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Influence of High Ambient Temperatures on Performance of Multiparous Lactating Sows


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Multiparous Large White sows (n = 63) were used to investigate the effects of five ambient temperatures (18, 22, 25, 27, and 29 degrees C) and two dietary protein contents on their lactation performance. At each temperature treatment, ambient temperature was maintained constant over the 21-d lactation period. Dietary protein content was either 14 or 17% with essential amino acids levels calculated not to be limiting. The animals had ad libitum access to feed between the seventh and the 19th day of lactation. Diet composition did not influence lactation performance. Over the 21-d lactation, feed intake decreased from 5.67 to 3.08 kg/d between 18 and 29 degrees C. Between d 7 and 19, the corresponding values were 7.16 and 3.48 kg/d, respectively. This decrease was curvilinear; an equation to predict voluntary feed intake (VFI) from temperature (T, degrees C) and body weight (BW, kg) is proposed: VFI = -49,052 + 1,213 T - 31.5 T2 + 330 BW - .61 BW2 (residual standard deviation: 1,018). Skin temperature increased regularly with increased ambient temperature (34.6 to 37.4 degrees C between 18 and 29 degrees C), whereas udder temperature reached a plateau at 25 degrees C (38.3 degrees C). The gradient of temperature between skin and rectum was minimal (2 degrees C ) at 27 degrees C and remained constant at 29 degrees C. This constancy coincides with the marked reduction of feed intake. The respiratory rate increased from 26 to 124 breaths/min between 18 and 29 degrees C, and this indicates that the evaporative critical temperature was below 22 degrees C. The BW loss increased from 23 to 35 kg between 18 and 29 degrees C, but its estimated chemical composition remained constant. Pig growth rate was almost constant between 18 and 25 degrees C (241 g/d) and was reduced above 25 degrees C (212 and 189 g/d at 27 and 29 degrees C, respectively). In conclusion, temperatures above 25 degrees C seem to be critical for lactating sows in order to maintain their performance.
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N. Quiniou and J. Noblet
Influence of high ambient temperatures on performance of multiparous lactating sows
1999, 77:2124-2134.J ANIM SCI
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The authors gratefully acknowledge J. Gauthier, H. Renoult,
and the technical staff at the Pig Research Station for their
technical assistance.
On leave from Institut Technique du Porc, BP 3, 35650 Le Rheu,
France (E-mail:
Received July 21, 1998.
Accepted December 16, 1998.
Influence of High Ambient Temperatures on Performance
of Multiparous Lactating Sows
N. Quiniou
and J. Noblet
Institut National de la Recherche Agronomique, 35590 Saint-Gilles, France
ABSTRACT: Multiparous Large White sows (n =
63) were used to investigate the effects of five ambient
temperatures (18, 22, 25, 27, and 29°C) and two
dietary protein contents on their lactation perfor-
mance. At each temperature treatment, ambient
temperature was maintained constant over the
21-d lactation period. Dietary protein content was
either 14 or 17% with essential amino acids levels
calculated not to be limiting. The animals had ad
libitum access to feed between the seventh and the
19th day of lactation. Diet composition did not
influence lactation performance. Over the 21-d lacta-
tion, feed intake decreased from 5.67 to 3.08 kg/d
between 18 and 29°C. Between d 7 and 19, the
corresponding values were 7.16 and 3.48 kg/d, respec-
tively. This decrease was curvilinear; an equation to
predict voluntary feed intake (VFI) from temperature
(T, °C) and body weight (BW, kg) is proposed: VFI =
49,052 + 1,213 T 31.5 T
+ 330 BW .61 BW
(residual standard deviation: 1,018). Skin tempera-
ture increased regularly with increased ambient
temperature (34.6 to 37.4°C between 18 and 29°C),
whereas udder temperature reached a plateau at 25°C
(38.3°C). The gradient of temperature between skin
and rectum was minimal (2°C) at27°C and remained
constant at 29°C. This constancy coincides with the
marked reduction of feed intake. The respiratory rate
increased from 26 to 124 breaths/min between 18 and
29°C, and this indicates that the evaporative critical
temperature was below 22°C. The BW loss increased
from 23 to 35 kg between 18 and 29°C, but its
estimated chemical composition remained constant.
Pig growth rate was almost constant between 18 and
25°C (241 g/d) and was reduced above 25°C (212 and
189 g/d at 27 and 29°C, respectively). In conclusion,
temperatures above 25°C seem to be critical for
lactating sows in order to maintain their performance.
Key Words: Sows, Lactation, Temperature, Feed Intake
1999 American Society of Animal Science. All rights reserved. J. Anim. Sci. 1999. 77:2124–2134
Voluntary feed intake of lactating sows is often
insufficient to meet the nutrient requirements for milk
production, and body reserves can be partly depleted,
which leads to subsequent reproductive problems.
Parity (O’Grady et al., 1985), body reserves at
farrowing (Dourmad, 1991; Revell et al., 1998), litter
size (Elsley, 1971), and stage of lactation (Neil et al.,
1996) influence voluntary feed intake. It is also
influenced by extrinsic factors; one of the most
important is ambient temperature. Feed intake is
usually reduced when ambient temperatures exceed
the thermoneutral zone, which ranges between 15 and
20°C (Black et al, 1993). This decrease seems to be an
adaptation that decreases heat production due to the
thermic effect of feed (Noblet et al., 1993). Tempera-
ture is usually above 20°C in practical situations;
thus, sows are often exposed to hot conditions.
From a compilation of literature data, Black et al.
(1993) proposed a linear relationship between feed
intake and temperature. However, most of the data
used to establish this equation originated from studies
that compared two temperature classes (ther-
moneutral vs hot). Results obtained with growing pigs
suggest that the relationship between feed intake and
temperature is not linear (Nienaber and Hahn, 1983;
Quiniou et al., 1998). The aim of the present study
was to investigate the response of lactating sows kept
at five temperatures chosen over a range of values
from 18 to 29°C. The 18°C temperature was consi-
dered as the minimum value observed in farrowing
rooms in western Europe; 22°C corresponded to the
mean value; and 25, 27, and 29°C were considered as
warm temperatures. In addition, two diets formulated
to provide similar amino acid contents but different
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Table 1. Composition of experimental diets
Estimated from digestible energy content (DE, MJ/kg) and
chemical components (g/kg) according to the relationship proposed
by Noblet et al. (1994): NE = .703 × DE + .0066 × crude fat + .002 ×
starch .041 × crude protein .0041 × crude fiber (residual stan-
dard deviation = .18).
Diet 14 CP 17 CP
Composition, g/kg
Wheat 235 210
Barley 235 210
Corn 235 210
Soybean meal, 45.4% CP 102 196
Wheat bran 95 82
Oil 25 25
L-lysine HCl 4.2 1.2
DL-methionine .6 .1
Threonine 1.3
Dicalcium phosphate 16.4 15.2
Calcium carbonate 6 6
Vitamin and trace mineral mixture 10 10
Sugar beet molasses 30 30
Salt 4.5 4.5
Analyzed chemical composition, %
Dry matter 89.2 88.9
Ash 5.5 5.8
Crude protein 14.3 16.8
Crude fat 4.7 4.7
NDF 13.7 14.0
ADF 4.2 4.4
ADL .7 .6
Starch 46.2 42.4
Crude fiber 3.2 3.6
Lysine .95 .91
Methionine + cystine .54 .61
Threonine .62 .63
Tryptophan .17 .21
Calcium 1.0 1.0
Phosphorus .7 .7
Digestibility coefficients and energy values
Digestibility coefficient of crude protein, % 85.7 86.8
Digestibility coefficient of energy, % 86.0 87.4
Digestible energy (DE), MJ/kg 14.3 14.6
Metabolizable energy, MJ/kg 13.6 13.8
Net energy (NE), MJ/kg
10.5 10.6
protein levels were offered to test the hypothesis of a
better tolerance of low protein diet (i.e., diets with a
lower heat increment; Noblet et al., 1994), at high
ambient temperatures.
