Sarah Kenyon Agronomy Specialist

Transcription

1 Sarah Kenyon Agronomy Specialist

2 Plant Growth or Yield Putting it Together Quality

3 Plant Growth or Yield

4 Sun O 2 CO 2 CHO H 2 O Mineral Nutrients

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6 9 Macronutrient elements: C H O N K P Ca Mg S 8 Micronutrient elements: Mn Zn Cu Cl B Fe Mo Ni Some other elements that are beneficial: Na Si V Co Al

7 Iowa State University Extension PM 1791 Grass Anatomy

8 Initially, tillers depend on carbohydrates developed the previous fall. Then as leaf area explodes with additional tillers, new sugars are made Tillers

9 Legume Anatomy Iowa State University Extension PM 1791

10 3 primary stages of forage development 1. Vegetative

11 Tillers emerge from buds in the crown Tiller growth uses stored carbohydrates Plants begin making new sugars Most new sugars supplement carbohydrates to help growth Very little if any is put into storage

12 Leaves get longer New tillers grow from buds, tillers branch More leaf area speeds up photosynthesis Some new sugars continue to be used in growth Some new sugars stored as carbohydrates

13 3 primary stages of forage development 1. Vegetative 2. Elongation/Jointing

14 Leaf growth slows down Photosynthesis continues making sugars Most new sugars stored as carbohydrates Reproductive tillers begin to elongate

15 3 primary stages of forage development 1. Vegetative 2. Elongation/Jointing 3. Reproductive

16 Leaf growth stops, formation of stems and reproductive structures Photosynthesis continues making sugars Most new sugars used for seed production Little stored carbohydrates used for seed development

17 Perennial Production of Seeds Vegetative Tillers Rhizomes Annual Production of Seeds

18 Iowa State University Extension PM 1791

19 3 primary stages of forage development 1. Vegetative 2. Elongation/Jointing 3. Reproductive

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22 In Tall Fescue growing point are not removed In Tall Fescue residual stubble contains chloroplasts In Alfalfa many auxiliary buds (growing points) are removed In Alfalfa most chloroplasts are gone

23 In both plants regrowth seen in light green In Tall Fescue regrowth from intact growing points In Tall Fescue regrowth uses some stored carbohydrates In Alfalfa regrowth from basal buds In Alfalfa regrowth uses most stored carbohydrates

24 Dry Matter Yield (lb/acre) Dry Matter Yield at Various Cutting Heights inch 2 inches 3 inches 4 inches 5 inches 6 inches 0 Per. Ryegrass Species Tall Fescue

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26 % Leaf Removed % Root Growth Stopped to To remain healthy, 30% of grass root systems must be replaced annually. Stops root growth 12 days Stops root growth 18 days

27 Dry Matter Yield (lb/acre) Overgrazing is removing too much of the Dry Matter canopy Yield at Various too often Cutting Heights inch 2 inches 3 inches 4 inches 5 inches 6 inches 0 Per. Ryegrass Species Tall Fescue

28 Cool Season Grasses Tall Fescue Orchardgrass Warm Season Grasses Native Grasses Bermudagrass Annuals Pearl Millett Winter Wheat

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31 Take Half / Leave Half Residual

32 Allows plant to recover completely after grazing Recovery of shoots and roots Allows for plant and stand persistence

33 During grazing periods: control stubble height Keep growing points Provide for good photosynthesis Keep roots growing Between grazing periods: schedule rest periods Allows for photosynthesis Allows leaves to regrow Vegetative reproduction can occur

34 Short-lived perennials reseed Red Clover Annuals reseed Annual Lespedeza, Crabgrass Grasses are given the chance to spread Bermudagrass Plants are allowed to thicken naturally by reseeding

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36 Incorporates a grazing strategy and rest periods Quality & quantity increases Enhanced forage utilization Persistence increases

37 Quality

38 Working definition: high protein, low fiber Measured Components Acid Detergent Fiber (ADF) = cellulose & lignin Neutral Detergent Fiber (NDF) = total cell walls = cellulose, lignin & hemicellulose Nitrogen Minerals Antiquality Calculated Components Net Energy (NE) calculated from ADF Total Digestible Nutrients (TDN) calculated from ADF Digestible Dry Matter (DDM) calculated from ADF Dry Matter Intake (DMI) calculated from NDF Relative Feed Value (RFV) calculated from NDF & ADF Crude Protein (CP) calculated from Nitrogen

39 1. Maturity The sharpest decrease in quality occurs during the reproductive phase. CP = 13 14% CP = 5-6% During this growth phase plants lose quality by the hour!

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41 What is the boot stage?

