WHEN sourcing supplementary feed for your livestock, there are two key issues to consider before purchasing a seemingly cheaper feed: feed testing and commodity declarations.
You need to know exactly what you are getting.
This will ensure that the feed value is right for the class of livestock being fed, and give you value for money and peace of mind that it’s safe to feed.
When sourcing feeds, always ask for the feed analysis before you buy.
Ensure you have any samples tested for the following qualities: metabolisable energy, protein, neutral detergent fibre (NDF) and dry matter.
Energy
Knowing the metabolisable energy (ME) values of different feeds is vital to working out how much you need to feed and the best value (as cost of energy) to buy.
A feed analysis report will inform the ME, expressed as either MJ ME/kg DM or as megajoules per kilogram of dry matter (MJ/kg DM).
ME is the amount of energy in the feed that is available for livestock to use.
Protein
Protein is measured as the crude protein (CP), as a percentage of dry matter.
It contains nitrogen, and this is used to estimate the protein content of feeds.
A portion of the nitrogen in feed is non-protein nitrogen (nitrates, ammonia and urea); crude protein is a measure of both this and the feed protein (amino acids).
Crude protein values give a good indication of whether a particular feed will satisfy the protein needs of an animal.
Fibre
Fibre is measured and reported as neutral detergent fibre (NDF) and acid detergent fibre (ADF) as a percentage of dry matter.
NDF is a measure of all the fibre (the digestible and indigestible parts) and indicates how bulky the feed is.
ADF is a measure of the proportion of feed that is indigestible to stock (mainly cellulose and lignin).
Feeds with a high ADF are low energy.
If both NDF and ADF are reported and the ADF represents a high proportion of NDF, this means most of the fibre content of the feed is indigestible to stock.
Dry matter
All measurements of energy and protein are made on a dry matter basis.
Knowing the dry matter percentage enables you to work out how much to feed to meet the energy requirements of the stock.
Digestibility
Digestibility is the percentage of the dry matter digested by the animal. High-quality feeds will have a figure above 65 per cent. Feeds below 55 per cent are of poor quality – if animals are given free access, they will be unlikely to maintain their liveweight if this feed was supplying all their diet.
