November 2015 - Nutrient values for the standard feeds in the PC-Horse feed lists
In the feed lists of the PC-Horse program, you find the nutrient content of standard grains and roughages (Generic feeds). The nutrient content of the standard feeds are taken from different tables (Sweden, Norway, Denmark, France, Germany, UK, USA). These generic feeds are to be regarded as examples that should be used when you do not have original analyzed values for you feeds. Commercial compound feeds and vitamin/mineral supplements have their nutrient content according to the information given and guaranteed by the manufacturer. For standard grains, the nutrient content is relatively stable. For roughages, however, nutrient values within one type of feed varies to a large extent. This means that the examples of roughage analyses presented in the PC-Horse feed lists are table values that represent mean nutrient content of a number of feed analyses. The roughage quality you have in your stable may vary considerably from the table values. It is therefore highly recommended that you have your roughages analyzed at least for energy (MJ), protein (CP) and the macrominerals calcium (Ca), phosphorus (P) and magnesium (Mg).
How is the nutrient content of horse feeds declared?
In general, the nutrient content of feeds are presented either per kg dry matter (DM) or per kg feed (as fed). Especially when it comes to feeds with a high content of water (fresh grass, haylages, roots), it is important to know if the nutrients are declared as per kg DM or per kg as fed.
Example: My haylage:
Dry matter: 0.70 (can also be written 70%)
Energy per kg DM: 10.0 MJ DE.
This corresponds to: 10.0 MJ x 0.7 = 7.0 MJ per kg feed (as fed).
The energy and protein content of feeds can be presented in different units according to the standards in each country. In the UK, the energy content is given as megajoule (MJ) digestible energy (DE). The protein content is given as crude protein (CP).
The content of macrominerals are declared in grams or as percent. To calculate from percent to grams/kg one has to multiply the figure in percent by 10.
Example: Your hay is analyzed to contain 0.3 % calcium per kg DM. This corresponds to 3 grams of calcium per kg DM.
The content of microminerals are declared as milligrams per kg (mg/kg) or as micrograms per kg (µg/kg). The conversion is: 1 mg = 1000 µg. Selenium (Se) is often declared as µg/kg. This then has to be recalculated into mg/kg to be correctly entered into the PC-Horse feed list where the unit for selenium is mg/kg.
Example: 20 µg selenium = 0,020 mg selenium.
The content of vitamins are listed as international units (IU) (Vitamins A and D) or as mg. However, notice that the content of vitamin B12 often is given in µg. If so, the value has to be divided by 1000. Example: 56 µg B12 = 0,056 mg B12.
How to enter values from roughage analyses into the feedlist of PC-Horse
If you have a roughage that has been analyzed, you can easily enter it into the feedlist of the stable where the feed is being used.
Open the actual feed list and choose “Create a new feed”. Give it a name and the correct feed type. Then it is recommended to select a template feed (the feed most corresponding to the one you have). By doing so, PC-Horse will enter standard values for the nutrients not included in the analysis report.
Thereafter, you can enter values for the analyzed nutrients (pink colour) and the other values remain standard values (yellow colour). Blue colour is where the cursor is.
After accepting and saving changes the new feed is found in the feedlist under “My feed” and it can be included in rations for the horses in the actual stable.
By entering your roughage analyses into the PC-Horse feed lists, you will have a much better control of what is the nutrient content of you rations, and any nutrient deficiency or surplus can easily be corrected.
This article was originally written by Dr. Day Austbø.
Copyright: PC-Horse International - Norway 2015
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