Small Grain Crop Forage Potential: I. Biological and Chemical Determinants of Quality, and Yield 1

Abstract

Complete, up-to-date information is not available on the forage quality and yield potential of spring-sown small grain crops. Our objectives were to determine forage quality and yield potential of cultivars of small grain crops representative of those currently recommended for grain production in the northern states, and to ascertain the relationship between chemical components and in vitro rumen digestibility of these forages at a wide range of maturity stages. Two cultivars each of wheat (Triticum aestivum L.), oats (Avena sativa L.), triticale (Triticum durum Desf. × Secale cereale L.), and barley (Hordeum vulgate L.) were grown at each of two locations during 2 years and harvested at each of six maturity stages. In vitro digestible dry matter (IVDDM) concentration of the average of the four small grain crop forages ranged from 80 to 58% as maturation ranged from flag leaf to dough stage. Cell wall constituents (CWC) and acid detergent fiber (ADF) concentrations increased with maturation at the early stages and then leveled offat the later maturity stages, whereas acid detergent lignin (ADL) concentration increased linearly with increased maturation. Acid detergent lignin concentration was highly negatively correlated with IVDDM of the crops at each of the six maturity stages, and ADL was best associated of all chemical constituents with IVDDM. The barley cultivars tested in this study often had greater nutritive value than did the cultivars of oats, wheat, or triticale. Barley also had the least grass tetany potential, but the greatest milk fever potential, as estimated by K/(Ca+Mg) and Ca/P ratios, respectively. The wheat cultivars often yielded less dry matter and the barley cultivars usually yielded more IVDDM than did those of the other species.