Animals, Materials, and Methods
Experimental Design
The effect of temperature on lactation performance
was studied in 63 multiparous Large White sows. The
objective was to study at least 12 sows per tempera-
ture. According to availability of animals from the
herd, 16 groups of three to six sows were used. Each
group was studied in one of the two climatized
farrowing rooms and exposed to one of the five
temperatures (18, 22, 25, 27, or 29°C) during a total
lactation period of 21 d. The change of temperature
between treatments was not linear, in order to get
more accurate response at the highest temperatures.
The temperature was kept constant ( ±.5°C) over the
day. Within each group, the sows were randomly
allocated to diets differing by their protein contents,
either 14 or 17% (14 CP and 17 CP, respectively)
(Table 1). The 14 CP diet was supplemented with
essential amino acids. Both diets were formulated to
not be deficient in essential amino acids according to
ratios of at least 60, 65, and 20% of methionine and
cystine, threonine, and tryptophan relative to lysine,
respectively. The analyzed total lysine content was at
least 9.1 g/kg. A higher lysine value was measured in
14 CP (.95%), and this reduces ratios between
essential amino acids and lysine. Mineral and vitamin
supplies were calculated to not be limiting (INRA,
1989). Care and use of animals met the requirements
of the Certificate of Authorization to Experiment on
Living Animals, No. 04739 (delivered by the Ministry
of Agriculture to J. Noblet, Head of the Research
Animal Management
The sows were inseminated artificially with
train semen. Over the gestation period, individual
feed allowances were calculated according to body
reserves (i.e., the BW and the backfat thickness) at
estrus, using the model proposed by Dourmad et al.
(1997). The diet was intended to provide a
21-mm subcutaneous backfat thickness at farrowing
and a 30- to 40-kg gestation BW gain, depending on
the parity. In order to avoid an effect of feeding level
during the late gestation on the organ size and
consequently on voluntary feed intake in lactation, the
feeding level was 2.9 kg/d between the 70th and 114th
d of gestation. The extra-feed allowance (when
compared to 2.9 kg/d) was provided during the 70
former d of gestation. For light sows or when the
backfat thickness was high enough at mating, 2.8 kg/d
were allowed over the whole gestation.
At 14 d before farrowing, the sows were moved to
the farrowing rooms at 24°C. The experimental
temperature began on Thursday (i.e., the average day
on farrowing). The photoperiod corresponded to 14 h
of artificial light (0830 to 2230). The quantity of air
recycled was minimal (25 m
/h per sow) and relative
humidity was not controlled. Each of the two rooms
was equipped with six farrowing pens on a metal
slatted floor in order to prevent skin wetness. Each
pen consisted of a commercial crate for lactating sows,
an infrared light, and a heating mat for the pigs. The
infrared light was activated on the day of farrowing
and was positioned near the rear of the sow. It was
moved forward near the pigs’ heating mat during the 2
d after farrowing and then switched off. The tempera-
ture of the heating mat was 33°C at birth, and it was
progressively decreased to 26°C at weaning (Rousseau
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et al., 1992). The litter size was adjusted to 11 pigs by
cross-fostering within the 48 h after farrowing.
During the last 14 d of gestation, the sows were fed
the 14 CP diet (2.9 kg/d). On farrowing day (d 0),
they received 1 kg of 14CP diet. After farrowing, the
sows were restrictively fed to standardize feed intake
until d 5. The ration was increased by .8 kg/d on d 1
and 2, and by 1 kg/d on d 3 and 4. For sows allocated
to the 17 CP treatment, the proportion of 17 CP diet in
the ration was increased regularly over the 3 d
postpartum, so that they were fed only the 17 CP diet
on d 4. Initially, the animals were supposed to have ad
libitum access to feed on d 5; because no diet refusals
were observed until d 6 for some sows, especially at
the lowest temperatures, it was considered that sows
were really fed ad libitum on d 7. The feed was
available as pellets, diet refusals were removed once
per day at 0845, and new feed was immediately
supplied in order to limit disturbance in the farrowing
room. Animals had free access to water provided from
a low pressure nipple drinker, which prevented sows
from wetting their skin. Each pen was equipped with
a 55-L water can. The day before weaning (d 20), the
sows were allocated 1 kg of feed so that they were
weighed on d 21 with an “empty” digestive tract.
The sows were weighed after farrowing and at
weaning. The backfat thickness was measured ultra-
sonically before farrowing and at weaning at the last
rib at 65 mm from the midline. The pigs were
individually weighed at birth, at d 7, and at weaning
(d 21). Pigs were also weighed at about d 13 to assess
milk production (Noblet and Etienne, 1989) and milk
composition at midlactation (results not presented).
For all sows, the daily amount of feed intake was
determined as the difference between the feed al-
lowance and the refusals collected on the next day.
On each Monday morning, the body temperature
( BT) and the respiratory rate were measured for each
lactating sow. A digital thermometer and a type T-
probe were used to measure the rectal temperature
and a type K-probe was used to measure the skin
temperature on the back (i.e., at the P2 position), on
the mammary gland, and on an intermediate point
between the back and the udder (on the flank). After
BT measurements of all sows were completed, the
respiratory rate was determined visually, without any
physical contact between the observer and the pig, by
counting flank movements over two periods of 1 min.
During these measurements, the pigs were considered
as being accustomed to the presence of the observer,
and within each crate, the sow and its litter were
resting (without feeding or nursing activity). An
infrared camera was also used to record suckling
frequency (including unsuccessful suckles) over 24 h
between d 7 and 12 for some sows and their litter (n =
The energy values of experimental diets were
assessed through digestibility trials with four sows.
The animals were fed twice daily with 2.4 kg/d and
had free access to water. Each diet was given to each
sow for 21 consecutive days and collection of excreta
occurred during the last 10 d as described by Noblet
and Shi (1993).
Calculations and Statistical Analyses
The physical and chemical composition of the
lactation BW loss was assessed from the BW and
backfat thickness losses using the equations proposed
by Dourmad et al. (1997). For calculation of average
litter size from farrowing to weaning, dead pigs were
taken into account according to the proportion of
lactation they experienced. The effects of temperature,
diet composition, and their interaction on the mean
lactation performance were tested through an analysis
of variance (General Linear Model procedure; SAS,
1990). The effect of group was tested within the effect
of temperature. The effect of lactation stage on the
daily feed intake was analyzed (PROC REPEATED;
SAS, 1990) with temperature considered as main
effect. Because temperature began on Thursday (i.e.,
the mean farrowing day) the measurements of BT and
respiratory rate occurred after 5, 12, or 19 d exposure
to experimental temperature. Consequently, the effect
of temperature on BT and respiratory rate was
analyzed through a multifactorial design (PROC
SPLIT-PLOT; SAS, 1990) taking into account the
duration of exposure to the experimental temperature,
the location of measurements (for BT), and interac-
The correlation between feed intake during gesta-
tion and lactation was calculated (PROC CORR; SAS,
1990). The response of mean feed intake during the
ad libitum feeding period (d 7 to 19) to temperature
and BW was studied through a covariance analysis
with temperature, BW, and their interaction as
covariates. Apparent digestibility coefficients of
energy, DE, and ME contents of diets were calculated
according to routine procedures (Noblet et al., 1989).
