Farm factors associated with increased free fatty acids in bulk tank milk

An elevated amount of free fatty acids (FFA) is a milk quality concern that can contribute to off-flavor, rancidity, reduced foaming ability, and inhibited fermentation that affects cheese coagulation. Free fatty acid concentrations >1.2 mmol/100 g of fat are considered high, although there are various thresholds and units used to quantify levels. The FFA result from milk fat breakdown through spontaneous, bacterial, or induced lipolysis. The amount of bulk tank milk FFA can vary between farms as well as within farms daily, and this mini-review aimed to identify those risk factors at the farm level associated with elevated FFA. A search of the literature identified 5 current sources selected for this review based on relevance. Cows that were milked by automated milking systems (AMS) are suggested to produce milk that is higher in FFA compared with conventional parlors. Factors associated with AMS contributing to spontaneous lipolysis include higher milking frequencies, reduced milking intervals, and low milk yields at each robot visit. Automated milking systems also have characteristics of quarterly milking and high milk lines that can increase vacuum fluctuations and air admission contributing to induced lipolysis. Both AMS and conventional systems with poor tank cooling or without precooling mechanisms can be at risk for higher bulk tank FFA. Bacterial lipolysis can occur when milk temperatures fluctuate and rise, or when there is insufficient milking system cleaning and sanitization. Feed factors such as high saturated fatty acid diets can increase the likelihood of spontaneous lipolysis. We concluded that the major factors associated with increased levels of FFA are non-parlor milking systems, increased air admission, the absence of additional cooling, temperature fluctuations in the bulk tank, and rations high in saturated fatty acids. Future research further investigating these factors can help to minimize FFA and ensure milk quality.