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.
If a test isn’t available, it may be possible to get a sample and send the test off yourself, before deciding to purchase.
If you purchase feed without a test, it’s still worth taking a sample and getting a test done so that you can fine-tune your rations and ensure that livestock nutritional requirements are being met.
Several companies do feed tests and can provide follow-up advice if needed. Their websites will provide details about how to sample, costs involved, how to access sampling kits and payment methods.
It is important to note that not all companies test and report on the same nutritional components.
Ensure that you have any samples tested for metabolisable energy, protein, neutral detergent fibre (NDF) and dry matter.
Energy
Because energy is the main requirement of livestock, 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. Protein 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. This allows feeds of different moisture contents to be compared.
Dry matter is the amount of feed left after all the water in the sample has been removed by oven drying. It is expressed as a percentage of the original sample.
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 provided on a feed analysis report as a percentage of dry matter — either DDM (digestible dry matter) or DMD (dry matter digestibility), depending on the company doing the analysis. It 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.
Check the feed is safe
When sourcing feeds, particularly new supplies or fodder from failed or harvested crops not originally intended for livestock, you should obtain a commodity vendor declaration form.
This will provide some background information about the feed source, including whether it has been sprayed or treated with a chemical that is still within a withholding period (WHP), export slaughter interval (ESI) or export animal feed interval (EAFI).
A blank commodity vendor declaration form can be downloaded from the Integrity Systems website.
– Michele Jolliffe,
AgVic dairy extension officer
16°C