Fodder Flow Planning and Forage Conservation Study Guide

Fundamentals of Fodder Flow Planning

• Definition & Scope:

  • Fodder flow planning is the strategic management process concerned with ensuring an appropriate supply of feed—of a given quality and/or quantity—to meet the specific requirements of animals.
  • The primary goal is to match the farm's feed-producing capabilities with the dietary needs of livestock to maximize profit margins over feed expenses while remaining within safe natural resource consumption limits.

• Matching Supply to Demand:

  • Evaluating Supply: Conduct a veld condition evaluation or determine available crop residues to establish the farm's long-term potential for generating fodder (measured in $\text{kg/ha/year}$) across natural veld, planted pasture, and crop residues.
  • Determining Demand: Accurately track livestock inventory, including exact animal numbers and their specific stages of development.

• Methods to Modify On-Farm Fodder Supply:

  • Species Selection: Choose forage species that provide a broad seasonal spread of growth. This requires detailed knowledge of grass species, which forms the basis for veld condition assessment.
  • Forage Conservation: Preserve excess biomass as hay, silage, or foggage.
  • Grazing Management: Regulate livestock grazing frequency and intensity to directly influence both the quantity and quality of forage produced.

• External Feed Sourcing:

  • Purchasing feed serves as a last resort to bridge seasonal deficits or quality gaps.
  • Common supplementary options include winter licks or feed formulations derived from accessible feed resources, particularly in dairy operations.

Seasonal Feed Dynamics and Forage Deficits in South Africa

• Veld Degradation Status in South Africa:

  • Natural veld is severely degraded across South Africa.
  • An estimated $60\%$ of the veld is in poor condition.
  • An estimated $30\%$ is in an intermediate or moderate condition.
  • Only $10\%$ remains in good condition.
  • Despite this degradation, many livestock farmers continue to rely on natural veld as their primary feed source.

• Bioclimatic Constraints:

  • Extreme seasonality in rainfall drives extreme fluctuations in forage availability and quality.
  • This seasonality frequently creates a severe feed gap during the dry season.
  • Mitigating current seasonal deficits and predicted future bioclimatic forage shortages necessitates improved fodder production, conservation, and preservation practices.

• Planning for Seasonal Feed Shortages:

  • Stockpiling & Reserves: Farmers can purchase and stockpile feed as hay or silage, or plant dedicated fodder reserves to be drawn upon during dry years.
  • Storage Requirements: Stockpiled feeds must be kept in a dry, secure storage facility.
  • Economic Strategy: Purchasing feed in bulk during the wet season is typically more cost-effective because feed prices are lower. During droughts, feed scarcity drives market prices up significantly.

Forage Conservation Principles and Factors

• Objectives of Forage Conservation:

  • Provides supplementary feed to complete animal rations.
  • Stores excess biomass produced during peak growing periods for future use.
  • Preserves the nutritive value of forage over extended periods.
  • Delivers a consistent, balanced diet year-round, particularly during deficit periods.
  • Enables structured, year-round feed flow planning.

• Factors Influencing Conserved Forage Quantity and Quality:

  • Forage Species: Resistant, fast-growing species allow for multiple harvests within a single growing season.
  • Leafiness: Higher leaf-to-stem ratios enhance overall nutritional density.
  • Maturity Stage: Harvest timing (early vs. late) directly determines nutrient concentration and total yield.
  • Harvesting Technique: Poor execution leads to field losses and reduced intake in animal rations.
  • Climate: Correct environmental conditions and temperatures must be maintained during drying or fermentation.
  • Foreign Matter: Contamination reduces intake and overall quality.
  • Storage Facilities: Proper storage preserves nutrients and prevents decay.

• Primary Methods of Forage Conservation:

  • Drying: Haymaking.
  • Fermentation: Silage and haylage production.
  • Dehydration: Artificial drying or pelleting.

Hay Production and Yield Metrics

• Definition & Core Goals:

  • Haymaking involves cutting, drying, and storing green forage (grasses or legumes) to feed livestock during dry seasons or droughts.
  • The main objectives are reducing plant moisture content to $15\% \text{--} 20\%$, preventing mold growth, and retaining maximal nutritional value.

