Aminoacids in diet formulation for Dairy Cows

As pointed out in some earlier discussions, the use of supplemental by-pass amino acids is economically justified either to promote additional milk production or to allow the use of more economical sources of supplemental protein (amino acids). My exerience is that we usually are more economical in working first with locally available feedstuffs than starting to add the more expensive by-pass amino acid sources but the use of specific amino acid sources is often justified by increases in total milk production. It is always more economical to maximize use of locally available ingredients and then use added specialty ingredients as a targeted nutritional program. One of the earlier posts mentioned the use of correct mineral/vitamin supplements and the addition of high quality supplements will often increase both rumen function and supply the added mineral/vitamin program needed to support higher milk production, increased feed efficiency and support for reproduction. Nutrition is not magic in a bag--it is simple numbers needed to help the cow reach her potential. We need to remember that most ingredients supply both rumen available and rumen by-pass nutrition. We need to balance and use these naturally occurring by-pass nutrients as well as use the rumen produced nutrients before working to add commercial by-pass products.

If you feed unprotected lysine and methionine, it will be quickly degraded to ammonia in the rumen. It is better to feed rumen protected lysine and methionine.
Or else, supplement live yeast that would help enhancing rumen microbial growth which in turn would supply all essential amino acids to the host animal, including lysine and methionine.

It is well known to us that methionine and lysine are the two most limiting amino acids in the ration dairy animals. Rumen microbial protein is the best source of these two amino acids. In fact, the level of lysine and methionine content of the microbial protein is very similar to that of milk protein.
Enhanced rumen microbial output by way of using various feed additives, including the proper strain of live yeast culture, could be of great value. This will not only help in the increased supply of lysine and methionine but will also improve the fermentation of dry matter in the rumen.
Manget Ram Garg

From personal experience in both temperate and tropical conditions, what is more important is understanding when to introduce protected Methionine, not lysine, in the ration. Optimizing the rumen condition to achieve optimum yields of microbial protein should be the main target. And, we can easily achieve this with very little or no soya or other expensive sources of by pass protein in the ration.

Most herd can formulate a more cost effective ration by target feeding of the right type of protected Methionine in place of expensive by pass protein sources like soya etc. Unfortunately, most nutritionist are obsessed with feeding soya and other expensive sources of by pass protein. The consequence of which is unnecessary high feeding cost to the farmer.

In my experience, the use of protected amino acids (lysine and methionine) can be useful economically, and in the aspect of reproduction in high producing cows. But it is very important to consider the kinds of protein sources in the diet. In addition, to pay attention to NFC is very important.