Lysine in Ruminant Feed:
In the Indian cattle feed industry, protein sources are mainly derived from plant sources such as soybean meal, cotton seed cake and mustard cake. Unfortunately, these plant sources are deficient in lysine in comparison to the requirement of the dairy animal. Lysine is one of the limiting amino acids for dairy animals in India. Feed protein is being divided into two categories RDP (Rumen Degradable Protein) and RUP (Rumen Undegradable Protein). RDP is being utilized by the ruminal microflora for microbial protein synthesis which is an ideal protein for the animal considering the lysine content. Balancing of the rumen undegradable part of the feed protein (i.e. RUP) with respect to the lysine gives profitable results in terms of milk yield and milk protein to the dairy farmer. Lysine also have protein sparing effect, which makes it possible to get the most benefits without increasing protein level (nitrogen level) and thus it gives space for energy in feed formulation.
The commonly used feed ingredients in India are from plant source and these are less in lysine content. The commonly used feed stuffs and their lysine content are as follows: