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Rumen8 can be downloaded and used straight away in trial mode but is restricted to 4 diet ingredients until it is registered. Registration is free.

To apply for a registration number please send an email to Richard Morris at with your name (first and surname) and the email you would like to be contacted on. If you don't mind telling us where you are (country and region will do) and your role in the dairy industry it helps us see who is using Rumen8 and better target improvements in the future. Rumen8 emails are very infrequent and your email address will not be shared.

Rumen8 3 can be registered with your Rumen8 2 user name and code so if you still have it just use that. If you have lost it send Richard and email on the address above.


Rumen8 runs on Windows 7, 8.1 and 10 computers and needs a minimum screen resolution of 1024 x 768. Other than that, if your computer can run Windows adequately it should run Rumen8.

Download the installer

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The Windows installer for Rumen8 3 (22 MB)

The Rumen8 User Guide (6 MB - included in the Rumen8 3 installer)

The Rumen8 Training Manual (3 MB - included in the Rumen8 3 installer)

The Rumen8 Feed Companion (2 MB - included in the Rumen8 3 installer)

If you are having trouble downloading and installing Rumen8, download the User Guide above which includes step by step instructions with screen shots to help you.
If the Windows 'SmartScreen' is preventing you running the installer look in the FAQ for instructions.

Updating from Rumen8 2

You can install Rumen8 3 alongside Rumen8 2 and they won’t interfere with each other as version 3 uses a completely updated file format for the feed library etc.

You can import your feeds from a version 2 feed.csv library in the Feed Editor with the Import button down the bottom of the window. It will step through each feed and you can skip it or provide the extra information Rumen8 3 needs about management category and particle size. All the feed definitions have been completely updated and expanded so even if they have the same name the version 3 feed definitions will be from much more recent information.

Version 2 diets can be imported from the File and then Import menu on the main window and then saved out in the new .rm8 format when you have finished.

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What's new version January 2018

  • Fixed a bug that caused a volume milk price to overwrite the component fat price in some circumstances.

What's new version January 2018

  • Fixed a bug with the new maximum milk prices.

What's new version January 2018

  • Maximum milk price has been increased.
  • Bug in the Optimiser spreadsheet has been fixed.
  • Bug loading stored diets after feed library changes has been fixed. Thanks to Hink P. for reporting this.

What's new version November 2017

  • Fixed a bug that was preventing the cow breed loading correctly from a save file.

What's new version November 2017

  • Minor bug fix in Costs tab.

What's new version October 2017

  • Bug fix in the Save As function. Thanks to Gonzalo T. for reporting this.

What's new version October 2017

  • Added current diet DM% to dry and fresh weight tooltips in the main window.
  • Changed ingredients drop downs to show nothing, not "None" so can now jump straight to feeds starting with the letter N.
  • Added Clear current diet menu option.
  • Fixed bug preventing deletion of feeds with long names.
  • Feed and Mix list positions now remain the same after editing or deleting.
  • Fixed calculation of NFC% where diets with extremely high CP contents calculated negatives.
  • Fixed bug reloading save files with stored diets with negative DCAD and no performance indicators.
  • Fixed a bug in the calculation of $Milk/$Feed that reset MS/DMI in error.

What's new version August 2017

  • Rumen8 will correct some errors if they exist in the Preferences and Feed databases when started.
  • A status bar has been added to the bottom of the Splash screen.
  • When deleting feeds the user is now warned if it is used in mixes as they are deleted too.
  • Fixed a bug when feeds are created and immediately used in a mix.
  • Increased the number of ingredients in the unregistered version from 2 to 4.
  • Minor cosmetic changes to text.

What's new version June 2017

  • Bug fix where large quantities of low dry matter feed would not calculate the wet weight. Thanks to Angus D. for reporting this.

