Sustainable pasture based dairy systems – meeting the challenges

Abstract

This review paper examines a number of the challenges of pasture-based dairy systems. Ensuring adequate nutrient intakes of highyielding dairy cows within grazing systems is one of the key challenges being faced by many dairy farmers. Options examined to increase nutrient intakes include: increasing herbage allowances, manipulating sward structure, modifying herbage composition, and the use of both forage and concentrate supplements. The potential to achieve high levels of animal performance with grazed grass combined with high levels of concentrate supplementation is examined, while forage supplements appear to offer much less scope by which to increase nutrient intakes. Low levels of herbage utilization provide another challenge on many farms, with options to extend the grazing season and to improve early-season forage utilization examined. The results of a whole systems approach to achieving high total nutrient intakes with grassland-based systems are highlighted. The potential to improve the sustainability of dairy systems through breed substitution and by identifying more appropriate strains of Holstein animals for use within grazing systems is also examined. A number of environmental challenges associated with grazing systems together with possible opportunities to reduce their impact are highlighted. These include reducing inputs of inorganic fertilizer nitrogen, reducing the crude protein content of concentrate feedstuffs offered during grazing, and reducing the phosphorus content of dairy cow diets. Key words: Dairy cows, grazing, herbage utilization, dairy breeds, environment