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Calculate adjusted 21-day weaning weight for piglets using actual weight, birth weight, and age. Standardize litter performance comparisons for swine.
Pigs Weaned per Sow per Year Calculator
Calculate pigs weaned per sow per year from litters per year, born alive, and pre-weaning survival rate. Key swine herd productivity metric.
Expected Born Alive⧉
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Litter size target
Born Dead⧉
0.5
Stillborns at birth
Weaned per Litter⧉
12.1
Live pigs to market
Total Deaths per Litter⧉
2.1
Stillborn + pre-wean mortality
PSY (Pigs/Sow/Year)⧉
28.4
Annual production per sow
Total Pigs Weaned/Year⧉
2,840.00
100 sows
Projected Born Alive (Parity Adj.)⧉
13.6
Adjusted for parity
Revenue Projection⧉
$113,600.00
At 40/head
Breed Averages
| Breed | Born Alive | Stillborn % | Price/Head |
|---|---|---|---|
| Landrace | 14.2 | 3.5% | $40.00 |
| Large Black | 13.5 | 4% | $45.00 |
| Hampshire | 13.8 | 3.8% | $42.00 |
| Duroc | 13.2 | 4.2% | $44.00 |
| Crossbred | 14.5 | 3.2% | $38.00 |
Planning notes, formulas, and examples
About the Pigs Weaned per Sow per Year Calculator
The Pigs Weaned per Sow per Year (PSY) Calculator determines the number of pigs each sow weans annually — the single most important productivity metric in commercial swine production. PSY combines three components: litters per sow per year, pigs born alive per litter, and pre-weaning survival rate.
Top-performing farms globally achieve 30+ PSY, meaning each sow weans more than 30 pigs annually. The U.S. average is approximately 25-27 PSY. Improving any of the three components — more litters, more pigs born alive, or higher survival — directly increases PSY and herd profitability.
Litters per year depends on gestation length (114 days), lactation length, and wean-to-estrus interval. Born alive is driven by genetics, sow nutrition, and boar fertility. Pre-weaning survival depends on management, environment, and sow mothering ability. This calculator helps identify which component offers the most room for improvement in your operation by turning those pieces into one PSY benchmark.
When This Page Helps
PSY is the standard benchmark for comparing swine herd productivity across operations and countries. This page helps show whether the main drag is sow turns, pigs born alive, or pre-weaning survival rather than treating breeding performance as one lumped result.
How to Use the Inputs
- Enter the number of litters per sow per year (typically 2.3-2.5).
- Enter the average pigs born alive per litter.
- Enter the pre-weaning survival rate as a percentage.
- Review the pigs weaned per sow per year.
- Adjust inputs to model improvement scenarios.
Formula used
PSY = Litters/sow/year × Born alive/litter × (Pre-weaning survival% / 100)
Litters/sow/year = 365 / (Gestation + Lactation + Wean-to-service interval + Non-productive days)
Gestation = 114 days (fixed)
Lactation = typically 18-24 days
Wean-to-service = typically 5-7 daysExample Calculation
Result: 30.6 pigs/sow/year
PSY = 2.40 × 14.5 × 0.88 = 30.6. This is excellent performance. With 1,000 sows, total pigs weaned would be 30,600 annually. If pre-weaning survival improved to 90%, PSY would increase to 31.3 — an extra 700 pigs.
Tips & Best Practices
- Focus on the component with the most room for improvement — often pre-weaning survival.
- Non-productive sow days (empty, not pregnant) are the biggest drag on litters per year.
- Heat detection and timely AI improve conception rate, which drives litters per year.
- Cross-fostering within 24 hours of birth improves survival by evening out litter sizes.
- Maintain warm, dry farrowing environments — chilling is the #1 cause of piglet death.
- Track PSY monthly to detect trends and evaluate the impact of management changes.
The Components of PSY
PSY is a multiplicative metric — improvement in any component compounds with the others. A 5% improvement in pre-weaning survival (from 85% to 90%) when combined with 0.1 more litters per year and 0.5 more pigs born alive can increase PSY by 3-4 pigs per sow. This multiplicative effect makes comprehensive improvement strategies more powerful than focusing on a single component.
Benchmarking and Goal Setting
Establish your current PSY and its three components, then set realistic annual improvement targets. Industry data shows that top-performing farms improve PSY by 0.5-1.0 pigs per year through continuous management refinement. Use your genetics supplier’s performance standards as the ceiling for your targets.
Economic Impact
Each additional pig weaned per sow per year, across a 1,000-sow farm, produces an extra 1,000 market pigs annually. At a $20 margin per pig, that’s $20,000 in additional profit. PSY improvement is one of the highest-return investments in swine production.
Sources & Methodology
Last updated:
Frequently Asked Questions
In the U.S., average PSY is 25-27. Top 10% of farms achieve 30+. Global leaders (Denmark, Netherlands) average 31-34 PSY. Your target should be the top quartile for your genetics and production system.
Reduce non-productive days by improving heat detection, conception rate, and farrowing rate. Shorter lactation length (within piglet health constraints) also increases litters per year. Each day saved in the reproductive cycle adds 0.01-0.02 litters per year.
Genetics (sow line prolificacy), sow parity (younger and very old sows have smaller litters), nutrition during gestation, boar fertility, and semen quality all affect born alive numbers. Modern genetics consistently deliver 14-16+ born alive.
The top causes of pre-weaning death are overlay (crushing), chilling, starvation, and scours. Heated creep areas, anti-crush bars, cross-fostering within 24 hours, and split suckling for large litters all reduce mortality.
Yes. Parity 1 sows have smaller litters and may have more non-productive days. Peak born alive occurs around parity 3-5. Maintaining an optimal parity distribution (40-50% of sows in parity 2-5) maximizes herd PSY.
Total born includes stillborns. Only born alive pigs contribute to PSY. High total born with high stillborns (>8%) suggests sow fatigue during farrowing or large litter syndrome. Assisted farrowing and proper sow condition reduce stillbirths.
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