Rayner Reckons

Jan 08

Understanding your feed test results

Posted on Tuesday, January 08, 2019

How good is the feed you are offering to your livestock?  I think this is a tricky question to ask.  I know that in 90% of the instances that I’ve asked a farmer this question, their response is generally “Oh its pretty good!” Sometimes the qualification is offered that someone they knew grew it, or that it cost a lot to buy!


Unfortunately cost isn’t actually an indicator of the feed value! 

 

Feed value is actually determined by levels of energy; crude protein; digestibility, fibre and the amount of moisture contained in the feed.  All these components contribute to the usefulness a particular feed has in meeting animals nutritional needs as well as impacting on the amount the animal can physically consume each day.

 

It’s actually pretty difficult to tell any of these things from a visual inspection.  And while looking at a hay, or silage you might be able to have a guess it the digestibility of the plant when it was cut and the general moisture content, its only ever going to be a guess.  

 

Over the past few months, many people have been full feeding their animals as the drought restricts paddock feed.  A lot of these rations have been well planned and meet the various needs of the stock.  However there are still plenty of rations put together on the basis of guess work!  And by guessing some classes of stock are being underfed.

 

Obtaining a feed test is the most reliable way to determine the value of a feed. Its also is essential if you want to develop a ration that actually meets the needs of your stock.

 

Feed tests kits can be obtained through private companies or state departments of agriculture.  Pretty much any feed can be tested.  The kits will provide instructions regarding the amount you nee to collect to send away. 

 

There are various levels of testing that you can request.  For most situations, a standard evaluation is enough to give you the information that will help you know how useful your feed really is.

 

The things I look for include the following key components:

 

DRY MATTER (DM):  All feeds contain some amount of moisture.  This moisture has no nutritional value.  When you prepare a ration, you need to allow for the water in the feed, and in many cases you will actually have to increase the physical or ‘as fed’ amount per animal to account for the moisture.  If you don’t, your rations may end up being lower than what your stock need each day.  Over a period of time, this can lead to significant underfeeding!

 

DRY MATTER DIGESTIBILITY:  This explains as a percentage, how much of a feed your animals will be able to digest. Digestibility and energy are positively related, so having high levels of digestibility not only means your animals can use more of a feed, it also means that the energy levels of the feed are at a level that will meet their needs. 

 

DRY ORGANIC MATTER DIGESTIBILITY:  A further measure of digestibility is made on the organic matter of the feed.  It is expressed as a percentage and again the higher the percentage, the higher value of the feed for animal production. 

 

CRUDE PROTEIN:  Crude Protein is expressed as a % of the Dry Matter.  Crude Protein is essential for rumen function.  Low levels will reduce the ability of a rumen population to effectively use a feed.  For maintenance cattle require Crude Protein to be a minimum of 8%.  Lower values may mean that you will need to add a protein source to your ration.

 

FIBRE:  Fibre is an important part of a diet.  Low levels of fibre can lead to digestive upsets.  More commonly, in rations I’ve seen recently, fibre is often very high. High fibre not only lowers digestibility (and energy) but it will also reduce the amount of feed an animal will actually eat.  

 

Fibre is measured by either; Acid Detergent Fibre (ADF) or Neutral Detergent Fibre (NDF). Acid Detergent Fibre (ADF) is a measurement of cellulose and lignin while 
Neutral Detergent Fibre (NDF)is a measurement of hemicellulose, cellulose and lignin.  Its possible to calculate how much of a feedstuff will be consumed by an animal by dividing 120 by the NDF.  

 

Lower NDF figures will see your animals eat more, and so potentially achieve their needs more easily each day.

 

METABOLISABLE ENERGY (ME): The energy that an animal can actually use in its daily needs is refereed to as Metabolisable Energy (ME).  It is expressed as Megajoules (MJ ME / kg of Dry matter).  To maintain cattle the ME of a feed must be at least 8MJ.  If a feed is below this level, you will need to add an energy source in order to achieve your stock requirements.

 

Knowing the levels of nutrient in your feed places you in a pretty powerful position!  This knowledge will determine if the feed is suitable for the stock you are planning on feeding.  


It will also help you determine the amount you need to feed. This information not only allows you to manage your animals more effectively.  


It also means you will be using your feed more efficiently and getting the best return on the money you’ve spent to purchase it and feed it out!


Don't forget, you don't have to work these things out on your own.  I'm always available to assist you with your feed tests, developing your rations or helping plan your strategies.  If you want a hand, please don't hesitate to get in touch with me!

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