Entering feed information allows you to calculate a more precise enteric methane value for your animals. Knowing how much feed your animals consume, in addition to what they consume, is crucial, especially for grazing animals where intake can be difficult to determine.
We specifically request dry matter intake (DMI) because it's directly related to the energy content consumed by the animal which could be converted into methane. However, we understand you might only know the "as fed" or "fresh weight" of feeds. This guide will help you convert "as fed" weights to dry matter weights and provides default values to assist with estimating DMI.

If you are unsure about your animals' average grazing consumption, use the following default values or consult the AHDB guides for further information:

Calculating dry matter intakes for rotational grazing of cattle | AHDB

Planning grazing strategies for Better Returns

General DMI Rates for Grazing Animals (kgDM/day)

• Suckler cow: 10-15 kgDM/day*
• Dry cow: 8-10 kgDM/day
• Calf: 1-2.5 kgDM/day
• Weaned calf: 5-7 kgDM/day
• Ewe: 1-1.9 kgDM/day
• Ram: 1.5-2.2 kgDM/day

*DM = Dry matter

Calculating DMI Based on Liveweight

For a more accurate input, DMI can be calculated based on body weight and the percentage of body weight allocated for feed. Use this formula:

Assumed DMI (kgDM/day) = Liveweight (kg) * (Animal Allocation (%) / 100)

Where:

• Assumed DMI: The daily intake of grazing animals, in kgDM/day.
• Liveweight: The average liveweight of the animals (default used if not entered), in kg.
• Animal Allocation: The allocation of feed as a percentage of the body weight, in %.

If you know the "as fed" weight but not the dry matter weight, use dry matter percentages (DM%) to convert:

Dry Matter Weight (kg) = As Fed Weight (kg) * (DM% / 100)

You can find DM% on various sites:

• Nutrient Values Of Feedstuffs – Lakeland Scottish Feeds & Services
• Feed Values - DairyNZ
• List of feeds | Feedipedia
• INRAE-CIRAD-AFZ Feed tables

If you only know you are feeding by the bale, you may not know the exact weight being fed to the animals. The table below provides average weights for different bale types. You can divide these assumed weights by the number of livestock to estimate the individual consumption rate.
Important: Bale and lot feeding is often associated with some waste, typically 10-20% of the material. Remember to account for this waste in your DMI entry (i.e. only 80% of the bale may actually be eaten and hence impact enteric methane).

The energy content and digestibility of the feeds you use directly affect how much methane your animals produce and how much energy is available for that methane production. By entering the specific types of feed you’re using, you get a more accurate picture of your animals’ enteric methane emissions.
In the following section we explain the key feed energy data used in our calculator to help you understand how it works. If you want to dive deeper into the science behind the enteric emissions calculations, check out our enteric emissions guide.

Key terms to know

• Gross Energy (GE): This is the total energy contained in the feed, measured in megajoules per kilogram (MJ/kg) of dry matter. It’s the starting point for understanding how much energy the feed holds.
• Digestible Energy (DE): This is the part of the gross energy that your animals can actually digest and use. Also measured in MJ/kg, DE tells you how much energy the animal can get from the feed.
• Digestibility (D-value): Expressed as a percentage, this shows how much of the feed can be broken down and absorbed by the animal. A higher D-value means better digestibility and more energy available to the animal.

Why it matters

Feeds with higher energy content and better digestibility usually mean your animals get more nutrition and produce less methane per unit of energy consumed. This is because more efficient digestion reduces waste fermentation in the gut, which is where methane is produced.
By using specific feed data, you can make informed decisions to improve animal nutrition and reduce methane emissions, benefiting both your farm’s productivity and the environment.

Foraged Feeds

These are fresh feeds grazed directly by your animals while they’re out in the field. This section covers typical forage types you’ll commonly find in pastures, such as grasses, clovers, and root crops.
Understanding the energy content and digestibility of these feeds can help you better estimate your animals’ intake and methane emissions.

Preserved Grasses and Forage

This section covers preserved feeds like hay and silage, with options reflecting different grass qualities based on their digestibility (D-value). You’ll also find maize and legume silage included. As the quality of hay or silage improves, both digestibility and digestible energy (DE) increase. Higher-quality feeds provide more usable energy to your animals, which can help reduce methane emissions because there’s less wasted energy lost as enteric emissions.

Concentrate components

The next section lists common components used in Total Mixed Rations (TMR) and other feed formulations. These ingredients can be combined to create custom feed systems. To simplify the list, feeds with similar Gross Energy (GE) and Digestible Energy (DE) values—such as wheat and barley grain—have been grouped together for easier reference.

The data for forages, conserved grasses and concentrate components is pulled from a combination of feedipedia, INRAE-CIRAD-AFZ Feed tables FAS , and AHDB, with other sites and info sources used to confirm selections, such as germinal and promar.

Feed blends

We’ve also included a selection of pre-mixed blends. These feeds contain varying components depending on their intended use. The Gross Energy (GE) and Digestible Energy (DE) values shown are calculated based on the proportions of each ingredient in the blends. These values correspond with the options you'll find in the purchased animal feeds section.

Systems level feed options

Finally, we present system-level options that represent standard diets for generic production systems. By selecting options like grazing combined with supplements, the GE and DE values are adjusted based on their assumed proportions within the overall diet.
Please note these options are generalized and should be used with caution, especially when estimating Dry Matter Intake (DMI).

If you feel we have overlooked a feed type or would like systems and blends added - please contact us at [email protected].