Byproducts of low digestibility and low nitrogen
Straws, husks, pods and haulms are the byproducts of this category. Very often the nitrogen content in these byproducts is so low that supplementary degradable nitrogen such as urea is required to speed up both rate and extent of digestion in the rumen. If given as a high proportion of diet, these byproducts have slow rates of digestion and long retention times in the rumen leading to lower levels of voluntary intake.
Rice hulls: Rice hulls or husk is the largest byproducts of rice milling industry and most of it is either burnt or used as bedding for poultry and animal. It contains 3.8 % CP, 1.4 % EE, 32.7% CF, 3.87% NFE, 23.6% ash, 16.0% silica, 69.4% NDF and 38% ADF. The DCP and TDN of rice hulls is 0.16and 11.7 %, respectively. Ground rice husk is often mixed to adulterate the rice polish/bran. Husk when substituted upto33% of rice straw in growing crossbred calves ration, there is insignificant depression in growth, while the depression in growth is significant at higher levels.
Sugarcane bagasse: Bagasse is one of the most important byproduct of sugar industry. It is a source of cellulose but poor in protein and high in lignin. Cattle and buffaloes can consume about 80% of their expected dry matter intake through bagasse impregnated with 1-2 % urea. It has been reported that 40% replacement of wheat straw with dried bagasse in feed blocks improve their physical attributes such as bulk density, post compression expansion and durability besides feed cost. Further, 40% wheat straw in a complete feed can be replaced without any adverse effect on nutrient digestibility.
Babul (Acacia nilotica) seed chuni/pods: Babul is a leguminous tree and grows extensively over a large area in India. Its pod contains about 14% CP, 1% Calcium and about 66% NFE. While seed contains 16-18% CP and pod husks contain about 8% CP. Animals do not consume babul seeds if it is fed alone due to peculiar smell, but accept when mixed with wheat bran or other palatable feeds. The presence of tannins (about 5-6%) poses limitations in its effective use. The chuni can safely be fed upto 30-45% levels in the concentrate mixture of bullocks, growing calves and lactating animals without affecting the performance. There are possibilities of achieving beneficial effects of tannins using within threshold level of tanniniferous feeds on animal performance by means of enhancing protection of dietary protein as well as value addition of milk.
Cassava (Mannihot esculenta) starch waste: The availability of the cassava starch waste in the country is estimated to be about 40 thousand tonnes. It contains very low DCP but is a rich energy source and can be included up to 25 % level in the concentrate mixture for crossbred calves. It is not known to contain any toxic factors.
Maize husk: Maize husk is superior to even gram husk in its nutritive value. It has about 8% CP. Upto 50% of the dry roughage portion in complete feed of adult non- producing cattles and buffaloes can be replaced by this product.