FORAGE MATTERS IT STARTS IN THE FIELD The importance of grass as a valuable feed source is often underestimated. If you treat your grass with respect you are well on track to producing cost effective quality forage, increasing yields and reducing costly dietary supplements. It’s often said that silage is made in the clamp, and this is true, however your actions in the field can have a big impact. The biggest influence you the farmer or contractor can have over making good quality forage is timing, from when to mow the crop, how long it should be left to wilt and how to present the crop ready for harvesting. There are two factors which dictate timings, weather and output; whilst many have tried to tame the weather and failed, you can be and should be in control of productivity and by owning and/or using forage equipment which is based on efficiency, comfort, value for money, reliability and durability, and ease of maintenance means you’re in the best possible position to produce quality forage. When it comes to harvesting, preparation is everything. Make sure equipment is well maintained and ready to go to avoid costly breakdowns at critical times. There are a number of different factors to consider when it comes to mowing, tedding, raking and harvesting, so it’s important to assess the farm needs, labour availability and handling capacity to maximise efficiencies and silage quality. Mowing The growth stage of the crop will determine the type of silage produced. Young leafy grass will be higher in energy and lower in bulk, as the crop matures the digestibility (D Value) will decrease, as the yield increases, a trade-off between yield and D Value is required to suit the livestock being fed. Mowing timing should be dictated by the plant’s growth stage and not the calendar. Grass sugar content is highest in the afternoon after the plant has photosynthesised and energy content will be peaking, when the pasture is free from rain or dew, so this should be the best time to mow. A conditioner breaks the waxy cuticle on the plant, speeding up water loss during wilting by up to 20%. The problem is if it rains, as the conditioned leaves will then reabsorb water more quickly; choosing whether to use a conditioner can be difficult. If a conditioner is used then it’s important it’s set correctly – too harsh and it will pulp the grass and increase fuel usage – too light and it will be ineffective. Correct stubble height is also important and should be set to approximately 5cm – if you cut too low it will impede grass regrowth and add little quality to the silage as the base of the plant is low in D Value. Mower blades will also be blunted, and the risk of contamination from soil and stones will increase. 10 It’s important to carry out in-field checks and understand settings as these are vital in producing cost effective quality forage. They don’t take long and can have huge benefits. Change mower blades regularly – if they are blunt they will not cut the grass cleanly, dramatically slowing regrowth. Deciding to spread or swath is down to individual circumstances; however this basic rule can help. If the ground is dry, set the mower to full width spread to maximum the surface area of the crop for rapid wilting. If the ground is wet, leave the grass in a swath, allowing the ground to dry out either side before tedding. Tedding Tedding will speed up wilting time, and mixes the grass to give a more uniform wilt and therefore more uniform quality, with fewer hot / wet spots in the clamp. The tedder height must be set in the field, with tines 2-4cm above the ground. To check the correct working height, drive forward slowly and check if the tines are scraping the soil or leaving grass behind. Too low and you’ll contaminate the silage and increase machinery wear, too high and you’ll leave a mat of grass behind. It’s also important to match the forward speed of the tractor with the RPM of the PTO shaft – if you need to cover more ground go for a wider spread; don’t drive faster as it will affect silage quality. The diameter of the tedder rotors and the number of tines will play an important role in the quality of the spread; different tedders have different sized rotors. Generally speaking there are 3 rotor diameters, suited to different applications. Large diameters (seven tine arms) are typically suited for silage, where one pass is required tedding out the mower swaths. When sizing a silage tedder each swath should fit between each pair of rotors. The smaller the diameter (five tine arms) the finer the spread and the more consistent the wilt, ideal for tedding hay. However many tedders are required to spread a variety of crops behind a range of mowers; a medium diameter rotor (6 tine arms) will provide the best all round solution. Raking Presentation of the swath to the subsequent harvesting machine has a big impact on efficiencies and quality – an even, box-shaped swath for a smooth, consistent flow is required. Row up just before harvest so that the grass quality remains uniform – too long in the swath and the top will wilt more than the bottom producing an inconsistent DM. Correct working height of the rake is important, otherwise you’ll either pick up stones and soil, or leave grass on the ground which will rot and damage the subsequent cuts. Ideally a rake with electric height adjustment should be used as the rotor working height can be adjusted on the move to suit varying conditions.
Mowing Tips • Establish the correct day to mow and consider time of day • Afternoon is preferable once the grass is free from dew and rain • Sugars are higher in the pm; a quick wilt will concentrate sugars • Leave a 5cm minimum stubble height to encourage regrowth • Conditioners can increase wilting by 20% • Ensure conditioners are correctly set • Spread or swath, depends on the ground conditions. Tedding Tips • Tedding will continue to speed up the wilting process • Effective tedding will produce quality forage • Correct working height essential, avoid soil contamination • Forward speed and rotor rpm matched to crop conditions, 3 – 5 mph • If more output is required then awider tedder is needed • Tedded grass should be even and lump free. Raking Tips • Swath presentation impacts on subsequent harvesting • Even box shaped swaths equal smooth crop flow - increase productivity and consistency of chop • Swaths should be made immediately before harvesting • Forward speed and rotor rpm should suit the crop • Tine working height crucial to ensure quality forage and minimise contamination. Producing cost effective quality forage can have a positive impact on livestock yields and performance Again, as with tedding, match the tractor forward speed to the RPM of the PTO shaft; higher dry matter crops will take less moving then wetter crops, so you risk throwing it too far or leaving some behind. Harvesting A farmer’s choice of harvesting technique depends on what type of silage they require. Many will use a forage harvester or wagon for high quality silage, with lower energy crops being baled for feeding to dry cows. When choosing equipment, ensure there is enough capacity to manage the crop in the clamp at the same time as harvesting, so that every stage of the silage-making process can be undertaken at the correct time. The same is true of using a contractor – ensure they can do what you want, when you want, to achieve the right quality silage. Savings on contractor fees can quickly be lost through reduced quality forage. 1 – Forage harvester. Whether trailed or self-propelled, a forage harvester ensures a uniform chop length and gets the crop into the clamp quickly. Having been chopped, it can also be consolidated quickly. Having a higher capital cost, this option will be chosen to suit the feeding regime. 2 – Forage wagon. Although it doesn’t give a precise chop length, a forage wagon is cheaper to run than a harvester. However, the less uniform silage can take longer to buck rake and consolidate in the clamp, although there is an argument that longer chop lengths are good at slowing the cows’ digestion process. 3 – Baler. Choices will depend on whether you want bales wrapped or not. Round combi-balers wrap on the move, saving labour, but they are more expensive to buy. Square bales have to be wrapped separately but can be stacked and stored more easily. 11 11