Changes in ganglioside and sialic acid contents of goat milk during lactation

The ganglioside content of goat milk has been determined from d 1 after parturition to d 60 of lactation. Marked changes occurred in milk over the course of lactation; the highest ganglioside content occurred in d-1 colostrum and then decreased to the end of the period studied. At least seven different ganglioside species were detected; three gangliosides containing sialyllactosylceramide accounted for 66 to 92% of the total lipid-bound sialic acid; this result reflected a very simple core structure of goat milk gangliosides. The most abundant ganglioside, II3(N-acetylneuraminic acid)2-lactosylceramide, was about 35 to 56%. The sialic acid content exhibited a trend similar to that of gangliosides; during early lactation sialic acid content was higher than in mature milk. Fat, protein, and total solids were high at initiation of lactation and decreased thereafter. However, lactose content remained almost unchanged during the period studied.