• Principles of Haymaking:

  • Harvest Timing: Cut grasses at the pre-flowering or early flowering stage (around $50\%$ flowering). Cut legumes at flower initiation to achieve the optimal balance of yield and nutrient content.
  • Drying (Curing): Spread cut forage across the field under sun and wind exposure until moisture drops below $15\% \text{--} 20\%$.

• Characteristics of High-Quality Hay:

  • Leafy texture with a bright greenish color.
  • Completely free of foreign material.
  • Free of mold, mustiness, or off-smells.

• Hay Yield Expectations:

  • Irrigated Lands:
    • Subtropical hay crops: $15 \text{ to } 35\,\text{t/ha/annum}$
    • Temperate hay crops: $8 \text{ to } 18\,\text{t/ha/annum}$
    • Yields vary based on soil potential, fertilization, and local climate.
  • Dryland Conditions:
    • Subtropical hay crops: $4 \text{ to } 15\,\text{t/ha/annum}$
    • Temperate hay crops: $3 \text{ to } 5\,\text{t/ha/annum}$

Silage Production, Biochemistry, and Quality Standards

• Definition & Suitability:

  • Silage is produced from high-yielding, thick-stemmed crops that are unsuitable for haymaking.
  • When using legumes, they should be blended with high-energy crops such as maize.
  • Properly made silage incurs lower dry matter losses ($< 15\%$) compared to haymaking ($> 25\%$).

• Fermentation Process Protocols:

  • Silage preservation relies on natural bacterial fermentation under strictly anaerobic conditions.
  • Finely chop plant material.
  • Compact the material thoroughly to eliminate oxygen pockets.
  • Seal the silo completely to maintain an anaerobic environment.

• Moisture & pH Control (Clostridia Suppression):

  • Wet forage material promotes the growth of undesirable Clostridia bacteria.
  • To suppress Clostridia, encourage the proliferation of lactic acid bacteria, which rapidly lower the silage pH.
  • If material moisture is kept at or below $70\%$, Clostridia bacteria remain inactive.

• Phases of Silage Preservation:

  • Phase 1 (Aerobic Phase): Living plant cells break down carbohydrates into carbon dioxide, water, and heat while oxygen is present. Chop fineness and degree of compaction dictate respiration levels. Plant respiration causes an initial temperature rise. A temperature range of $27^\circ\text{C} \text{--} 38^\circ\text{C}$ is ideal for lactic acid bacteria; temperatures reaching $45^\circ\text{C}$ are excessively high.
  • Phases 2 to 4 (Acid Formation): Phases 1 through 3 span $3 \text{ to } 4\,\text{days}$. Phase 2 initiates under aerobic conditions with active acetic acid bacteria. Phase 3 marks the start of lactic acid formation, which continues into Phase 4. Both temperature and pH fall as lactic and acetic acids preserve the forage. Fermentation stops once soluble carbohydrates are fully consumed.
  • Timeframe & Chemical Changes: Complete preservation occurs within $2 \text{ to } 3\,\text{weeks}$. Processes include the breakdown of plant proteins into amino acids, ammonia, and non-protein nitrogen (NPN) products.
  • Phase 5 (Undesirable Secondary Fermentation): Occurs if moisture and pH remain elevated while soluble sugar levels are low. Inadequate lactic acid production allows Clostridia to thrive, forming butyric acid (imparting a rancid odor and taste). Proteins and amino acids degrade into ammonia and amines, causing poor livestock intake.

• Silage Additives:

  • Additives Without Feeding Value: Enzymes, bacterial cultures, and yeast cultures.
  • Additives With Feeding Value: Grains and roughages, limestone powder, molasses, and Non-Protein Nitrogen (NPN).

• Silage Quality Classification Standards:

  • Class 1 (Excellent): Clean, acid taste and smell; zero butyric acid; zero mould; pH $3.5 \text{ to } 4.2$; Ammonia-N $< 10\%$ of total N.
  • Class 2 (Good): Acid taste and smell; trace of butyric acid; pH $4.2 \text{ to } 4.5$; Ammonia-N $10\% \text{ to } 15\%$ of total N.
  • Class 3 (Fair): Small amount of butyric acid present; some mould; pH $4.5 \text{ to } 4.8$; Ammonia-N $15\% \text{ to } 20\%$ of total N.
  • Class 4 (Poor): High butyric acid; extensive proteolysis; visible mould; pH $> 4.8$; Ammonia-N $\approx 20\%$ of total N.

