Livestock turn only 5-25% of the food energy in their feed into meat, milk or eggs, so every calorie of grain fed to an animal costs several calories of human food. Feed animals what people cannot eat, such as pasture, scraps and crop residues, and limit animal feed grain to 10-15% of cropland.
Part of Caloric Budget for a Community
Livestock feed conversion is the ratio between the feed an animal eats and the meat, milk or eggs it produces, which fixes how much land an animal food costs.
Every Animal Calorie Is Paid For With More Plant Calories
Animals burn most of their feed to stay warm, move and grow bones and hair, and only the rest becomes food. The caloric guide tabulates this for seven kinds of livestock:
| Animal | Feed:product ratio | Stated efficiency |
|---|---|---|
| Chickens (eggs) | 2.5:1 | 20-25% |
| Chickens (meat) | 3:1 | 15-20% |
| Goats (dairy) | 4:1 | 15-20% |
| Pigs | 5:1 | 10-15% |
| Cattle (dairy) | 6:1 | 12-18% |
| Cattle (beef) | 8:1 | 5-10% |
| Rabbits | 3.5:1 | 15-20% |
The detail of what these numbers mean, and where they can and cannot be reproduced, is in Feed-to-Meat Ratios by Animal.
What The Land Is No Longer Doing
An acre of grain fed to animals is an acre not feeding people directly. The guide’s rule is to dedicate at most 10-15% of cropland to animal feed grain and to feed the rest of the herd on land unsuitable for crops: steep hillsides, woodlots and marshes. Animals that eat what people cannot are the case for keeping livestock at all: goats and cattle on pasture, woodlot browse and crop residues; pigs on kitchen scraps, whey, fallen fruit and forest mast; chickens on insects, weeds and grain screenings; rabbits on grass, weeds and garden trimmings.
What To Keep, For 100 People
The guide’s reasonable livestock count: 40-60 laying hens (15-20 eggs a day), 2-4 dairy goats or 1-2 dairy cows, 4-8 breeding pigs, 20-30 rabbits in a breeding colony, and meat chickens in seasonal batches. The corpus has husbandry guides for each: Poultry Keeping, Goat Raising, Cattle Management, Pig Husbandry.
Method: Decide What To Keep
Step 1: List the land that cannot grow crops (steep, wet, wooded) and the by-products you will have (scraps, whey, residues, screenings). Step 2: Choose the animals that eat those, before any that need grain. Step 3: Compute the grain acres the rest would need and check they stay within 10-15% of cropland. Step 4: Compare each animal’s food with what the same feed would give a person directly (Pasture vs Grain-Fed Calculations).
Common Mistakes
- Feeding grain because it is convenient. Check the cost in people-food first.
- Keeping the wrong animals for the land. Cattle on good cropland waste the soil’s best use.
- Reading the efficiency as the whole value. Animals also give manure, draft power, hides and dairy fat and protein that are hard to get elsewhere.
What’s Next
- Learn next: Feed-to-Meat Ratios by Animal — checking the table’s numbers
- Combine with: Land Allocation Planning — where the pasture and feed grain fit