Tratamento do bagaço de cana-de-açúcar para alimentação de ruminantes

Abstract

The objective was to review the existing knowledge about the treatment of sugarcane bagasse for ruminants feed. The production of sugarcane bagasse in Brazil is approximately 192.63 million of tons, representing a source of abundant food for animal feed. This food is characterized because of being a source of effective fiber, mainly composed of the cell wall components (hemicellulose, cellulose and lignin), of low utilization by ruminants. Nevertheless, the sugarcane pulp can be widely used in diets with high concentrate for beef cattle, comprising from 10 to 20 % of the dry matter from diets, without great losses on animal performance. Treatment by pressure steam reduces cell wall components, increasing the digestibility of sugarcane bagasse. However, this treatment reduces the pH of the sugarcane bagasse, which requires the use of the buffering in the diets to avoid reducing the digestibility of the fiber. Because of its low stimulating rumination, the sugarcane bagasse treated with steam and pressure must be used along with an effective fiber source, which enables an increased use of sugarcane bagasse in the diet. The chemical treatment with sodium hydroxide, oxide or calcium hydroxide has similar mode of action, culminating in the reduction of neutral detergent fiber of sugarcane bagasse. Although more efficient, the treatment with sodium hydroxide is difficult to handle and can cause environmental damage. The use of microprocessor limes is easier to handle and less harmful for the environment. Treatment with alkaline products reduces the cost compared to treatment with pressure and steam. Treatment with anhydrous ammonia and urea improves the nutritive value of sugarcane bagasse for providing non-protein nitrogen, mainly. The delignification by biological treatments increases the digestibility and protein content of the sugarcane bagasse. However, these treatments have not been adapted to field conditions, which hinders their use. The use of bagasse from sugarcane for ruminant feed, regardless of the treatment used (physical, chemical or biological), must be linked to the amount of additional feed concentrate, enabling the completion of dietary nutrients and meeting the nutritional requirements of the animals.