The ME intake corresponded to the difference between
the DE intake and the energy losses in urine (Table
The chemical composition of experimental diets is
reported in Table 1. The measured contents of
methionine plus cystine and tryptophan were lower
than estimated in the 14CP diet. Consequently, the
ratios of those amino acids relatively to lysine supplies
were lower than planned. Because no effect of diet was
found for almost all criteria studied, only the effects of
temperature are presented in the text. As presented in
Table 2, sows were comparable between treatments
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Table 2. Effect of ambient temperature and diet composition on performance of
lactating sows (adjusted means)
Residual standard deviation.
From analysis of variance including the effects of ambient temperature (T), diet (D), interaction between temperature and diet, and the
effect of group of sows (G) within temperature. Statistical significance: ***P < .001, **P < .01, *P < .05, NS P > .05.
Within each line, values not followed by the same superscript differ ( P < .05).
Temperature, °C Diet
Item 18 22 25 27 29 14 CP 17 CP RSD
Observations 14 14 12 11 12 32 31
Parity 3.3
3.7 3.4 1.2 T*
Duration of lactation, d 21.2
21.6 21.4 .5 T***, G***
Litter size from farrowing
to weaning 10.0
10.2 10.3 .7 T***, G**
Daily food intake, g/d
From farrowing to
weaning 5,666
4,660 4,792 779 T***
From d 7 to d 19 7,161
5,609 5,817 1,068 T***
Body weight, kg
After farrowing 274 269 283 279 268 276 274 19
At weaning 251 247 258 249 233 247 248 22
Lactation BW loss 23
29 25 10 T**, T × D*
Backfat thickness, mm
Before farrowing 20.4 20.1 20.8 20.2 22.6 20.6 21.1 4.1
At weaning 18.3 18.2 18.1 16.7 19.1 17.4 18.8 3.7
Backfat thickness loss 2.1 1.9 2.7 3.5 3.5 3.2 2.3 1.9 G*
for their BW and backfat thickness at farrowing. The
backfat thickness at farrowing corresponded to what
was expected from the individual feeding level applied
during gestation (20.8 mm on average vs 21 mm).
Parity number was higher for the sows kept at 25 and
27°C than in other thermal treatments (fourth vs
third parity on average) but no difference in parity
number was observed between dietary treatments.
The mean lactation duration was 21.5 d. At 22°C, the
duration was longer due to practical conditions at the
beginning of the study. The lactation feed intake was
not correlated to feeding level during gestation (P >
Feed Intake of Sows
Temperature significantly influenced feed intake; it
decreased from 5,666 to 3,079 g/d between 18 and
29°C over the total lactation (Table 2). However, this
variation was not linear. Daily feed intake decrease
was more important between 25 and 29°C than
between 18 and 25°C. Similar differences were ob-
served over the ad libitum feeding period (i.e.,
between d 7 and 19). Covariance analysis of average
daily feed intake (ADFI) (g/d) with temperature ( T;
°C) and mean lactation BW (kg) as covariates
indicates that the effects of temperature and BW on
feed intake were both quadratic. Between d 7 and 19,
the relationship was:
ADFI = 49,052 + 1,213 T 31.5 T
+ 330 BW
.61 BW
(residual standard deviation: 1,018)
From farrowing to d 4, sows were restrictively fed
according to the same feeding plan. As a consequence,
the daily feed intake increased similarly at all
temperatures over this period (Figure 1). Between d 4
and 6, the effect of temperature on the increase was
significant ( P < .001). According to the tests of
Student, calculated step by step for each temperature,
feed intake seemed to reach a plateau at d 4 at 27 and
29°C. At 25, 22, and 18°C, the plateau was reached at
d 6, 5, and 7, respectively, and this plateau was
maintained until d 19.
Body Weight Loss
Over the total lactation, the BW loss was signifi-
cantly affected by temperature; it amounted to 23 kg
at 18, 22, and 25°C on average but increased up to 36
kg at 29°C, the value at 27°C being intermediate
(Table 2). A significant interaction between tempera-
ture and dietary treatment was observed in connection
with a lower BW loss at 25°C with the 14 CP than
with the 17 CP diet, which was connected with a
higher level of feed intake of 14 CP than 17 CP at this
temperature. The backfat thickness loss was not
affected by temperature (2.8 mm on average). The
composition of lactation BW loss over the total
lactation is presented in Table 3. Temperature signifi-
cantly influenced the fat and lean losses that in-
creased from 309 and 642 g/d, respectively, at 18°Cto
483 and 968 g/d, respectively, at 29°C. In connection
with tissue losses, the protein and lipid mobilizations
were also influenced by temperature. At 18°C, the
daily protein and lipid losses averaged 173 and 389 g,
respectively. These losses increased significantly with
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Table 3. Effect of ambient temperature and diet composition on estimated composition of the BW loss
of lactating sows (adjusted means)
Empty body weight, physical composition and chemical composition were assessed at farrowing and weaning using equations (Dourmad
et al., 1997).
From analysis of variance including the effects of ambient temperature (T), diet (D), interaction between temperature, and diet and the
effect of group of sows (G) within temperature. Statistical significance: ***P < .001, **P < .01, *P < .05, NS P > .05.
Within each line, values not followed by the same superscript differ ( P < .05).
Temperature, °C Diet
Item 18 22 25 27 29 14 CP 17 CP RSD
Empty body weight loss, kg/d 1.16
1.42 1.27 .45
Backfat thickness loss, mm/d .10 .09 .13 .17 .16 .15 .11 .09 G*
Mobilization of body tissues, g/d
Fat 309
408 338 130 T**, G**
Lean 642
769 704 281 T*, T×D*
Mobilization of chemical
components, g/d
Lipid 389
514 426 165 T**, G**
Protein 173
203 189 83 T*
Mobilization of body energy, MJ/d 20.42
26.33 22.37 7.82 T**
Figure 1. Daily intake during lactation.
temperature and reached 259 and 608 g/d, respec-
tively, at 29°C. The energy losses increased with
increase of temperature from 20.4 to 31.6 MJ/d, but
when expressed in MJ per kilogram of empty BW loss,
it remained constant (17.6 MJ/kg).
Litter Performance and Milk Production
The litter size was 10.3 on average over the total
lactation, and 10.0 pigs per litter were weaned (Table
4). Higher average litter sizes were obtained at 27°C
than at other temperatures. Between birth and
weaning, the BW gain of the litter was similar at 18,
22, 25, and 27°C and lower at 29°C. Expressed per pig,
the BW gain was similar at 18, 22, and 25°C (241 g/d)
but reduced at 29°C (189 g/d). An intermediary value
was obtained at 27°C (212 g/d). Lighter pigs at
weaning were then obtained at these higher tempera-
tures (Table 4). According to the 25 measurements
performed, the number of sucklings per 24 h was
significantly higher at 29°C than at 18°C (40 and 26,
respectively), the value being intermediate at the
three other temperatures (33).
Body Temperatures and Respiratory Rate
For one group studied at 25°C, BT was not recorded
for technical reasons with a subsequent lower number
of observations at this temperature (Table 5). The
effect of feed intake level during the day prior to the
measurements and on the day of measurements was
introduced as a covariate in the analysis of variance;
its effect was not significant on any criteria, and it
was removed from the statistical model. Neither
dietary treatment nor the duration of exposure to the
temperature had any influence on BT and respiratory
rate. The interaction between temperature and dura-
tion of exposure was due to small variations of BT
between d 5 and 19 at temperatures ranging between
18 and 27°C, whereas it remained constant at 29°C.
For skin temperatures, values obtained at back and
flank locations were close but significantly different
(36.3 and 36.6°C on average, respectively); these
values were lower ( P < .05) than the rectal and
cutaneous BT (39.0 and 38.1°C, respectively).
