Rust Cow Genetics & Breeding Guide

Everything you need to breed better cows in Rust, updated for the November 2026 "Printed and Polished" update: what each gene does, the new Potential stat, how calves inherit genes, how to avoid inbreeding, and a step-by-step plan for a 4-green herd.

Where these numbers come from: Facepunch's own Livestock notes explain the systems but don't publish gene numbers. The values here are the ones several community sources agree on (game-data wikis, tested servers and server-host guides; see sources). Where sources disagree, we say so. Facepunch is still tuning livestock, so numbers can change with updates. Last checked against the November 5, 2026 update.

1. Rust cow genes explained (D, Y, F, H)

Since the November 2026 update every cow has four genes, shown as D Y F H. Each one is good (green), ok (grey) or bad (red). Good is usually about 1.6× the normal effect and bad about 0.6–0.67×. The old L (Longevity) gene was removed when cows stopped dying of old age.

• Milk per hour works out to about 7 (red), 12 (grey) and 38 (green), so green Yield is roughly 3× the milk of grey. Cows now store up to 3 milk, so you don't have to milk them the moment they're ready.
• Dung times are at full condition. Dung slows down when a cow's condition drops. Bread and brioche dung boosts now work on livestock too.
• Hardiness: one wiki puts it as about two-thirds of the pen floor needing grass and a third needing sun (or a ceiling light) for a grey-Hardiness cow, and about half that for green. Another says green Hardiness keeps full condition with needs down to 50%, while grey and red need them topped up.
• Bulls rest after breeding too: about 15 min (red), 10 min (grey) or 6 min (green) Fertility.

2. Green, grey and red genes

• G Green: good. Always the one you want.
• G Grey: ok. Normal.
• R Red: bad. Breed it out.

A "god cow" (Facepunch's own name for it is a "god clone") is good on all four genes. Wild cows roll every hidden gene copy at random: about 20% good, 50% ok and 30% bad. That makes a wild god cow practically impossible to find, so you breed one.

3. How calves inherit genes in Rust

This is the part most players get wrong. Every gene has two copies, and the cow shows the better one. The other copy is hidden, but it can still be passed on. When two cows breed:

1. The calf gets one random copy of each gene from its mother and one from its father.
2. The calf shows whichever of its two copies is better.
3. Genes don't mutate: a calf can only get copies its parents had.

A parent with two good copies always passes a good one. A parent with one good copy passes it half the time. Because you can only see the better copy, a green cow might be hiding a red one.

Here are the odds for a single gene when both parents' hidden copies follow wild odds (good for freshly caught or bought cows):

If you've been keeping only your best calves for a few generations, your cows are likely hiding better copies, so their real odds are probably better than this. Once a cow has two good copies of every gene, it breeds true: every calf it has gets at least one good copy of each gene from it.

4. Rust cow inbreeding and herd numbers

Community testers report that every cow carries two hidden family markers, one from each parent, and a cow is inbred when both of its markers match. That happens when its parents are related. Players keep track of family with the cow's herd number: cows with the same herd number are family, and breeding them together gives inbred calves.

• What inbreeding does: an inbred cow's genes work worse than they look, and it sells for less (the Ranch vendor now comments on inbred cows). Most sources say a good copy only works like ok, and an ok copy works about halfway between ok and bad. One source instead says every gene is cut to 70%. Either way, it's bad.
• Inbred cows can still pass on good copies to their calves, so a great inbred cow isn't useless for breeding. Its own stats just suffer.
• Wild and bought cows are inbred about 1 in 16 times. The game shows when a cow is inbred.
• Nobody has published exact inbreeding odds for siblings, cousins and so on, so the safe rule is simple:

