Cool-Season Annual Forages and Mixtures to Extend the Grazing Season into the Fall.

The low biomass and nutritive value of perennial forages during the late-fall and early-winter months can be offset by growing cool-season annual forages and their mixtures. Ten forage species/mixtures were seeded in early August into pearl millet (Pennisetum glaucum L.) hay stubble that was either sprayed with glyphosate or allowed to regrow. Species/cultivars included: spring triticale (×Triticosecale Wittm ex A. Camus), Willow Creek winter wheat (Triticum aestivum L.), and P-919 winter forage barley (Hordeum vulgare L.). Each grass was then combined with a brassica mixture (Barkant turnip [Brassicas rapa L. var. rapa], Barnapoli rape [Brassica napus L. var. napus], Groundhog radish [Raphanus sativus var. oleifer Strokes], and Pasja hybrid [Chinese cabbage {Brassica rapa L. chinensis} x Turnip hybrid]). A legume mixture (Hairy vetch [Vicia villosa Roth] and Austrian winter pea [Pisum sativum subsp. Arvense]) was then added to the cool-season grass plus brassica mixtures. All species/mixtures yielded enough dry matter (DM, 3080-5580 kg ha^-1) to be considered for stockpiled fall grazing. Unsprayed grass monocultures had higher DM yields than sprayed grass monocultures (4415 and 4040 kg ha^-1, respectively) while the sprayed mixtures had higher yields than unsprayed mixtures (5150 and 4655 kg ha^-1, respectively). The millet and brassicas dominated and influenced both the yield and nutritive value of the unsprayed and sprayed mixtures, respectively. The sprayed mixtures had higher levels of crude protein (CP, 185-202 g kg^-1) and in vitro true digestibility (IVTD, 909-922 g kg^-1) than unsprayed treatments, but their low levels of neutral detergent fiber (aNDF, 229-246 g kg^-1) may require supplementation with fibrous feeds. The nutritive value of the unsprayed mixtures (510-579 g kg^-1 aNDF, 169-180 g kg^-1 CP, and 755-799 g kg^-1 IVTD) will meet the requirements of beef cattle without the need for supplementation. However, their lower yield potential must be weighed against the extra inputs (herbicides and supplementation with fibrous feeds) and higher yield potential and nutritive value of the sprayed mixtures when deciding whether or not to control the millet regrowth.

Keywords: annual forages, annual forage mixtures, brassicas, fall grazing, stockpiling.