Feed vs Fuel

By now users of propane in the upper Midwest have experienced sticker shock. So far I haven’t heard of any production site that failed to receive propane when needed but I have heard of very high prices, prepay deliveries only, partial fills only, etc.

At the same time I’ve heard of innovative methods to keep this production expense under control. At least one producer chose to heat his empty facility between turns with a kerosene fired space heater versus the barn’s LBWhite heaters. With no animals in the barn the variations in temperature associated with the kerosene heater location weren’t a concern and kerosene was determined to be cheaper than propane for this period.

A second propane saving method many have investigated is lowering the set point of their ventilation controllers. While this clearly saves on propane, the savings come with a potential risk. If the set point was too high relative to the size of pigs in a facility, lowering of the set point is the correct management decision. A return to higher set points once propane drops in price is not recommended as it only increases production expense and risks putting pigs in minor heat stress situations when outside temperatures begin to warm.

If the set point in the controller was already resulting in temperatures in the facility at the low end of the pigs thermal neutral zone, then a further reduction in temperature risks putting the pigs in a moderate cold stress. This then becomes the age old question of ‘ feed vs fuel’. Is it cheaper to heat the facility with $5/gal propane to maintain thermal neutral conditions in the pig zone or is it cheaper to allow the pig to use a little more feed for heat production with a slight worsening of feed conversion?

I worked with 2 swine nutritionists last week on modeling the impact of lowered controller set points in gestation facilities. The expectation was that 68F was the lower critical temperature for gestating females housed in individual maternity pens. Long term exposure to temperatures lower than this resulted in an increase in feed allowance to maintain body condition, etc. Relying on published data using corn-soybean meal diets the nutritionists estimated that for every 1F decrease in temperature below set point the daily feed intake per female required to maintain body condition increased 0.12 lb/d.

I modeled the estimated propane usage for a gestation facility and we then compared the increase in feed need ($200/t delivered cost for gestation diet) versus the estimated propane savings. Even with $5 per gal propane, heating the gestation facility to 68F was still a cheaper production alternative than increasing the amount of feed fed per female per day. Of course this modeling assumed that the minimum ventilation was set correctly, etc.

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