Introduction: The long hot humid days of summer can result in heat stress issues in pig operations. A study released by Ohio State several years ago concluded that heat stress costs the US pork industry over $300 million a year. Although pigs are generally raised in facilities with a controlled environment, it is not always possible to avoid high temperatures within the barns. Temperatures above 23oC can have negative impacts on animal performance. For both animal welfare and business reasons, measures should be taken to help reduce the impact of hot weather on pigs.
When and How Does Heat Stress Occur?: Heat stress occurs when the environmental temperature rises above the point where the animal is producing more heat from digestion and/or receiving more heat from its surroundings than it is releasing to the surrounding environment. Figure 1 shows a Heat Stress Index for grow-finish pigs determined by temperature and relative humidity that can be used to assess the risk to animals under various conditions.
Figure 1: Heat Stress Index for Grow-Finish Swine
Heat
stress is a concern with pigs because they do not have functional sweat glands
to help them reduce body heat. They gain
and lose heat to their surrounding environment in four ways (conduction, thermal
radiation, convection and evaporation) in order to maintain their ideal core
body temperature.
Under
heat stress conditions, the goal is to minimize heat transfer to the animal
from the surroundings and maximize heat transfer from the animal to its
environment. Even though the animal has
the potential to be in a heat stress condition due to the ambient temperature,
effectively the animal “feels” comfortable because its core temperature is near
normal.
Signs of Heat Stress:
Evident discomfort/distress, pigs lying apart, body stretched out.
Manure patterns change, pen floors become wet/unclean
Increased water consumption (up to 6x normal).
Noticeable decrease in pen activity, slowness and lethargy.
Muscle trembling.
Rapid fall in feed consumption/reduced weight gains, pigs seem to stall out.
Very high respiration rate (panting).
Coping With Heat Stress: Pigs will try to increase heat dissipation and decrease body heat production. To support this:
Make sure pigs have unrestricted access to a good supply of clean water.
Install a timed water sprinkler or mister system triggered by room temperature for group housed pigs (sows, grow-finish). Sprinklers should activate for 1-2 minutes every 20-30 minutes to allow moisture to evaporate off the pigs’ skin before starting the process again. Larger water droplets also work better than a fine mist.
Install a drip cooling system and/or sow cooling pads for individually housed sows.
Ensure proper ventilation rates for the size of room, weight of pigs, time of year (Table 1).
Do not overcrowd the pigs. Provide enough pen space for size of pigs so that all the pigs can lie down without touching each other and still access feeders, waterers and the dunging area without stepping on pen mates.
Work with your nutritionist to reformulate more nutrient dense diets during hot weather.
When pigs are fed at given time points, alter the time of day in which the bulk of feed is offered. By providing the majority of feed during cooler hours, it will help to reduce decreases in feed intake.
Type of Animal
Ventilation Rate CFM/Animal
Ventilation Rate CFM/Animal
Cold Weather
Warm Weather a
Breeding/Gestating Sow
10
200
Farrowing Sow with Litter
15
400
Nursery Pigs 4-25kg
1.0-3.0 b
15-35 c
Grower Pigs 25-60kg
4.0-6.0
50-70
Finishing pigs 60-120kg
6.0-8.0
70-90
Table 1: OMAFRA Recommended
Ventilation Rates
a Summer ventilation rate for large pigs may need to be increased to 1 air change per minute during hot summer weather b For reasonably good air quality, this minimum winter ventilation rate may need to be increased to ensure at least 3-4 room air changes per hour c Limit the maximum summer air changes to 1 per minute for sensitive livestock
Source:Ventilation for Livestock and Poultry Facilities, Pub 833, OMAFRA.
Be Prepared: The weather cannot be controlled. Plan ahead and have strategies in place to deal with hot weather when it happens.
Death loss due to heat stress is most often attributed to power
outages in hog barns when there is no alternate power source or power loss
back-up plan. Test your alternate power
generation and power outage alarms monthly for fan operated barns (static
pressure barns). Check panic doors/drop
curtain releases for naturally ventilated barns. Heat build-up in non-ventilated barns can
cause fatalities in all seasons.
