# NorFor Updates 27th of June 2024

NorFor updated some equations in the Feed Ration Calculator (FRC) on 27^{th} of June 2024. Equations in Feedstuff Table and (FST) and One-day Feed Control (OFC) are the same as before.

The update includes changes concerning nitrate and 3-NOP, absorption coefficient for calcium, phosphorus and magnesium, young stock, feed cost, and in Norway: changes for dry NRF cows and inclusion of the methane equation used in Norway’s national inventory reporting.

**Nitrate and 3-NOP, missing values assumed to be zero **

Nitrate (NO3) and 3-NOP are two substances that reduce enteric methane emission. Most feeds in NorFor feed table lack values for these two parameters. Therefore, we assume all feeds with missing values have no addition of NO3 or 3-NOP and thus set to zero in the calculations of ration parameters.

The following ration parameters are changed:

- Intake of NO3, with the units g/day and g/kg DM, will always present a value even if NO3 has no value in the NorFor feedstuff table.

- Intake of 3-NOP, with the units mg/day and mg/kg DM, will always present a value even if 3-NOP has no value in the NorFor feedstuff table.

- Methane reduction, with the unit %, will always present a value even if NO3 and 3-NOP have no values in the NorFor feedstuff table.

**Absorbtion coefficient in feed table not in use **

There are absorption coefficients for calcium, phosphorus and magnesium in the administration tool but these are not shown in the tools used for formulating rations (NRFO, Optifôr, DMS, FoderOpti and TypFoder). In most cases, feeds have values for absorption coefficients and the values are 1000 g/kg, but there are a few feeds that have missing values. In such isolated cases, it is difficult for a user of the ration formulation tool to know what is missing in regards of calcium, phosphorus or magnesium. Since NorFor does not work actively with this parameter for specific feed materials, we let all calcium, phosphorus and magnesium for all feeds to be included in the calculations.

Following ration parameters are changed:

- Calcium intake, with the units g/day and g/kg DM, sums up all calcium even if absorption coefficient for calcium (acCa) lacks a value in NorFor feedstuff table.

- Phophorus intake, with the units g/day and g/kg DM, sums up all phosphorus even if absorption coefficient for phosphorus (acP) lacks a value in NorFor feedstuff table.

- Magnesium intake, with the units g/day and g/kg DM, sums up all magneisum even if absorption coefficient for magnesium (acMg) lacks a value in NorFor feedstuff table.

**Young stock**

__Fill value__

Users can optimize on Fill value balance, with minimum and maximum limits in the NorFor setting. Minimum value for Fill value and Fill value balance are increased. For heifers, minimum fill value is 85% of maximum intake, and for steers and bulls it is 90%.

__Rumen load index__

The maximum limit on Rumen load index for bulls is increased to 0.8. Heifers and steers still have the maximum limit of 0.6.

__Age__

Age, with the unit months, can be chosen as a ration parameter. This is a complement to the former ration parameter Age in days.

**Feed cost **

Feed cost per kilo ECM is presented in two ways. Feed cost is normally based on actual price in the herd feed table. Often actual price and optimization price is the same but they can differ. Feed cost based on optimization price per kg ECM is the new parameter and is a complement to the former Feed cost based on actual price per kg ECM.

**Only in Norway**

**Dry cows**

Dry NRF cows in close-up period will get correct minimum and maximum limits for energy balance.

**Extra methane equations**

Researchers from NMBU have created two equations to estimate enteric methane emissions from dairy cows to be used in the National Inventory Reporting. One is estimated on the cows’ consumption and diet composition. The other one is based on variables that can be easily measured on farm such as milk production and concentrate intake, although this equation has more uncertainty. Both equations are presented as methane (g/day) and corresponding carbon dioxide equivalents (CO2e, kg/d). In total, there are 4 new ration parameters.

**Version information**

NorFor server version: 1.0.51

FST model version: Revision 2.10

FRC model version: Revision 2.17

OFC model version: Revision 1.43