Relationships among Agronomic Characteristics of Corn and Sorghum Cultivars and Silage Quality¹

Abstract

Abstract If agronomic characteristics could be used as criteria for judging quality of corn and sorghum cultivars for silage, the selection of genotypes best suited for silage would be facilitated. The objective of this study was to determine if agronomic characteristics of corn ( Zea mays L.) and sorghum [ Sorghum bicolor (L.) Moench, S. sudanense (Piper) Stapf, and their hybrid] cultivars are related to their silage quality. Over a period of 3 years, 49 silages, involving 11 corn cultivars and 14 sorghum cultivars, were produced and fed to sheep in conventional feeding trials. Eleven of the 14 sorghum cultivars were the sweet‐stem silage type. We measured fodder yield, height, %dry matter, and % plant parts [stems, ears or heads (EH), and leaves]. The quality measurements were acid detergent fiber (ADF); in vivo measurements, with sheep, of digestible dry matter (DDM); average daily gain (ADG); and dry matter intake/animal/day (DMI). The highest correlations were obtained between % stems or % EH and quality for both corn and sorghum silages. Percent leaves and plant height were in some cases highly correlated with quality measurements, but these relationships could be explained by high correlations of % leaves and plant height to % EH and stems. ADF concentration was lower in corn silage (29.0%) than in sorghum silage (34.9%). The low ADG of sheep fed sorghum silage (18.1 g compared to 64.5 g for corn silage) was primarily due to low DMI (649 g) and low DDM (55.6%) of the sorghum silage compared to the high DMI (777 g) and high DDM (63.8%) of corn silage. A regression analysis showed that nearly equal amounts of DDM intake above maintenance were needed for a unit of ADG from corn silage and from sorghum silage.