Transportation: Transport during any season can cause heat stress in pigs and may result in death loss. When possible try to:
Load animals in groups less than five.
Adjust transport to early morning or at night during the summer.
Load fewer pigs per load on hot, humid days.
Provide wet shavings when temperature is over 15oC; do not use straw.
When temperature is over 27oC, sprinkle pigs with water prior to loading.
Do not pour large amounts of cold water onto an overheated pig.
Load and unload promptly to avoid heat build-up.
OMAFRA’s Heat Stress in Livestock and Poultry App: Enter temperature and relative humidity on your Blackberry or Android smartphone to estimate heat stress risks quickly and easily with the Heat Stress in Livestock and Poultry App. It also suggests steps to take to reduce heat stress to maintain feed intake and productivity.
Download the FREE Heat Stress in Livestock and Poultry App now. Visit Blackberry World or Google Play. Features English, French and Spanish.
In December, 2018 OMAFRA, Ontario Pork, Ontario Pork Industry Council, and The Prairie Swine Centre, with support from industry, held a London Swine Conference special seminar in Stratford, ON. Its objective was to help pork producers address challenges of sow management, in particular challenges related to group housing.
If so, the Prairie Swine Centre would like to recruit you to participate in a research project! The overall goal of the study is to determine whether the pattern of antibiotic use on farms is correlated with the prevalence of specific pig pathogens and antimicrobial resistance. The project will use both RWA and non-RWA farms, and is currently recruiting RWA farms located in Canada for the project.
The research trial will be conducted over a 2 year period, and the research team will need access to all pig treatment records, as well as fecal and manure sampling every 6 months (training will be provided). Reimbursement will be offered to each barn enrolled in the study for any incremental project-related costs.
If you are interested and would like to learn more, please contact: Dr. Bernardo Predicala Research Scientist – Engineering Prairie Swine Centre bernardo.predicala@usask.ca 306-667-7444
Both the Code of Practice for the Care and Handling of Pigs, and the new Canadian Pork Excellence program require that pigs of all production stages be provided with enrichment. In 2018 we included two different articles on enrichment for pigs in Pork News & Views; the first in August 2018 called “Environmental Enrichment to Improve Pig Health and Performance” and the second in December 2018 called “Enrichment for Nursery Pigs”. I highly recommend reading these previous articles if you have not yet done so!
As producers and industry representatives have become more aware of enrichment requirements, and more commercial products have become available as ‘pig toys’, we began receiving questions such as “what is the best enrichment option for my pigs?”, “can I use commercial pig toys with group housed sows?” and “how long do commercial pig toys last?”.
Every barn is different, and what works for one may not be the best option for another. Producers need to evaluate all possible options and determine what they would prefer to use. For example, natural items such as wood blocks can make great enrichment items for sows, but they can also cause some splintering and could potentially end up in the manure pit or caught in the sows’ mouth. Many producers use wood successfully, whereas others have had issues. Other natural options include rope or burlap, which pigs of all ages love! However, as pigs can be quite destructive, they do not last very long (although they are much cheaper than commercial toys). Since natural items tend to not last very long, many producers are considering the use of commercial toys. They cost more but may last longer.
We couldn’t find a lot of information on commercial toys for group housed sows, so we decided to test a few different ones out on farm. With the help of a South Western Ontario producer, and donated toys from several different companies, we installed commercial toys into a sow barn with electronic sow feeding and monitored how long the toys lasted, general interest levels in the toys, and if there were any challenges encountered with the different toys. Table 1 shows the different toys that were installed in the barn.
Table 1: different commercial toys that were installed in the group housed sow barn
Toy Name
Toy Description
Donated By
Retail Price *
Bite- Rite Blue
Hanging plastic cone with replaceable rubber chew sticks. Blue size designed for finisher pigs.
