Abstract
Twenty-four multiparous crossbred Friesian dairy cows (60-90 days in lactation) were randomly assigned into a $2{\times}2$ factorial arrangement in a randomized complete block design. Factors were two levels of concentrate supplementation (1:2, high vs 1:1.2, very high; concentrate:milk yield) and two levels of high-quality feed block (HQFB) supplementation (non vs ad libitum block licking). Ruzi grass (Brachiaria ruziziensis) was fed as a roughage throughout the 70 day feeding trial. High level of concentrate fed group resulted in higher roughage and HQFB intakes, compared with very high concentrate supplemented group. HQFB supplementation tended to increase roughage intake and significantly improved milk yield (2 kg/hd/d in high concentrate supplementation) and quality (% fat) which resulted in higher economical return. HQFB was recommended to be used as a strategic supplement in lactating dairy cows especially when fed on low-quality roughages or crop residues.