Improving dry-matter intake of perennialryegrass pasture by dairy cows. Pp. 159-174 in Fresh Herbage for Dairy Cattle, the Key to a Sustainable Food

Abstract. Dairy cows fed on perennial-ryegrass pasture produce higher-quality milk in terms of fatty-acid composition; however, they produce much less milk compared to dairy cows under other systems. The low dry-matter intake (DMI) has been identified as the main factor responsible for the lower milk production in pasture-based systems. To maximize milk production from those systems it is important to maximize DMI from pasture. Many interventions have been studied, such as: manipulating herbage allowance, feeding frequency, time of allocating the new pasture, pasture maturity, fertilization rate and the choice of perennial-ryegrass variety. The results have shown that pasture DMI increases in a curvilinear asymptotic manner as herbage allowance increases. However, increasing herbage allowance decreases milk production per hectare and increases production cost due to the increased need for pasture and land. More frequent allocation of pasture has shown no effect on pasture DMI. Allocating the new pasture after the evening milking has sometimes shown to increase pasture DMI without any negative effect in terms of productivity per hectare. Allocating a young and leafy grass has shown to increase DMI, but at the same time pasture holding capacity was reduced and milk production per hectare decreased. Using high-sugar grass was advocated as a way to improve DMI of dairy cows on pasture. Research findings with regard to the effect of high-sugar grass on DMI are very inconsistent. Som