FeedTest Report Content Summary
Unless otherwise requested your FeedTest report will contain the following terminology to describe results and parameters tested. Moisture Is the amount of water in the feed, varying from about 10% in grains and to over 80% for fresh pasture. Dry Matter (DM) DM refers to the amount of feed remaining after the water has been removed. Because the water content of feeds can vary considerably, all analyses are expressed on a dry matter basis and expressed as a percentage. Crude Protein (CP) Protein is composed of nitrogen, carbon, hydrogen, oxygen and sometimes sulphur or phosphorus. As protein contains nitrogen this is used to estimate the protein content of feeds. It is assumed that true protein has 16% nitrogen, so to calculate protein the found nitrogen content is multiplied by 6.25. However some portion of the nitrogen found is non protein nitrogen (ie. Nitrates, ammonia and urea) so this value is referred to as crude protein rather than true protein. Expressed as a percentage. Neutral Detergent Fibre(NDF): (reported for fodder packages) So called after the method used to determine it, NDF describes the make up of the cell walls of a plant. It is the portion of fibre composed of hemicellulose, cellulose, lignin, silica, tannins and cutins. NDF is related to feed bulk and can be used in ration formulation to predict forage intake and quality. Forages lower in NDF are usually of high quality and have high levels of intake. NDF is reported as a percentage. Acid Detergent Fibre (ADF): (reported for cereal, pelleted feed, horse and pig packages) ADF is composed of cellulose and lignin and is relatively undigestible. As ADF represents digestibility it is used to calculate energy. Forages with a low ADF value are high in energy and vice versa. ADF also derives its name from the method used for testing. Expressed as a percentage. Water Soluble Carbohydrates (WSC): (reported for cereal hay only) WSC is a measure of the total soluble sugars which are present in a forage. These sugars include glucose, fructose, sucrose and fructans. They are almost completely digestible. Digestibility of Dry Matter (DMD) Is the percentage of the feed dry matter actually digested by the animal. It is estimated by using a laboratory method which is standardised against DDM values from feeding trials. High quality feeds have a DDM of over 65%, whilst feeds below 55%DDM are of poor quality and will not maintain liveweight even if stock have free access to it. Ash The ash content of a feed is the inorganic portion which is not utilised by an animal. This is determined by heating a known weight of material at a very high temperature.
The organic components (carbon, nitrogen, oxygen and hydrogen) are burned off and the residue is weighed to calculate ash. Crude Fat Crude fat is also known as ether extract due to the method of using petroleum ether to determine its value. True fats, oils, fatty acid esters, compound lipids and fat soluble vitamins are all soluble in ether and have nutritional value. But the ether also dissolves other components which have little nutritional value or cannot be digested (such as waxes, resins and essential oils), hence the term "crude" fat. The crude fat measurement is often used in the soybean industry. Digestibility of the Organic Dry Matter (DOMD) This value is calculated to represent the amount of organic matter that is digested by the animal. This value takes into account the inorganic matter (ash) such as sand, dirt and clay present in the sample. DOMD is calculated from an Australian Fodder Industry Association agreed regression equation relating DMD to DOMD. This is reported as a percentage. Digestible Energy (DE): (reported on pig, poultry AusScan and horse packages) Is the total energy an animal can use minus the energy lost in manure. Measured in megajoules per kilogram (Mj/kg) on an as fed basis. Metabolisable Energy (ME) ME is the feed energy actually used by the animal and is expressed as megajoules per kilogram of dry matter (Mj/kg DM). It involves the measurement of energy excreted in faeces, urine and exhaled as methane. This requires very specialised and expensive equipment and is conducted at only a very few locations around the world. In Australia, ME cannot be measured by a laboratory and is instead predicted from other tests, most accurately from digestibility. New prediction equations for ME came into effect on FeedTest analytical reports as from September 1st 2005. These changes arise from decisions taken by the Quality Evaluation Committee (QEC) of the Australian Fodder Industry Association (AFIA), and as a result of efforts to improve agreement and standardisation of fodder analysis methods among Australian laboratories. The predicted ME for silage from the new equation may be considerably higher now than it was when predicted with the old equation. The new equation was derived from a large UK database containing measured ME values and measured digestibility values on a wide rang of feeds over many years. It has been recognised for many years that oven drying of silage, necessary for measurement of dry matter and preparation of samples for other tests, can result in the losses of volatile compounds produced during silage fermentation. If this loss is not accounted for an underestimation of dry matter, digestibility (and hence predicted ME) and total nitrogen (hence crude protein) may occur. It was decided to adopt a separate prediction equation for silage, to take account of the volatile compounds present. Depending on the type of sample you submit, the equation used to determine the ME will be listed on the bottom of your report. As Fed Basis This term refers to the volume of feed actually fed to the animal including the moisture present.
