Comparing the Fatty Acid Composition of Organic and Conventional Milk

a) Percentages of saturated fatty acids (SFA); b) ratio of polyunsaturated FA (PUFA) to monounsaturated FA (MUFA); c) percentages of n-3 FA; d) percentages of n-6 FA; e) ratio of n-6:n-3 FA; f) percentage of vaccenic acid; and g) percentage of conjugated linoleic acid (CLA) in organic (▴) and conventional (■) milk each month for the 12-mo study (where month 5=May 2003 and month 4=April 2004). Mean values are taken across all farms of each type.

Effects of breed type and farm system type from model 1 on mean milk n-3 fatty acid (FA) proportion; C1=conventional pedigree Holstein, C2=conventional Holstein-Friesian, C4=conventional mixed breed, O1=organic pedigree Holstein, O2=organic Holstein-Friesian, O3=organic Friesian, and O4=organic mixed breed (there were no conventional Friesian farms). Dashed line represents mean overall proportion of n-3 FA in all milk samples.

Effects of herd-yield quartile and farm system type from model 2 on mean milk n-3 fatty acid (FA) proportion (C=conventional, O=organic, 1 to 4=lowest to highest herd average yield quartile). Dashed line represents mean overall proportion of n-3 FA in all milk samples.