The rectal temperature was constant between 18
and 22°C (38.6°C), but it increased at higher
temperatures (39.0 to 39.4°C between 25 and 29°C)
(Table 5). The temperature of the mammary gland
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Table 4. Effect of ambient temperature and diet composition on litter performance between birth
and weaning (adjusted means)
From analysis of variance including the effects of ambient temperature (T), diet (D), interaction between temperature, and diet and the
effect of group of sows (G) within temperature. Statistical significance: ***P < .001, **P < .01, *P < .05, NSP > .05.
Assessed from litter growth rate and litter size (Noblet and Etienne, 1989).
Within each line, values not followed by the same superscript differ ( P < .05).
Temperature, °C Diet
Item 18 22 25 27 29 14 CP 17 CP RSD
Observations 14 14 12 11 12 32 31
Mean number of pigs
From farrowing to weaning 10.0
10.2 10.3 .7 T***, G**
Weaned 9.8
9.9 10.0 .9 T*, T×D*, G*
Litter growth rate, g/d 2,458 2,422 2,275 2,367 1,941 2,339 2,247 397 T*, T×D**, G*
Pigs growth rate, g/d/pig 244
230 219 39 T**
Weaning body weight,
kg/pig 6.89
6.73 6.38 .89 T*
Milk yield between d 0
and d 21, g/d
7,185 7,060 1,088 T*, T×D*, G**
Table 5. Effect of ambient temperature and duration of exposure on body temperatures and respiratory rate
in lactating sows (adjusted means)
For each temperature, adjusted mean values with the same superscript are not significant ( P > .05) within each line.
For each location of measurement of body temperature, adjusted mean values with the same superscript are not significant ( P > .05)
within the column.
From the analysis of variance with a split-plot design including the effects of temperature (T), duration of exposure to the temperature
(E), dietary treatment (D), interactions, and the effect of animal (A).
The effect of location of body temperature measurement (L) and its interactions with other factors was taken into account in the analysis
of variance.
Within each line, values not followed by the same superscript differ ( P < .05).
Temperature, °C
Exposure, days
Item 18 22 25 27 29 5 12 19 Mean
Observations 42 42 21 33 36 58 58 58
Body temperature,
Back 34.6
36.3 36.4 36.3 36.3
T***, T×E**
Flank 34.8
36.5 36.6 36.5 36.6
.6 L***, T×L***
Mammary gland 37.6
38.2 38.2 38.0 38.1
Rectum 38.6
39.0 39.0 38.9 39.0
Gradient of body
temperature, °C
Rectal-back 4.1
2.7 2.6 2.6 2.7 .6 T***, T×E*, A***
Rectal-flank 3.8
2.5 2.4 2.4 2.5 .6 T***, A***
gland 1.0 .7 .7 .8 1.0 .7 .9 .8 .8 .5 A**
Respiratory rate,
Observations 38 34 18 27 34 48 53 50
Rate 26
70 80 68 73 27 T***, A***
was also affected by ambient temperature but to a
lesser extent; it increased from 37.8°C at 18 and 22°C
to 38.4°C at 25, 27, and 29°C (Figure 2). The skin BT
at the back increased with each increase of ambient
temperature, but this increment was not linear
because + 1.2, + .8, + .6, and +.2°C were obtained from
18 to 22, 22 to 25, 25 to 27, and 27 to 29°C,
respectively. The ambient temperature also affected
the gradient observed between the rectal temperature
and the other estimates of BT. As presented in Table
5, at 18°C the udder and skin temperatures were 1
and 4°C below the rectal temperature (37.6, 34.6, and
38.6°C, respectively). When ambient temperature
increased, the gradient between rectal and skin
temperatures decreased to reach 2°Cat29°C, whereas
the gradient between the rectal and udder tempera-
ture remained constant. No effect of duration of
exposure was found on the gradients.
Fewer observations were available for respiratory
rate than for body temperature; some sows were not
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Figure 2. Effect of ambient temperature on respiratory
rate, and rectal and cutaneous body temperature
measured at the back and at the mammary gland.
recorded because they were continuously standing
during the measurement. The respiratory rate in-
creased with ambient temperature (26 to 124 breaths
per min between 18 and 29°C).
One of the most important effects of increase of
temperatures above 20°C in multiparous sows
(Schoenherr et al., 1989; Prunier et al., 1997; the
present study) and in primiparous sows (Barb et al.,
1991; Black et al., 1993; Messias de Braganc¸a et al.,
1998) is a decrease of their feed intake. From a
literature review, a linear relationship between feed
intake and temperature was proposed by Black et al.
(1993). According to this relationship, the decrease of
daily DE intake per extra degree between 16 and 32°C
is 2.4 MJ·°C
. When results of literature studies
are considered separately (Table 6), the slope of
decreased DE intake with increased temperature
seems rather variable among experiments and ranges
between .9 and 5.2 MJ DE·°C
in primiparous
sows studied by Black et al. (1993) and Barb et al.
(1991), respectively. In multiparous or mixed parity
sows, the response of DE intake to temperature would
be less variable and ranges between 1.3 and 2.8
. The corresponding value obtained in the
present study between 18 and 29°C averaged 3.4 MJ
, which is higher than values obtained in
other studies with multiparous sows. Because feed
intake and milk yield were both higher under
thermoneutral temperature in the present experiment
than in former ones, it was probably associated with a
higher heat production. Consequently, our sows would
have been more sensitive to the ambient temperature
rise with accentuated negative effect on their feed
As hypothesized by Black et al. (1993) and
suggested by the variation of the response of feed
intake to temperature exhibited from the literature,
the present data demonstrate that the effect of
temperature on feed intake is not linear or, in other
words, that the extent to which temperature affects
feed intake depends on the level of temperature.
Indeed, in the present study, the decrease of DE
intake averaged 1.5 MJ·°C
between 18 and 25°C,
and 3.3 and 10.2 MJ DE·°C
between 25 and 27°C
and between 27 and 29°C, respectively. Such a result
is in agreement with relationships obtained by
Nienaber and Hahn (1983) and more recently by
Quiniou et al. (1998) for growing pigs. The main
consequence of the decreased feed intake under hot
temperature is a decrease of associated heat produc-
tion due to metabolic processes of nutrient intake
(Noblet et al., 1994), which contributes to a reduction
of the total heat production in the warm-exposed
The 18°C treatment was supposed to be in the
thermoneutral zone as defined by Black et al. (1993).
At 18°C, the rectal BT was below 39°C, in agreement
with results of Neil et al. (1996) obtained for
primiparous sows, and the respiratory rate was
similar to the value reported by Schoenherr et al.
(1989) for multiparous sows exposed at 20°C (26 and
27 breaths/min, respectively). In agreement with
previous studies carried out with gilts and sows, the
elevated ambient temperature induces an increase of
rectal temperature (Lynch, 1977; Schoenherr et al.,
1989; Lorschy et al., 1994; Prunier et al., 1997), which
contributes to maximizing the gradient between core
and ambient temperatures and to improving conduc-
tive heat losses. In addition, the measurements of BT
indicate a shift in the partition of body heat storage
from the core to the peripheral area when the
intensity of heat exposure increases.
Between 18 and 25°C, the homeothermia was
maintained through a linear increase of mammary
and skin BT (+ .10 and + .29°C BT per extra degree of
temperature, respectively), whereas the decrease of
feed intake per extra degree of temperature was
limited. At the same time, the respiratory rate
increased also linearly and contributed to higher
evaporative heat losses. Above 25°C, the skin BT and
the respiratory rate continued to increase, but the
mammary BT remained stable. As a consequence, the
conductive heat loss probably increased to a lesser
extent than below 25°C, whereas the evaporative heat
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Table 6. Influence of ambient temperature on digestible energy intake (DE, MJ/d) variation in lactating sows
Creep feed was offered to pigs 14 d after birth.
