Have you enough fodder for this winter?

Date published: 24 October 2017

The poor weather has left the fodder situation very difficult on many farms across Northern Ireland. The quantity and quality of fodder should be assessed on all farms.

A batch of replacement heifers eating quality silage this winter.

Assess the quantity of silage available

Pit Silage

Measure your silage pits and do a simple calculation to assess the tonnage that is available. You can go online and use the DAERA online calculator to complete the calculations or manually work them out using the example below.

Pit silage calculation example

A silo measuring 20 metres long and 10 metres wide with silage ensiled to an average depth of 2.5 metres has a volume of 500 cubic metres of silage. The dry matter of this silage will affect the tonnage. Convert the cubic metres to tonnes of fresh weight silage by multiplying the volume by the figure in Table 1 below which best relates to the dry matter of your silage.

Table 1 Conversion from cubic metres to tonnage of fresh weight silage
Silage Dry Matter (%) Tonnes of silage per cubic metre 
18 Multiply by 0.81
20 Multiply by 0.77
25 Multiply by 0.68
30 Multiply by 0.60
35 Multiply by 0.54
Whole crop 40 %  Multiply by 0.67

Round Bale

Round bales can vary considerably in both weight and quality and taking time to weigh a representative sample will enable a more accurate assessment to be made of the tonnage available.

Remember that dry silage contains more nutrients per tonne and that water has no nutritive value.

Assess the demand of the livestock

Calculate the demand of each batch of livestock. Again the online calculator can be used to complete this or manual calculations can be done using the figures in Table 2.

Table 2 Monthly silage intakes of various livestock categories
Livestock Category Silage required per month (tonnes)
Autumn calving suckler cow & calf 1.5
Spring calving suckler cow 1.0
500 kg store animal 1.2
350+ kg store animal 1.0
250-350 kg weanling calf 0.8
200-250 kg weanling calf 0.7
100-150 kg calf 0.3
Ewe 0.12

Assess the quality of the silage

An analysis of the silage will give a prediction of the silage intake potential and likely output in terms of live weight gain or milk production. The dry matter, digestibility, energy and protein content are all measured and the quality of the fermentation assessed.

Silage analysis is relatively inexpensive and will enable you to feed your livestock more accurately to achieve the required performance. It can be completed within a few days in a laboratory such as AFBI Hillsborough or in a few minutes on the farm using the latest hand-held scanning equipment. Contact your feed company or development adviser to arrange a test.

A good representative sample should be analysed in all situations and bales or pits should ideally be cored or sampled on several occasions during the winter.

Supplementation and Alternative Feeds

If silage stocks are limited consider supplementing or using alternative feeds. Dry cows can be fed 3 kg of rolled barley and ad lib straw (this diet is protein deficient) each day completely replacing the daily requirement for 30 kg of silage.

Soya hulls can replace up to 30% of the silage in the diet and are a good high fibre safe feed for suckler cows. Availability can be a problem.

Fodder beet can replace up to 30% of the daily silage requirement of cows, young stock and finishing cattle but it contains low protein and growing cattle should be fed a protein supplement.

Potatoes can replace 20-25% of the daily silage requirement and have a higher protein content (11%) than does fodder beet.


  1. Take action now to assess the amount of fodder and demand of current livestock numbers using DAERA Calculators.
  2. Complete a silage analysis to determine the potential feeding quality.
  3. Where there is a significant short fall in either quantity or quality consider sale of surplus stock and/or use of alternative feedstuffs.

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