In recent times, the dairy industry has made huge improvements in reducing amount of protein needed to improve performance. This has improve the farm's profitability as well as reducing nitrogen flowing into the environment.
Although feed efficiency for cows is important, but what about proving feed efficiency of rumen microbes?
Studies from the 80s and 90s have showed that the more protein is given to the rumen microbes, the more microbial protein was produced from the same amount of carbohydrates.
In other words, giving microbes more feed protein at the same time carbohydrate is available will increase the efficiency of growing microbes.
Timing the protein and carbohydrate so that they are available to the microbes in the optimal amount at the same time is called "synchrony".
It is recommended to have a ratio of 2-1 for nonfiber carbohydrates and rumen degradable protein to optimise for microbial protein yield.
Many studies are investing synchrony in order to improve animal performance but the results were mixed.
One way is to find out why microbes make more microbial protein when given more feed protein which would give us a clue on how to make synchrony work.
Here are some other factors to consider in order to make synchrony work:
1) What types of degradable protein have this effect?
2) What feed sources of proteins work?
From research, increasing rumen degradable protein using soybean meal seemed to have the desired effect with dry ground or high moisture corn as starch sources.
Alfalfa can also be a good source of amino acids, peptides as well as non-protein nitrogen in the soluble protein fration that might be tried with sugars.
More work need to be done to explore which sources to combine in order to get the desired results.
It is a matter of having the optimal amounts of degrading protein at the right time instead of just feeding more protein.
3) Perhaps there are times when slower rate of fermentation is beneficial?
If acid production in the rumen is a concern, increasing rate of fermentation would further decrease rumen pH and possibly reduce fiber fermentation or increase the risk of ruminal acidosis.
Protein is not the only factor but reducing the amount of degradable protein may help slow down the rate of fermentation.
4) Do the passage rates matter for protein effect to affect cow's performance?
In order for the microbes produced in the rumen to provide nutrients to the cow, they need to pass to the abomasum and small intestine where they can be digested.
If the microbes die and recycle in the rumen, their amino acids would not be useful for the cow.
For synchrony between protein and carbohydrate to improve cow's performance, the liquid passage rate needs to harvest the microbes and deliver them post-ruminally.
Nutritional synchrony is an old idea that made sense but there are a lot of challenges to make it work. However, if done right, improving efficiency of microbes would help to improve efficiency of the dairy system and this is something worth exploring.