4. BYPASS PROTEIN SUPPLEMENT PRODUCTION PROCESS
Protein is usually the first limiting nutrient for cattle and buffeloes fed low quality forages. All ruminants derive their protein requirement from two sources. One is rumen un-degraded feed protein that gets enzymatically digested in the abomasums and small intestine and another source of protein is rumen microbes. The microbial fermentation of soluble protein in the rumen is an unavoidable consequence of digestion and under many circumstances; it is a wasteful process because high quality proteins are broken down to ammonia, excess converted to urea in the liver and excreted through urine. The solubility of proteins change when subjected to special chemical treatment, advantage of which is to protect good quality proteins from rumen degradation (Fig. 4.1). Number of chemicals like acetaldehyde, formaldehyde, glutaraldehyde, ethanol, tannic acid, acetic acid, sodium hydroxide etc. have been tried to protect proteins. Amongst all, aldehyde suggested for protection of protein, formaldehyde has been extensively used for production of bypass protein feed.
Usually, protein meals are fed to ruminants in India, which have variable degree of naturally rumen protected proteins. Protein meals, particularly rumen escape proteins, play a very important role as excellent protein supplement, in livestock feeding. When these meals are fed as such to ruminants, about 70 per cent of the protein is broken down to ammonia by the rumen microbes in the rumen and a significant portion is converted to urea in liver and excreted in the form of urea through urine. However, if these protein meals are subjected to suitable chemical treatment, then their efficiency of utilization can be significantly improved. When chemically treated protein meals replace untreated one, then due to less degradability of the protein in the rumen, excessive loss of both nitrogen and energy could be avoided, resulting in an increased energy and nitrogen balance, leading to increase in milk yield and milk constituents. Bypass protein feed is a new generation cattle feed in India and is manufactured by a special chemical treatment, developed by the National Dairy Development Board (NDDB). Bypass protein feed contains a large percentage of solvent extracted protein meals in treated form, grain by-products, whole grains, molasses, minerals and vitamins. The special feature of the formulation is that more than 70 per cent of the total protein in the feed is rumen undegradable protein.
Characteristics considered desirable for protected protein supplements
• High level of crude protein.
• Optimal essential amino acids profile.
• About 70-75 per cent of the protein to be in a rumen un-degradable form (UDP).
• Approximately 80 per cent of the rumen un-degradable protein to be digestible in the small intestine.
