Intensively managed pasture in the Great Lakes Basin: A future-oriented review

Abstract

The contribution of pasture to agriculture in the Great Lakes Basin, and specifically in Ontario, is reviewed from both historical and futuristic perspectives. The ascendency of confinement-based ruminant agriculture is currently under challenge by environmental, societal, and market forces which may favor a less resource intensive approach to livestock feeding. Managing pasture for profitable ruminant productivity represents both opportunities and challenges for contemporary producers, as highlighted with examples from beef, dairy, and sheep research. The premise that research intended to benefit pasture enterprises must incorporate the grazing animal is supported by evidence from several sources, including the comparative performance of livestock grazing alfalfa versus other, less highly bred forage legumes. Emphasis is given to the predominant influence of climatic, soil, and managerial factors on pasture performance, through comparisons of sown and indigenous swards, as well as simple and complex mixtures. It is argued that the contribution of pasture to contemporary agriculture could be enhanced by focusing on alternative selection and management indices, such as stability of nutritional quality with both maturation and temperature, rather than quality per se, vertical profiles in nutrient bulk density in an intact sward, and herbage protein partitioning toward rumen bypass rather than rumen-degradable forms. Research in support of intensively managed pasture must effectively integrate grazing livestock, both as a vehicle to apply realistic stresses against which to test breeding materials and management practices, and as the ultimate indicator of biological and economic response. Key words: Pasture and grazing management, beef, dairy, sheep, alfalfa, bird's-foot trefoil, grass, herbage quality