Relative feed value

Date published: 16 November 2017

This summer and autumn has seen rainfall totals at least 30% above average each month since July and 17-21 days with rain each month. This prolonged unsettled weather has resulted in many issues around harvesting silage and cereal crops. Grass growth has been reasonably good but managing and utilising it has been more problematic. The knock-on effects have been early housing of some stock, a potential shortage of fodder for some businesses, poor quality silage with low dry matter and metabolisable energy (ME) contents and silages with soil contamination.


Therefore winter feed budgeting and planning is critical, the initial step is to assess fodder requirements, quantity and quality.

  • Know how much fodder is required to carry all livestock groups through the winter
  • Calculate the amount of fodder available on farm
  • Have silage analysed to determine quality

These figures can be calculated using the DAERA silage calculators.

Ideally the majority of the diet on beef and sheep farms will be provided by good quality conserved forages. However if silage is of poorer quality or there isn’t enough for the winter, some additional feed will have to be purchased. There are a range of feedstuffs to substitute and/or complement what is available and it is essential to ensure value for money.

Purchasing fodder - points to consider

  • Round bales are highly variable depending on the dry matter and density of the bale. It may be difficult to obtain an accurate weight or tonnage and hence final price paid may be much more expensive than expected.
  • Silage also varies considerably in terms of nutrient content and the price paid may bear little reflection of its quality – water has no nutritive value! 
  • There may be areas of spoilage in a bale or clamp due to damage to the cover or wrap and there may be losses at the face during feedout.  Hence tonnage actually consumed by the animals may be significantly lower than the tonnage purchased.
  • It is therefore vital to weigh and analyse purchased forage to avoid paying over the odds for a poor quality feed.

Relative feed value of feedstuffs

In some cases hay, silage or straw is simply not available, irrespective of price and it will be necessary to purchase a concentrate. A wide range of feeds with differing nutrient contents is available. The relative feed value is a technique used to establish whether a particular feed is value for money compared to reference feeds such as barley and soya. It is based on the energy (ME) and protein (CP) of the feed. The figure for each feed indicates the highest price at which it will be value for money relative to barley and soya. Feedstuffs are good value if they can be purchased at less than the price in Tables 1 & 2.

Table 1. Relative feed values of straights compared with dried rolled barley at £185 / tonne and soyabean meal at £310 / tonne.
Feed £
Dried Barley (14% MC) 185
Wheat (14 % MC) 190
Maize meal (High silage) 204
Maize meal (High conc) 224
Maize Gluten 189
Citrus Pulp 163
Soya Hulls 183
Molasses 121
Molassed sugar beet pulp 173
Soyabean meal 310
Rapeseed Meal 266
Maize distillers dark grains 243
Sunflower meal 198

Values based on rolled Barley at £185 /tonne and Soyabean at £310/tonne. These prices were valid at time of printing.

The values have been calculated using the DAERA relative feed/value programme, other feeds stuffs not listed above can also be calculated if energy (ME) and protein (CP) values of the feed is known. The programme can be accessed via the calculator below:

Table 2. Relative feed value of forages compared with dried rolled barley at £185 / tonne and soyabean meal at £310 / tonne.
Feed DM %


(MJ/Kg DM)




(fresh weight)

Good quality silage  25 11.5 15.5 45
Average quality 20 10 14 31
Poor quality 17 9 9 24
Straw 87 6.5 4 90
Hay 85 8.5 8.5 118

Key points to consider

  • Compare the price of compounds/straights/roughages from several different sources
  • Consider the use of value for money by-products to replace a shortfall in roughage
  • Ensure the concentrate purchased complements the forage available
  • Analysis of roughages should be carried out before any rations are formulated
  • Prioritise best quality forages to the most productive stock such as dairy cows in peak lactation, finishing cattle and pregnant ewes.


  • Purchased straights, compounds and forages must be selected based of relative feed value to ensure value for money
  • Restricting the amount of good quality silage fed and increasing the amount of concentrates will be more economical than purchasing poor quality forages at high prices.


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