5. How to breed cows in Rust: getting a 4-green god cow

1. Get cows from several different herds. Catch wild ones or buy calves at the Ranch (300 scrap each). A cow becomes yours as soon as you buy it or it eats from your trough, and only cows you own can breed. More herds means more safe pairs. Log each cow's genes and herd number in the tracker.
2. Breed your best female with your best male from different herds, where every gene is green on at least one of them.
3. Keep the calves happy while they grow. A calf's Potential only grows while its needs are high, and it locks in when the calf grows up. Potential multiplies the sale price, so a calf raised in a cramped, hungry pen is worth much less later.
4. Keep the calves with the most greens. Log each calf as it's born; it grows up in about an hour.
5. Cull the rest. Set a kill rule (for example, fewer than 3 greens) so weak cows go to your kill list, then sell them at the Ranch. Since the November update, animals you bred (with good Potential) are the ones worth selling; wild and bought animals sell for very little.
6. Repeat. Each generation, your best cows hide fewer bad copies, and green calves become more likely. Bring in cows from new herds to keep inbreeding away.
7. Go for green Fertility early: cows rest about 41 minutes instead of 66 and can have twins, which speeds up every step after.

6. How to own, feed and breed cows in Rust

Owning a cow

• Since the November update you own a cow as soon as you buy it or it eats at your trough. You don't have to stay near it to bond any more, and it doesn't forget you (except while someone else is leading it).
• Bonding (staying near a cow for about 15 minutes) is now only needed to lead it on a rope. Leading breaks from further away than before, and the cow matches your speed.
• Calves bought from the Ranch's livestock vendor (300 scrap) are yours straight away.
• Wild cows have no name. Once you own one it gets a name, and you can now rename cows, sheep and horses. You can also pet them.
• A Crocodile Pie keeps animals at a distance; bulls and rams won't run, but they won't charge you either.

Needs, food and space

• Cows need food, water and space. Their condition follows whichever need is lowest.
• Food: a trough, plus any grass in the pen. Cows can now eat any food a horse can. With enough grass in the pen they use the trough about half as often, and "grazed bare" overgrazing is gone. The trough now shows how long its food will last for your group.
• Water: fresh, shallow water or a water container.
• Space: the game now just measures your pen's floor area. Wikis put it at about 8 m² per animal (calves included) for full space and breeding. At about 4.5 m² per animal or less the pen is dangerously overcrowded, and crowding is now the main way a cared-for cow dies.
• No more old age: cows no longer die of old age, and a starving cow now lies down at 1 HP until it's fed again, instead of dying.

Breeding

• You need an adult female and adult male that you own, near each other, in good condition. Cows without an owner don't breed. Breeding pauses when condition falls to about 60% and starts again at about 70%.
• Herd limits: owned cows out in the open stop breeding once the group passes about 5–6 animals (the patch notes say "past 6", wikis say 5). In a pen they stop when there isn't enough floor space for everyone.
• Pregnancy lasts 10 minutes. The mother then rests for her Fertility time before she can breed again. The cow's panel now shows pregnancy, the father and the cooldowns.
• A calf is male or female 50/50 and grows up in about 1 hour (54–66 min). It only grows while owned, and a hungry calf will now leave its mother to reach the trough.

Potential (new)

• Potential measures how happy an animal was while it was young, from 0 to 100%. It locks in when the animal grows up, and the sale price is multiplied by it.
• It fills from 0 to 100% in about 10 minutes while the young animal is happy (its lowest need at about 80% or more) and drains back in about 15 minutes while it isn't. A calf that grows up in an hour has plenty of time to max it out if you keep its pen fed, watered and roomy.
• Only animals born in captivity earn Potential. Wild and bought animals have it capped (server owners can change the cap), which is why they sell for so little now.

7. Rust cow milk, dung and selling

• Milking: only adult females you own, no tool needed. How much and how often depends on Yield, and a cow holds up to 3 milk.
• Milk: drink it, or keep it in a fridge for 4 hours and skim it into Skimmed Milk and Cream. Milk makes teas last longer; cream makes them stronger.
• Dung: livestock are a better dung source than horses. Use it as fertilizer for your crops.
• Selling: lead a grown cow to the Stable/Ranch livestock vendor. The vendor now explains what it's looking for and comments on hidden bad genes, inbred cows and good recessive genes, because hidden copies count towards the price too. Pregnant cows can't be sold, and an animal with 0 Potential can't be sold at all.
• Price, as wikis work it out: the average of the gene multipliers × species (cow 1, sheep 0.6) × condition (full from 80%) × Potential. A total of 1.5 or more is a perfect animal worth 700 scrap. A bred all-ok cow at 100% Potential is about 466, an all-bad one about 293. Wild or bought animals get a much bigger penalty than before (Facepunch raised it from 0.2 to 0.85), so breed them and sell their young instead.
• Harvesting a cow gives raw beef, bone fragments, leather, animal fat and cloth. Calves give nothing.

