Entering feed information helps you calculate a more accurate enteric methane value for your animals.

Knowing both what your animals eat and how much they eat is essential for estimating enteric methane emissions. This is especially important for grazing livestock, where intake can be harder to track.

We focus on Dry Matter Intake (DMI) because it reflects the total energy your animals consume — some of which can be converted into methane. Even just entering DMI gives us a better emissions estimate. But for the most accurate results, specify the feed types too, since different feeds have different methane potentials.

If you only enter DMI and not feed types, the calculator will use UK average rations for your livestock.

If you only know the "as fed" or fresh weight of feed, don’t worry — this guide can help. It includes tools and defaults to make estimating DMI easier.

This page will help you:

1. Estimate DMI for grazing animals
   • General DMI rates for grazing
   • DMI estimates based on liveweight
   • How to include supplemented grazing diets
2. Convert "as fed" weights to dry matter weights
   • Dry matter conversion process
   • Default DM percentages for common feeds
   • How to estimate bale weights
3. Understand how diet affects methane emissions
   • Basic principles behind the calculations
   • Key terms and assumptions
   • Why specifying diet matters
4. Review feed options in the calculator
   • Foraged, preserved, and concentrate feeds
   • Blended and systems-level options

Each section is collapsible. Some tables are hidden by default to reduce scrolling — just click "view table" or the arrow to expand.

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 %.

How to deal with supplemented diets

If you supplement grazing, include that in the calculation.
Choose a pre-set “grazing + supplement” option or create a breakdown with individual components using our diets wizard.

Diets Wizard

This wizard helps with calculating percentages of the reporting period, which can be complex with multiple feeds.

Often you will only know the weight of what you have fed wet, but it is the dry matter that matters in these calculations. Use this section to convert between as fed and dry weights. You will also find information on the assumed weights of bales if bale feeding.

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

Bale weight assumptions

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 type of feed you choose plays a key role in how much methane your animals produce. Feeds with higher energy content and digestibility not only support better animal performance, but also reduce methane emissions per unit of energy consumed.

Entering specific feed types into the calculator gives you more accurate emissions results. In this section, you'll learn how our tool uses feed energy values — and why they matter. If you're curious about the full science behind it, check out our enteric emissions guide .

Key terms to know

• Gross Energy (GE): The total energy in a feed, measured in MJ/kg of dry matter. This is your starting point — how much energy the feed *contains*.
• Digestible Energy (DE): The portion of GE that an animal can actually use. Also measured in MJ/kg, this tells you how much energy is *available* for growth or maintenance.
• Digestibility (D-value): Expressed as a percentage. A higher D-value means the feed is easier to break down, which improves energy absorption and reduces methane output.

Why feed quality matters

Feeds that are more digestible and energy-dense support better animal health — and produce less methane per unit of feed. That’s because efficient digestion reduces fermentation in the gut, where methane is generated.

By using detailed feed data instead of averages, you can make informed choices that boost productivity and lower emissions — helping both your business 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 Forages

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].