Dairy cows eating grass produce milk with a higher proportion of fat-soluble antioxidants

摘要

The optimisation of milk production includes a rational use of forages, respect for the environment, and offers better quality to consumers. Pasture-based milkproduction is widely spread throughout the Atlantic Arc in order to maximise milk yield per hectare. Furthermore, it is well known that grazing cows producemilk with a healthier fatty acid profile. However, grass may provide other healthy components to milk, The aim of this study was to evaluate the effect of grass intake on fat-soluble antioxidant concentration in milk. For this, a 3 x 3 Latin square experiment was performed with 18 lactating cows in the second half of lactation. Experimental treatments consisted of grass silage, zero-grazing, both offered ab libitum in housing, or grazing for 24 hours. The results show that grazing cows had a higherdry matter intake and greater milk yield and higher concentration of protein and lactose in milk than housed cows. The milk from grazing cows had a greater proportion of xanthophylls and carotenes than cows eating grass silage, with the zero-grazing system having intermediate values. In conclusion, dairy cows eating fresh herbage produce milk characterised by a higher proportion of antioxidants than when eating grass silage.