CHANGES IN GANGLIOSIDE AND SIALIC-ACID CONTENTS OF GOAT MILK DURING LACTATION

The ganglioside content of goat milk has been determined from d 1 afte r parturition to d 60 of lactation. Marked changes occurred in milk ov er the course of lactation; the highest ganglioside content occurred i n d-1 colostrum and then decreased to the end of the period studied. A t least seven different ganglioside species were detected; three gangl iosides containing sialyllactosylceramide accounted for 66 to 92% of t he total lipid-bound sialic acid; this result reflected a very simple core structure of goat milk gangliosides. The most abundant gangliosid e, II(3)(N-acetylneuraminic acid)2-lactosylceramide, was about 35 to 5 6%. The sialic acid content exhibited a trend similar to that of gangl iosides; 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 remain ed almost unchanged during the period studied.