Dried cassava tubers can be efficiently used in poultry feeding. The problems related with cyanogenic compounds are overcome by the use of sweet varieties and/or proper post-harvest treatments as simple as sun-drying on a concrete floor (Gomez et al., 1983b; Chauynarong et al., 2009). Other processes such as boiling, autoclaving and fermentation have been found to be efficient but are unnecessary when sun-drying is sufficient. However, grinding cassava results in high levels of fine particles which can reduce feed intake and possibly irritate respiratory organs (Garcia et al., 1999). Pelleting reduces dust and increases the bulk density, favoring an increase in feed intake especially in young animals.
The protein content of cassava is low, which requires correcting when formulating a diet. Particularly, sulphur-containing amino acids (methionine and cystine) have to be supplied in large amounts because they can be altered during the metabolization of HCN. The metabolizable energy value of good cassava meal (72% starch) is equivalent to that of maize (Sauvant et al., 2004). Lower quality cassava (less starch, more fibre) has lower ME values, and the ME of unpeeled cassava meal is reduced to about 85% that of maize (Agwunobi et al., 2000).
Cassava tubers have also been used together with cassava foliage as a whole plant feed (Akinfala et al., 2002) (see the Cassava foliage datasheet).
In well-formulated diets, good quality cassava can be used at high levels in broilers without reducing performance (Chauynarong et al., 2009, Daghir, 2008). For example the inclusion of 50% pelleted cassava results in performance comparable to that obtained with maize diets (Stevenson et al., 1983). With more than 30% unpelleted cassava meal in the diet, some authors report a reduction of feed intake, resulting in a non-significant decrease in growth while maintaining feed efficiency (Mafouo Ngandjou et al., 2011). Fine grinding (<1 mm) can decrease performance compared to coarse grinding (Mafouo Ngandjou et al., 2010). Feed consumption can be affected in young animals at high inclusion rates (50%) while older animals maintain their performance (Brum et al., 1990). Early reports of growth depression with cassava were probably due to high HCN levels or protein/amino acid deficiencies (Chauynarong et al., 2009).
While there is no hard limit on the inclusion level of high-grade cassava in pelleted diets for grower-finisher broilers, the low protein content of cassava limits its inclusion to 30-40% to meet dietary requirements. When diets are fed in meal form, inclusion of cassava should not be higher than 20-30%, particularly in young animals (Buitrago et al., 2002a). Lesser grade cassava root products, such as dusty, unpeeled, or high-HCN roots or roots processed with little or no quality control, should be used more carefully, and the inclusion rate should not exceed 20% of the diet.
High levels of cassava meal can be used in layer diets when the HCN level is low and the diet is balanced for protein and amino acids (Buitrago, 1990). Up to 50% cassava did not significantly decrease production, feed efficiency and body weight. Water consumption increased when cassava was fed in meal form, while this effect was not observed with pelleting. Egg mass produced was also improved by pelleting (Stevenson, 1984).
Unpeeled cassava meal could be included at 30% in layers, completely replacing maize grain in the diet without adverse effects, including on egg quality (weight, shell, Haugh units, etc.) (Eruvbetine et al., 1997). However, the low carotenoid content of cassava requires supplementation with natural or synthetic sources of pigments if the egg yolk colour is to be maintained (Garcia et al., 1999).
Good quality cassava meal can be used in layer diets without limit provided that the diet is properly balanced, especially with amino acids. As in broilers, lower quality cassava should not exceed 20-30% of the diet.
When cassava meal was included at high levels (up to 45%) in geese diets, feed intake was maintained but performance and feed efficiency decreased (Sahle et al., 1992).
While early research reported problems when including cassava in turkey diets (Göhl, 1982), no evidence of negative effects has since been found in scientific literature when correctly formulated diets are fed.