall goal is to enable dairy farmers to move toward production systems compatible with a sustainable industry. To accomplish this, we will integrate outreach, education, and research initiatives focused on improved milk quality, lowered disease costs, and greater revenues on farm. As part of this process, we established the baseline status of milk quality at the start of the project on dairy operations in FL (n=126), GA (n=221), KY (n=753), MS (n=82), TN (n=404), and VA (n=814), which are the partnering states of the SQMI. SCC and SPC bulk tank milk data for 2012 were evaluated from records maintained by state regulatory agencies. At least one SCC and SPC were collected each month from each dairy farm with a Grade A permit and data were summarized using the Timeseries procedure of SAS. Most SPC samples (65%) had < 5,000 colony forming units (CFU)/ml and 82% fell within the recommended range (< 10,000 CFU/ml). The SE SCC averaged 324,204 ± 174,083 cells/ml (mean ± SD). The annual mean SCC of individual states ranged from 279,603 ± 160,665 to 417,146 ± 210,692. For herds enrolled in DHIA, which comprised 30-44% of the total herds within a state, annual mean SCC was approximately 50,000 fewer cells/ml. Considerable state-by-state variation occurred in frequency of samples, with SCC > 400,000 cells/ml having the greatest effect evident in the summer months. At this time, 20 to 60% of samples from individual states were > 400,000 cells/ml. In summary, milk quality in the SE lags behind the US as a whole, and hot, humid summers of the region present one of the major challenges to producing quality milk. Continued evaluation of this information will provide a basis to evaluate the success of the SQMI. This work was supported by a grant award from USDA-NIFA-AFRI (2013-68004-20424).
Keywords: Mastitis, Extension, Milk Quality