Forty Years of Forage Quality Research: Accomplishments and Impact from an Animal Nutrition Perspective

Many important advancements have been made during the past 40 yr as regards forage quality and its effect on ruminant animal nutrition. In the early days of this 40‐yr period, forage quality was considered as a product of digestibility and intake, with intake being the more important of the two processes. Factors affecting each of these processes were heavily studied. At the same time, analytical methodology and developed that had relevance to animal nutrition. Examples include the two‐stage Tilley and Terry in vitro procedure and the Van Soest detergent system of forage analysis. On the pasture side, definition of plant‐animal interrelationships influencing output per animal and per hectare of pasture was a key goal. In more recent years, significant accomplishments have occurred in a number areas including (i) development of near infrared reflectance spectroscopy (NIRS) for forage quality determination; (ii) forage conservation procedures; (iii) role of crop residues in feeding systems; (iv) minerals and secondary plant compounds that affect forage plant digestion, metabolism, and health; (v) digestive kinetics and nutrient availability at different points in the ruminant digestive tract; (vi) development of modeling and systems approaches to the study of forage digestion and to pasture and forage management feeding; (vii) forage supplementation strategies; and(viii) developing an understanding of microbial and animal limitations to fiber digestion and utilization.