22.0 SILAGE MAKING FROM LOCAL CROP RESIDUES AND BY-PRODUCTS.

22.1 Why make silage?

The problems usually encountered with agro-industrial by-products is seasonality of supply which is often accented by their high moisture content. Hence, they easily spoil creating a nuisance and are often wasted. Ensuing by-products is the most suitable method for their conservation for a long period. The main advantages are:

- Silage can be used strategically for efficient use for off-season feeding.

- It is a means of increasing feed resource availability and a form of insurance for good feeding

management, especially for freshly calved dairy cows.

- It can be efficiently used as a supplement for cattle grazing under coconut plantation.

- It can be stored in a well chosen area close to the farm and provide an excellent and cheap I feed to dairy cows and calves.

- The method improves palatability, significantly reduces toxic substances present in some fresh vegetables and destroy harmful micro-organisms possibly present in poultry litter or fish wastes.

- Silage can also provide a major diet source, and be used as basal ration as well as a feed supplements for grazing animals.

22.2 How to succeed in silage - making?

The ensiled feed supplements should be stored in airtight conditions, preventing contact with air. This will allow foodstuffs preservation and minimise losses in nutrient content. The factors that contribute efficiently to the successful silage are the following:

- Moisture content: ensiled material should contain between 25 and 50 % of moisture. Water can be added to drier feeds to obtain such moisture,

- Length of chop: The finer the chop, the better the silage. Chopping into small pieces can be done by hand or in a stationary forage chopper.

- Presence of enough easily fermentable energy (naturally present or added). For this reason, protein-rich feeds with low content of energy are very difficult to successfully ensile and should be mixed with easily fermentable energy-rich products, such as molasses, rejected bananas and root crops.

22.3 How to make silage?

Leaves and root crops are finely chopped and sliced ( see Photo 26 ). They are mixed with fine ingredients, such as spent grain and poultry litter ( see Photo 27 ) then properly blended with molasses. when the mix is too dry, molasses is therefore diluted in order to reduce total dry matter content.. The moisture content in the mix can be assessed manually by squeezing strongly a handful of mix. The moisture content is considered satisfactory when liquid trickles, slowly flowing between fingers.

The silage can be stored in stacked layers, packed in succession on the soil which has been beforehand covered with a plastic sheet and banana leaves. This heap, once finished, is then tightly covered with banana leaves and plastic sheets, pressed down by some heavy objects which are placed on its top ( see Photos 28, 29 ). Packed silage in plastic bag that is tightly closed is also an effective storage method. This storage method is easy to handle and has the potential to produce high quality silage with less waste in a well-sealed bag ( see Photo 30 ). It is ideal for spent grain storage. However, it is not recommended for coarse materials, such as banana trunk and cassava leaves, which can puncture the bag and render the contents useless.

After approximately 6 weeks, the farmer can open the silo and start to feed silage to animals. Silage can be suitably preserved for as long as air is kept away from the ensiled material, it is therefore possible to store airtight silage for 6 months. Once the silo is open, care must be taken to cover the ensiled material after each opening that is made to feed the animals.

22.4 Practical examples of successful silage combinations.

In order to succeed silage making, one should keep in mind that there are different crop residues and by-products and each one has its own specific composition and physical structure:

- Carbohydrate or energy-rich feeds: such as crop roots; spent grain, rejected bananas, and fruit wastes can be successfully ensiled alone.

- Agro-industrial by-products, such as spent grain, which is rich both in energy as well as in protein may be successfully ensiled alone.

- Fibre-rich feeds with low energy and protein contents, such as banana pseudostems should not be ensiled alone..

- Protein-rich feeds with low energy-content , such as cassava leaves, fish wastes and poultry litter should not be ensiled alone. However, in order to ensure adequate preservation, this type of feeds can be successfully ensiled when mixed with one or various energy-rich products such as crop roots, rejected bananas, spent grain and molasses. This silage making is highly recommended because it would provide a balanced diet.

- Incorporation of molasses to silage is optional, nevertheless this is an excellent additive to ensure a good conservation and enhance high silage quality of any ensiled feed resource.

Incorporation rate of the different ingredients to be ensiled are function of (i) available amount of by-products and (ii) animal categories to be fed. For example a high-quality silage, containing increased proportions of energy-rich ingredients such as spent grain and crop roots, should be prepared for high producing dairy cows. whereas high proportions of cassava leaves and banana pseudostems can be used when there is seasonal feed shortage and therefore when silage would compose the bulk diet, as for instance during off-season feeding. The following associations have been successfully ensiled during on-farm demonstrations carried out in

Samoa:

Table 14. High quality silage making

Ingredients (for 100 kg dry matter basis)

Kg

Equal to Kg fresh matter basis (or Kg fresh ingredients per mix)

Cassava leaves

15

100

Chopped crop roots (Cassava roots)

25

100

Chopped banana pseudostems

10

70

Spent grain

30

150

Poultry litter

10

15

Molasses

10

15

Total

100

450

Table 15. Medium quality silage

Ingredients (for 100 kg dry matter basis)

Kg

Equal to Kg fresh matter basis (or Kg fresh ingredients per mix)

Cassava leaves

25

150

Chopped crop roots (Cassava roots)

15

60

Chopped banana pseudostems

20

150

Spent grain

15

75

Poultry litter

20

25

Molasses

5

7

Total

100

467