Grazing value of grain sorghum residue How cover crops fit in

1. Grazing value of grain sorghum residueHow cover crops fit in Galen Erickson 402 472-6402; gerickson4@unl.edu

2. Grazing Forage Residue • Cornstalks and other forage residues are important sources of feed for cows and growing steers throughout the winter

3. Why Interest in Grain Sorghum Residue Grazing? • Grain sorghum residue useful for grazing • Compares well to corn stalk grazing • Leaves are readily consumed - not much stalk • Better than corn stalks with ice, or lots of snow

4. Grazing Residue • Grain sorghum close to corn residue • Excellent use, cattle remove 20 to 30% (deposit half back) • Cattle select leaf first, stem is similar to leaf in quality, but not palatability • Understanding stocking rate important • Certainly do (growing cattle, lactating cows) or may not (dry, gestating cows) require supplementation • Protein • Energy (if growing calf) • TDN = 56 (old number) Texas # TDN = 60

5. Grazing Residue • Quality decreases over time • Due to grazing best stuff first (not much change due to time) • Nutrient removal is a non-issue • Cows remove 0 amounts of N, P, or other minerals • Remove 10-20% of organic matter (50% replaced in manure) • If growing cattle, then supplementation likely. Actually fertilizing fields • Compaction or yield issues are a non-issue • 17 year study: no decrease in corn yield, significant increase in soybean yield. Spring grazing was the treatment. In a no-till system.

6. Advantage to sorghum residue • Stalk quality similar to leaf • Better than corn stalks for winter grazing • Little risk of down grain (digestibility of grain low if not processed) • Previous comparisons favored corn residue: probably due to down grain

7. Ward, J. K. 1978. Utilization of Corn and Grain Sorghum Residues in Beef Cow Forage Systems. J. Anim. Sci. 46:831-840. Ward, J. K., L. J. Perry, D. H. Smith, and J. T. Schmitz. 1979. Forage Composition and Utilization of Grain Sorghum Residue by Beef Cows. J. Anim. Sci. 48:919-925.

10. Ward publications • Leaf: 8.5 to 10.5% CP, IVOMD of 30-55% • Grazing decreased quality, so did time some • Lb/ac yields

12. DDG supplementation on grazed corn residue – 3 trial pooled summary ADG, lb Supplementation, % BW

13. Residue grazing supplementation Tibbitts et al., 2016 Beef Report

14. Residue grazing supplementation Tibbitts et al., 2016 Beef Report

16. What is brown mid rib? • First discovered in 1924 • Mutation made by soaking sorghum seeds in diethyl sulfate • Produced 19 lines • 2 enzymes with decreased activity - Leads to less lignin and increased digestibility • Currently, three genes, BMR-6, BMR-12 and BMR-18 are used in the sorghum industry to produce brown midrib hybrids. Comparative effects of the Sorghum bmr-6 and bmr-12 genes: Forage Sorghum Yield and Quality A.L. Oliver, J.F. Pederson, R.J. Grant and T.J. Klopfenstein

17. Fiber Fraction of Plant Cells • Neutral Detergent Fiber (NDF) - total fiber content of a forage is neutral detergent fiber (NDF) - cellulose, hemicellulose, and lignin - NDF predicts feed intake and rumen fill • Acid Detergent Fiber (ADF) - cellulose and lignin - ADF predicts digestibility of forages (energy content) • Lignin component found in cell walls of forages. - measured by acid detergent lignin (ADL) or permanganate lignin - lignin is almost completely indigestible - as lignification increases, digestibility decreases.

18. What are the downsides?

20. Forage Quality (2005)Previous Year 48 hr IVNDFD, Mallory Becker undergrd project; 2005 season; Havelock and Mead

21. BMR Grain Sorghum Residue Grazing • Graze grain sorghum forage residue from two hybrids: AWheatland x RT430 and AWheatland bmr-12 x RT430 bmr-12 • Collect clippings from leaves and stems of residue for forage digestibility analysis • Evaluate cattle performance on both hybrids

22. Crop Information

23. Sorghum Field (2006)

24. Crop Information Brown Midrib Sorghum 116.3 bu/acre 112.9 bu/ac Non BMR Sorghum 120.1 bu/ac 124.2 bu/ac 2006 2008

25. Grazing Performance • 564 lb steers (2006); 492 lb steers (2008) • Limit feed at 2% of body weight for 5 days before and after trial, collect weights for 2 days 2 consecutive days • Randomly assign to grazing paddock to ensure equal weights; • 8 paddocks - 4 for each hybrid; 7 steers/paddock; Nov 26 – Feb 1 (2006) 6 steers/paddock; Dec 2 – Feb 5 (2008)

26. Grazing Performance-2006 TRT: CON BMR P-value Initial BW 564 564 0.85 Ending BW 618 652 0.01 ADG, lb 0.75 1.23 0.01 0.48 lb difference

27. Grazing Performance-2008 TRT: CON BMR P-value Initial BW 495 489 0.06 Ending BW 575 584 0.30 ADG, lb 1.32 1.55 0.14 0.23 lb difference

28. Grazing Performance-2 years TRT: CON BMR P-value Initial BW 530 526 0.19 Ending BW 597 618 <0.01 ADG, lb 1.03 1.39 <0.01 0.36 lb/d difference

29. Forage Quality Leaves Stems

30. a a a a b b Day*treatment p=.4177 Treatment p<.0001

31. a x b y z c

32. a a a a b b

33. a x b x ab y

34. P < 0.01 P < 0.01

35. Conclusions on Brown Mid Rib • Grain sorghum residue with bmr-12 trait • Does not affect fiber content (NDF %) much • Dramatic improvement in digestion (7-15% units) • Increases ADG by 0.36 lb/d (over 65 d grazing) • Equates to 23 lb or more in weight ($1.50/lb)

36. Other Considerations: double crop annual forage Photo by Kristen Ulmer

37. Overview-cover crops • Cover crops can be used to background calves • Late summer planted oats or other spring small cereal grasses can provide fall grazing • Late fall planted rye or triticale can provide spring grazing • Quality high enough to provide 1.3 to 3.0 lb/d gains without supplementation • Weather huge factor with rate of gain in winter • Grazing management big impact on gain in spring

38. What to plant for cover (secondary forage) crop? • 1st factor to consider is planting date • After August 10th but before Sept 1st (fall forage) • Cool season winter sensitive • Oats, spring barley, or spring triticale with or without brassicas (turnips, rape) • After Sept 1st (spring forage) • Winter hardy cool season • Rye, Triticale Planting guidelines: http://beef.unl.edu/planting-annual-forages

39. Growing degree days (GDD) accumulation during the summer and fall Drewnoski and Redfearn,

40. Effect of planting date on late summer planted oats Sept. 17th Sept. 3rd Ulmer et al., 2017 Nebraska Beef Report

41. Sorghum for Grain: Usual Planting and Harvesting Dates

42. Effect of fall planting date on spring growth of winter hardy small cereals Oct. 10th Oct. 20th Aug. 28th Sept. 8th NE, CEN, SW South East Sept. 18th Sept. 29th Gibson et al., 2007; Agron. J. 99:49-58

43. Picture taken April 18th near Fall City NE Elbon Rye VNS Rye 2.2 vs 1.6 tons DM/ac (April 8th)

44. Yield and quality of winter cereals in spring April 8th 2016 near Fall City NE; Planted Late September

45. DGS and corn residue hard to beat $6.27/hd *1.2 hd/ac = $5.23/ac for conservation

46. Questions 402 472-6402 http://beef.unl.edu gerickson4@unl.edu