Interaction of factors which influence the extent of lipolysis during milking and storage of raw milk

Abstract

SUMMARYThe effect of aeration and agitation during milking on free fatty acid (FFA) levels in raw milk was investigated by comparing (a) a dual vacuum system with a ‘round the barn’ installation and (b) a claw piece requiring high air bleed with conventional claw pieces. Reduced milk transfer pressure resulted in a reduction in lipolysis of 54%, while high air bleed led to a 21% increase. FFA values were related to milk yield, stage of lactation and to a lesser extent the incidence of mastitis. These relationships were largely independent of the type of milking equipment. Fat content and somatic cell count did not affect the level of lipolysis. Increases in FFA due to activation by added blood serum were strongly related to the initial FFA concentrations.