By Dwayne Summach, PAg, Livestock and Feed Extension Specialist, Kindersley, SK
Feed testing is a tool that allows producers to know the nutrient content of a particular forage or feed in order to provide that feed, in combination with other feeds, to closely match the provision of nutrients an animal needs to meet their nutrient requirements. This results in a cost effective feeding program that minimizes waste, optimizes performance and allows the use of readily available, alternative feed sources. Feed testing may also include analysis for potential toxins such as deoxynivalenol (DON) or ergot alkaloids.
The first step in feed testing is obtaining a representative sample using a forage probe. Forage probes are available to borrow from Saskatchewan Ministry of Agriculture Regional Services offices and Saskatchewan Crop Insurance locations. Accurate identification of the lot being sampled is necessary. If the hay from a field was all cut in one day, and baled three days later with no weather event, it will be natural to consider it one lot. However, if that same field was cut on three different days with some rain delays causing extended drying times, it is possible for there to be multiple lots of hay on the same field. Once you have determined which bales belong to a sample group, you will require at least 20 cores from approximately ten per cent of the bales in the lot. Pit silage needs to be sampled using a much longer silage probe, but more practically, taking samples of fresh chopped material while filling the pit can provide a baseline for ration planning. Once the pit is opened, confirmation samples will be required from the face, often obtained as grab samples taken in a "W" or "M" pattern. These cores need to be compiled and thoroughly mixed, prior to filling a medium sized sealable plastic bag. Dry samples are best kept cool and should be submitted to a lab as soon as possible. Samples from wet forages such as silage bales or pit silage, should be refrigerated, or even frozen and placed in an insulated container with chill packs to minimize spoilage during shipping.
Deciding where to send the samples and which test(s) to do can be daunting, but our water testing and feed contacts, laboratories and companies listing aims to make it easier. Each lab may have slightly different test combinations, but the most important things to look for are dry matter, crude protein (CP) and both acid detergent fiber (ADF) and neutral detergent fiber (NDF). Acid detergent fiber is used to estimate energy content (total digestible nutrients (TDN)), while NDF is used to estimate potential intake. Most test packages also include macro minerals like calcium, phosphorus, potassium, magnesium and sodium with the option to add others as requested. For silage, it is advisable to include pH as an indicator of the extent of acid production and acid detergent insoluble nitrogen (ADIN), to determine if heat damage has occurred. Anything other than legume crops, that were put up with a risk of nitrates (drought, hail or frost) should include a nitrate test. Additional factors such as mycotoxins, sulphur and chemical residues can also be tested for if required.
Regional Livestock and Feed Extension Specialists can assist producers with the interpretation of their feed test results. The results provide an opportunity to target feeds to meet animal needs corresponding to their production cycle as winter progresses. Feed test results can also help identify if additional supplements are required. Using average values to plan results in a plan that may over or underestimate nutrient provision. In many cases, neutral detergent fiber is higher than book values, limiting intake and therefore nutrients to the animal. On the flip side, if the forage is better than the average book value, there is potential to be overfeeding nutrients, costing you money. Knowing the specific levels of nitrates, other toxins and molds can allow you to determine to what degree the feed can be used with minimal risk.
Help us help you by feed testing and balancing rations for the winter feeding period. The awareness and ability to manage nutrients and potential toxins far outweighs testing costs.
For more information, contact your nearest Ministry of Agriculture Regional Office or call the Agriculture Knowledge Center at 1-866-457-2377.