Elevated free fatty acids in bulk tank milk: a dairy farm case report

Hannah M Woodhouse^*David Kelton

• University of Guelph, Guelph, Canada

While most fatty acids in milk are bound, some are in free form. Although free fatty acids (FFA) only represent approximately 0.1 % of total milk fat, they can have a large, detrimental impact on milk quality. Free fatty acids are products of milk fat lipolysis and begin at the farm level. Elevated concentrations of FFA in milk (≥ 1.2 mmol FFA/ 100 g of fat) can reduce milk foamability, impair cheese coagulation, decrease shelf life, and increase milk rancidity. By directly deteriorating the quality of milk, elevated FFA is a concern to the sustainability of dairy production that impacts all stakeholders. Since 2018, Dairy Farmers of Ontario (DFO) have tested FFA levels on every bulk tank milk sample, which is collected at every pick-up on all Ontario, Canada dairy farms. Results are reported to farmers, allowing for milk quality transparency and monitoring. In 2023, DFO field staff triggered an investigation of elevated FFA on a dairy farm with an average FFA of 1.32±0.50 mmol/ 100 g of fat (between August 2018 and October 2022). The objective of this case report was to apply previously identified FFA risk factors in this on-farm investigation to identify farm-specific contributors to elevated FFA. The main FFA risk factors present on the farm were short and unequal milking intervals, poor milking equipment maintenance and sanitization, increased bulk tank milk agitation, and temperature fluctuations. High levels of fat supplements used in the lactating ration at certain times of the year may have also been a contributing factor. Elevated FFA concentrations are multifactorial, and increased awareness of farm-level risk factors through real-world examples can help farms implement management changes to improve milk quality.