Ruminal nitrogen balance
The ruminal nitrogen balance (RNB) (from rumen , the anatomical name for the rumen ) is a measure of the sufficient supply of rumen microorganisms in dairy and rearing cattle with nitrogen .
The RNB is calculated as follows:
where XP stands for the ingested raw feed protein and nXP stands for the usable raw protein .
The RNB should be around zero. So that the microbial activity in the rumen and the performance potential of the animals can be fully exhausted, a balanced nitrogen-rumen balance should be aimed for. When designing the ration, it is therefore important to prevent nitrogen over- or under-supply of more than 10%.
Negative RNB
If the RNA was negative, too little protein was fed. Rations that are based on corn silage usually result in a negative RNB.
Positive RNB
If the RNB is positive, too much protein is being fed. In the case of rations with an emphasis on grass silage , there is a positive RNB. With full pasture, there is usually no need to supplement protein. A high milk urea content (over 300 mg / LTR milk) is an indication of a positive RNB. In general, an RNB up to 30 is aimed for, but up to a value of 70 is possible depending on the situation.
Web links
- Influence of the ruminal nitrogen balance (RNB) on rumen fermentation, microbial protein synthesis, amount of usable protein (nXP) flowing into the small intestine and nitrogen excretion (dissertation), online at the Federal Research Center for Agriculture, Braunschweig