Glass-pac
Toy- $44 Sticks- $6.21
Porky Play
Hanging plastic toy with antimicrobial protection.Available in different sizes.
Ketchum Manufacturing
$21.95
Tri-Star
Hanging plastic disc with replaceable chew sticks.
Farmers Farmacy
Toy- $21.95 Sticks- $1.75
MS Schippers Yellow Ball
30cm polyethylene plastic ball which can be hung or filled with and used on the ground.
Farmers Farmacy
$19.99
MS Schippers AntiBite Ball
Small polyurethane rubber ball that can be hung or mounted.
Farmers Farmacy
$11.50
Easyfix Astro
Natural rubber suspended toy designed for finishing pigs and sows.
Easyfix
$31
Easyfix Luna 142
Natural rubber spiked ball designed to go on the floor of the pen. Green size for finishing pigs and sows.
Easyfix
$51
Future Cow Calf Ball
Extra strength vinyl suspended ball designed for group housed sows.
Easyfix
$120
*Prices may vary from those listed in tabs
The barn had
2 large group pens. 150 gilts in one pen, and 240 sows in another. In addition
to that, we also used a few smaller pens containing 10 gilts or sows located
beside the large group pens. The farm has Topigs sows and DNA semen and a Nedap
ESF system. Three toys were suspended in
the large sow pen, and 2 toys were suspended in the smaller gilt pen, all in
open areas of the pens away from feeders and drinkers. Single toys were
suspended in the small pens, with 2 toys suspended in the gilt training pen
(one on each side of the ESF training system).
Toys were suspended from ceiling trusses using ¼ inch zinc chain, 4” eye screws (5/15”) and ¼” quick links. Toys were attached to 2’ of chain using a quick link. This was then attached to 5’ of chain hanging from the ceiling. By using a quick link 2’ above toy height, the toys could easily be adjusted up or down, and removed if needed, without having to reach the ceiling. Shortly after the trial began, quick links at toy level and mid-chain were replace with carabiner style clips, as sows were able to loosen the quick links easily. Approximate cost for the hanging set up (chain, eye hook and links) was $28 per toy, which is reusable long-term. Barn staff were asked to observe interactions with the toys daily and keep records of how long the toys lasted. They were also asked to record any challenges they came across with the toys.
Results:
Bite-Rite Blue: This toy was installed in the large sow pen, as well as in one side of the gilt training pen. The sows liked this toy and groups were observed interacting with it multiple times daily. When it was first installed, the chew sticks lasted about 3 weeks, at which point they were replaced. When replaced, they lasted only 2 days, as the sows had figured out they could easily destroy them. The cone itself held up well throughout this time, but barn staff were worried if there were no chew sticks left, the cone wouldn’t hold up for long.
Figure 1a: New Bite-Rite toyFigure 1b: Bite-Rite toy, two weeks after being added to the group sow pen
Porky Play: This toy was originally installed in a small pens with approximately 10 sows, as well as in the gilt training pen. Barn staff noted that the pigs were not interacting with this toy very often but was likely due to lack of space in the pens for pigs to play properly. The toy was then moved to the large sow pen where it held up well; however, barn staff reported it was used less frequently than some of the other toys available to them. The sows liked to play with the chain hanging below (attached to) the toy.
Figure 2a: New Porky PlayFigure 2b: Porky Play toy after 4 weeks of use in a large group pen
Tri-Star: This toy was installed in the large gilt pen. Within the first hour of putting the toy in the pen the gilts were able to remove all of the chew sticks from the central disc. The barn staff decided to leave the chew sticks off of the toy as they didn’t want them ending up in the manure pit. The gilts regularly interacted with the disc portion of the toy and the chains hanging from it. Sows can chew and bite the toy, and at the time of writing this article it has held up for 3.5 months and is still in good condition.
