Abstract
Dietary protein ingested by ruminant animals is extensively degraded by microorganisms inhabiting their forestomachs. Mechanism of microbial breakdown of dietary protein is very complicated and not yet entirely understood. Experimental results, both in vitro and in vivo show a varying degradation of dietary protein, with differences in degradation between individual amino acids. Part of this variation, particularly in vivo, must be attributed to inadequate measuring techniques. Among other factors influencing degradation are nature and solubility of dietary protein, rate of passage of digesta through the forestomachs and level of feed intake. Decreasing the extent of degradation of dietary protein can be achieved in various ways. Two possibilities include formulation of diets from ingredients with low protein solubility and chemical treatment of the dietary protein, for instance, with formaldehyde. Under present feeding regimens this seems profitable only if level of animal production is high (early lactation, fast growing young animals). Protection may result in an inadequate supply of nitrogen or even amino acids for microbial growth in the forestomachs. Shortage of N can easily be overcome by addition of some nonprotein nitrogen such as urea to the diet, provided that the energy supply to the microbes is not a limiting factor as well. Copyright © 1979. American Society of Animal Science . Copyright 1979 by American Society of Animal Science