Enhancing growth rate and well-being of pigs raised on pasture through the use of mobile evaporative cooling while improving pasture fertility and reducing environmental degradation

Final Report for FNE13-783

Project Type: Farmer
Funds awarded in 2013: $11,033.00
Projected End Date: 12/31/2014
Region: Northeast
State: Connecticut
Project Leader:
Peter Lowy
Pete and Jens Backyard Birds
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Project Information


The goal of this project was to construct and test a new system for managing pigs on pasture.  Through the use of a farm wagon outfitted with water tanks and misting/watering system our aim was to keep pigs comfortable on open fields, without woodlot access, and rotate them through annual forage crops during the hottest months of the summer.  The goal being to increase forage intake, spread maure loads evenly, all while maintaining pig comfort and optimal growth rates.  This project faced many hurdles during the two seasons of implementation but the overal concept proved successful.  Hard scientific data is elusive for this project due to implementation complications, but the physical cooling wagon mechanism, used in a pasture-based system was effective and easy to use.  The pigs clearly used the wagon cooling system during the hot weather and manure deposition in the fields and physical impact on land was dispersed much more evenly than in past seasons without the use of the cooling wagon.  While we do not have data on improved weight growth rates we do believe the use of the cooling wagon provided comfort to the pigs during warmer months.  The wagon allows a farmer to move pigs from overused and abused woodlots to open fields and provides a humane space for pigs to relax during otherwise intolerable weather.


The use of a mobile cooling wagon for pigs on pasture is a concept that mimics the industrial farming system in a more humane setting.   The shade of the wagon combined with the cooling effects of the misting system provides a comfortable and stress-free environment for the pigs while allowing them easy and direct access to growing forage.  Allowing animals to express their natural instincts to explore their enviornment via rooting is highly desirable on any farm that wishes to humanely grow livestock. The ease of movement of pigs through a land base over the course of a growing season allows impact and manure loads to be more evenly disbursed and will positively affect soil health in the future.

Project Objectives:

The farm wagon and misting system were constructed in 2013 and mostly finished in 2014. Additional wings making the shaded area still needs completion and enhancement of design. The water reservoirs on the wagon, the pumping system, and the emitters all worked as built and were deemed a success.  

Data loggers were placed under the wagon, under the water tank on the wagon surface but shielded from the sun and in the woodlot where the control pigs were grown. 

We experienced some issues with the data loggers in this project.  The most important logger which was placed under the wagon where the effects of the cooling misters could be measured, was dislodged by the pigs and could not be found.  Unfortunately, while we did monitor that the logger was in place several times over the course of the measurement period, when it came time to retrieve the monitor to capture the data, the logger could not be located.  The remaining loggers in the woodlot and on the surface of the wagon, shielded from the sun, were recovered and data was analyzed.


Click linked name(s) to expand/collapse or show everyone's info
  • Michael Darre
  • Jennifer Hashley


Materials and methods:

A group of 20 pigs were rotated through a 4 acre field which was sown to various cover crops through the growing season.  Each paddock was approximately 1/2 + acre in size (200'x100').  The earliest annual crop was winter rye, followed by oats/peas, BMR sudan grass and finally oats/peas and winter rye to finish the season.  All cover crops were sown with a broadcast spreader and lightly tilled in with a rototiller at commonly prescribed rates.  Higher seeding rates can be used to more quickly establish a dense cover.  This method of seeding/incorporation worked well as it limited our field cultivation.  After the pigs consumed most of the forage in a field, the seed was broadcast then lightly tilled into the soil. This rototilling action lightly incorporated the manure, any organic residues and the large cover crop seeds into the top several inches of the soil.  Pigs are not very even grazers to it is important to move the wagon in such a way to encourage more even consumption/trampling/manure deposition.  Germination was excellent and soil structure was maintained by minimum tillage.  Subsequent cover crops could be no-tilled into the soil but this would leave manure on the soil surface.  Conversely, the soil could be mold-board plowed but this would then require additional disc harrowing and field soil levelling and finally seeding and light tillage to incorporate.  We felt this amount of tillage was excessive for our purposes.  A grain drill could also be used but some tillage would also be needed.

The 8'x22' cooling wagon was built with a standard 8 ton farm wagon running gear.  24' stringers (created by marrying 2"x10"' boards together to create one 4"x10"x24' stringer) were bolted to the frame and 4"x4" pressure treated posts were then screwed onto the stringers from above at 16' intervals.  A pressure treated deck of 2"x10" boards was then screwed to the 4"x4"'s to create the platform.  Two 275 gallon caged water tanks were placed on the deck and connected together using common garden hoses and a y connection.  The mist system powered by a 12 volt car battery and 12v on-demand water pump and charged via a 40 watt solar panel worked flawlessly.  A charge controller was used to ensure over charging of battery would not occur.  These devices were placed inside an old insulated cooler for protection from rain.  The pump was controlled by a simple garden hose-type digital water timer with multiple on/off cycles.  When the valve on the timer opens, the pressure drops within the water line and the pump senses this pressure drop, causing the pump to turn on.  Most of these pumps operate within 40-60psi.  The timer was set to turn on 1x per hour from 11am-2pm, for 2 minutes per cycle effectively pumping approximately 8 gallons of water onto the pigs during each cycle, up to 4 x per day.  This cycle could be manually overridden if the weather was cool or rainy.  The mist heads were placed every 2-3 feet with the emitters hanging just lightly under the deck of the wagon.  The misters were simiple Ein-dor heads from DripWorks.  They are inexpensive emitters which plug directly into the black poly water line and varying heads can be used to control the throw pattern/distance of the water as well as flow rates.  The downside was that the pigs were sometimes able to nibble on the tips dislodging the heads.  Replacement heads were kept on hand.  Screens need to be fitted to eliminate pig tampering and a higher overal deck height would also lessen this problem (or growing shorter pigs!)

