Creating Animal Packs

Technical reference for modders who want to create animal packs for Realistic Livestock RM. An animal pack is a standard FS25 mod that RLRM discovers and loads automatically — no registration or code changes needed.

Note: This documentation was generated with AI assistance and may contain inaccuracies. If you spot an error, please open an issue.

Overview

An animal pack is any FS25 mod that contains an rlrm_pack.xml file in its root directory. When RLRM starts, it scans all enabled mods for this file. If found, the mod is treated as a pack and its resources are loaded on top of RLRM's base animal definitions.

Packs can do two things:

Override properties on existing breeds — change prices, food consumption, production rates, reproduction parameters, weights, and more
Add new breeds — define entirely new subtypes with custom visuals, fill types, and translations

You can do either or both in a single pack.

Pack Types

Balance Pack (property overrides only)

The simplest kind of pack. It changes values on existing breeds without adding any new ones. No models, no textures, no fill types — just an XML file with the properties you want to change.

FS25_RLRM_MyBalance/
├── modDesc.xml
├── rlrm_pack.xml
└── animals.xml

Use this when you want to adjust prices, food curves, reproduction timing, or other simulation parameters to your preference.

Breed Pack (new breeds with visuals)

A more complex pack that adds entirely new breeds. This typically requires custom model configurations, store images, fill types, and translations.

FS25_RLRM_MyCowBreeds/
├── modDesc.xml
├── rlrm_pack.xml
├── animals.xml
├── fillTypes.xml
├── translations/
│   ├── translation_en.xml
│   └── translation_de.xml
├── images/
│   ├── store_myBreed.dds
│   └── store_myBreedBaby.dds
└── models/
    └── cow/
        └── animals.xml          (model config with texture atlases)

Pack Descriptor

Every pack must have an rlrm_pack.xml in its mod root. This file tells RLRM what resources the pack provides.

<?xml version="1.0" encoding="utf-8" standalone="no" ?>
<rlrmPack name="My Pack Name" author="Your Name" version="1.0">
    <!-- Path to animal definitions (overrides and/or new subtypes) -->
    <animals path="animals.xml"/>

    <!-- Path to fill type definitions (only needed when adding new breeds) -->
    <fillTypes path="fillTypes.xml"/>

    <!-- Prefix for translation files (only needed for new breed names, fill type titles, etc.) -->
    <translations prefix="translations/translation"/>
</rlrmPack>

All paths are relative to the mod's root directory. Omit any element you don't need — a balance pack typically only needs <animals>.

Descriptor attributes

Attribute	Required	Description
`name`	No	Display name shown in the game log. Defaults to the mod name.
`author`	No	Pack author, shown in the game log.
`version`	No	Pack version, shown in the game log.

Resource elements

Element	Required	Description
`<animals path="..."/>`	No	Animal definitions file — property overrides and/or new subtypes
`<fillTypes path="..."/>`	No	Fill type definitions — needed when adding new breeds
`<translations prefix="..."/>`	No	Translation file prefix — for localized breed names and fill type titles

Animal Definitions

The animals.xml file is where the main work happens. It can contain:

Property overrides for existing breeds
New subtype definitions for new breeds
Config overrides for model replacement
Breed metadata for display names and marker colours
Breeding groups for breeding restrictions

Property Overrides

Override specific properties on existing breeds. Only the properties you specify are changed — everything else keeps RLRM's default values.

<animals>
    <animal type="COW">
        <!-- Override Holstein cow prices and food consumption -->
        <subType subType="COW_HOLSTEIN">
            <buyPrice>
                <key ageMonth="0" value="300"/>
                <key ageMonth="24" value="3000"/>
            </buyPrice>
            <sellPrice>
                <key ageMonth="0" value="250"/>
                <key ageMonth="24" value="2800"/>
                <key ageMonth="36" value="3200"/>
                <key ageMonth="60" value="2000"/>
            </sellPrice>
            <input>
                <food>
                    <key ageMonth="0" value="80"/>
                    <key ageMonth="12" value="300"/>
                    <key ageMonth="18" value="420"/>
                </food>
            </input>
        </subType>

        <!-- Override pig reproduction timing -->
    </animal>

    <animal type="PIG">
        <subType subType="PIG_LANDRACE">
            <reproduction minAgeMonth="6" durationMonth="4" minHealthFactor="0.8"/>
        </subType>
    </animal>
</animals>

