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close this bookBetter Farming Series 43 - Feeding Animals on Straw (FAO, 1995, 30 p.)
close this folderMethod of treatment
View the document(introduction...)
View the documentStraw as animal feed
View the documentTreatment of straw
View the documentTo treat or not to treat
View the documentSupplementation
View the documentDoes it pay?
View the documentHow to treat straw

How to treat straw

What tools are needed?

22. A scale to weigh the straw.

Weigh the straw

A typical basket or bundle of straw should be weighed with a spring balance or similar weighing scale.

23. containing 0.5 kg urea.

A measure

24. A 1 0- litre watering can or bucket.

25. A big barrel or trough which can contain a large quantity of water.

Which types of straw can be treated?

26. Straw from cereals. Straw from all types of cereal and even poor- quality hay - can be used. Rice straw is normally so soft that it can be used as it is. Wheat, barley and oat straw does not need to be chopped if it is compressed during treatment. This can be done by placing a layer of soil on top of the straw.

27. Stalks. Stalks of maize, millet and sorghum can be used but need to be chopped or extremely well compressed during treatment by placing a heavy layer of soil or stones on top of them.

28. Wet straw and stalks. Straw or stalks can become wet from rain but, if they are fresh, there are no problems in treating them. In fact treatment is a way to prevent them from being spoiled. Water can be saved and a stronger urea solution applied. Because of the high content of water in wet straw and stalks, the quantity of urea should be reduced to half. It is difficult to be completely accurate but the rule is that a 5 percent urea solution should be applied on an air- dried basis.

29. Mouldy or rotten straw and stalks. These must never be used. They will make poor and dangerous feed.

How much straw to treat?

30. Animals have different appetites, but you should use approximately 3 to 3.5 kg of treated straw daily per 100 kg of animal liveweight. Thus, an animal weighing 200 kg will need 3 to 3.5 x 2 = 6 to 7 kg. A young animal weighing 75 kg will only need 3 to 3.5 kg x 0.75 = 2 to 2.5 kg. If you plan to feed the animals as much as they will eat, you can expect them to eat one- third more treated than untreated straw. (See the following table.)

Untreated and treated straw feed quantities according to liveweight

Animal liveweight

Untreated straw

Treated straw

100 kg

2.0 - 2 5 kg

3.0 - 3.5 kg

200 kg

4.0 - 5.0 kg

6.0 - 7.0 kg

300 kg

6.0 - 7.5 kg

9.0 - 10.5 kg

400 kg

8.0 - 10.0 kg

12.0 - 14.0 kg

The urea solution

31. As an example, if you want to treat 10 kg of air- dried straw (straw that is dry enough for stacking), you need to dissolve 0.5 kg of urea in 5 litres of water. But if you want to treat 100 kg of air- dried straw, you need to dissolve 5 kg of urea in 50 litres of water. (See the following table.)

Amount of urea solution required




50 kg

25 litres

2.5 kg

100 kg

50 litres

5.0 kg

200 kg

100 litres

10.0 kg

32. and stir until the urea has completely dissolved.

Mix the urea and the water

33. The urea solution should be distributed evenly, using a watering can or something similar.

Storage during treatment

34. There are different ways to store wet straw that is undergoing treatment. The best result is obtained when the straw is kept airtight. This condition can be achieved in several ways. Following are some examples.

35. Trampling the wet straw carefully before sealing the stack is an important first step.

Trampling the wet straw carefully

36. The straw can be stacked against a wall or in a corner and covered with old bags, banana leaves or bamboo mats and a layer of soil or clay to ensure airtight conditions.
The smaller the quantity of straw, the greater the care needed to make it airtight.

Make it airtight

37. The straw can be stacked in a separate heap and sealed with a mud plaster.

Separate heap

38. Chicken- wire or welded wire mesh can be used to make a stack, lined with used plastic sheets or old fertilizer bags.

Make a stack

39. The straw can be stacked in smaller or bigger clamps made of locally available materials.

Smaller or bigger clamps

40. Depending on the site where treatment is actually taking place there may be other possibilities. The point is that every effort should be made to keep the straw in an airtight condition during treatment.

Treatment time

41. The straw should now be kept in an airtight condition for one to five weeks before it can be fed to the animals. A short treatment time can be used when it is hot (25 to 30°C) and a long treatment time when it is cold (below 15°C). Urea as a source of ammonia does not work below 5 to 10°C. A way to bypass this problem is to treat large quantities before it gets too cold.

42. Following are the signs of successful treatment:

- The straw has changed colour to dark yellow or brown.
- The straw has a strong ammonia smell.
- The straw is softer than untreated straw.
- The animals - after adapting - eat one- third more treated than untreated straw.

Adapting the animals

43. You can adapt animals to the treated straw over a week or ten days by gradually mixing more and more of the treated straw into the fodder they are used to. Adaptation can be quicker if animals are used to eating straw and if the treated straw is left out in the fresh air for some hours before it is eaten. This practice should only be required during the first week to ten days. It should then be stopped and the straw taken directly from the stack for feeding.