milk performance (protein and fat content) and milk fatty acids (fa) profile of dairy cows under supplementation with two sources of concentrate, oilseeds (c, cottonseed) at two levels, low (5kg dm/cow/day) and high (7 kg dm/cow/day), and cereal grains (b, barley) at high rate (7 kg dm/cow/day), were studied in three herds (n=36) of spring calving holstein-friesian dairy cows (200 days in milk)...