Overridable subtype properties

Property	XML	Format
Gender	`subType#gender`	`"female"` or `"male"`
Breed	`subType#breed`	Breed name string (uppercase)
Birth weight	`subType#minWeight`	kg (float)
Target weight	`subType#targetWeight`	kg (float)
Maximum weight	`subType#maxWeight`	kg (float)
Reproduction	`<reproduction>`	`supported`, `minAgeMonth`, `durationMonth`, `minHealthFactor`
Health rates	`<health>`	`increasePerHour`, `decreasePerHour` (0–100)
Buy price curve	`<buyPrice>`	AnimCurve: `<key ageMonth="X" value="Y"/>`
Sell price curve	`<sellPrice>`	AnimCurve
Transport price curve	`<transportPrice>`	AnimCurve
Food consumption	`<input><food>`	AnimCurve
Water consumption	`<input><water>`	AnimCurve
Straw consumption	`<input><straw>`	AnimCurve
Manure output	`<output><manure>`	AnimCurve
Liquid manure output	`<output><liquidManure>`	AnimCurve
Milk output	`<output><milk fillType="MILK">`	AnimCurve (with fill type)
Pallet output	`<output><pallets fillType="...">`	AnimCurve (with fill type)
Visual stages	`<visuals><visual>`	Override or insert by `minAge` match (see Visual Overrides)

Overridable type-level properties

These are set on the <animal type="..."> element and affect all breeds of that type:

Property	XML	Format
Pregnancy	`<pregnancy average="2" max="6"/>`	Average and max offspring count
Fertility curve	`<fertility>`	AnimCurve: breeding probability by age
Average buy age	`animal#averageBuyAge`	Months (integer)
Maximum buy age	`animal#maxBuyAge`	Months (integer)
Pasture space	`<pasture sqmPerAnimal="X"/>`	Square metres per animal (float)

AnimCurve format

Price, production, and consumption curves use age-based keyframes. The game linearly interpolates between keyframes.

<buyPrice>
    <key ageMonth="0" value="200"/>     <!-- At birth: $200 -->
    <key ageMonth="24" value="2500"/>   <!-- At 24 months: $2500 -->
</buyPrice>

Adding New Subtypes

To add a new breed, define a full subtype within the appropriate animal type. New subtypes need:

A unique subType name (uppercase, e.g., COW_CHAROLAIS)
A matching fillTypeName (defined in your fillTypes.xml)
Visual stages with store images
All the properties a breed needs (prices, reproduction, weights, etc.)

<animals>
    <animal type="COW">
        <subType subType="COW_MYBREED" fillTypeName="COW_MYBREED"
                 gender="female" breed="MYBREED"
                 minWeight="40.0" targetWeight="600.0" maxWeight="1200.0">
            <visuals>
                <visual minAge="0" visualAnimalIndex="1"
                        image="images/store_myBreedBaby.dds"
                        canBeBought="true">
                    <description>$l10n_animal_descriptionCowMilk</description>
                    <description>$l10n_animal_descriptionCowFeed</description>
                </visual>
                <visual minAge="18" visualAnimalIndex="2"
                        image="images/store_myBreed.dds"
                        canBeBought="true">
                    <description>$l10n_animal_descriptionCowMilk</description>
                    <description>$l10n_animal_descriptionMature</description>
                </visual>
            </visuals>
            <reproduction minAgeMonth="12" durationMonth="10" minHealthFactor="0.75"/>
            <buyPrice>
                <key ageMonth="0" value="200"/>
                <key ageMonth="24" value="2500"/>
            </buyPrice>
            <sellPrice>
                <key ageMonth="0" value="150"/>
                <key ageMonth="36" value="2800"/>
                <key ageMonth="60" value="1800"/>
            </sellPrice>
            <input>
                <food>
                    <key ageMonth="0" value="50"/>
                    <key ageMonth="18" value="400"/>
                </food>
                <water>
                    <key ageMonth="0" value="20"/>
                    <key ageMonth="18" value="80"/>
                </water>
                <straw>
                    <key ageMonth="0" value="10"/>
                    <key ageMonth="18" value="60"/>
                </straw>
            </input>
            <output>
                <milk fillType="MILK">
                    <key ageMonth="0" value="0"/>
                    <key ageMonth="12" value="0"/>
                    <key ageMonth="12" value="200"/>
                    <key ageMonth="36" value="350"/>
                    <key ageMonth="120" value="180"/>
                </milk>
                <manure>
                    <key ageMonth="0" value="50"/>
                    <key ageMonth="36" value="400"/>
                </manure>
                <liquidManure>
                    <key ageMonth="0" value="50"/>
                    <key ageMonth="36" value="200"/>
                </liquidManure>
            </output>
        </subType>
    </animal>
</animals>

New subtypes are loaded through the game engine's own loadSubTypes function — the same one the base game uses. This means subtypes added by packs behave identically to built-in breeds.

