Primarily, we will explore how to spot heat stress, review visible signs of heat stress, how KuneKunes regulate their body temperatures and provide some resources if you wish to further understand this especially important topic.

Introduction

Mud Puddles are particularly important for pigs in general and this holds true for KuneKunes. I have been told about the loss of several KuneKune during these summer months and it is just heart breaking. However, this can usually be prevented with mud puddles. Those pigs that passed is what has prompted me to write this post today. Unlike those owners, we want to ensure that you are informed.

Unlike dogs, pigs cannot pant or balance their body temperatures like other animals. Consequently, they cannot sweat. Have you heard the express “sweat like a pig”? Well, it is certainly just not true as pig cannot sweat. Therefore, that is a myth.

Here is what Babette LeBlanc says, 

“Without sweat glands it’s impossible for them to keep cool. Pigs die from heat exhaustion and heat stroke daily. They need plenty of water and lots of shade. That’s why you always see pigs in a mud puddle or wallow. 

To further complicate pigs getting heat stress.

Another issue is that pigs LOVE the heat, so they can get heat exhaustion without even realizing that they are in trouble. On the other hand, one of their favorite things pigs do is tip over their water dish, even tipping those kiddie pools which are heavy when full of water. Most importantly, owners should check on their pigs every couple of hours.” 

As a result, I certainly agree with her! We change the water for our pigs during the summer months twice daily. They have access to kiddie pools, multiple water dishes and ALWAYS a nice big mud puddle. Likewise, they have multiple puddles in their areas. At times, they will knock over their water bowls which is why we have so many. (Salt Toxicity can occur when pigs don’t have access to water which we will be learning more in another blog post). It is vital to provide shade and mud puddles for KuneKunes so that they can cool down. Kiddie pools are great but, the mud puddle will provide mud which will stay on them longer and keep them cool longer. It also helps “coat” them so that biting insects cannot bite as well. 

How to spot the heat stressed pig

Firstly, pigs will be suffering heat stress when any of the following signs are evident:

In all pigs

Evident discomfort and distress

Increased water consumption (up to 6x normal)

Increase urine output (and loss of electrolytes) 

Increased wallowing

Slowness and lethargy

Muscle trembling

Stupor, staggers, and terminal convulsions

Light body weight, poor coloring, and rough skin

Increased mortality

Rapid fall in feed consumption

Low weight gain

Reduced pulse rate

Extremely high respiration rate (panting)

In Boars and Sows - like the sign in all pigs but, some are a bit different

Poor milk production in sows

Cessation of milk flow

Deleterious influence on farrowing rate and litter size

Changes in estrus behavior

Reduced fertility, due to poorer semen quality and female infertility (farrowing in sows can be reduced as much as 30%)

Increased embryonic resorption resulting in small litter numbers

Increased variation in the number of days from weaning to next mating

Litter Reabsorbed

Invisible signs of heat stress

Embryonic development inhibited

Ovarian follicles development altered

pH of blood plasma rises

pH within the cells falls

Stress hormones appear in the blood

Resources being diverted to unproductive e orts by the pigs to restore balance (homeostasis)

Response to intercurrent diseases or pathogens decline rapidly

All production is stopped due to loss of homeostasis

Bicarbonate (HC0) is lost3

Gene function is disturbed

Some Science

Heat shock proteins are activated to shut down metabolic reactions and to protect heat sensitive tissues. Even if pigs are not sick, these are serious matters for the farmer because he knows by experience that production falls in direct proportion to the pigs’ temperature and discomfort. With no treatment and worsening conditions, the pigs will die. This is so easily avoided with mud puddles for Kunekunes.

At an environmental temperature of 280C (820F), appetite is depressed by 12% and likewise, where high relative humidity is 40% or more, by as much as 50%.

When the body is heat stressed, pigs drink more and eat less. (Appetite is depressed by 1½% for each degree of environmental temperature rise above 200C (680F). But it is not sufficient give the pigs water alone. This only increases the problem by further stimulating the loss of electrolytes.

Most importantly, when pigs are sick or stressed, they have a higher body temperature (for every 10C rise in body temperature, metabolism increases 20-30%). Therefore, pigs drink more, respiration rate increases, pulse rate falls and the number of scouring increases. As a result, diarrhea hastens dehydration. It is a vicious circle ruining production and culminating in death.

Learn how pigs regulate their deep body temperature

First, it is not enough to give the pig water alone. This only increases the problem, by further stimulating the loss of electrolytes. When pigs are sick or stressed, they have a higher body temperature. (For every 100C (500F) rise body temperature, metabolism increases 20-30%). Pigs drink more, respiration rate increases, pulse rate falls, and the number of wet droppings increases. Diarrhea hastens dehydration.

The intensive domestication of pigs leading to new breeds and faster growth has meant that all pigs farmed in hot and humid countries are genetically derived from strains bred in the cool climates of Europe and North America. As a result, this has meant that pigs, which are physiologically unsuited to hostile climates, start with a series of major disadvantages when faced with the problem of alleviating the effects of heat and humidity:

 Most importantly, they do not have active sweat glands except in the snout and are unable to sweat. Therefore, they must rely on other forms of heat loss.

 Loss of water from the lungs (evaporative cooling) is a vital route for the loss of heat from the body. However, the pig’s lungs are small when compared with other animals and the evaporative cooling much less efficiently.

KuneKune special considerations

 In addition, this disadvantage is exaggerated by a dished face and short nose which reduce air flow and therefore evaporative cooling. Those pigs with darker skins have an additional problem in losing body heat because they get hotter and tend to stay hotter longer than white pigs. Furthermore, fat pigs are further disadvantaged by the layer of fat under the skin which operates against the loss of heat by conduction and convection. The bigger and fatter the pig the less able it is to transfer body heat to the environment because the fat inhibits heat transference. This is another reason mud puddles for KuneKunes are so important.

So, a pig depends on shade and wallowing to keep cool. Changes in posture are an attempt to control deep (internal) body temperature by increasing the area of skin available for heat loss by convection, conduction, and radiation. The wallowing in their mud puddles helps to regulate their body temperatures. Pigs are genetically related to animals such as the hippopotamus and whale. It has been suggested that their need to wallow in shallow murky water could have been a step in the evolution of whales and other marine animals. 

Covering themselves with mud when wallowing is believed to slow down the rate of evaporation of water and thus maintain their deep body temperature for longer periods.

Postmortem Signs

Muscles are dry and sticky                  Blood is thicker and darker than normal

Skin is dry and wrinkled                       Gastrointestinal tract is dry and empty.

by:  https://www.heatstress.info/HeatStressExplained/Identifyingpigssufferingfromheatstress.aspx

In conclusion, you can see that it is extremely important for KuneKunes to have a mud puddle. First, it keeps them cooler since they are unable to sweat. Secondly, it will keep biting insects off them. Most importantly, it will save their lives.

Additional Resources to learn more about this important topic

https://www.agric.wa.gov.au/feeding-nutrition/heat-stress-pigs

https://extension.umn.edu/swine-production-management/heat-stress-swine-affects-production

https://agriculture.vic.gov.au/livestock-and-animals/livestock-health-and-welfare/caring-for-animals-during-extreme-heat