Silage Quality and Feeding Dr GNANASEKAR Chief Executive Officer, G.S. Dairy Farm Consulting, Erode March 10, 2019 Silage is fermented, high moisture stored fodder for the feeding of ruminants. The process of making silage is called as ensiling. Crops like maize, sorghum and grass etc can be used for silage making. Focusing on silage preparation is very important to preserve the green fodder when it is available plenty. Silage also gives great flexibility for the dairy nutritionist as the nutritive value is ensured throughout year. Role of fodder crops in managing the nutrient requirement for dairy cows and buffaloes is very important apart from its role in reducing the cost of production of milk. Getting green fodder throughout year is another challenging task as it depends upon the water availability and rain etc. Focusing on silage preparation is important to preserve the green fodder when it is available plenty. Advantages of silage feeding Silage gives an option of feeding green fodder throughout year. Cost of production of silage is very low when cost of green fodder is low and its availability is in plenty. Farmers can opt for cultivating more green fodder in their land available and convert it to silage. This helps them to get the silage for lower cost. Smart farmers make silage when green fodder is available in high quantity and use for their farm throughout year. They sell the green fodder produced during summer when the market price is very high for green fodder. This gives two key benefits as they save cost of green fodder in summer as they made silage when the cost of green fodder was very low. They also make more profit from their green fodder produced during summer. Silage has nutritive value throughout the year. The process of ensilage enhances the taste and flavour of the fodders and the animals prefer to eat it over other fresh fodders/grasses. Silos For preparation of silage and its storage, various types of silos are used. A farm can go for a suitable type and design depending upon the quantity to be stored, availability of space, manpower or machinery. The dimensions of length, breadth and depth/height are also decided based on these considerations. For example a trench type may be suitable when large area is available, quantity is large and tractor is available for pressing while feeding. A bunker of sustainable size can be constructed when pressing will be done by farm workers. A bunker could be below ground level or half below ground level. If it is above ground level then the open sides will have to be closed by wooden planks by arranging them one over the other with their ends inserted in slots on both sides. Silos can be fabricated or constructed as towers when the pressing will have to be done mechanically. Silos in form of polythene tubes or bags have become more common as they offer wide choice for storing and also yield better quality of silage (See Box: Silage in Bags). Size of silo Approximately 20-25 kg can be stored in one cubic foot after good pressing. Pressing the fresh fodder helps in removing the trapped air and that results in good silage. Size of a silo can be determined based on the requirement of silage. Planning for silage preparation Quantity: The quantity of silage to be preserved is calculated based on the quantity required per animal and the number of animals in the farm etc. For example, for a farm with 10 adult animals and feeding 20 kg of silage then 200 kg of silage is needed every day. Mechanical Harvesting Reaper: Mechanical fodder harvesting helps to save time and cost of labour at a commercial dairy farm. Reaper is a tractor operated machine that harvests the crop 1-2 inches from ground and it can harvest one acre per hour. Maize chopper: It is an economical machine powered directly by the tractor power-take-off shaft and used to perform high-quality cutting that is without losing nutrients and moisture of plants. Length of maize cuttings can be adjusted as per requirements. Harvesting of crop: Crops having good percentage of sugar and appropriate moisture (35-40% dry matter; 65-60% moisture) are good for silage making. Crops like maize, jowar, bajra, napier bajra and oat are most suitable for silage making. Crops should be harvested at pre-flowering to flowering stage for silage making. Preparation of corn silage: Corn silage may be made from maize fodder that is after harvesting it at milking stage that is achieved between 55-60 days after sowing or it may also be prepared from corn along with cobs. Milking stage is when the harvested corn grain actually yields a milky exudates when squeezed or pressed. Process of silage making Moisture level in the crop: This is the most important factor to be considered for silage preparation. Moisture level of 60-65% is recommended on the day of filling. So as to get fodder at an appropriate moisture level, irrigation of the crop should be stopped at least one week before harvesting. Alternately the harvest is allowed to lie in the shed for some loss of moisture, called as wilting over several hours. Chopping: Fodder must be chopped into pieces of one inch width. Machines are available to chop the fodder in the field and load it to the tractor. Pressing and coverage: Compact the forage as tightly as possible. Using sharp knives at harvest to enhance packing, aiming for a fill rate of 1 minute/ton and a packing density of at least 700kg/m3. Complete the entire storage quickly within 1-2 days. Cover the silage with polythene sheet properly and weighing down plastic adequately (> 20 tires/100 square). The science behind silage making–What happens inside silo after sealing Phases Important changes Day Phase 1 Cell respiration, production of Co2, Water, Heat Temperature and pH changes inside 1-2 Phase 2 Production of acetic acid, lactic acid and ethanol 2-3 Phase 3 Lactic acid fermentation 3-4 Phase 4 Lactic acid fermentation and pH drops to 4.0 4-21 Phase 5 Material stored Phase 6 Aerobic decomposition on the exposure to oxygen Role of silage additives Different varieties of silage additives are available in the market. These help in improving silage quality by altering the rate, amount and kind of acid production; acidifying the silage and stimulating acid production; and, inhibiting growth of bacteria and fungi. Opening the silo pits The opening of silage is very important as the silage would get exposed to air and that may lead to aerobic fermentation. To avoid this, silo pit should be opened from one end so that minimum area is exposed to the environment. The silage should not have rancid odour which indicates clostridial fermentation. A vinegar odour is associated with high levels of acetic acid. An alcohol odour indicates fermentation by yeast. Ideally the silage should have mild, pleasantly acidic, sour aroma which indicates normal lactic acid fermentation relished by dairy animals. Conclusion It is better to make sure that the roughage portion is available in the farm to control the cost of production. Preservation in the form of silage helps you to feed the cows with the nutrients that are available in the green fodder for throughout year. Make a small quantity of silage initially and experience yourself and understand the art of silage making!! *The author acknowledges inputs received from Dr J.S. Bhatti & Dr J.S. Hundal, Department of Veterinary and Animal Husbandry Extension Education, Guru Angad Dev Veterinary & Animal Sciences University, Ludhiana.