Creep feed was offered to pigs 10 d after birth.
When DE content was not available, its value was assumed to be 13.3 MJ/kg (i.e., estimated DE content of a corn and soybean meal diet).
Duration of Dietary protein Dietary DE Temperatures DDE per extra
Parity Authors lactation, d content, % content, MJ/kg studied, °C degree
Schoenherr et al. (1989) 22 16.7 11.0 20, 32 1.33
Schoenherr et al. (1989) 22 16.1 13.2 20, 32 2.79
Schoenherr et al. (1989) 22 17.1 15.1 20, 32 2.23
Prunier et al. (1997) 21 17.2 13.0 18, 27 2.46
The present study 21 17.0 14.3 18, 22, 25, 27, 29 3.39
The present study 21 17.0 14.3 18, 22, 25 1.49
The present study 21 17.0 14.3 25, 27, 29 6.73
Mixed parity
Lynch (1977)
29 14.1 21, 27 1.52
Stansbury et al. (1987)
28 14.0 13.3
18, 25, 30 2.50
McGlone et al. (1988)
28 14.0 13.3
24, 30 1.37
Lynch (1989)
29 14.1 16, 27 1.80
Barb et al. (1991) 25 14.0 13.1 22, 30 5.24
Black et al. (1993) 28 14.0 12.6 18, 30 .93
Messias de Braganc¸a et al. (1998) 21 17.2 13.2 20, 30 2.77
Vidal et al. (1991) 28 15.5 13.3
20, 30 3.56
Figure 3. Effect of temperature on the difference
between rectal and skin temperature measured at the
back (o) and mean daily feed intake () measured
around the days of body temperature measurement.
losses increased markedly; however, it did not prevent
an increase of rectal BT. Similar results have been
reported by Stombaugh and Roller (1977) for weaned
pigs and by Giles and Black (1991) for growing pigs.
Above 25°C, the gradient between rectal and
peripheral BT was reduced and the daily feed intake
remained low. In fact, the increase of rectal BT when
temperature increases above 25°C seems to adjust the
gradient between rectal and skin BT at a minimum
value that is reached around 27°C; this minimum
gradient coincides with the marked decrease of feed
intake (Figure 3). The present results would then
indicate that, above 25°C, pathways implicated in BT
regulation are all saturated and(or) not efficient
enough to prevent hyperthermia and decreased lacta-
tion performance.
According to Black et al. (1993), the temperature
at which evaporative heat loss increases markedly,
particularly from the lungs through increased respira-
tory rate, corresponds to the evaporative critical
temperature ( ECT). In the present experiment,
evaporative heat loss depends solely on respiratory
rate because the skin of sows was always dry. Because
each increase of temperature generated an increase of
respiratory rate, it can be concluded that ECT is below
No significant effect of duration of exposure to
temperature was observed on BT and respiratory rate,
which indicates a fast apparent acclimation of sows to
ambient temperature within the five previous d of
exposure at the beginning of lactation. Similar conclu-
sions have been reported for growing pigs by Verhagen
et al. (1988) and Rinaldo and Le Dividich (1991).
This conclusion is reinforced by the constancy of feed
intake after the seventh d after farrowing in the
present experiment even if a slight increase of
voluntary feed intake is usually observed over longer
lactation in sows kept at thermoneutrality (Neil et al.,
The litter growth rate obtained at 18°C in the
present study (2,458 g/d) is higher than the average
daily gain reported for multiparous sows by Schoen-
herr et al. (1989) at 20°C and by Prunier et al.
(1997) at 18°C (1,880 and 2,150 g/d, respectively)
and for primiparous sows by Messias de Braganc¸a et
al. (1998) at 20°C (2,048 g/d), despite comparable
litter sizes and durations of lactation in all studies. In
agreement with the previous results of Schoenherr et
al. (1989), Black et al. (1993), and Prunier et al.
(1997), the present results indicate that exposure of
lactating sows to high ambient temperatures (i.e.,
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30°C), in comparison with thermoneutral conditions
(about 20°C), induce a significant reduction of litter
growth. But our study further demonstrates that this
effect would become noticeable above 25°C and
significant above 27°C. It should be noticed that litter
growth is proportional to litter size (Elsley, 1971).
The constancy of litter growth at 25 and 27°C in the
present experiment is then mainly related to the
higher litter size at 27°C; indeed, when expressed per
pig, the litter growth rate was significantly reduced.
Because litter growth rate and milk production are
closely connected (Noblet and Etienne, 1987), the
decreased litter weight gain suggests a decrease of
milk yield under hot temperatures. This decrease
could be attributed to a decline in the suckling activity
of pigs and(or) to a lower milk production of the sows
and(or) to a direct effect of reduced feed intake when
lactating sows are exposed to high ambient tempera-
The nursing frequency and the duration of the
massage of the udder play a key role in adjusting the
milk output (Spinka et al., 1997). Data from the
present experiment indicate that the suckling fre-
quency does not decrease under warm conditions but
even increases. Azain et al. (1996) also observed that
providing supplemental milk replacer improves
growth rate of pigs during summer and concluded that
the decrease of litter daily gain under warm conditions
is only due to a decreased milk yield. Reduction of feed
intake has been shown to have moderate or even
negligible effects on milk yield except when body
reserves are too depleted (Noblet et al., 1998). In our
present study, body weight loss was higher at highest
temperatures, but it remained within reasonable
values. It is then likely that the reduced milk yield
observed above 25°C is not explained by the reduced
feed intake. In fact, the decreased milk yield under hot
temperatures would be mainly due to a direct effect of
temperature on milk production as demonstrated by
Mullan et al. (1992, cited by Black et al., 1993) and
more recently by Messias de Braganc¸a et al. (1998)
when sows kept at normal and high temperatures are
pair-fed. Some mechanisms were suggested. On one
hand, this effect would be partly explained by
differences in circulating blood levels of catabolic
hormones such as triiodothyronine and thyroxin with
subsequent reduced mobilization of body reserves
(Prunier et al., 1997) and, on the other hand, by
differences in partition of circulating blood between
different body areas that would induce lower nutrient
supplies to the mammary gland under hot tempera-
tures, as suggested by Barb et al. (1991) and the
present results with subsequent reduced milk yield.
The increase of skin BT under hot temperatures could
be attributed to vasodilatation of peripheral vessels,
but measurements of blood flow through the udder
would be required to confirm this mechanism.
The lactation BW loss averaged 23 kg at 18°C, and
it was considerably higher than the BW loss reported
at 20°C by Schoenherr et al. (1989) in multiparous
sows studied over 21 d ( 2.1 kg) or by Stansbury et
al. (1987) in mixed parity sows studied over 28 d
( 3.1 kg). From multiparous sows studied over 21 d
and originating from the same herd, Prunier et al.
(1997) reported a BW loss similar to the one observed
in the present study ( 19 kg). Comparable levels of
feed intake were obtained in those studies, but
differences in BW loss between studies are related to
the production level of the sows, which was higher in
the studies of Prunier et al. (1997) and the present
Most of the BW loss during lactation corresponds to
lean and fat tissue depletions implied in meeting the
nutritional deficit of sows for milk yield, and a small
proportion is associated with variation of the weights
of udder, uterus, and digestive tract (Noblet et al.,
1998). On average, the BW loss doubled between 18
and 29°C, but the partition of BW loss between fat and
lean tissue losses remained rather constant. Calcu-
lated fat and lean losses represented 27 and 55% of
empty BW loss. This result is consistent with the fact
that temperature induces a decrease of total feed
intake (i.e., of both energy and protein intake). In the
case of a moderate protein restriction, a subsequent
increased mobilization of lean tissue has been
reported by Dourmad et al. (1998), whereas, in the
case of energy restriction with adequate protein
supplies, variation of body reserves corresponds
mainly to an increased mobilization of fat tissue
(Etienne et al., 1985; King and Dunkin, 1986;
Brendemuhl et al., 1987).