What's new version June 2017

  • Rumen8 now allows the Rumen8 folder to be located on a network drive without it being mapped to a drive letter.
  • The maximum cost for feeds and mixes has been increased to $99999/t DM. If you wish to use these expensive feeds you must delete your ~Rumen8\Libraries\Preferences.db file, start Rumen8 and allow it to copy an updated file (your preferences will be reset to the defaults).
  • Excess protein in the detail form now shows a dash not 0 when no diet is loaded.
  • Fixed a bug in the calculation of mix costs after losses in the ingredient tooltip.

What's new version June 2017

  • Linked the slider min and max values on the Animal tab to the values in the Preferences database. Thanks to Alastair G. for noticing the fat maximum was too low. It is recommended you delete your ~Rumen8\Libraries\Preferences.db file, start Rumen8 and allow it to copy an updated file (your preferences will be reset to the defaults).

What's new version May 2017

  • The 8 Queensland pastures in the feed library were incorrectly named perennials. They have been changed to annuals.

What's new version May 2017

  • Fixed a corruption in the feed library that was causing the feed editor to only show the first 62 feeds.

What's new version May 2017

  • Added keyboard shortcuts for the main menu options.
  • Changed the way the minerals calcium, phosphorus and magnesium supply and demand is presented.
  • Supply is now total mineral present in the diet. Previously is was total absorbable mineral present in the diet.
  • Demand is now total mineral required in the diet. Previously it was total absorbable mineral required in the diet.
  • Added a mineral detail window with a breakdown of demand into maintenance, lactation, growth and pregnancy. Also shows supply and absorption for the diet.
  • Detail windows can now be closed with the escape key and opened with a keyboard shortcut.
  • Updated Optimiser3.xlsm to version - bugfix for ADIN and added dry cow calculation for ME and MP for growth.
  • Maximise pellets added to the feed library.
  • The User Guide has been updated to include the minerals detail window.

What's new version April 2017

  • Fixed a bug in the calculation of mix NDF and eNDF. Thanks to Daniel E. for reporting this.
  • Fixed a bug in the calculation of mineral absorption in mixes.

What's new version March 2017

  • The number of diet ingredients has been increased from 10 to 15.
  • The window layout has been improved with important diet financial parameters always visible.
    • Feed mixes can be created and used in multiple diets as a single ingredient.
  • Animal demand and supply of the minerals calcium, phosphorous and magnesium has been included.
  • Diet DCAD is now calculated if ingredient DCAD is available.
  • The feed library has been updated and expanded to over 260 feeds.
  • Greatly expanded help and nutrition information is available via tooltips.
  • Four sets of recommended levels can be set for important diet parameters and then feedback is provided via traffic lights.
  • Notes about the current diet can be kept within Rumen8.
  • An expanded range of cost, margin and feed efficiency parameters allow better comparisons between diets.
  • ME and MP Detail windows can remain open allowing easier monitoring of supply and demand calculations.
  • The Fat: Protein ratio and energy corrected milk have been added to the Animal tab.
  • The Forage: Concentrate ratio is now calculated for the diet.
  • Concentration and proportion units can be changed to percent by the user in the Preferences.
  • Multiple feed libraries are now supported.
  • The Optimiser now works with Microsoft Excel 2010, 2013 and 2016.
  • Animal activity has been simplified.
  • The standard cows have been expanded to include 9000 and 10000 litre lactations.
  • Changing animal values has been made faster and easier with sliders instead of input boxes.
  • Days in milk and days pregnant can now be set on a calendar.
  • Diets being compared can now have a description.
  • The dry cow period has been split into early and springer mobs.
  • Energy, protein and ingredient details are now accessible from the menu.
  • Feed and mix details are available by hovering the mouse over the ingredient name.
  • The traffic lights are now suitable for most colour blind users.
  • The total diet weight is now displayed as fed and on a dry matter basis.
  • The Preferences can be reset to the default values.
  • Rumen8 is compatible with Windows 10.
  • Amino acids have been removed.
  • A saved diet file (.rm8) have been associated with Rumen8 so can be opened in Windows Explorer.
  • The User Guide and Training Manual for Rumen8 has been updated.
  • A Feed Companion has been written that provides a easy visual reference for feed values.
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