Visual Overrides

Visual stages define how an animal looks at different ages (calf, juvenile, adult). Each stage is matched by minAge. When overriding visuals on an existing breed:

If a stage with the same minAge already exists, its properties are updated
If no stage with that minAge exists, a new stage is inserted (sorted by age)

<subType subType="COW_HOLSTEIN">
    <visuals>
        <!-- Override the adult visual (minAge=18 already exists on Holstein) -->
        <visual minAge="18" image="images/store_myHolstein.dds" canBeBought="true"/>
    </visuals>
</subType>

Overridable visual properties: visualAnimalIndex, image, canBeBought, description.

Texture Filtering

When multiple breeds share the same 3D model but use different texture rows from a texture atlas, use textureIndexes to restrict which variations a breed displays:

<visual minAge="18" visualAnimalIndex="2" image="images/store_myBreed.dds">
    <textureIndexes>
        <value>3</value>
        <value>4</value>
    </textureIndexes>
</visual>

This tells the engine to only use texture variations 3 and 4 from the model's variation list for this breed, rather than randomly picking from all available textures. This is essential when multiple breeds share one model config but need distinct appearances.

Config Overrides

Config overrides replace the entire model configuration for an animal type. This is needed when your pack adds new 3D models or expanded texture atlases that aren't in the base game's model config.

<animals>
    <configOverrides>
        <override type="COW" configFilename="models/cow/animals.xml"/>
    </configOverrides>

    <!-- ... subtypes and overrides below ... -->
</animals>

The configFilename path is relative to the pack's mod directory. It points to a model config file (the same format the base game uses to define animal 3D models and their texture variations).

When a config override is applied, RLRM:

Replaces the model config path for that animal type
Reloads all model data from the new config
Re-links all existing subtypes' visual references to the new model objects
Re-applies any texture filtering (textureIndexes) on existing subtypes

Important: Config overrides are a total replacement — not additive. If two packs both override the model config for the same animal type (e.g., both replace the COW config), the second one completely overwrites the first. The first pack's visual references will point to models that no longer exist, causing broken or missing visuals.

Only one pack should provide a config override per animal type. If you're creating a balance-only pack, don't include config overrides — you don't need them and they'll prevent breed packs from working alongside yours.

Config overrides are processed before subtypes are loaded, so your new subtypes can reference visualAnimalIndex values from your custom model config.

Breed Metadata

When adding new breeds, register their display names and marker colours so the GUI shows them correctly:

<animals>
    <breeds>
        <breed name="MYBREED"
               displayName="$l10n_breed_mybreed"
               markerColour="0.8 0.3 0.1"/>
    </breeds>

    <!-- ... subtypes below ... -->
</animals>

Attribute	Description
`name`	Breed identifier (uppercase, matches the `breed` attribute on subtypes)
`displayName`	Localized name for the GUI. Use `$l10n_` prefix to reference translations.
`markerColour`	RGB colour for the breed's map marker, as three space-separated floats (0.0–1.0)

The $l10n_ references are resolved from the global translation table, which includes your pack's translations (loaded before breed metadata).

Breeding Groups

Define breeding restrictions for your breeds. Animals in a breeding group can only breed with other animals in the same group.

<animals>
    <breedingGroups>
        <group name="MYGROUP" maxFertilityAge="120">
            <subType name="COW_MYBREED"/>
            <subType name="BULL_MYBREED"/>
        </group>
    </breedingGroups>
</animals>

Attribute	Description
`name`	Group identifier (uppercase)
`maxFertilityAge`	Maximum breeding age in months for males in this group (optional)

Translations

Translation files provide localized text for breed names, fill type titles, and store descriptions. English is the required base language — always provide an English translation file. Additional languages are optional.

File naming

Files use the prefix from rlrm_pack.xml plus _{lang}.xml:

translations/
├── translation_en.xml    (required — English base)
├── translation_de.xml    (optional — German)
├── translation_fr.xml    (optional — French)
└── ...

RLRM tries the player's game language first, then falls back to English.

File format

Standard FS25 translation XML:

<?xml version="1.0" encoding="utf-8" standalone="no" ?>
<l10n>
    <texts>
        <!-- Fill type names (shown in transport/trading UI) -->
        <text name="fillType_cow_mybreed" text="My Breed Cow"/>
        <text name="fillType_bull_mybreed" text="My Breed Bull"/>

        <!-- Breed display names (shown in animal details) -->
        <text name="breed_mybreed" text="My Breed"/>
    </texts>
</l10n>

These translations are loaded into the global translation table, so they work with $l10n_ references in your animals.xml and fill types.