Taking into account the chemical composition of
tissues, most of the energy mobilized from body
reserves originated from fat tissue through its lipid
content. Lipid loss corresponded to 35% of empty BW
loss (15% for protein) and contributed to about 80% of
total energy mobilized from body reserves. As a
consequence of the constancy of the BW loss composi-
tion throughout the different ambient temperatures
studied, the energy content of empty BW loss was
identical in all treatments (17.6 MJ/kg on average)
and close to the value reported by Noblet and Etienne
(1987). Even if reproductive performance were not
recorded in the present study, available results clearly
indicate that increased depletion of body reserves has
major consequences on reproductive performance
(Quesnel et al., 1998).
The nutritional strategy chosen in the present
study failed to exhibit any interaction between diet
formulation and temperature. No benefit of the
decreased heat production associated to the 14 CP diet
was found for the sows, especially no greater feed
intake was observed with the 14 CP diet under high
temperatures, and the BW loss was similar with both
dietary treatments. The significant interaction found
for some of the criteria studied between diet and
temperature was due to a higher feed intake in 14 CP
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sows exposed to 25°C that was not observed at the
other temperatures. Regarding the high individual
variability between multiparous sows, it can be
questioned 1) if the number of observations was
sufficient, and(or) 2) if the difference in crude protein
level was too small to obtain significant differences. In
addition, the crude methionine, cystine, and trypto-
phan contents were less than planned in the 14 CP
diet. This resulted in lower supplies of sulfur amino
acids and tryptophan, relatively to lysine, than values
recommended by Dourmad et al. (1991). This problem
in amino acid concentration could have masked the
expected effect of temperature on the intake of the
different diets.
The relationship between feed intake of lactating
sows and ambient temperatures is quadratic, with a
marked reduction of feed intake above 25°C. Based on
body temperatures and respiratory rate measure-
ments, the adaptation of sows to their thermal
environment seems rapid, and the estimated evapora-
tive critical temperature seems to be less than 22°C.
The difference between rectal and skin temperatures
could be considered as an indicator of the potential
gradient of heat loss with a minimum value that
coincides with the marked negative effect of ambient
temperature on feed intake and performance. Under
warm temperatures, milk yield is reduced, which
reduces pig weights at weaning; also, sow body weight
loss is increased, which would cause reproduction
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... Relevance for farrowing and lactating sows: Farrowing sows exert high muscular activity while lactating sows have a high metabolic heat production associated with milk production. Quiniou and Noblet (1999) investigated the influence of high ambient temperature on performance of lactating sows. Comparing five ambient temperatures (18,22,25,27 and 29°C) maintained constant over the 21-day lactation period, they found that skin temperature increased with increased ambient temperature (34.6-37.4°C between 18°C and 29°C), whereas udder temperature reached a plateau at 25°C (38.3°C). ...
... Interpretation: The respiratory rate was reported to increase linearly with ambient temperature and contribute to higher evaporative heat losses (Quiniou and Noblet, 1999). A respiratory rate of more than 28 breaths per minute in sows and more than 55 breaths per minute in piglets is considered as panting (Welfare Quality ® , 2009). ...
... Interpretation: The elevated ambient temperature induces an increase of rectal temperature (Lynch, 1977;Schoenherr et al., 1989;Lorschy et al., 1994;Prunier et al., 1997), which contributes to maximising the gradient between core and ambient temperatures and to improving conductive heat losses (Quiniou and Noblet, 1999). ...
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This scientific opinion focuses on the welfare of pigs on farm, and is based on literature and expert opinion. All pig categories were assessed: gilts and dry sows, farrowing and lactating sows, suckling piglets, weaners, rearing pigs and boars. The most relevant husbandry systems used in Europe are described. For each system, highly relevant welfare consequences were identified, as well as related animal-based measures (ABMs), and hazards leading to the welfare consequences. Moreover, measures to prevent or correct the hazards and/or mitigate the welfare consequences are recommended. Recommendations are also provided on quantitative or qualitative criteria to answer specific questions on the welfare of pigs related to tail biting and related to the European Citizen's Initiative 'End the Cage Age'. For example, the AHAW Panel recommends how to mitigate group stress when dry sows and gilts are grouped immediately after weaning or in early pregnancy. Results of a comparative qualitative assessment suggested that long-stemmed or long-cut straw, hay or haylage is the most suitable material for nest-building. A period of time will be needed for staff and animals to adapt to housing lactating sows and their piglets in farrowing pens (as opposed to crates) before achieving stable welfare outcomes. The panel recommends a minimum available space to the lactating sow to ensure piglet welfare (measured by live-born piglet mortality). Among the main risk factors for tail biting are space allowance, types of flooring, air quality, health status and diet composition, while weaning age was not associated directly with tail biting in later life. The relationship between the availability of space and growth rate, lying behaviour and tail biting in rearing pigs is quantified and presented. Finally, the panel suggests a set of ABMs to use at slaughter for monitoring on-farm welfare of cull sows and rearing pigs.
... They are even more affected by ambient temperature changes according to their particularly high voluntary feed intake at thermoneutrality (Figure 3.9). In addition, the reduction in voluntary feed intake per °C change is as high as ambient temperature is high with a reduction averaging 200 g/°C between 20 and 25 °C and up to 500 g/°C between 25 and 30 °C in lactating sows (Quiniou and Noblet 1999); corresponding values would be 10 and 30 g/°C in 25 kg piglets (Collin et al. 2001) and 40 and 70 g/°C in 60-kg growing pigs (Quiniou et al. 2000). These negative effects of high temperatures on (Quiniou et al. 2000a), and lactating sows (Quiniou and Noblet 1999). ...
... In addition, the reduction in voluntary feed intake per °C change is as high as ambient temperature is high with a reduction averaging 200 g/°C between 20 and 25 °C and up to 500 g/°C between 25 and 30 °C in lactating sows (Quiniou and Noblet 1999); corresponding values would be 10 and 30 g/°C in 25 kg piglets (Collin et al. 2001) and 40 and 70 g/°C in 60-kg growing pigs (Quiniou et al. 2000). These negative effects of high temperatures on (Quiniou et al. 2000a), and lactating sows (Quiniou and Noblet 1999). Feed intake is expressed as a multiple of the ME requirement for maintenance. ...
This chapter describes the different steps of energy utilization in swine with a description of available energy systems for evaluating the feeds and explores the different components of energy requirements in swine production and the response of growing pigs and reproductive sows to energy intake. It considers some aspects of energy intake and its regulation by feed characteristics, animal characteristics, and environmental factors. For growing pigs, net energy intake is usually calculated as the sum of retained energy at a given production level and the fasting heat production at zero activity. The metabolizable energy content of a feed equals the digestible energy content minus the material energy losses in the urine and combustible gases resulting from fermentation. Diet energy density can be modified by including either fiber‐rich ingredients that reduce the energy concentration or fatfiber‐rich ingredients that increase the energy concentration.
... Although temperatures of 29°C in farrowing are favorable for piglets (Ribeiro et al., 2018), sows are uncomfortable at temperatures above 22°C (Quiniou & Noblet, 1999). Temperature control measures in the farrowing environment are essential for good milk production by the dam and better litter performance. ...