The wagons were pulled through each paddock length wise over a 2+ week period.  A 1-ton round hog feeder was also located within the paddock providing 16% gmo-free grain ration free-choice.  Two 250 gallon water tanks were located on the wagon providing cool water for drinking and to supply the mist-spraying system.  Each paddock was sorrounded by single strand electric wire powered by a plug-in energizer.   

Trojan cup waterers were used on the rear of wagon to provide on-demand clean water fountains for the pigs. (see photo)  These nose-activated drinkers were supplied with water from the tanks on the wagon and also powered by the same on-demand water pump.  A Y was used in the system to provide water to both the drinkers and the mist system.  The waterers were screwed with timberlok screws into 4"x6" timbers hanging down from the wagon ending approximatel 8" above the ground. This height allowed the pigs easy access to the drinker while also allowing the wagon to be pulled over uneven field terrain without getting caught in soils or organic debris.

We used Thermoworks Data loggers to measure temperature and relative humidity. These simple data loggers can be programmed to record temp/rh at preset intervals.  Data is then uploaded to a computer to view and graph.  These waterproof loggers worked well, though they need to be placed and secured in areas where pigs cannot access them.  We had one logger which was lost during the project due to pig curiosity. 


Research results and discussion:

It is believed the mobile cooling system itself is a success in that the implementation of the hardware associated with the project all worked as designed.  While the improved weight gain could not be quantified the ability to move pigs onto an open field setting in mid-summer and providing a healthy and humane living conditions - this was proved possible.  

As mentioned earlier, we encountered a few instances when pigs from various ages on our farm comingled when electric fences were compromised.  In 2014 we purchased pigs from a previously unknown farm and we later came to realize that these pigs were infected with whipworms.  These pigs were wormed on arrival and kept separate from our other pigs. They were wormed, however, with Ivomec which does not control whipworm.  Lesson learned. The pigs with whipworm infected our entire population and after losing several pigs and having a necropsy performed to determine the cause, we began treating our entire group with Safeguard which effectively controls whipworm.  Unfortunately, this type of worm stays present in soils for many years.  This experience demonstrates the need for closed herds, proper worming, and field rotations.  With the use of the cooling wagon we will actually be able to access more distant fields on our farm which were not used during 2014 and thus the soils are uninfected.  Without the cooling wagon accessing these pigs in summer would be a great challenge.

The cooling wagon will be another tool our farm uses to manage our field rotations and to expand the forage land for our pigs.  Fertility will improve in these distant fields and we anticipate some reduced feed as the pigs consumer greater amounts of self-harvested forage crops.

The data logger data we were able to analyze from the top of the farm wagon (in shade) and in the woodlot indicated a stable humidity and temperature difference.  On the hottest days when temperatures reached 90 outside (on top of the wagon in the shade) the woodlot temps were usually 5 degrees cooler.  On cooler days the temperature differential was smaller but always present.  Relative humidity differences on these same 90 degree days were 5-7% higher in the woodlot and on all occasions the relative humidity was higher in the woodlot.

Research conclusions:

As mentioned we completed the building of the wagon and emitter system and all worked flawlessly.  Design changes that could be made would be the make the deck wider so their is more shade under the wagon.  Increasing the height of the deck would also be desirable so the pigs have a harder time accessing the spray heads.

Participation Summary

Education & Outreach Activities and Participation Summary

Participation Summary:

Education/outreach description:

We hosted outreach to several groups of farmers and university students about the project.  In June, we hosted a livestock tour for CRAFT farmer group of young farmers and apprentices who work on local farms.  Over 35 attended our tour, which included extensive discussion of the cooling wagon.  Over 20 students from Brandeis University's environmental science program attended a farm tour in November and a group of aspiring farmers from the New Entry Sustainable Farming project visited the farm in December to learn about this SARE project.  Two additional classroom presentations were presented on the project (in addition to our overall livestock production systems) at the Tufts University Cummings School of Veterinary Medicine to 20 students in the Masters' of Animals and Public Policy program (MAPP) and at the Tufts Friedman School of Nutrition Science and Policy to 25 graduate students in U.S. Fundamentals of Agriculture Course.  Several farmers around the country have contacted us after reading our interim reports on this project with several interested in building their own cooling wagons.

We have added a page to our website briefly explaining the project and will expand on this page as our experience with the cooling wagon continues.

Project Outcomes

Assessment of Project Approach and Areas of Further Study:

Future Recommendations

We will continue to the use the mobile cooling wagon on our farm.  We plan to expand the deck surface area to provide additional shade/cooling area so more pigs can comfortably rest under the surface and perhaps add additional water tanks.  The emitters need some modification to prevent pigs from accessing the heads.

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.