Starts with the soil - Soil analysis Nutrient management planning Silage Quality 1. Fermentation (pH & Ammonia N) 2. Feeding value (D-Value, CP & Dry Matter) Silage Quantity 1. Tonnage required D-value depends on stage of growth and timing of harvesting Very high D-value High D-value Moderate D-value Low D-value >75 >70 65-70 <65 Seed head not visible but moving up the shoot Seed heads fully emerged and elongated Grass at 67 D-value 60 D Very stemmy with a dead base 12 Relationship between silage yield and D-value D-value 80 Total DM yield 10 8 DM yield of digestible material 6 67% D 70 4 65 2 0 24-Apr 4-May 14-May 24-May 3-Jun Date 13-Jun 23-Jun 3-Jul 60 13-Jul D-value Yield (t DM /ha) 75 Why? To assess feed value, predicted animal performance and the need for supplementation To identify early the stability of the silage and possible impacts on waste and animal health How? Wait until 6 weeks post harvest Take several cores across clamp pH of between 3.8 and 4.2 is desirable In the field after mowing - Respiration occurs breaking down sugars. Plant proteins are also broken down. In the silo during filling –sugars are converted to lactic acid in the absence of air until a pH of 3.8 – 4.2 is reached. In silo – If pH above 4.2 then undesirable bacteria grow converting sugars to butyric acid and protein to ammonia resulting in poor quality silage. During feed-out – if pH is above 4.2 then sugars in the presence of oxygen are converted to CO2 & heat. Yeasts & moulds also grow rapidly. 1. Sward type – PRG is better 2. Nitrogen Application 3. Stage of growth 4. Weather & Grass Dry Matter 5. Silo filling & sealing technique 1. 2. 3. 4. Ensure sugar content of grass is high (greater than 2.5% fresh weight) by: Harvesting swards with a high PRG content. Applying slurry & fertiliser at correct rate & time. Harvesting in bright sunny weather. Carry out ensilability analysis. Indicates the potential fermentation quality by giving information on: 1. 2. 3. 4. 5. Dry matter Crude protein Water soluble carbohydrates (sugars) Nitrate Buffering Capacity Rule of thumb – allow a day for every 2 units of Nitrogen to grow out of grass Hence 3 bags 27%N = 81 units 81 divided by 2 units/day 41 days required between fertiliser application and cutting Ensure silage dry matter is high by: 1. 2. assessing % DM before harvesting. harvesting grass at and/or wilting to 25 -30% DM. Spread the herbage over as large an area as possible immediately post mowing Max wilting period 24-30 hours Prolonged wilting reduces digestibility Wilting results in increased silage DM intakes 1. Can be used as an aid to make good silage but not a remedy for poor management Inoculants are the main type Inoculants contain one or more lactic acid bacteria and promote efficient fermentation Grass placed on top by hand 50mm drainage pipe 0.125mm polythene 125 mm 600 mm Clean pit thoroughly Hang plastic side sheet to ensure good seal Spread grass over pit evenly in shallow layers (6 – 9 inches) Roll continuously Rapid filling is best All silage effluent must be collected. The tank must be checked regularly to ensure that it does not overflow or that it is not leaking. Empty the tank regularly to prevent effluent reaching drains or watercourses Same principles apply as with pit silage Bales should be dense and cylindrical in shape Wrap as soon as possible after baling 4 - 6 layers of plastic film Wrap at the stacking area if possible If not, move bales from the field immediately after wrapping Oxygen will enter a bale every time it is handled Avoid spiking if possible at any time (even before wrapping) Example: Width of pit = 10m matter Assume silage is 30% Dry Section A: 30 x 3 x 10 = 900m3 Plus Section B: 5 x 3 x 10 = 150m3 X 0.5 = 75 m3 Total = 900 + 75 = 975m3 3 m A B 30m 5m Conversion Factors Silage Dry Matter Conversion factor Measuring Quantity Silo/Pit: Length (m) x Width (m) x Height (m) = Volume (m3) X Dry Matter Conversion factor = Tonnes of silage Measuring Quantity kg/bale or t/bale Round (unchopped) 1.3m 500 0.5 Round (chopped) 1.3m 650 0.65 Square (2.5mx1.2mx0.9m) 730 0.73 (8x4x3’) Will vary enormously with dry matter, sward type and operator! Requirement Silage Silage Requirements Type of stock No Months per month (t) requirement Spring calver 1.0 250 – 350 kg store 0.8 Calves 0.3 Ewes 0.15 Total silage required Cut silage around 50% ear emergence to optimise yield and quality Allow 2 units N/day from sowing to cutting Don’t overwilt – 30 hours max Seal silo carefully Handle bales carefully Do a budget before winter The amount of grass grown depends on many factors 1. Soil temperature (>6° C) 2. Light 3. Water 4. Nutrient availability 5. Grass type/breed At peak growth there is a new leaf every 4-5 days (May) Peak growth all 3 leaves replaced in 2-3 weeks Best time to graze is at 2 ½ to 3 leaves 4 main grazing systems used 1. Set stocking 2. Rotational grazing 3. Strip grazing 4. Paddock grazing Set stocking Rotational Paddock grazing Animals have unrestricted access over a wide area throughout the grazing season Pros Cons Low management input Lower grass yield Low capital cost (1 drinking trough, external fence) Difficult to manage and maintain grass quality and height Can work well if sward height maintained at correct level Uneven manure distribution Lower utilisation due to trampling Weeds allowed to build up Animals move around a small number of fields based on sward height or after a certain number of days Pros Cons Higher production than set stocking More fencing required Allows pasture to rest and recover Can extend the grazing season More even distribution of manure Extra drinking troughs needed Grass production and utilisation not optimum Animals given a new allocation of grass each day by mean of electric fence Pros Cons Useful when excess of grass at points in the year Labour intensive. Fence needs moved each day Good utilisation of grass – very little trampling or spoiling of grass Water availability a problem Very good for forage crops like kale and rape Not ideal as cattle are usually allowed back over previous days grazings Hampers re-growth Can lead to trampling along fence line Animals are moved frequently through a series of paddocks based on measured grass heights or grass covers Pros Cons Highest grass production and use Initial cost of fencing and water troughs High quality grass & higher stocking rates More intensive management – skill required More even manure distribution Requires careful monitoring Can extend grazing season Allows for excess grass to be cut out as silage (bales) Quieter/more manageable stock? System Set stocking Annual Utilisation Usable % increase Yield yield (t DM/ha) (%) (t DM/ha) 8.5 50 4.3 Rotational 10.2 65 6.6 56% Paddock 10.2 80 8.2 92% To be continued!