... Feed intake was determined as the difference between the allowance and leftover feed collected the next morning. The backfat thickness was measured ultrasonically (SSD-500V, Aloka, Wallingford, CT, USA) on each sow before farrowing and at weaning at the last rib and 65 mm from the dorsal midline [20,21]. The weights of suckling piglets were measured on day 1 and 21. ...
This study was performed to development the alternative farrowing pen (AFP) and to investigate performance and behavior of lactating sows and their litter. A total of 64 multiparous sows were randomly divided into two groups and were allocated to farrowing crates (FCs) and AFPs. The AFPs contained a crate and support bars that could be folded to provide the sows with extra space on day 5 postpartum. Behavior was recorded by charge-coupled device cameras and digital video recorders, and the data were scanned every 2 min to obtain an instantaneous behavioral sample. Farrowing systems did not affect feed intake, back-fat thickness, litter size and piglet weight at birth and weaning (p > 0.05). In addition, there were no differences in the number of crushed piglets between the two farrowing systems (p > 0.05). However, the weaning-to-estrus interval was shorter in the sows of the AFPs than in thous of the FCs (p < 0.05). The sows spent most of their time lying down during the lactating period, at about 80% lateral recumbency and 10%-15% ventral recumbency. The only significant differences were in the feeding and drinking behavior between sows in the two farrowing systems (p < 0.05). The FC sows displayed more feeding and drinking behavior than the AFP sows, especially in the late lactating period (p < 0.05). Piglets in the FCs tended to spend more time walking than piglets in the AFPs (p < 0.05), whereas there were no differences in suckling and lying behavior between piglets in the two farrowing systems (p > 0.05). It is concluded that the AFPs with temporary crating until day 4 postpartum did not negatively affect performance and crushed piglet compared with the FCs. It also may improve animal welfare by allowing sows to move and turn around during the lactating period. Further research is needed to find suitable housing designs to enhance productivity and animal welfare.
We studied the effects of heat waves (HW), defined as three consecutive days with an ambient temperature ≥ 25 °C and a temperature and humidity index (THI) > 74, on the reproductive performance of sows. Meteorological data were obtained from the National Institute of Meteorology and reproductive data from a commercial farm with 51,578 inseminations and 49,103 pregnancies from September 5, 2013, to July 12, 2019. Sows were divided into the following groups according to the parity order: group 1 (sows that did not experience HW on the day of insemination) and group 2 (sows exposed to HW on the day of insemination). The percentage of days that pregnant sows were exposed to HW was calculated as 0 to 25% (1), 26 to 50% (2), 51 to 75% (3), and > 75% (4). Out of a total of 2137 days, there were 160 HW and more than 10 HW per month, except in May, June, and July. Gilts in group 2 showed a decrease in the percentage of gestation (98.21% and 98.78%, respectively, P = 0.0267) and the percentage of births compared with those in group 1 (95.53% and 96.61, respectively, P = 0.0065). Primiparous sows in group 2 had a higher percentage of abortions than gilts in group 1 (3.20% and 2.42%, respectively; P = 0.0334). Sows exposed to more than 50% HW during gestation produced more mummified piglets than sows exposed to less than 50% HW. The number of stillborn piglets was higher in sows exposed to temperatures above 25% HW during gestation. The occurrence of heat waves in gilts and primiparous sows impairs reproductive performance.
Because of their intense metabolism, lactating sows are highly sensitive to high ambient temperature which induces a reduction in their voluntary feed intake and milk production, which decreases piglet weaning weight. This also results in an increase in mobilisation of body reserves that may impair reproduction after weaning. The aim of the study was to quantify, on the basis of a quantitative analysis of the literature data, the effect of ambient temperature on the performance and physiology of lactating sows, with the perspective of integrating this knowledge in sow nutrition decision support tools. A literature database with 38 publications and a total of 227 observations was built in order to adjust prediction equations according to temperature, using a Mixed linear or quadratic model with random effect of publication, for different criteria such as feed intake, litter and piglet growth rate, milk production, maternal body reserve mobilisation, respiratory rate (RR) and core body temperature. The first criterion with the highest response to temperature was RR which increased by 175 % between 22 °C and 32 °C. The second most affected criterion was feed intake which was reduced by 36 % between 22 °C and 32 °C, and the third one was milk production which was reduced by 20 % between 22 °C and 32 °C. The equations obtained from the meta-analysis were incorporated into a nutrition model, based on InraPorc®, in order to predict, in the context of climate change, the effect of temperature on feed intake, milk production, energy and aminoacid utilisation, and body reserve mobilisation. The simulations performed using this model clearly indicate that nutrient requirement of sows per kg feed is affected by variation in ambient temperature due to seasons or to expected climate change. In practice, the integration of these new equations in nutritional models will enable feed composition to be better adapted to the season and to the geographical location of farms.
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Background Resveratrol has numerous beneficial properties, including antioxidant, anti-inflammatory, and immunomodulatory properties. High summer temperatures in Southern China affect the reproductive performance of sows. The present study aimed to investigate the effects of dietary resveratrol supplementation in different thermal environments on the reproductive performance, antioxidant capacity, immune function, and intestinal microbes of sows and piglets during late gestation and lactation, as well as their relationship with colostrum immunoglobulin. Methods A two-phase experiment was conducted with 40 healthy multiparous sows. In the first phase of the experiment, 20 sows were used in a moderate temperature environment, and in the second phase of the experiment, the remaining 20 sows were used in a high-temperature environment. In both phases, sows were fed either a control diet or a diet consists of control diet and 300 mg/kg resveratrol starting on day 75 of gestation. Plasma, milk, and fecal samples were collected to obtain the indices of antioxidant capacity, immune function, and intestinal microbes. Results The results showed that resveratrol supplementation increased the number of live births by 13.24 and 26.79% in the first and second phases, respectively, compared with the control group. In the second phase, resveratrol supplementation increased litter weight at weaning and in the concentrations of growth hormone (GH), insulin (INS), progesterone (PROG), triglycerides, and uric acid (UA). The plasma superoxide dismutase (SOD) level on day 110 of gestation and day 14 of lactation, as well as glutathione peroxidase (GSH-Px) on day 14 of lactation in the first phase, showed an increasing trend ( p = 0.0728, p = 0.0932, and p = 0.067, respectively) in the resveratrol group, compared with the control group. On day 14 of lactation, the plasma total antioxidant capability (T-AOC) level was higher in the second phase, while the plasma malondialdehyde (MDA) level was lower in both phases in the resveratrol group. Resveratrol supplementation increased the abundance of immunoglobulin A (IgA), immunoglobulin G (IgG), and immunoglobulin M (IgM) in colostrum and the relative abundance of Lactobacillus and Alloprevotella but decreased the relative abundance of Escherichia-shigella in piglet feces in the second phase. In addition, Spearman's correlation analysis indicated that the weight gain of weaned piglets was positively ( p < 0.05) associated with IgM content in colostrum and the abundance of Lactobacillus in the fecal microbiota of piglets in the second phase. Moreover, the abundance of Alloprevotella was positively correlated with the contents of IgA and IgG in colostrum, while the abundance of Lactobacillus was positively correlated with IgM content. Conclusion These findings indicated that maternal resveratrol supplementation could enhance the growth performance, antioxidant capacity, and intestinal health of piglets in a high temperature environment, which might be associated with increased immunoglobin secretion from colostrum.
