The endogenous vitamin K1 content of bovine milk: temporal influence of season and lactation

A liquid Chromatographic technique was applied to the estimation of phylloquinone at endogenous levels in the milk of cows exclusively grazed on pasture. The temporal variation ranged between 3.1 and 6.9 μg/litre (mean, 4.4 μg/litre) across the production season and was independent of milk-fat content. A single animal was also studied serially over 35 days lactation. High levels were measured in early colostrum (>20 μg/litre), while normal levels (4.0–6.6 μg/litre) were established beyond day 5 transition milk. Cowsʹ milk was confirmed as containing higher vitamin K content, as compared to human milk (2.7 ± 0.3 μg/litre).