Genetics Guide

Every animal in Realistic Livestock RM is born with a unique set of genetic traits that affect its production, value, health, and appetite. Understanding genetics is key to building a profitable herd through selective breeding.

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

The Five Traits

Productivity is species-specific: it shows as "Milk production" for cows and goats, "Wool production" for sheep, "Egg production" for chickens, and "Fleece production" for alpacas. Pigs and horses don't have this trait - they have no special production output.

Metabolism is double-edged: high metabolism means faster weight gain but also higher food costs. Low metabolism means cheaper to feed but slower growth.

Rating Scale

Each trait is displayed in-game with a rating and colour:

How common each rating is depends on where the animal came from - see Distribution. The overall genetics rating uses Good/Bad labels instead of High/Low, calculated from the average of all traits.

Special Case: Fertility

Fertility has one additional rating:

Infertile animals still produce wool, fleece and eggs, but milk only starts after a birth, so an infertile cow or goat never gives milk. Castrating a male does not change his other genetics or his overall rating.

What Each Trait Does

Health

• Affects how quickly health recovers or deteriorates
• Higher health genetics = more likely to survive a disease (they do not make an animal less likely to catch one)
• Animals in poor health face a daily death risk - good health genetics lower it and help keep health up
• Impact: Survival and longevity

Fertility

• Directly affects the chance of successful breeding
• Higher fertility = more likely to produce offspring each breeding cycle
• Extremely rare chance of being born completely infertile, and a freemartin heifer is almost always infertile
• Impact: Breeding success rate

Productivity - Cows, Sheep, Goats, Chickens, Alpacas

• Directly scales production output (milk, wool, eggs, goat milk, fleece)
• An animal with Extremely High productivity produces many times more than one with Extremely Low
• The large production ranges shown in each factsheet are primarily driven by this trait
• Impact: The single biggest factor in milk, wool, fleece and egg output

Pigs and horses don't have productivity - they have no special production output.

Quality

• Directly affects sell price
• Higher quality = better meat value = higher sell price
• Impact: All animals sell for more or less based on this trait

Metabolism

• Affects both food consumption and weight gain
• Double-edged trait:
• High metabolism: Eats significantly more, grows faster, reaches target weight sooner
• Low metabolism: Eats much less, grows slower, cheaper to maintain long-term
• It also moves each animal's own target weight: noticeably higher with high metabolism, noticeably lower with low metabolism
• The large food consumption ranges shown in each factsheet are primarily driven by this trait
• Impact: Determines how expensive an animal is to feed

Distribution

How likely each rating is depends on where the animal came from. Dealer stock is what the dealer offers you. Animals the mod rolls itself are ones that reach a pen another way, such as animals placed by the base game or another mod. Bred animals take their genetics from their parents - see Breeding & Inheritance.

Animals the mod rolls itself get a separate roll for each trait, and bred animals inherit each trait separately, so both can have excellent health but terrible productivity.

Dealer Animals

Each animal the dealer offers gets one overall quality roll, and all its traits sit close to that. So a dealer animal tends to be good all round or poor all round, not strong in one trait and weak in another. At the default Standard setting of Dealer Animal Quality this gives a wide spread, with Average about 1 in 5 and the extreme ratings about 1 in 50. Budget stock is mostly Low and Very Low, Premium stock is mostly High and Very High, and a few animals in each fall outside that band. Check genetics before buying when possible.

Breeding & Inheritance

Offspring inherit traits from both parents. The mod calculates the average of both parents' trait values, then adds random variation. This means:

• Breeding two high-productivity cows tends to produce higher-productivity calves
• But individual offspring can end up better or worse than either parent
• Breeding two animals with poor genetics risks passing those traits on
• Over multiple generations, focused selection can significantly improve your herd's average genetics

Important: High-genetics parents don't guarantee high-genetics offspring. Each young centres on the average of its two parents, then varies up or down, so a herd left alone keeps about the same average and just spreads wider. At the very top the genetic ceiling trims the luckiest rolls, so the very best parents usually have young a little below them. See the FAQ for a full explanation.

Breeding Strategy

1. Identify your goals: Milk production? Sell value? Low feed cost?
2. Check genetics on all animals before breeding
3. Keep the best: Animals with High or Very High in your target trait
4. Sell or castrate the rest: Remove animals with Low or worse genetics from your breeding stock - don't let them reproduce
5. Be patient: Genetic improvement takes multiple generations and active culling each generation

The CVM Dilemma

CVM (Complex Vertebral Malformation) is a genetic disease unique to cattle. It is never caught and never spreads - it follows recessive inheritance, settled at conception:

At conception an affected parent passes the gene to every calf: with a non-carrier every calf is a carrier, and with a carrier half the calves are affected. Artificial insemination, or a conception with no live bull, counts the cow's genes only.

• Carriers (one copy) are healthy for life and never sick from CVM.
• Affected animals (two copies) are sick from birth and cannot be treated; with Animal Death on they die within a few months.

The Trade-Off

CVM carrier cows produce considerably more milk than non-carriers while the Diseases setting is on. This makes them valuable for dairy operations - but breeding two carriers together risks producing affected calves.

Identifying carriers: a carrier shows the grey DNA icon on its card, and CVM is listed in its detail panel. Carriers remain healthy and productive; affected animals show the red medical bag and, with Animal Death on, are the ones that die.

Dealer animals: about 1 in 200 dealer cattle carry the gene - most as carriers, a few affected. Check new purchases!

Inheritance and dealer stock carrying the gene need the Diseases setting on and CVM ticked under Choose Diseases - see the Disease Guide.

Overall Genetics Rating

The game displays an "Overall" genetics rating that combines all traits:

The overall rating is calculated from the average of all applicable traits. Use it as a quick quality indicator, but check individual traits for specific breeding decisions.