Rust cow and sheep breeding calculator

What are the best cow genes in Rust?

Prioritize Yield for milk and Fertility for breeding stock. For sheep, Yield serves the same purpose for wool. Good grades across all five traits are desirable, but a reliable breeding line needs good hidden copies too. The calculator separates a calf or lamb that looks all green from one carrying two Good copies of every trait.

Choose parents for the resource you actually need, then record offspring before choosing the next pair. A visible Good trait can carry Good/Good, Good/OK or Good/Bad. Unknown hidden copies can leave a range of possible odds; visible grades alone do not identify every carried copy. Selecting a guessed hidden grade above gives a conditional result, not evidence that the animal carries it.

How to breed cows and sheep

The inspected server code requires an adult male and female of the same species. Both must be alive and fully bonded. The female cannot already be pregnant; neither animal can still be on a lead. Handling an animal enough to lead it is not the same as completing the bonding requirement.

1. Bring home a compatible pair, complete bonding and let young animals reach adulthood.
2. Release their leads and provide food, water and enough personal space. Check the animal panels themselves.
3. Wait for breeding cooldowns and for poor condition to recover. A newly filled trough does not instantly clear every gate.
4. Keep your intended pair apart from other eligible mates. The male searches reachable candidates nearest first; another female can be chosen.
5. Inspect the offspring’s grades and keep a record. Good visible traits alone do not establish good hidden copies.

Inbreeding is separate from gene inheritance. In this captured build, it lowers trait performance: a Good trait can perform at the OK level. It does not change the allele-selection probabilities shown above. The lineage display alone is insufficient to guarantee an unrelated pair, so these results are not the odds of a perfect, healthy animal.

Why are my cows or sheep not breeding?

Check the lowest need first. In build 25902425, food, water and personal space must each be above 50%. Overall needs follows the lowest value, not their average. Two full bars cannot make up for a third that is too low.

Condition has a separate recovery gate: breeding pauses at 60% or below and resumes at 70% or above. An animal recovering from neglect can therefore have adequate needs while it still cannot breed. Check age, full bonding, pregnancy, cooldown and leads before assuming the genes are the problem.

Stocked food and water only help when the animals can reach and use them. Watch the actual need values after changing the pen. This page does not promise a universal pen size, animals-per-trough count or overnight feed budget; those require runtime checks and can depend on server settings.

Server settings can disable breeding, cap the species population or require a home tool cupboard. If the visible care checks pass but breeding still fails, establish the server’s settings before rebuilding the farm.

October livestock update and version limits

Facepunch’s 1 October 2026 Livestock update introduced cows and sheep, breeding, milk, wool, livestock selling and the biofuel generator. Animal genes are a separate system from plant crossbreeding: six-letter plant targets such as GGGYYY do not describe a cow.

The calculations and care checks here come from server build 25902425, captured 20 October and reviewed 26 October 2026. They were read from game code, not reproduced in a live pen. A newer client build exists. Later development work changes ownership, ageing and sale-value calculations; this page does not treat development commits as proof those rules have shipped.

October update coverage · All Rust tools