Conservation of Fodder: Silage Making

March 28, 2021

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Conservation of Fodder: Silage Making

INTRODUCTION

Availability of nutritious fodder throughout the year is very essential for profitable dairy farming but it varies from season to season. Therefore, every dairy farm must preserve the surplus fodder in the form of silage. The surplus forages of the two surplus seasons i.e. rainy season (August-September) and winter season (February-mid March) could easily be carried over to the succeeding lean periods of fodder supply. During the lean periods of May and mid July and November -December silage can supplement the dry fodder and limited quantity of green fodder avail able to over come the scarcity of fodder.

With judicious selection of crops, their rotations and the conservation of seasonal surplus either as silage, it is not only possible but also practical to maintain all the year-round supply of quality roughages for milch and drought animals. The practice of fodder conservation is inseparable from a good herd management programme. Fodder conserved in a season of plenty is an insurance against under feeding and economic losses during scarcity period.

Silage

Silage is the preserved green fodder in succulent form under air tight conditions. Ensiling is a process which involves the conservation of green fodder crops, grasses and the storage over long period. Good quality silage is yellowish-green in colour with a pleasant vinegar smell.

The technique is more or less similar to that commonly employed in the preparation of pickles. Pickling of fruits and vegetables is a universal practice in most indian homes, rural and urban alike. Therefore, it is not difficult for the farmers to grasp the technique of silage making and use it successfully. The process fits ideally irrespective of the size of the farm and the extent of mechanization employed.

Crops suitable for silage

There is a wide range of crops suitable to this purpose. Excellent silage may be may be made from crops like Jowar, Maize, Bajra Oats and Barely. Among the perennial grasses large amounts of surplus fodder is available for silage making from the luxuriant growth of Hybrid Napier grass, Guinea grass, Para grass, Sudan grass and Rhode grass. During monsoon season a considerable portion of natural grasses such as dub, Kolu Katai could very well be converted into silage instead of allowing them to mature and become less nutritious. Legumes like berseem, lucerne and cowpea are not suitable for silage making. However when mixed with non-legume crops in the right proportion, the mixture yields a well balanced silage. Silage can be made successfully by mixing of paddy straw and berseem, paddy straw and water-hyacinth and berseem and oats.

Stage of harvesting the crop:

The fodder crop should be harvested at a stage when nutrient content is at peak stage and it has produced enough through dry matter. The crop must have sufficient sugars to permit the quick production of preservative acids of which lactic acid is the most important one. The crop should be neither immature nor over mature. Flowering to milk stage is recommended for making silage from maize, Jowar and oats crops. In case of bajra and teosinte boot stage is best harvested at blooming stage but Hybrid napier and Guinea grass should be harvested at 1- 25meter height stage. Good quality silage can be made when the dry matter of crop is 30-35 per cent. Take a handful of chaffed fodder in between the hands and press. If hands do not moist, the fodder has the desired dry matter.

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Silage Making

Silage is made by compressing the chaffed green fodder in tight pits called silos. There are many types of silos such as pit silo, tower silo, trench silo but under village conditions the ordinary pit silo is recommended.

Pit Silo

Dig a circular or rectangular pit of desirable dimension on a site located at the higher elevation and near the animal shed. It may be located in an area with a lower water table to avoid rise of water into the silo during the rainy season through capillary action. The size of the pit depends on the fodder available for ensiling as well as the silage requirement of the cattle. It may be roughly calculated on the basis that one cubic meter of the silo can have 650 to 700kg settled silage. A silo pit measuring 30meter length, 25meter width and 20 meter depth a convenient size for making silage for feeding five dairy animals at the rate of 20 kg silage per head per day for three months. Such pit can be prepared by a farmer without much expense. A circular pit is better than rectangular one, because the chaffed fodder has comparatively less surface contact and while filling air can be expelled easily. Before filling, plaster the sides with mud and line with long stalks of dried fodder to prevent fodder coming into direct contact with earth. Alternatively line these with polythine sheet or brick line and plaster. The bottom should not be plastered.

Filling the pits

Chaff the fodder into small pieces (2.5 to 4.0 cm) with a chaff cutter before ensiling for better compaction. If the fodder is found withered due to a bright sun, sprinkle a little water during the course of filling the pit. In case the silage is to be prepared from leguminous fodders like barseem, lucerne or cowpea or immature grass rich in protein, the addition of carbohydrates is essential. Such types of crops, before ensiling, should be wilted to the moisture content of 65 to 70 per cent or a dry matter content of 30 to 35 per cent. Wilting before ensiling will bring the desired dry matter and will reduce the water content which will consequently increase the sugar content in the forages and help in effective fermentation. It also helps to lower the seepage and leaching losses site. Molasses, at the rate of 40 to 50 kg per ton of ensiled material should be added in the case of legume fodder crops. Other alternate additives recommended are ground maize, ground barely 80 to 100 kg per ton of chaffed fodder. These additives provide favourable conditions for the bacteria to produce lactic acid.

To check the growth of undesirable organisms and to increase the growth of lactic acid producing bacteria, certain preservatives may be added while making silage. The preservatives like common salt (18-20 kg) ton sodium meta-bisulphite (5 kg) dilute acetic acid (10 litres) or phosphoric acid at the rate of 6 kg per tonne of chaffed forage may be added.

