There is no such thing as a silver bullet balancing for Amino Acids in calf milk replacer
Amino acids are certainly the buzz word in ruminant nutrition, and rightly so. Nevertheless, will AA supplementation change the world of calf milk replacers too?
There are two overarching themes in research and ongoing farm trials:
- We are scratching the surface.
- A silver bullet does not exist.
Will Amino Acid supplementation change the world of calf milk replacers too?
In principle, ruminants have a requirement for amino acids rather than crude protein. Can calf milk replacer be supplemented with amino acids to improve growth rates, reduce crude protein levels, and/or reduce total feed costs?
The first complication in milk replacer is finding the amino acid requirement of young calves. Milk phase calves are neither monogastric nor fully functioning ruminants. A model does not currently exist which will accurately predict the AA requirement of pre-weaned calves.
Several studies have tried to establish AA requirements based on growth rates. Drackley et al., 2006 state the base to formulate CMR is whole milk- being ideal for calves, adequate AA profile and a high biological value. Hill et al., 2008 state for daily feeding of 17g of lysine and 5.4g of methionine for calves under the age of five weeks, has been proven to be adequate to supply AA requirements and assure adequate growth rates.
Dairy proteins (whey and skim) are biologically high in essential amino acids. The ability of any milk replacer to provide adequate amounts and profile of essential amino acids for growth depends on the individual protein amino acids profile, the milk replacer processing, and protein digestibility. It is worth bearing in mind high temperatures during drying processing may negatively affect quality.
As this topic is further researched and explored, there is possibly an opportunity to lower CP levels of high-quality powders and supplement AA.
However, there is a danger of producing cheaper powders with poorly digestible proteins that are supplemented with AA. Consideration still needs to be given to digestibility, abomasal emptying and rumen development when choosing raw materials.
The silver bullet does not exist
Many practices will change the face of calf rearing on your farm. Good colostrum management. A vaccination programme for in-calf cows and calves. A comprehensive hygiene protocol amongst others.
What these all have in common is that they are fundamental system practises, not a singular product change. A balanced calf milk replacer, a nutritionally sound starter feed or an electrolyte correcting for acidosis have all been discussed within this focus on calves. These changes will go a long way to fine-tuning and improving calf rearing. However, these, and many other changes will do little without the basics being correct.
At the minute, research around amino acids in milk replacer is promising, so watch this space.
Nonetheless, if someone calls to your farm claiming methionine, lysine or threonine will change your life and does not take a whole system approach…walk away.
A well balanced, high dairy protein content milk replacer should be the first nutritional parameter.
Are AA supplemented, high veg protein, cheap milk replaces in fact, a step in the wrong direction?
