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Low Protein Silages This Year?

1 October 2015

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 AnimalMinimum Crude Protein in Ration
(g/kg DM)
Minimum Crude Protein in Ration
Dry suckler cow909
Lactating suckler cow11011
Newly weaned suckler calf14014To help with adjustment to weaning rations.
Store animals11011
Fattening animal12012
Intensive beef ration15012Ad-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,

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