• Feeding Protocols & Haylage:

  • Silage is ready for feeding after $3 \text{ to } 4\,\text{weeks}$ and can be stored for $2 \text{ to } 3\,\text{years}$.
  • Haylage: Silage made at lower moisture levels. Due to lower moisture, it does not compact as well and ensiles with greater difficulty.

Foggage (Spared Veld) Management

• Definition & Characteristics:

  • Foggage (spared veld) is pasture accumulated in paddocks during late summer to be grazed in situ by livestock during winter.
  • In sourveld regions, foggage plays a limited role because winter veld drops significantly in palatability and feeding value.

• Strategic Reasons for Utilizing Foggage:

  • Bridges autumn pasture quality deficits in sourveld before crop residues become available.
  • Avoids haymaking difficulties common in high-rainfall and misty areas.
  • Simplifies production systems by lowering labor and mechanization inputs.
  • Promotes soil cover and water retention in veld and pastures, supporting climate change adaptation.

• Pasture Species & Fertilization:

  • Requires grass species capable of maintaining digestibility and palatability into maturity, such as Smuts finger grass (Digitaria eriantha).
  • Nitrogen ($\text{N}$) is the chief determinant of yield and quality, alongside Phosphorus ($\text{P}$) and Potassium ($\text{K}$).
  • Apply fertilizer containing $150 \text{ to } 250\,\text{kg N/ha}$ during January.

Fodder Flow Calculations and Rules

• Core Purpose of Fodder Flow Planning:

  • Determines the specific periods of the year each fodder source can be utilized.
  • Indicates the duration (in months) each fodder source can sustain the herd.
  • Calculates the total Large Stock Unit ($\text{LSU}$) carrying capacity of the farm.

• Master Fodder Flow Formula:     $\text{Fodder Ha/t} \div \text{CC} = \text{LSU} \times 12 = \text{Grazing units} \div \text{Total LSU} = \text{Months}$

• Rule 1: Determining Column A (Hectares or Tons):

