Enhancement values of cassava by-product diets on production and haemato-biochemical indices of sheep and goats: a review.

The competition for maize and soybean between humans and livestock for food has led to an increase in the cost of livestock feeds. Therefore, this has necessitated the search for alternative non-competitive feedstuffs in order to partially replace maize and soybean in small ruminant diets. The use of cassava products as a partial replacement for maize and soybean in small ruminant diet has been investigated. Cassava is a tropical crop, and its fodder is rich in crude protein (CP), minerals and vitamins with about 85% of the CP fraction exist as true protein. Cassava by-products are also high in nutrients and could contribute significantly to the nutritional needs of sheep and goats. Specifically, cassava leaves are high in CP (25.10%) with an amino acid composition similar to soybean. Evidence also exist that ruminal degradability of cassava fodder is similar to that of maize and soybean with comparable outflow rates (75%). However, the use of cassava fodder in livestock production is limited by the presence of cyanogenic glucosides (linamarin and lotaustralin) that releases hydrogen cyanide (HCN) known to cause pathophysiological changes in the liver of sheep and goats. Importantly, several processing techniques are well known to reduce or eliminate the concentrates of cyanogenic glucosides in cassava with great success. Blood chemistry and production indices of sheep and goats fed differently processed cassava by-product-based diets have been evaluated by different authors. This review revealed that cassava root sievate meal, cassava root meal and cassava peel meal are low in CP (2.29, 3.40 and 7.05%, respectively), while cassava leaf meal is high in CP (32.43%). Feed conversion efficiency of sheep and good fed cassava leaves were 9.49 and 11.24, respectively, indicating that goats utilize cassava leaves better than sheep. It is concluded that cassava by-products are low in quality protein and should be supplemented with other rich protein sources before their use in ruminant diets.