8. Telling a cow's genes from its coat

Players have noticed the coat gives hints about genes. These are community observations, not official:

• Yield: more patch coverage means more milk.
• Dung: rusty, reddish-brown patches are good; near-black patches are bad.
• Fertility: ragged patch edges are good; smooth edges are bad.
• Hardiness: a longer, shaggier coat means a hardier cow.

9. Rust sheep: wool, lambs and genes

Sheep came in the same Livestock update and work almost exactly like cows: the same four genes with the same effects, and the same inheritance and inbreeding rules (two copies per gene, one random copy from each parent, herd numbers). The big difference is that Yield means wool instead of milk.

• Shearing: use the new Shears (default blueprint, Level 1 workbench). They give more wool and can't hurt the sheep. A knife or hatchet still works, one of four fleece sections per hit, but hitting a bare section hurts the sheep.
• Wool Armour Insert: new this month; a small boost to melee and projectile protection and a big boost to cold resistance.
• Lambs give no wool, grow up in about an hour, and cost 150 scrap at the Ranch (half the price of a calf). Pregnancy is 10 minutes, the same as cows.
• Fertility (including the 60% twin chance), Hardiness and Potential work the same as for cows, and sheep don't die of old age either.
• Selling: a sheep is worth about 60% of the same cow at the Ranch vendor: about 280 scrap for a bred all-ok sheep at full Potential and up to about 476 for an all-green one. Wool can be sold to the vendor too, and it now tells you how much wool you need.
• Telling them apart: rams have horns, ewes don't. Lambs are hard to tell apart by looks.
• Fleece clues: for Dung, white fleece is good, brown is ok and black is bad. For Yield, thick, long fleece is good and thin, patchy fleece is bad. No reliable clues are known for the other genes.
• Wool can be recycled into cloth (sources disagree on how much).

10. What changed in the November 2026 update

The November 5, 2026 "Printed and Polished" update reworked livestock to be "more intuitive and less punishing." Here's what matters for breeders:

• No more old age. Cows and sheep don't die of old age, so the Longevity (L) gene is gone; animals now show four genes. Starving animals lie down at 1 HP instead of dying.
• Simpler ownership. Buying an animal or having it eat at your trough makes it yours. Unowned cows can't breed.
• New Potential stat that multiplies sale price; only animals born in captivity earn it.
• Selling: the vendor focuses on grown, player-bred animals. Hidden (recessive) genes now affect the price, and the panel and vendor hint at them.
• Breeding limits: owned cows in the open stop breeding past about 5–6; in pens it depends on floor space.
• Food: cows eat any horse food, grass in the pen halves trough use, overgrazing is gone, and troughs show how long they'll last.
• Quality of life: cows store up to 3 milk, a more detailed stats panel (owner, pregnancy, father, cooldowns), rare spawns are clearly marked, renaming and petting, livestock have collision, and cows moo less.
• Sheep: new Shears and a Wool Armour Insert.

Already live from October: a cap of 300 livestock per species per server, and livestock can't be hurt in safe zones.

11. Rust cow and sheep FAQ

Sources

Official: Facepunch: Printed and Polished (November 2026), Facepunch: Livestock update, changelist, and Facepunch's public commits. Community: RustHelp (cow, calf, bull, vendor), RustHelp (sheep, lamb, wool), RustLite wiki, RustTip calculator, Corrosion Hour, VGTimes, Rustafied hotfix notes, NoLimit hotfix notes, Rustfront devblog notes. Last checked November 6, 2026.