The green fodder should be chaffed carefully and spread over the entire area. The material should be well trodden, during filling, in order to compress the mass, so that maximum quantity of air is excluded. Whole material should not be filled at one time. As the pit is being filled, the chaffed fodder should be spread in uniform thin layers over the entire area and thoroughly compacted by trampling with foot. When the filling is just approaching the ground level, heavy animals like bulls or buffaloes or even tractor may be used to trample over it and further layers of fodder should be spread more evenly. In this way the compressed material in the pit should stand at least 2.5 to 3.0 feet above the ground level in a dome shape to facilitate draining out of rainy water. It is essential to complete the filling of the silo in the shortest possible time; otherwise the quality of silage is adversely affected.

Sealing the pit

After the completion of filling, the silo needs to be sealed. Provision must be made to protect it from rain water seepage. The silo should be covered from the top up to ground level by polythene sheet and on which a layer of 10 cm moist earth should be spread. Alternatively spread a 10-15 cm layer of dry fodders and cover it with and a layer of earth, and plastered with cow dung and earth mixture to make it air tight and water proof.

After care of the pit

After few days the earth covering shows cracks caused by sinking down of the green material due to fermentation. With the sinking down of the material, some portion may bulge out; such portion should be chaffed off to allow the whole mass to go down properly. The cracks should be covered with some waste fodder or weed grass and plastered over with a mixture of mud and cow dung, so that an air tight condition is maintained. If water accumulates around the pit, it should be drained off. Once the pit is closed it should be kept air tight till it is opened for taking out the silage. Silage should be ready for feeding in about 45 days. When opened the pit should be used up as quickly as possible to avoid wastage and drying up. It is advisable to remove one third or fourth of the surface area of the pit by cutting straight to the bottom with a silage knife.

Techniques of silage making

Dry matter :- Dry matter should be above 30% crops of high moisture content should be ensiled with the addition of preservatives and additives in poor weather. Wilting should be avoided and additive should be used for good fermentation.

Stage of growth:- Crop should be cut at a proper stage of maturity as it is the most important factor for controlling the silage quality. The appropriate stage of growth for cutting different fodder crops for silage making is given below:-

Sorghum – flowering to dough stage

Maize – milk to dough stage

Oat – 50% flowering to dough stage

Barley – preflowering stage

Bajra – flowering to dough stage

Grasses – early flowering stage

Chopping:- Crop should be chopped before ensiling. For good silage, the shorter the chop length, the better is the quality. Chopped silage is more palatable to livestock and has little chance of secondary fermentation.

Filling of silo:- Silo should be filled rapidly and should not be left open. It should be sealed as soon as possible. Packing is important to create anaerobic condition. It should be thoroughly pressed so that no air pocket is left in the silo otherwise chances of mould formation will be there which will spoil the silage. After filling, silo should be covered with polythene sheet followed by that of a layer of soil etc.

Removal of silage:- After 45-60 days of ensilage, the silage can be removed for feeding to animals. Care should be taken in removing the silage from silo. It should not be allowed to deteriorate after the silo is opened for feeding. Covers should be kept firmly in place as long as possible and the minimum face should be exposed at one time. The sugars, protein and lactic acid present in the silage are subject to attack by mould growth and oxidation as some air is allowed to fermentation and causes loss of feeding value and intake by the animals.

Characteristics of good silage:-

Physical :-

It should have an acceptable aroma with no mould growth
A good silage keeps a greenish yellow colour and highly palatable to animals.

Chemical:-

pH value should be between 3.5-4.5
Volatile substance/ fatty acid in the silage must be comparatively less to that of lactic acid.
Ammonia nitrogen should not be less than 10-12% of total N.
Butyric acid less than 0.2%.

Losses during silage making

During ensiling, respiration, fermentation and effluent losses take place. When crops are cut and ensiled the same day the field losses are not more than 1to 2 per cent. During longer period of wilting considerable losses of dry matter as high as 6 to 10 per cent is reported. The fermentation (actual acid forming process) and respiration losses may be 10 to 15 per cent of dry matter in the original crop, seepage losses may account for about 6 per cent. But ensiling a suitable crop and restricting the supply of air by compaction controls fermentation, respiration and heating losses.

Nutritive Value

The value of silage as cattle feed has been well recognized. Apart from its nutrient content good silage has higher vitamin A content and better palatability than hay and other dry roughages. Cattle prefer silage to coarse, mature and less palatable green fodder. During ensiling the concentration of toxic constituents such as hydrocyanic acid, nitrate and oxalic acid is reduced drastically thus, the fodder having very high concentrations can be safely fed to animals after ensiling.

Feeding the silage

The animals may not like its taste for the first few feedings. Help them to develop the taste by mixing 5 to 10 kg of silage in their green fodder ration for the first 5 to 6 days. After the taste is developed 20 to 30 kg of silage along with other fodders may be fed per head per day. Silage feeding is especially suited to milch cow as silage and concentrate ration produces more milk than straw and concentrate ration.

Conclusion

The availability of nutritious fodder is very essential for profitable dairy farming. Hence every dairy farm must preserve the surplus fodder in the form of silage. The surplus forages of the two surplus seasons i.e. rainy season and winter season could easily be carried over to the succeeding lean periods of fodder supply. During the lean periods of May and mid-July and November -December the silage can supplement the dry fodder and quantity of green fodder available to overcome the scarcity of fodder. With judicious selection of crops, their rotations and the conservation of seasonal surplus either as silage, it is not only possible but also practical to maintain all the year-round supply of quality roughages for milch and drought animals. Fodder conserved in a season of plenty is an insurance against under feeding and economic losses during scarcity period.