Sow Productivity
Worked Examples
Three sows with identical biology. The only thing that differs is whether anybody was watching, and it is worth more than two extra piglets a litter.
What PSY is, in one paragraph
Pigs weaned per sow per year. Two numbers multiplied: how many litters she gives you in a year, and how many piglets survive to weaning out of each one. That is all. It is the only figure that tells you whether a sow is a business or a pet, and it is almost never the number people quote — they quote litter size, which is half of it and the half you control least.
| Herd | PSY band | Why |
|---|---|---|
| Philippine backyard (one to five sows) | 12–18 | Two litters a year and a hard weaning is the ceiling for most backyard setups, and the usual reason the number is at the bottom of this band is empty days rather than small litters. Nobody publishes a national average for this, so treat the band as what raisers report, not as a statistic. |
| Semi-commercial (roughly 5 to 50 sows) | 18–22 | Where record-keeping starts paying for itself. The jump from backyard is almost never a better sow — it is knowing which sow is empty and for how long. |
| Commercial (50+ sows, controlled housing) | 22–30 | Controlled housing, batch farrowing and a herd big enough that one bad sow does not move the average. Comparing a two-sow backyard against this band is comparing two different businesses. |
These are ranges rather than statistics, and deliberately so. Nobody publishes a Philippine average for backyard PSY — the same gap that makes backyard FCR uncitable, recorded on our gaps page. Quoting a commercial benchmark at a two-sow backyard herd would be comparing two different businesses.
Example 1 of 3
The sow nobody is watching
Ten born alive, 15% lost before weaning, weaned at 35 days — all perfectly ordinary for a backyard herd. She is then served again 45 days after weaning, because nobody wrote down when she was weaned and her first heat went past unnoticed.
| Input | Value |
|---|---|
| Born alive per litter | 10 |
| Pre-weaning mortality | 15% |
| Weaning age | 35 days |
| Weaning to next service | 45 days |
| Weanling price | ₱3,500 |
| Result | Value | Notes |
|---|---|---|
| Farrowing interval | 194 days | 114 pregnant + 35 nursing + 45 empty. |
| Litters per year | 1.88 | 365 ÷ the interval. |
| Weaned per litter | 8.5 | 10 born alive, 15% lost. |
| PSY | 16 | Against the 12–18 backyard band: within. |
| Value of a year | ₱56,000 | In weanlings, per sow. |
Example 2 of 3
The same sow, served on her first heat instead
Identical litter, identical mortality, identical weaning age. The only change is that somebody wrote the weaning date on the pen and watched her, so she went back in pig six days later instead of forty-five.
| Result | Value | Notes |
|---|---|---|
| Farrowing interval | 155 days | 39 days shorter. |
| Litters per year | 2.35 | Was 1.88. |
| Weaned per litter | 8.5 | Unchanged — same litter. |
| PSY | 20 | Was 16. above the band. |
| Value of a year | ₱70,000 | ₱14,000 more, per sow, per year. |
4.0 more weaned pigs a year, worth ₱14,000 — for the same feed, the same sow and the same litter. The entire difference is thirty-nine days of somebody paying attention.
How to use this on your farm
If you keep one record on your whole farm, keep the weaning date. Every empty day after it costs about 0.08 of a weaned pig a year, which is roughly ₱280 a day, per sow. A month of not noticing is ₱8,400.Bisaya / Cebuano
Parehas ra nga baboy. Parehas ra nga anak. Ang kalainan lang, adunay nagsulat sa petsa sa paglutas ug adunay nagbantay.
Matag adlaw nga wala siya mabuntis human sa paglutas kay mga ₱280 ang kantidad. Usa ka bulan nga wala nimo namatikdi kay ₱8,400. Ang kalendaryo mas barato pa kaysa sa pagkaon.
Example 3 of 3
Two more piglets a litter, and still nobody watching
The upgrade everybody reaches for first: a better sow, twelve born alive instead of ten. The forty-five empty days stay, because the litter size did not fix the record-keeping.
| Result | Value | Notes |
|---|---|---|
| Born alive | 12 | Two more than example 1. |
| Weaned per litter | 10.2 | Was 8.5. |
| PSY | 19.2 | Against 20 for the same old sow with the empty days fixed. |
| Value of a year | ₱67,200 | Against ₱70,000 in example 2. |
This is the finding worth the page. Two extra piglets a litter is worth 3.2 PSY. Thirty-nine fewer empty days is worth 4.0. The calendar beats the genetics, and the calendar is free. Buying a better sow is a real upgrade and it is the second one to make, not the first.
Do both and you are at 24 PSY — ₱84,000 a sow a year, against ₱56,000 where this page started. Same barn, same feed.
Where the empty days come from
Almost never one big cause. A missed heat because nobody was looking on the right week. A thin sow that took an extra fortnight to cycle. A boar that was not available the day she stood. A service that did not take and was not noticed for three weeks — which is its own 21-day hole, and the reason the farrowing calendar puts the return-to-heat window on the second row rather than in a footnote.
A thin sow cycling late is a feeding question and worth asking a vet or your municipal agriculture office about. This page counts days; it does not prescribe anything, and a calculator that offered you a hormone protocol would be well outside what a website should be doing.