Chemical and amino acid composition of colostrum and mature milk differ only slightly in mink (Mustela vison).

To determine differences in chemical composition between colostrum and mature milk in mink, milk samples were collected from 12 dams as close to the end of parturition as possible (n = 12), and at 24 h (n = 3), 48 h (n = 3) and 1 week (n = 12) postpartum. The milk samples were analysed for dry matter (DM), ash, crude protein, fat, carbohydrate, and amino acid composition. The DM content was higher (p < 0.05) in milk sampled at parturition than at 24 and 48 h postpartum. Also, the crude protein content decreased (p < 0.05) after the first 24 h postpartum. However, the fat, carbohydrate and ash contents did not change (p > 0.05) during the first week of lactation. The proportion of essential amino acids tended to decrease during the first 24 h postpartum. During the first week of lactation, the phenylalanine and tyrosine contents decreased while the cysteine content increased. However, in general, the differences between colostrum and mature milk were less pronounced in the mink than in many other species. Thus, colostrum seems to be of little importance in the mink in conferring passive immunity and hence for kit survival.