42 Changes in botanical composition and forage quality of forage groups at different maturity stages. Forage Group Leaves CP NDF % DM Grasses Vegetative > 50 > 18 < 55 Boot Heading Mature < 8 > 65 Legumes Vegetative > 19 < 40 Bud Early Flower Late Flower < 30 < 13 > 51 Source: Schroeder, 1996

43 When 4 th leaf emerges, the first leaf begins to die Most grasses will have no more than 3 live leaves any point in time Pasture quality begins to decline and is wasted The 3 to 3½ leaf stage is the optimum stage for grazing

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45 Iowa State University Extension PM 1791

46 1. Maturity 2. Plant Part 1 st bite: leaves with low fiber 2 nd bite 3 rd bite: stems with high fiber

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48 CP NDF NeL 1 st bite: leaves low fiber nd bite rd bite: stems high fiber

49 Crude Protein Content of Pastures 12-Paddock Rotation

50 Variation in Milk Production Between Pastures

51 Dry Matter Yield (lb/acre) Dry Matter Yield at Various Cutting Heights inch 2 inches 3 inches 4 inches 5 inches 6 inches 0 Per. Ryegrass Species Tall Fescue

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53 Dry Matter Yield (lb/acre) Dry Matter Yield at Various Cutting Heights inch 2 inches 3 inches 4 inches 5 inches 6 inches 0 Per. Ryegrass Species Tall Fescue

54 1. Maturity 2. Plant Part 3. Species

55 Annual & Perennial Cool-Season & Warm-Season Grasses & Legumes Forbs & Browse

56 Palatability of Cool-Season Forage Grasses Univ. of Wisconsin Specie Variety Palatability* Orchardgrass TAKENA 4.3 Timothy CLIMAX 4.3 Perennial Ryegrass KEMAL 4.2 Orchardgrass BARIDANA 4.0 Orchardgrass DAWN 4.0 Perennial Ryegrass ANACONDA 4.0 Smooth bromegrass BLIZZARD 3.8 Orchardgrass BENCHMARK 3.7 Timothy DOLINA 3.7 Orchardgrass HAYMATE 3.5 Orchardgrass WARRIOR 3.0 Smooth bromegrass ALPHA 2.3 Tall fescue KY Tall fescue BRONSON 1.2 Tall fescue SEINE 0.6 *Palatability rating 0=0% grazed, 1=20%, 2=40%, 3=60%, 4=80%, 5=100% grazed. Palatability of grasses under grazing is determined by visual estimation of percent defoliation of plots. The visual determination is made midway during mob grazing by beef cows of the grass plots for yield determination.

57 1. Maturity 2. Plant Part 3. Species 4. Anti-quality Factors

58 Nutrient Deficiency Grass Tetany Weeds Poison Compounds Nitrate Poisoning Prussic Acid Bloat Fescue Toxicosis

59 Early spring production Medium to high yield Excellent persistence Good tolerance to: Poor drainage Low soil fertility Drought Heat stress Cold temperatures Insects Nematodes

60 Fungus found in stem, leaf sheaths & seed Increases progressively season long Minimized in young growth Cannot survive outside of the plant host Roberts and Andrae, 2004

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62 Mutualistic Symbiosis Plant providses habitat and nutrition for the endophyte Endophyte (fungus) provides plant with multiple benefits Drought Tolerance Insect Resistance Increase Nutrient Acquisition Grazing Tolerance Others

63 Produces alkaloids which confer pasture pest resistance but can also cause animal health problems Peramine Lolines Ergovaline

64 Medicinal Alkaloids Morphine, quinine, atropine, vincristine Addictive Alkaloids Cocaine, heroin, caffeine, nicotine Very toxic in small amounts Strychnine, coniine

65 Lower conception rates Reduced milk production Reduced feed intake Rough hair coat Increased core body temperature in summer (leads to heat stress) Frozen nose, ears, tails, etc (in winter) Fescue foot

66 US beef industry over $600 million annually Missouri beef industry over $160 million annually All US livestock sectors over $1 billion (Roberts and Andrae, 2010)

67 Test < 20% = Low Infection > 55% = High Infection

68 Endophyte generally necessary for persistence south of this line (West, 1998)

69 Bouton et al.,

70 Non-toxic endophytes (Novel or Friendly) Retain persistent qualities Animal performance similar to E- Available Varieties: Jesup Tall Fescue with MaxQ Advance with AR37 Bar-Optima with E34 Others AR4 E- E+ Location Average Daily Gain (lb) Fayetteville, AR Mt. Vernon, MO West et al., 1998

71 Roberts and Andrae, 2004

72 1. Maturity 2. Plant Part 3. Species 4. Anti-quality Factors

73 Plant Growth or Yield Putting it Together Quality

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75 Monitor forage before, during and after the grazing event Determines forage availability for livestock Identifies which paddocks to graze, rest, and cut for hay Helps to prevent overgrazing Helps to identify weak pasture stands

76 Monitor pastures at least twice a month Weekly is better Walking is better than driving

77 Forage available for livestock in KNOWN Able to construct pasture budgets and establish paddock rotations Able to Adjust: Forage Allocation Number of Cattle in Paddock Number of Days for Grazing

78 Write down pasture measurements and management decisions Rest Periods Number of Cattle on Pasture/ Days Cattle are on Pasture Forage Demand Paddock Rotation Schedule Many More

79 Write down pasture measurements and management decisions

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81 Grazing Wedge

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83 Ranchers should adopt the philosophy that pasture production is their business. Therefore, the health of the pastures is the most important aspect of ranching.

84 THANK YOU!

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86 Observe pasture growth regularly Yield Stand Density and Health Over time can help to identify: Low producing paddocks Need to weed control Management strengths and weaknesses

87 Allow adequate rest between grazing for plant recovery Begin Grazing at the 3 3 ½ leaf stage Harvest hay during the boot stage Manage stands for improved pasture quality Keep pasture records!!!

88 Questions?

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