Nutrition Economics for Commercial Pig Production

Most ration discussions begin and end with nutrient specification: protein, energy, lysine, calcium, phosphorus, additives.

Far fewer end with the only question the owner ever actually asked: did this ration make more money than the last one?

Nutrition that ignores economics is biology. Nutrition that ignores biology is accounting. Commercial pig production needs both, integrated, in the same conversation.

Feed is 65–75% of variable cost in commercial pig production. A 3% nutrition-driven improvement in cost per kg of gain typically outperforms a 10% improvement in pig price, because feed is the larger and more controllable variable.

Yet nutrition is still routinely managed as a biology problem — meet the nutrient spec, tick the box — rather than as an economics problem. The gap shows up directly in the margin, every quarter.

Modern least-cost formulation software optimises for the cheapest ration that meets the spec. It does not optimise for the cheapest cost per kg of gain at acceptable carcass value. That higher-order optimisation belongs to the nutritionist and the owner, working together.

Nutrition economics evaluates rations on three combined metrics: cost per kg of gain (the input efficiency), days to market (the throughput effect), and carcass value at sale (the output quality).

A ration that lowers cost per kg of gain but worsens carcass grading is not a winning ration — and you only see that if you measure all three together.

Useful framework: Net margin per pig = (carcass value) − (cost per kg of gain × weight gained) − (fixed cost per finishing day × days on feed). Every ration change should be evaluated against this full equation.

Run every meaningful change as a measured trial: two barns, same week, same genetics, same protocols, ration as the only variable. Anecdotal trials produce anecdotal results.

A grower ration was reformulated to swap 4% of soya for a cheaper local protein source. Cost per tonne dropped 6% — a clear win on paper.

Measured in barn: ADG fell 30 g/day, finishing took 7 extra days, and carcass lean percentage dropped 1.2 points (moving a meaningful share of pigs from a higher grade to a lower grade).

Net economics per pig sold: feed cost saving $0.80, additional days-on-feed cost $1.20, carcass grading loss $1.00. Net effect: $1.40 worse per pig sold, on a change that looked like a 6% saving.

On a 20,000-pig annual throughput operation, the 'saving' destroyed $28,000 of margin. Without measuring the full chain, the change would have looked successful in the feed-cost line and stayed in the ration permanently.

• Brief the nutritionist on cost per kg of gain and carcass value targets, not just nutrient specs. Change the brief and you change the formulation.
• Run every ration change as a measured trial — two barns, same week, same genetics, ration as the only variable, agreed evaluation criteria up front.
• Track carcass grading data, not just live weight, in the economic comparison. Many 'wins' on live weight are losses on carcass value.
• Re-evaluate rations whenever a major ingredient price shifts more than 10%, or seasonally for grains.
• Build cost per kg of gain into the nutritionist's monthly review. Make it the headline KPI of the nutrition relationship.
• Document and version every ration change with the trial result. Institutional memory is the cheapest insurance against repeating expensive mistakes.

Nutrition is the largest controllable cost in pig production. Manage it as economics, not just as biology — and demand that every change is justified in margin per pig sold, not just in dollars per tonne of ration.