Nutritive Value Change during the Fall of Late-Summer-Planted Oats, Radishes, and Turnips

Abstract

Core Ideas• Nutritive value of late-summer-planted oats, radishes, and turnips is high in early fall.• Oats, radishes, and turnips maintain a high nutritive value through early winter.• Brassicas remain high in sulfur through the fall with potential for toxicity. AbstractThe change in nutritive value of late-summer-planted oats (Avena sativa L.) and brassicas (Brassica spp.) during the fall in the Midwestern US is not well documented. A mixture of 'Jerry' oats, 'daikon' oilseed radish (Raphanus sativus L.), and 'purple top' turnip (Brassica rapa ssp. rapa L.) was drill-seeded in late August/early September in southcentral Nebraska over two years. Forage was collected in early November, early December, and mid-January. The mean in vitro organic matter digestibility (IVOMD) of radish (86%) and turnip (87%) tops were high and were greater than oats (75%). Within forage type, IVOMD did not decline from November to December, but due to a decline in total ethanol soluble carbohydrates in January, IVOMD decreased 10 percentage units for oats and 5 percentage units for brassica tops from December to January. However, these forages would still be considered high energy even in January. In both years, crude protein (CP) of all forages was high, with oats (16% CP) being less than both radish (27%) and turnip (24%) tops. Little change in CP occurred over the sampling period. Sulfur content of the brassicas was high in November (0.8-0.9% S) and remained above 0.5% S through January, suggesting that the potential for sulfur toxicity, if grazed alone, persists. Delayed grazing of these cool-season forage mixtures late into the fall and early winter is an option for cattle producers in the Midwestern US, as nutritive value remains appropriate for growing cattle or lactating beef cows.

Production cow-calf responses from perennial forage-based and integrated beef-cropping systems

“…Oat IVOMD decreased linearly ( P = 0.02) over the grazing season from approximately 65% to 48% ( Figure 5 ). This agrees with previous research ( Lenz et al, 2019 ), which reported decreased IVOMD in January (67.4%) compared to October (79.0%) for oats planted in late August and early September. In the current experiment, crude protein for mid-August planted oats decreased quadratically ( P = 0.04) over the grazing season from approximately 11% to 6% ( Figure 6 ).…”

“…In the current experiment, crude protein for mid-August planted oats decreased quadratically ( P = 0.04) over the grazing season from approximately 11% to 6% ( Figure 6 ). Lenz et al (2019) did not observe a change in CP of oats, ranging of 13.8% to 17.9%, for oats planted in late August and early September. The higher IVOMD and CP values reported by Lenz et al (2019) may be due to later planting dates compared to the current experiment.…”

“… Lenz et al (2019) did not observe a change in CP of oats, ranging of 13.8% to 17.9%, for oats planted in late August and early September. The higher IVOMD and CP values reported by Lenz et al (2019) may be due to later planting dates compared to the current experiment.…”

“…Planting date of cover crops is one of the most significant factors determining forage production of the late-summer planted cover crop with earlier planting resulting in greater yields ( Koch et al, 2002 ). Energy and protein content of late-summer planted cool-season winter sensitive annuals such as oats remains elevated in early winter ( Lenz et al, 2019 ), whereas corn and soybeans are the predominant crops planted in Nebraska and other Midwest states. Production and harvest of wheat, seed corn, and corn silage can provide an opportunity for producers to capitalize on late-summer planted cover crops as a double-crop annual forage.…”

Dry matter yield and nutritive value of early‐ or late‐maturing spring wheat, spring barley, and oat cultivars planted in late summer

“…Generally, the yield advantage before winter that is associated with these differences in developmental physiology is approximately 2:1 (Coblentz & Walgenbach, 2010; Gunsaulis et al., 2008). Some studies have also included other forages, such as other cereals, radish ( Raphanus sativus L.), or turnip ( Brassica rapa L.), within mixed‐species evaluations that included oat (Lenz, Cox‐O'Neill, Hales, & Drewnoski, 2019; Maloney et al., 1999). Other advantages of using oat for autumn forage production include reduced lignification, improved fiber digestibility, accumulation of water‐soluble carbohydrates in response to frost events, and general stabilization of energy density over a wide time interval for potential mechanical harvest as silage or utilization by grazing livestock (Coblentz & Walgenbach, 2010; Coblentz et al., 2013; Coblentz, Bertram, Martin, & Berzaghi, 2012).…”