Effect of pasture botanical composition on milk composition in organic production

Summary

Milk samples from sixteen Norwegian Red dairy cows grazing mixed swards of either grass-red clover (GR) or mixed swards of sown and unsown species of grass, clover and other herbs (GCH) were collected during four periods. Both pastures were organically managed. Pasture botanical composition had no effect on milk fat, protein or vitamin concentration and only minor effects on fatty acid composition. Milk from GR had higher concentrations of the phytoestrogens equol, genistein and biochanin A than the milk from GCH. Concentrations of equol in milk from GR were higher than concentrations reported from experiments with red clover silage. The oxidative stability of the milk lipids was not affected by pasture type.