Mid-summer annual forage performance in organic, grass-fed production

Abstract

Grass-fed ruminant production does not have the convenience of feeding easily-storable grains during periods of low forage availability. This study examined the forage yield, quality, and utilization of warm- and cool-season annual forages grown under organic management during the mid-summer “feed gap” period. Annual ryegrass (Lolium multiflorum Lam. cv. Tetra Brand), winter triticale (× Triticosecale Wittmack cv. common), oat (Avena sativa L. cv. Souris), millet (Panicum miliaceum L. cv. Crown Proso), corn (Zea mays L. cv. BMR84 and CM440 Canamaize), and sorghum-sudangrass (Sorghum bicolor [L.] Moench × Sorghum sudanense [Piper] Stapf cv. common) were grown in Carman, Manitoba, over 3 site-years in 2018 and 2019. Combined forage and weed dry matter (DM) yield was 7159 kg·ha−1 for sorghum-sudangrass (29% weeds), 5506 kg·ha−1 for corn (36% weeds), 4687 kg·ha−1 for oat (45% weeds), 4617 kg·ha−1 for annual ryegrass (95% weeds), 4542 kg·ha−1 for millet (28% weeds), and 2945 kg·ha−1 for winter triticale (51% weeds); significant differences in crop and weed biomass were observed. All forage systems were palatable to sheep with utilization rates from 47% to 65%. When all quality parameters were considered, corn, winter triticale, millet, and oat displayed adequate quality for mid-summer grazing, while sorghum-sudangrass had suboptimal crude protein concentrations. Direct measurements of forage quality on weeds showed that weeds did not compromise forage quality. This Canadian first study demonstrated the potential of forage production for mid-summer grazing in an organic, grass-fed regime with oat, millet, and corn resulting in the best combination of yield and quality.