Heat Stress Solution
Technology for Swine
Thermal Care S is an innovative
product developed by ADM researchers after five years of extensive
swine research. Thermal Care S is specifically designed to help
ameliorate the negative effects of heat stress, based on ADM
researchers' understanding of the underlying physiology of heat
stress. Specific ingredients have been scientifically selected to
address different aspects of physiological changes associated with
heat stress. As a result, Thermal Care S may improve blood flow
and heat dissipation, overcome osmotic challenge, and enhance gut
health and integrity while supporting the immune system and
increasing nutrient intake. When used in conjunction with
appropriate feeding and management practices, Thermal Care S may
be an effective solution technology for heat-stressed lactating
PHYSIOLOGY OF HEAT STRESS
The thermal environment has direct effects on pigs' energy
expenditure and voluntary feed intake and therefore on their
production performance. The thermoneutral zone, or the comfort
zone or zone of thermal comfort, is simply the range of
temperatures in which the pig is not cold or hot.
Young pigs are very sensitive to cold, whereas older pigs
including sows are more sensitive to heat. The thermoneutral zone
for lactating sows is 59° F to 68° F. When ambient temperatures
are above the upper range of the thermoneutral zone, pigs
experience heat stress. When heat stress occurs, thermoregulatory
mechanisms are activated. These mechanisms consist of behavioral
and metabolic changes that reduce body heat load in an effort to
maintain normal body temperature. Common responses to heat stress
in swine include decreased feed intake, increased respiration
rate, and increased water consumption.
These responses in lactating sows contribute to higher maintenance
energy expenditure, reduced milk production which reduces litter
growth rate, increased sow backfat loss, and compromised
subsequent reproductive performance.
Several theories have been proposed to explain the negative
effects of heat stress. One of the most recent theories is that
damage to gut integrity plays a critical role in mediating the
adverse consequences of heat stress. Animals experiencing heat
stress redirect blood flow from the body core to the periphery to
facilitate dissipation of body heat to the environment. The
increased blood flow to the skin is counter-balanced by reduced
blood flow to the gut and other body organs (liver, spleen,
pancreas, and mammary glands).
The reduction in blood flow to the gut results in insufficient
supply of nutrients (energy) and oxygen, which cause imbalanced
osmotic pressure and gut cell damage. The barrier function of gut
lining may eventually become so compromised that endotoxin, a
component of bacteria in the gut, enters the body. The presence of
endotoxin induces an exaggerated inflammatory response from the
gut immune system, which may precipitate multiple organ failure,
compromised performance, and potentially death with severe heat
AND LACTATING SOW PERFORMANCE
university and industry research studies have been published
regarding heat stress effect on lactating sow performance. Data
published by Quiniou and Noblet (1999) have shown that increasing
ambient temperatures from 64° F to 84° F increased sow backfat
loss from 2.1 mm to 3.5 mm, increased sow lactation weight loss
from 50.6 lb to 77.0 lb, reduced sow 21-day lactation feed intake
from 12.5 lb/day to 6.8 lb/day (see Figure 1), and reduced piglet
weaning weight from 15.2 lb/pig to 12.8 lb/pig.
This study indicated that sow feed intake and litter weaning
weight reduction is a curvilinear response to increased ambient
temperature. Specifically, greater feed intake and litter weaning
weight reduction occurred when temperatures were above 77° F. In
addition, piglet growth rate reduction due to heat stress is more
pronounced with the advancement of lactation, which may result
from a more pronounced milk shortage in later stages of lactation.
The ADM Thermal Care research project is an initiative across
species. Some active ingredients were tested individually and in
combination across species and are used in both Thermal Care R
(ruminant formulation) and Thermal Care S (swine formulation).
Major active ingredients used in Thermal Care S were evaluated in
a growing cattle trial (B07501). In this ADM research trial, 16
growing dairy cattle were subjected to heat stress and monitored.
of these cattle consumed the Thermal Care product while half did
not. During heat stress, rectal temperature increase was 21% (0.6°
F) less for the cattle consuming Thermal Care than for the control
cattle (see Figure 2). Cattle consuming the product also gained an
additional 0.27 lb/head/day. This data indicates that Thermal Care
helps animals adjust to the added stress of high heat situations
by improving their ability to maintain body temperature and lean
ADM Alliance Nutrition conducted two commercial sow trials to
evaluate efficacy of Thermal Care S. The first sow trial (S06307)
used 766 mixed parity sows at an Indiana commercial facility, with
369 sows on control treatment and 397 sows in Thermal
The trial was conducted from May 2006 to September 2006.
Sows were moved into farrowing rooms five to seven days
before farrowing due dates and were fed experimental diets from
the time they were moved into farrowing crates until weaning.
Thermal Care S decreased piglet pre-weaning mortality by 37% (from
9.2% for control to 5.8% for Thermal Care S; see Figure 3), which
resulted in 0.2 additional pigs per litter (8.85 vs. 8.62) at
The second sow trial (S07301) was performed in Mexico from
February 2007 to November 2007. Nine-hundred twenty-seven sows
were used in this commercial sow trial, with 451 sows on control
and 476 sows on Thermal Care S. Among the 927 sows, 108 sows had
enough time to complete two reproductive cycles. Thermal Care S
was fed during gestation and lactation.
sows fed Thermal Care S had significantly higher feed intake and
less backfat loss during lactation than sows fed the control diet.
Backfat loss was 11% less for sows fed Thermal Care S (2.30 vs.
2.59 mm; see Figure 4).
Lactation feed intake was greater in the second cycle for sows fed
Thermal Care S in the previous cycle (16 vs. 14.6 lb/day),
suggesting a positive carryover effect of Thermal Care S. This
finding may need to be repeated due to limited number of sows
completing two reproductive cycles in this trial. In addition,
number of sows was 2% more at the end of this trial for sows fed
Thermal Care S than for sows fed the control diet. This suggested
2% greater sow retention rate (i.e. 2% less sow culling rate) when
Thermal Care S was fed.
Heat stress has dramatic negative impacts to various life stages
of swine, especially lactating sows. Adverse effects of heat
stress may be due to gut integrity damage and compromised immune
function. ADM Alliance Nutrition research has shown possible
benefits of feeding Thermal Care S during hot weather. These
benefits include improved sow feed intake, reduced sow backfat
loss, reduced piglet pre-weaning mortality, and reduced sow
culling rate. Consequently, Thermal Care S may increase sows'
resilience to heat stress.
Reference available upon request
Nutritional Tips to Minimize Adverse Consequences of Heat Stress
Provide clean, fresh, cool water at
Offer more feed at night when the
Clean feeder frequently to encourage
sow feed intake.
Install proper cooling equipment,
such as water drip.
Ensure adequate building ventilation
to allow fresh air flow and minimize room humidity. Pigs
increase respiration rate to help increase heat loss. Compared
to other mammalian species, heat loss via sweating in the pig is
ineffective due to limited functional sweat glands.
Choose proper floor type ? concrete
vs. plastic; total solid vs. partial slotted vs. total slotted.
Increase dietary energy density in
summer to compensate for lower feed intake.
Decrease dietary fiber by using less
fibrous byproduct ingredients in diets. High-fiber diets
generate more heat during digestion than lower fiber diets.
Use more synthetic amino acids to
reduce dietary crude protein levels. Excessive dietary protein
or amino acids generate more heat during digestion and
Consider using feed additives that
help increase sow feed intake, modify gut microbial population
and gut integrity and maintain proper cation and anion balance.
Consider using Thermal Care S to
assist gut health, heat dissipation, nutrient intake and immune
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