Effects of chromium picolinate on milk production and plasma insulin concentration in dairy cows.

Chromium picolinate (CrPic) is a biologically active molecule in which chromium is chelated to an isomer of niacin. It is claimed to reduce plasma cholesterol levels in humans, pigs and hens and to have beneficial effects on muscle and fat composition of humans, pigs and lambs. The metabolic responses recorded in lambs were similar to those observed in cows of high genetic merit for milk production, suggesting that CrPic may increase milk yields by altering aspects of glucose and insulin metabolism. The trial reported in this paperis work investigated the effect of supplementation with CrPic on milk yields and plasma insulin concentration in multiparous Friesian dairy cows grazing pasture. Preliminary measurements of milk yield and composition were made during a pre-treatment period of 1 week in 59 mixed-age dairy cows before separation into four treatment groups balanced for previous milksolids yield, live weight and condition. Beginning at peak lactation, groups received 0, 5, 20, or 100 mg CrPic/day administered once daily by oral drenching. Milk yields were measured and samples taken at weekly intervals for compositional analyses (fat, protein and lactose %). Blood samples were taken from the jugular at weekly intervals for insulin analysis. Chromium Picolinate had no effect on milk yield or composition. Plasma insulin concentrations did not differ between treament groups.