Figure 3a: New Tri-Star with chew sticksFigure 3b: Tri-Star toy (without chew sticks) 14 days after being added to the large gilt pen
Yellow Ball: This toy was hung in the large sow pen. The toy comes with a plug at the top, but we drilled a small hole in the bottom and then used airplane cable to create a hanging system through both of the holes, which was attached to the chain above. For the first week or so the sows were very interested in the ball, as they could toss it up in the air and play with it as a group. Over time interest levels decreased, likely because they could not chew or bite it. However, there were always some pigs that still played with it. At the time this article was written the ball was in great shape, 3.5 months after it was added to the pen.
Figure 4a: New Yellow BallFigure 4b: Sows crowded around the Yellow Ball when it was first added to the pen
Small Ball (Anti-Bite Ball): This toy was hung in the large gilt pen, and it came detached from the chain within the first hour of hanging. The staff re-tightened it and it has remained in place ever since (3.5 months so far). The usage for this toy is about the same as the yellow ball and tri-star toys, used moderately by the gilts. The gilts are able to put the entire ball into their mouth and chew it. The rubber has gradually decreased in size, but there is no signs of cracking or destruction, and there is still plenty of ball left.
Figure 5a: New Anti-Bite ballFigure 5b: Small (Anti-Bite) ball 14 days after being added to the gilt pen.
Easyfix Astro: This toy was hung in the large sow pen. According to the barn staff, this was the toy that got used the most. The toy lasted about 1.5 months before the sows has completely chewed off the rubber projections (Easyfix has recently improved the durability of the Astro toy by using the same material as the Luna 142). The eye hook that the toy came with needed to be bigger and longer with a lock nut in order to successfully hang it without it coming off, something that was easily fixed on farm.
Figure 6a: New Astro toyFigure 6b: Sows playing with the Astro 142 days after being added to the pen.
Easyfix Luna 142: This is the only toy that we tried that wasn’t suspended from the ceiling. We put one in with a boar located in the boar station, and the other went into the large sow pen. The sows and boar all enjoyed playing with it, however in the group pen only one sow could play with it at a time, so the barn staff preferred the hanging options as more sows could interact with the toys. The Luna lasted for about 3 months in the sow pen. There were two challenges that occurred with the Luna. First, the toy would occasionally get stuck at the window of the boar station, and when sows went to play with it they were being detected as in heat due to their heads being in the RFID zone. Second, sows figured out that they could put the toy in the door of the ESF feeder to keep it open, creating issues with the ESF feeding system.
Figure 7a: New Luna 142Figure 7b: Boar playing with the Luna 142
Future Cow Calf Ball: This toy was hung in the large sow pen. There was very little interest at all in the toy, and thus the barn staff removed it and hung one of the other toys in its place. The sows were also able to remove the toy from the chain (which also happened when we hung this toy in a finisher pen on another farm).
Figure 8: New Cow Calf Ball
General Observations:
When the toys were first installed the sows couldn’t leave them alone. With multiple different toys in each pen, we watched sows go from one to another to check them all out. Over time interest levels decreased slightly in the toys, but each time a member of the OMAFRA swine team visited the farm there was at least 1 sow playing with each toy. In general, we found that sows and gilts preferred toys with chewable projections over balls or discs, but the balls and discs were also used regularly. The sows liked to be able to get their mouth around the toy to chew it. The barn staff and farm owner were happy with the reaction of the sows to the toys and will continue to monitor durability on the toys that were still in tact after 3.5 months.
So, which toy is best? That is a tough question to answer! We found that sows played with all of the toys offered to them. Some lasted longer than others, which could be due to the level of interaction and the nature of the shape of the toy. Some of the toys are designed to be chewed and destroyed, whereas others are meant to last longer. We recommend that if you are considering commercial toys for your sow barn, get a few different ones and give the girls some options on which they want to play with!
Acknowledgements:
A huge thank to you Graham Learn from Richmar Farms for providing access to the group housed sow barn, and to barn staff Jan and Yulia for their invaluable assistance with the project. Additional thanks goes to each of the companies that donated toys for the project: Easyfix, Farmers Farmacy, Glass-Pac and Ketchum Manufacturing.
