Rust Breeding Calculator for Cows and Sheep
Set the genes of two parents and see the odds for each gene in the calf or lamb, including the chance of a god clone. Tap a gene to cycle Bad, OK, Good. The example shows a real cow paired with a bull that shows Good Dung and Yield.
Cow (mother)
Bull (father)
What the calf will get
- No chance of Good Longevity and Fertility: neither parent carries a Good copy (or can, given what it shows). Swap in a parent that shows Good on those genes.
- Some calves can show Bad Dung and Fertility, because both parents can pass a Bad copy. A parent that is Good/Good or OK/OK there removes the risk.
For a parent where you only know what it shows, hidden copies are estimated from wild odds (Good 20%, OK 50%, Bad 30%). Farm-bred animals will differ, so treat these numbers as a guide.
How the calculator works
Each parent has two copies of every gene. A newborn gets one copy of each gene from each parent, picked at random, and shows whichever of its two copies is better. The calculator works through every combination and adds up the odds. See the genetics guide for the full explanation.
Both copies or only what it shows?
If you know both copies of a gene (for example on a server where admins show you the full panel), choose Both copies and the odds are exact. If you only know what the animal shows, from its looks or its performance, choose Only what it shows. The calculator then estimates the hidden copy using the odds a wild animal rolls: Good 20%, OK 50%, Bad 30%. It knows a hidden copy can't be better than what the animal shows.
That estimate is honest but rough: animals from a carefully bred line are more likely to hide Good copies than wild ones.
What it can't tell you
- Inbreeding. Related parents can produce an inbred young, but the chance isn't published, so the calculator only warns you. Inbred animals show weaker genes but still pass on their real copies.
- Sex. Young are 50/50 male or female.
- Twins. A mother with Good Fertility has a 60% chance of a second calf or lamb; each one rolls its genes separately.
Picking a pair
- A parent that is Good/Good on a gene guarantees every young shows Good on it, whatever the other parent has.
- If neither parent carries a Good copy of a gene, no amount of breeding that pair will produce one. Bring in another animal.
- Avoid pairing siblings or parent with young.
- Prioritise by goal: Yield for milk or wool, Fertility to speed up the whole programme. The cow and sheep pages list the best genes for each goal.