Environmental impacts of keeping piglets warm

By Lee Johnston, U of MN WCROC Swine Scientist

August 2020

Heat lampsConsumers and food retailers increasingly desire food products with a reduced environmental footprint.  One of many approaches to reduce the environmental footprint of pork production is to reduce the use of fossil fuels.  In many parts of the world, electricity is generated from combustion of fossil fuels which releases greenhouse gases that contribute to global warming.  If pork producers could reduce their consumption of electricity generated from fossil fuels, a reduction in greenhouse gas emissions could be realized.  A first step in reducing electrical use is to quantify what processes and equipment use the most electricity.  In a previous study of six commercial pig farms, we learned that heat lamps used to warm newborn, suckling pigs are one of the largest consumers of electricity on a pig farm.  So in subsequent research, we set out to measure the amount of electricity used by incandescent heat lamps to warm suckling piglets in confinement farrowing systems.  Heat lamps used in pig barns are similar to the warming lamps one might see in a restaurant to keep food warm before it is served.  We also wanted to determine if using heat mats to warm piglets could reduce electricity consumption and greenhouse gas emissions.  Heat mats lay on the floor and are warmed by electric coils embedded in the mat.  Piglets can lay on the mat to stay warm similar to how one would use an electric heating pad on a sore back or injured shoulder.  

To achieve our objectives, we monitored electricity used at two commercial pig farms (Commercial sow farm A, 2,600 sows and Commercial sow farm B, 3,300 sows) over two years and at the West Central Research and Outreach Center’s (WCROC) farrowing rooms.  In both the commercial farms and the WCROC rooms, piglets were warmed by incandescent heat lamps (125 W) mounted above the piglets’ sleeping area.  We also recorded the number of weaned pigs produced in each facility.  Our results in Table 1 demonstrate a fairly consistent use of electricity by heat lamps when expressed on a “per weaned pig” basis.  The use of electricity by heat lamps ranged from 5.06 to 7.27 kWh/weaned pig across large commercial farms and our small University research farm.  The average electricity used by heat lamps was 6.4 kWh/weaned pig.  Clearly, heat lamps used to warm piglets are a large consumer of electricity on pig farms and represent a segment of energy use that might be improved in pig production.   

Table 1

Heat matsOnce we documented that heat lamps are important users of electricity in pig production, we wondered if electric heat mats might be a more energy efficient approach to warming suckling pigs.  In one farrowing room at WCROC, we installed electric-heated mats to provide warmth to suckling piglets, see the gray mounted pads in the sleeping area.  We compared pig performance and electricity use of heat mats to traditional heat lamps.  We found no difference in piglet survival rate or growth rate between heat mats and heat lamps.  However, heat mats used only 2.84 kWh to produce one weaned pig which was about 50 to 60% less electricity compared with heat lamps.  This reduction in electricity use equates to a reduction of about 3.6 lb carbon dioxide equivalents of greenhouse gases per weaned pig produced. 

Our research in collaboration with commercial pig farmers has demonstrated that incandescent heat lamps used to warm suckling pigs are a significant user of electricity in commercial pig production.  Switching to electric heat mats could be a viable approach to reducing the environmental footprint of pig production by reducing use of electricity.  Our current economic analyses need to be finalized to determine if the high initial cost of installing electric heat mats will be offset by the lower electricity consumption and longer service life compared with heat lamps.  Ideally, the environmental benefits will coincide with improved profitability of commercial pig production.

This article is based on research conducted with K. T. Sharpe, M. H. Reese, E. S. Buchanan, J. E. Tallaksen, A. M. Hilbrands, K. A. Janni, B. Hetchler, and Y. Li of the University of Minnesota. 

The authors gratefully acknowledge financial support from the Minnesota Environment and Natural Resources Trust Fund and the Rapid Agricultural Response Fund of the Minnesota Agricultural Experiment Station.