Bovine sialyl oligosaccharides: seasonal variations in their concentrations in milk, and a comparison of the colostrums of Jersey and Friesian cows

In this study, we measured the levels of 6' sialyl lactose, 3' sialyl lactose, 6' sialyl lactosamine and disialyl lactose in the colostrum of individual Jersey and Friesian cows at first milking, individual Jersey and Friesian cows over the first five milkings, and also in colostrum pooled from Friesian or Jersey herds over the first 2 days postpartum. Our results show significant differences between the breeds in the proportions of the sialyl oligosaccharides present, but not in the total concentration of the sialyl oligosaccharides. Friesian colostrum sialyl oligosaccharides contained a higher proportion of 6' sialyl lactosamine while Jersey colostrum had higher proportions of 3' sialyl lactose. The concentration of all measured sialyl oligosaccharides was highest in colostrum from the first milking post partum, dropping rapidly in successive milkings. We also measured the levels of selected individual oligosaccharides in milk (not separated by breed) over the entire milking season. The average concentrations over the season were 17 mg L-1 6' sialyl lactose, 42 mg L-1 3' sialyl lactose, 11 mg L-1 6' sialyl lactosamine, 4 mg L-1 disialyl lactose, 11 mg L-1 free N-acetylneuraminic acid and 4mgL(-1) N-acetylgalactosaminyl galactose. (C) 2004 Elsevier Ltd. All rights reserved.