How do you calculate the cost of a sow nonproductive day?
There are several methods of estimating the cost of a nonproductive sow day. One method is to calculate the cost of maintaining a nonlactating sow. A new crated-sow gestation building costs about $600 per crate. If that is depreciated over 10 years there is cost of $60 per space per year or $0.16 per day. Taxes and insurance would round that up to $0.17 per day.
Feed is the major cost. A nonlactating sow will get 5 lb per day at $.07 per lb or $0.35 feed per sow per day. Nonfeed gestation variable costs will be about 1/3 of feed costs or $0.12 per day. If we total the depreciation, taxes, and insurance ($0.17) plus feed ($0.35) plus nonfeed variable ($0.12) the cost of maintaining a nonlactating sow is $0.64 per day, whether she is pregnant or open. Obviously if she is open there will be no pig produced income. However, she is gaining half a pound per day which is probably worth about $0.16 when and if she is sent to market.
Another method is to estimate the opportunity cost of not having a pig farrowed, proposed by Dr. Morgan Morrow. He assumed a sow produces 20 pigs per sow per year or 0.0548 pigs per day. If the marginal profit on a 250-lb market hog is $30, then the opportunity cost of a nonproductive sow day is $1.64 (.0548 pigs per day x $30 per pig).
Another method would be to look at the profit on a weaned-pig basis, as a quoted market is developing for them and the sow probably should not receive credit for profits or losses after the pig is weaned. Cost of producing weaners is around $27-$33 head. If you can sell the weaner for $35, that is about an $8 ($35-$27) profit. Following on Dr. Morrow's 0.0548 pigs produced per day x $8 profit per weaner, the opportunity cost is $0.44 per day, which is probably less than what it costs to maintain a nonlactating sow.
As you can see, there is not any one best method to calculate the cost of nonproductive sow days.
--Submitted by Dr. Palmer J. Holden
Iowa State University
This practice tip was based on a posting to SWINE-L