Many beef and sheep silages sampled so far appear to be lower in protein than we would normally expect. A possible explanation could be less nitrogen taken up by the plants due to the late spring and cooler weather we had in April and May.
It is important that you analyse your silage as this will affect rationing. Sufficient protein needs to be supplied to the rumen to provide nitrogen to the rumen bugs and enable efficient fermentation. If protein supply is insufficient, fermentation slows down and intakes drop leading to poorer performance.
Below is a table of the minimum crude protein levels in the overall diet for different classes of stock that are recommended to maintain rumen function (these are expressed in the dry matter):
|Type of Animal||Minimum Crude Protein in Ration|
|Minimum Crude Protein in Ration|
|Dry suckler cow||90||9|
|Lactating suckler cow||110||11|
|Newly weaned suckler calf||140||14||To help with adjustment to weaning rations.|
|Intensive beef ration||150||12||Ad-lib cereal based ration|
Urea can be used as a nitrogen source but care has to be taken to feed little and often (ideal in a intensive cereal based ration). It is not usually advised to feed it in silage based diets as there is already a lot of free nitrogen in these rations. Seek advice if you are considering feeding urea.
Karen Stewart, email@example.com
Sign up to the FAS newsletter
Receive updates on news, events and publications from Scotland’s Farm Advisory Service