Wednesday 29 January 2014
The Cassava plant (Manihot esculenta)
The crop is known in the New World as manioc or yucca it is a herbaceous shrub or mini tree which grows up to 4 metres high with thin hand-like leaves. It was introduced to Gambia by the Portuguese between the 17th and 18th centuries. It is one of the highest starch yielding plants grown in Gambia and on average Gambians consumption levels is about 100kg per person per annum in 2002 (FAO). This tuber is poisonous unless processed in a certain way, so 
it is best to seek advice before attempting to make your own nyambe nyebe! (beans & cassavas in palm oil). The root of the cassava plant, a large thick-skinned tuber like the potato when boiled, that is eaten in many tropical countries and is the source of tapioca.
Toxicity Levels:
The crop's tubers must be processed very carefully as they include a glucoside, linimarin, which is acted upon by an enzyme to liberate prussic acid. The peeled roots contain much less prussic acid than unpeeled roots because most of the prussic acid is in the skin.
There are 2 main varieties:
1. Bitter varieties with roots containing 0.02-0.03% prussic acid.
2. Sweet varieties with roots containing less than 0.01% prussic acid. These can be used raw for feeding.
The prussic acid content depends not only on the variety, but also, and possibly even more, on soil conditions. Usually the bitter varieties have longer and thicker roots than the sweet varieties, but there is no simple safe method to judge the level of prussic acid in the roots.
The toxic elements can also be removed by cooking or by drying slices of the roots for about two weeks. Cassava root meal is not attacked by insects; the same is true, of feed concentrates to which 15% cassava root meal has been added.
Uses of Cassava:
Both fresh and dried cassava roots and peels are consumed by ruminants such as cows and goats in different forms (sliced, chopped, ground). Dried cassava roots have given satisfactory, results as the principal energy source for dairy cattle, intensive beef fattening and lamb growth. Cassava can replace almost all of the grain in the diets with little reduction in performance. Inclusion levels of up to 65%, preferably pelleted, do not seem to affect health, carcass quality or overall performance when the diets are carefully balanced. Palatability can be enhanced by the addition of molasses if pelleting is not possible. The whole cassava plant (including root and aerial part) can be chopped and ensiled in simple pit silos for dry-season feeding at the village level. Simple equipment is required both for harvest and preparation of the silage. The silage is fairly well balanced for ruminants.
Complete replacement of grain by cassava root meal in layer feed has yielded similar egg production.
The crop is known in the New World as manioc or yucca it is a herbaceous shrub or mini tree which grows up to 4 metres high with thin hand-like leaves. It was introduced to Gambia by the Portuguese between the 17th and 18th centuries. It is one of the highest starch yielding plants grown in Gambia and on average Gambians consumption levels is about 100kg per person per annum in 2002 (FAO). This tuber is poisonous unless processed in a certain way, so 
it is best to seek advice before attempting to make your own nyambe nyebe! (beans & cassavas in palm oil). The root of the cassava plant, a large thick-skinned tuber like the potato when boiled, that is eaten in many tropical countries and is the source of tapioca. Toxicity Levels:
The crop's tubers must be processed very carefully as they include a glucoside, linimarin, which is acted upon by an enzyme to liberate prussic acid. The peeled roots contain much less prussic acid than unpeeled roots because most of the prussic acid is in the skin.
There are 2 main varieties:
1. Bitter varieties with roots containing 0.02-0.03% prussic acid.
2. Sweet varieties with roots containing less than 0.01% prussic acid. These can be used raw for feeding.
The prussic acid content depends not only on the variety, but also, and possibly even more, on soil conditions. Usually the bitter varieties have longer and thicker roots than the sweet varieties, but there is no simple safe method to judge the level of prussic acid in the roots.
The toxic elements can also be removed by cooking or by drying slices of the roots for about two weeks. Cassava root meal is not attacked by insects; the same is true, of feed concentrates to which 15% cassava root meal has been added.
Uses of Cassava:
Both fresh and dried cassava roots and peels are consumed by ruminants such as cows and goats in different forms (sliced, chopped, ground). Dried cassava roots have given satisfactory, results as the principal energy source for dairy cattle, intensive beef fattening and lamb growth. Cassava can replace almost all of the grain in the diets with little reduction in performance. Inclusion levels of up to 65%, preferably pelleted, do not seem to affect health, carcass quality or overall performance when the diets are carefully balanced. Palatability can be enhanced by the addition of molasses if pelleting is not possible. The whole cassava plant (including root and aerial part) can be chopped and ensiled in simple pit silos for dry-season feeding at the village level. Simple equipment is required both for harvest and preparation of the silage. The silage is fairly well balanced for ruminants.
Complete replacement of grain by cassava root meal in layer feed has yielded similar egg production.
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