In the current drought a number of farmers decided to salvage what they could of their dying crops by cutting what was left and making silage, with different levels of success. If you have to choose between waiting for the rain to save your crops or to do what you can to save your animals, the choice is obvious. Given the weather situation in Southern Africa, it is better to always prepare for ample feed reserves for the bad years.

Now, when all the seed companies are presenting their tested technology, is a good time to find out more about their silage products and to plan ahead for next season.

    Silage, especially maize silage, provides more nutrition per hectare and also better animal production per hectare than any other method of feed preservation. Silage can also be stored for an almost unlimited period, providing that it doesn’t come into contact with air or water.Now, when all the seed companies are presenting their tested techno-logy, is a good time to find out more about their silage products and to plan ahead for next season.

    Traditionally dairy farmers were the main users of silage, but recently it is gaining in popularity in feedlots and with commercial cattle farmers. Even sheep farmers are turning towards silage, especially as winter feed.

You can make silage of almost any green plants, but maize remains the best choice.

    Good maize silage begins with choosing the right cultivar. Normally, the cultivar producing the most grain in an area will also be the cultivar providing the most material for silage with the highest energy value.

    Medium-short and medium-long growers provide the best balance between quality and quantity. These growth classes also mean a longer window period for cutting silage.

    Ultra-fast growers may provide two silage harvests in one season if there is sufficient water and heat units, but mostly they do not produce adequate plant material for a satisfactory silage yield.

    Experts recommend that maize for silage should be planted at 10% more plants per hectare than maize planted for grain. You need to achieve a balance between your green material and your grain – fewer plants per hectare mean more grain with more nutrients, but less green material and thus a smaller total yield.

    Another balancing act is the height of the cut. If you cut low above the ground you get more stalk in relation to soft greens and therefore the food is less palatable. But the higher you cut, the less material you have. Your seed agent can give the best advice in this regard, because some cultivars are more palatable than others.

    You only have a short period for cutting while the moisture level of the maize is at its best for silage. If possible, try to spread out your planting to correspond with your capability of cutting and making silage, for example, if your equipment allows you to ensilage 100 hectares per week, try to plant 100 hectares per week. 

Some golden rules

Rudi Kuschke, feed expert of K2Agri, says there are a few golden rules for producing the best silage:

    Do not use material that is either too wet or too dry. The moisture level of the plant should be between 65 and 75% and the bottom leaves of the plants should just be beginning to dry out.

    The milk line should be halfway in the kernel and the kernels should all be dented inwards at the tops. If you squeeze some of the chopped plant material between your hands, your hands should feel moist, but not wet – then your maize is exactly right for silage.

If you are still not sure, use the following method recommended by Pieter Rademeyer from PANNAR:

–  Chop up 10 plants representative of the field.

–  Mix it well and measure off exactly 1 kg

–  Put in the oven at 105⁰C for 24 hours leaving the door of the oven slightly open. Then keep another 24 hours in the oven with the door closed.

–  Let it cool down and weigh it again. The weight equals the percentage dry material times 100.

–  If that percentage is between 30 and 40%, your maize is ready to make silage.

If plant material is too dry, you are not producing silage but compost. The material will become too warm and turn brown. It means less protein, less palatability and loss of dry material.

    You can try and salvage the situation by adding water to the blower, by cutting the material finer and by adding preservatives such as antibiotics, sterilising aids such as salt, sulphur dioxide, sodium metabisulphite,

sodium nitrate, fatty acid and formalin, and carbon dioxide. Sodium metabisulphite works best and 4 kg need to be added to every ton of silage.

    If the material is too wet, on the other hand, it can lead to leaching of nutrients, rancid and unpalatable silage. The best way is to wait until the material is dry enough to ensilage the material.

    Adjust your silage cutter for a cut of 5 to 8 mm in size and stamp it down properly in the silage pit. If it is not stamped down tightly, air may pene-trate and spoil the silage by destroying the nutrients.

    Silage can be made in a special silage bunker, a silage pit or a ditch, in specially made silage bags, as wrapped bales or even simply as a heap on the ground. If done correctly, every one of these options can be effective.

    The silage heap or ditch must be narrow enough so that you can take out the silage you need every day and then cover it up tightly again to keep air out.

    The chopped plant material must be offloaded layer by layer into the silage pit, and each layer must be tightly stamped down by driving over it with a tractor. Afterwards course salt can be spread over it to prevent mildew from forming and then it must be closed tightly with canvas or plastic held down with soil, stones or old tyres.

The silage process

As soon as the material is ensilaged, a fermentation process and certain chemical reactions commence. As long as there is oxygen in the material, acetic acid is formed, but as soon as the oxygen has been used up, lactic acid is produced. The ph and temperature of the silage then start to go down.

    Within three weeks, the process is completed. After six weeks, your animals can start enjoying the best feed ever.

What does good silage look like?

–  The moisture level is between 60 and 67%.

–  The colour is a bright light yellow-green or khaki.

–  It has a pleasant, slightly sour, fruity smell.

–  It has a pleasant, sour taste, not stinging or bitter.

–  It does not contain mildewed or spoilt material.

–  It has a crude protein content of 7 to 9%.

What can be used to make silage?

Silage can be made of any green crop, but maize is best. Certain cultivars of feed sorghum are perfectly suitable for silage production. Famers even use grass for silage in order to capture the advantages of nutritiousness and palatability during its peak growth season and extend its value to a longer time in the feed programmes.

    Plants such as maize, sweet sorgho, oats and rye have sufficient sugar to form the needed lactic acid during the fermentation process. When plants with higher protein levels, such as lucerne, cowpeas, soy beans, vetch, canola and lupines are being used, sugar in the form of diluted molasses should be added to prevent the formation of butyric acid which will spoil the silage and make it smell rancid.

The starch levels can be increased with maize meal in the following

relations:

–  Grasses, feed sorghum and millet: 2% molasses or 4,5% m
aize meal.

–  Legumes: 4% molasses or 9% maize meal.

–  No additives are needed when sugar rich grain crops are added to

   legumes or grasses in a relation of

   2 to 1.

When to cut other crops:

Lucerne: 10% flowering

Soy bean: From the middle to full flower stage before the leaves start falling down

Cowpeas and other beans: As soon as the pods are well filled

Grass: Full flower stage

Feed sorghum: In the soft dough stage, just after the grain has been formed

Sunflower: 10 tot 15% flower stage

Small grain: Hard dough stage

Grain sorghum: In the early hard dough stage.

Lupine and seradella: Cut during the soft dough stage and allow a few days to wither before chopping and ensilaging.