Fill Types

Each new breed needs a fill type registered in the game's fill type system. This is how FS25 tracks animals internally.

<?xml version="1.0" encoding="utf-8" standalone="no" ?>
<map>
    <fillTypes>
        <fillType name="COW_MYBREED" title="$l10n_fillType_cow_mybreed" showOnPriceTable="false">
            <physics massPerLiter="600.0" maxPhysicalSurfaceAngle="0"/>
            <economy pricePerLiter="4000"/>
            <image hud="$dataS/menu/hud/fillTypes/hud_fill_cow.png"/>
        </fillType>
        <fillType name="BULL_MYBREED" title="$l10n_fillType_bull_mybreed" showOnPriceTable="false">
            <physics massPerLiter="750.0" maxPhysicalSurfaceAngle="0"/>
            <economy pricePerLiter="4000"/>
            <image hud="$dataS/menu/hud/fillTypes/hud_fill_cow.png"/>
        </fillType>
    </fillTypes>
</map>

This uses the standard FS25 fill types format. The $l10n_ titles reference your pack's translation files. You can reuse base game HUD icons ($dataS/...) or provide your own.

Fill types are only needed when adding new breeds. Balance packs that only override existing breeds don't need them.

Load Order and Priority

Packs are loaded in alphabetical order by FS25 mod name. This order is deterministic and reproducible.

If two packs override the same property on the same subtype, the alphabetically later mod wins. You can use naming to control priority:

FS25_RLRM_CowBreeds loads before FS25_RLRM_ZZ_MyOverrides
A pack named with a ZZ_ prefix can serve as a "final word" override layer

The load sequence within each pack is:

Translations — loaded first so $l10n_ keys resolve in later steps
Fill types — registered so new subtypes can reference them
Config overrides — model configs replaced before subtypes load
Model reload — Lua-side model data refreshed from new configs
Breed metadata — display names and marker colours registered
New subtypes — loaded through the engine's loadSubTypes
Property overrides — applied last, patching both existing and newly added subtypes
Breeding groups — registered after all subtypes exist

The modDesc.xml

A pack's modDesc.xml is a standard FS25 mod descriptor. It doesn't need any special entries — the rlrm_pack.xml file is what RLRM looks for.

<?xml version="1.0" encoding="utf-8" standalone="no" ?>
<modDesc descVersion="106">
    <author>Your Name</author>
    <version>1.0.0.0</version>
    <title>
        <en>RLRM My Balance Pack</en>
    </title>
    <description>
        <en><![CDATA[Description of what your pack does.

Requires Realistic Livestock - Ritter version (FS25_RealisticLivestockRM).]]></en>
    </description>
    <iconFilename>$dataS/menu/hud/fillTypes/hud_fill_cow.png</iconFilename>
    <multiplayer supported="true"/>
</modDesc>

Mention the RLRM dependency in the description so players know the pack requires the base mod.

Tips

Start with a balance pack to learn the format. Override a few prices, test it, then build up from there.
Test in singleplayer first. Use the console command rmSetLoglevel * DEBUG for detailed loading output in the game log.
Check the game log for messages starting with MapBridge: Animal pack — these show exactly what was detected, loaded, and any warnings.
Name your mod consistently. Use the FS25_RLRM_ prefix so players can identify it as an RLRM pack and so load order is predictable relative to other packs.
Don't use config overrides unless you need them. If you're only changing values (prices, food, reproduction), skip config overrides entirely. This keeps your pack compatible with breed packs that do need them.
Use RLRM's own xml/animals.xml as reference for the full subtype definition format, property names, and AnimCurve structures.

Limitations

Cannot remove breeds. Packs can add new breeds and override properties on existing ones, but cannot remove a breed that RLRM or another pack defines.
Cannot add new animal types. Packs can only add subtypes within existing types (COW, PIG, SHEEP, HORSE, CHICKEN, and any types added by the map). Creating an entirely new animal type requires map-level support.
Cannot modify diseases. The disease system is not exposed to packs.
One config override per animal type. If two packs both override the model config for the same animal type, only the last one loaded takes effect and the other pack's visuals will break. See Config Overrides.
No explicit priority system. Load order is strictly alphabetical by mod name. There's no way to declare "load after pack X" — use naming conventions to manage order.