Preference and Forage Quality of 13 Cultivars of Forage Barley and 2 Cultivars of Oats when Grazed by Sheep

Abstract

Annual forages are an increasingly important feed source for ruminants in the western region of the U.S. However, little information is available on the grazing value and forage quality of many cultivars. The objectives of this project were to evaluate sheep grazing preference and forage quality of thirteen forage barley cultivars and two oat cultivars. Eight Rambouillet rams were used in a randomized complete block design. Rams were allowed to graze a single replication of all fifteen entries for a 24-h period before being moved to another replication. Quadrats were hand-harvested from each plot immediately before and after grazing to evaluate herbage mass production and herbage mass removal. Subsamples were collected and sent to a commercial lab for quality analysis. Visual scores of herbage mass removal were taken from each plot post-grazing. No differences were observed between herbage mass production or herbage mass removal, although there were differences in visual pre- and post-grazing assessment scores (P < 0.001). Significant differences were observed amongst cultivars for acid detergent fiber (25.9-35%, P = 0.011) and nitrate concentrations (2.1-2.5% NO3; P < 0.002), with the oat varieties having the highest nitrate. Other forage quality parameters evaluated were not significantly different among cultivars. Based on nutrient quality, without accounting for nitrate concentrations, these cultivars are a high-quality forage source. This research shows that these annual forage cultivars can be utilized as a high-quality grazing source to meet animal requirements; however, care must be taken to avoid elevated nitrate levels.