  • Natural Veld: Always recorded exactly as given in hectares. Naturally occurring or planted grazing grasses include Weeping love grass (Eragrostis curvula), Couch grass (Cynodon dactylon), Guinea grass (Panicum maximum), Smuts finger grass (Digitaria eriantha), and Blue buffalo grass (Cenchrus ciliaris).
  • Dryland Cultivated Pasture (CP-dryland): Unirrigated, fertilized pastures.
    • Scenario 1 (Known Production): Multiply hectares by yield per hectare ($\text{Hectares} \times \text{t/ha}$). Example: $20\,\text{ha}$ of Eragrostis teff yielding $8\,\text{t/ha} = 160\,\text{t}$.
    • Scenario 2 (Unknown Production): Assume production is double natural veld production due to fertilization ($2 \times \text{Hectares}$). Example: $20\,\text{ha}$ of Eragrostis teff without yield data $= 20 \times 2 = 40\,\text{t}$.
  • Irrigated Cultivated Pasture (CP-irrigated): Irrigated, fertilized pastures.
    • Scenario 1 (Known Production): Multiply hectares by yield per hectare ($\text{Hectares} \times \text{t/ha}$). Example: $10\,\text{ha}$ of Sugar Graze yielding $20\,\text{t/ha} = 200\,\text{t}$.
    • Scenario 2 (Unknown Production): Assume production is triple natural veld production due to fertilization and water ($3 \times \text{Hectares}$). Example: $10\,\text{ha}$ of Sugar Graze without yield data $= 10 \times 3 = 30\,\text{t}$.
  • Silage: Silage is harvested green and contains high moisture. Because daily intake per $\text{LSU}$ is based on dry matter, total silage tonnage must always be divided by $3$ ($\text{Tons} \div 3$). Example: $900\,\text{t}$ of maize silage $\div 3 = 300\,\text{t}$.
  • Crop Residue: Post-harvest leftovers (stems and leaves). Grain yield equals residue yield. Calculate raw yield as $\text{Hectares} \times \text{Yield t/ha}$. Due to losses from trampling, dung, urine, wind, and unpalatable/indigestible parts, divide raw yield by $2$ to account for a $50\%$ loss ($(\text{Hectares} \times \text{Yield}) \div 2$). Example: $100\,\text{ha}$ of maize yielding 3\,\text{t/ha} = (100 \times 3) \div 2 = 150\,\text{t}$.\n * **Hay**: Always used exactly as given in tons (e.g., 500\,\text{t} \rightarrow 500\,\text{t}).\n\n* **Rule 2: Determining Column B (Carrying Capacity - CC)**:\n * **Grasses (Natural Veld, CP-dryland, CP-irrigated)**: Use the farm's specified carrying capacity (e.g., 8\,\text{ha/LSU}).\n * **Stored/Residue Feeds (Silage, Hay, Crop Residue)**: A fixed Carrying Capacity constant of 5 is always used.\n\n# Fodder Flow Table Step-by-Step Worked Example\n\n* **Farm Inputs & Data**:\n * Natural Veld: 200\,\text{ha}\n * Cultivated Pasture – Irrigated: 40\,\text{ha} (no yield given)\n * Cultivated Pasture – Dry land: 60\,\text{ha} (no yield given)\n * Maize Crop Residue: 20\,\text{ha}$with estimated yield of$4\,\text{t/ha}\n * Hay: 100\,\text{t}\n * Silage: 900\,\text{t}\n * Farm Grazing Carrying Capacity: 8\,\text{ha/LSU}\n\n* **Tabular Solution**:\n * **Natural Veld**:\n * Column A (Ha / ton): 200\n * Column B (÷ CC): 8\n * Column C (= LSU): 200 \div 8 = 25\n * Column D (x 12): 12\n * Column E (= Grazing units): 25 \times 12 = 300\n * Column F (÷ Total LSU): 143\n * Column G (= Months): 300 \div 143 = 2.1\,\text{months}\n * **CP – Irrigated**:\n * Column A (Ha / ton): 40 \times 3 = 120\n * Column B (÷ CC): 8\n * Column C (= LSU): 120 \div 8 = 15\n * Column D (x 12): 12\n * Column E (= Grazing units): 15 \times 12 = 180\n * Column F (÷ Total LSU): 143\n * Column G (= Months): 180 \div 143 = 1.6\,\text{months}\n * **CP – Dry land**:\n * Column A (Ha / ton): 60 \times 2 = 120\n * Column B (÷ CC): 8\n * Column C (= LSU): 120 \div 8 = 15\n * Column D (x 12): 12\n * Column E (= Grazing units): 15 \times 12 = 180\n * Column F (÷ Total LSU): 143\n * Column G (= Months): 180 \div 143 = 1.6\,\text{months}\n * **Silage**:\n * Column A (Ha / ton): 900 \div 3 = 300\n * Column B (÷ CC): 5\n * Column C (= LSU): 300 \div 5 = 60\n * Column D (x 12): 12\n * Column E (= Grazing units): 60 \times 12 = 720\n * Column F (÷ Total LSU): 143\n * Column G (= Months): 720 \div 143 = 5.0\,\text{months}\n * **Hay**:\n * Column A (Ha / ton): 100\n * Column B (÷ CC): 5\n * Column C (= LSU): 100 \div 5 = 20\n * Column D (x 12): 12\n * Column E (= Grazing units): 20 \times 12 = 240\n * Column F (÷ Total LSU): 143\n * Column G (= Months): 240 \div 143 = 1.7\,\text{months}\n * **Crop Residue**:\n * Column A (Ha / ton): \frac{20 \times 4}{2} = 40\n * Column B (÷ CC): 5\n * Column C (= LSU): 40 \div 5 = 8\n * Column D (x 12): 12\n * Column E (= Grazing units): 8 \times 12 = 96\n * Column F (÷ Total LSU): 143\n * Column G (= Months): 96 \div 143 = 0.7\,\text{months}\n\n* **Total Farm Carrying Capacity & Duration Summary**:\n * **Total Farm LSU (Column F)**: Summing Column C yields 25 + 15 + 15 + 60 + 20 + 8 = 143\,\text{LSU}.\n * **Total Months Provided**: Summing Column G yields 2.1 + 1.6 + 1.6 + 5.0 + 1.7 + 0.7 = 12.7\,\text{months}$. This demonstrates complete year-round feed security for$143\,\text{LSU}$$.