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In the framework of its Farm to Fork Strategy, the Commission is undertaking a comprehensive evaluation of the animal welfare legislation. The present Opinion deals with protection of pigs during transport. The welfare of pigs during transport by road is the main focus, but other means of transport are also covered. Current practices related to transport of pigs during the different stages (preparation, loading/unloading, transit and journey breaks) are described. Overall, 10 welfare consequences were identified as highly relevant for the welfare of pigs during transport based on the severity, duration and frequency of occurrence: group stress, handling stress, heat stress, injuries, motion stress, prolonged hunger, prolonged thirst, restriction of movement, resting problems and sensory overstimulation. These welfare consequences and their animal-based measures are described. A variety of hazards were identified, mainly relating to factors such as mixing of unfamiliar pigs, inappropriate handling methods and devices, the use of pick-up pens, inexperienced/untrained handlers, structural deficiencies of vehicles and facilities, poor driving conditions, unfavourable microclimatic and environmental conditions and poor husbandry practices leading to these welfare consequences. The Opinion contains general and specific conclusions relating to the different stages of transport of pigs. Recommendations to prevent hazards and to correct or mitigate welfare consequences are made. Recommendations were also developed to define quantitative thresholds for microclimatic conditions and minimum space allowance within means of transport. The development of the welfare consequences over time was assessed in relation to maximum journey duration. The Opinion covers specific animal transport scenarios identified by the European Commission relating to transport of cull sows and ‘special health status animals’, and lists welfare concerns associated with these.
The objective of this study was to describe the physiological response of gestating and lactating sows to naturally-occurring environmental conditions, and to identify factors that may contribute to or prevent heat stress, while being kept outdoors in Québec, Canada during the summer. Six groups of 4 Yorkshire-Landrace sows lived in outdoor pens equipped with a wallow, shade structure, farrowing huts and access to a pasture from July to September, 2018. Between week 15 of gestation and week 3 of lactation (inclusive), we recorded the location of each sow 5 days/week during 5 daily 15-min observation periods, and additionally measured the sow's respiratory rate and mud cover at the end of each observation period. Simultaneously, we collected sow body temperature data with vaginal temperature loggers 24h/d on week 15 of gestation and week 2 of lactation, and monitored environmental conditions with temperature and humidity loggers to calculate the temperature humidity index (THI). Sows had significantly higher and more variable body temperatures during lactation compared to gestation (P≤0.0001), and when THI was analyzed as a continuous variable, it was positively associated with sow body temperature during the night in lactation. During gestation, neither respiratory rate nor body temperature were associated with high or low levels of THI (P=0.15 and 0.79, respectively) or mud cover (P=0.29 and 0.94, respectively). However, in lactation, respiratory rate was higher when, simultaneously, THI exceeded 74 and mud cover was low (P=0.006), while a THI higher than 74 and a low mud cover had independent effects on body temperature (P=0.012 and 0.004, respectively). In lactation, sows that spent an entire observation period in the farrowing hut also had a higher respiratory rate than sows that left the hut at least once (P=0.009). In summary, lactating sows were more likely to show increases in respiratory rate and body temperature in warmer conditions than gestating sows, and our findings also suggest that time in the farrowing hut may be a risk factor for heat stress. However, mud cover may limit these physiological consequences when sows have access to a wallow.
Metabolic demands of modern hybrid sows have increased over the years, which increases the chance that sows enter a substantial negative energy balance (NEB) during lactation. This NEB can negatively impact reproductive outcome, which is especially evident in primiparous sows causing a reduced second parity reproductive performance. The negative effects of the lactational NEB on reproductive performance can be partly explained by the influence of the premating metabolic state, during and after lactation, on the development of follicles from which oocytes will give rise to the next litter. In addition, the degree and type of body tissue mobilization during lactation that is, adipose tissue or lean mass, highly influences follicular development. Research investigating relations between the premating metabolic state and follicular and oocyte competence in modern hybrid sows, which experience higher metabolic demands during lactation, is limited. In this review we summarize current knowledge of physiological relations between the metabolic state of modern hybrid sows and follicular developmental competence. In addition, we discuss potential implications of these relations for current sow management strategies.
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Two trials were conducted on pure Large White multiparous (Trial 1, n = 36) and primiparous (Trial 2, n = 24) sows exposed to an ambient temperature within the zone of thermal comfort (18 or 20°C) or above the evaporative critical temperature (27 or 30°C). During a 3-week lactation, all sows in Trial 1 and those maintained at 30°C in Trial 2 were fed ad libitum whereas sows at 20°C in Trial 2 were paired-fed with those at 30°C. The same standard diet containing 17.2% crude protein, 0.84% lysine and 13.0 MJ DE/kg was used during lactation. Single blood samples were drawn from the jugular vein before the morning meal at day 107 of gestation, at days 13 and 20 post-partum (p.p.), at days 1 and 12 post-weaning in Trial 2. After weaning, sows were checked daily for oestrus in the presence of a mature boar. Daily feed intake was lower at 27°C than at 18°C from day 4 p.p. until weaning in Trial 1 (-28%) and very low in both groups of sows in Trial 2 (2.8 kg/day). Lactational loss of sow liveweight did not differ between groups in Trial 1 whereas it was lower at 30°C than at 20°C in Trial 2 (1.32 vs. 1.80 kg/day, P < 0.001). Daily litter growth was lower in the warmer environment in both trials (Trial 1: 1.58 vs. 2.15 kg/day, Trial 2: 1.60 vs. 1.95 kg/day, P < 0.05). In Trial 2, plasma concentrations of thyroid hormones were lower at 30°C than at 20°C (T3: 0.51 vs. 0.61 ng/ml; T4: 22.5 vs. 28.5 ng/ml), those of free fatty acids and insulin-like growth factor-I did not differ between treatments and, glycemia was higher at 30°C (P < 0.05). The weaning-to-oestrus interval was longer at 27°C than at 18°C in Trial 1 but did not differ between temperatures in Trial 2, being delayed in both environments. In conclusion, high ambient temperature reduces appetite, milk production and body reserve mobilization of sows in order to limit heat production. Reduction in feed intake plays probably a role in the delayed return-to-oestrus after weaning under elevated temperature.
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Prediction equations were determined from results of dissection and chemical analysis of primiparous and multiparous sows obtained at mating, at farrowing or at weaning. One hundred and eighty nine sows were dissected and among them, 23 were chemically analysed. The equations were calculated using the double regression technique, empty body weight (EBW, kg) and backfat depth (P2, mm) being used as predictors of the chemical composition. The following relationships were obtained: Lipids (kg) = -26.4 + 0.221 EBW + 1.331 P2; Energy (Mcal) = 257 + 3.267 EBW + 10.99 P2; Protein (kg) = 2.28 + 0.178 EBW - 0.333 P2; Minerals (kg) = 0.58 + 0.037 EBW - 0.081 P2. These relationships can be used to evaluate the variations in chemical composition of sows according to their physiological stage in the successive reproductive cycles, and quantify the amounts of nutrient, especially energy, required to meet targets of body weight and backfat depth.
L’objectif de cet article est de préciser les effets de la température ambiante sur le métabolisme énergétique, les performances de croissance et les besoins nutritionnels du porc en croissance-finition en élevage intensif et d’estimer son optimum thermique. Au plan énergétique, la température critique est estimée à environ20°C en croissance et 15 °C en finition. Elle correspond à une utilisation maximale de l’énergie alimentaire et sa signification zootechnique est discutée. La température ambiante influence la nature des dépôts tissulaires, l’accrétion lipidique étant la plus affectée. Pour ce qui est des performances, en alimentation libérale,la consommation spontanée d’aliment d’un porc de 60 kg diminue de 22 g/j/°C entre 10 et 20°C, sans effet sur le gain de poids. Entre 20 et 30°C, cette diminution est plus marquée (73 g/j/°C) et s’accompagne d’une réduction du gain de poids(40 g/j/°C) et de l’adiposité corporelle. L’indice de consommation décroît de 0,044unité/°C entre 10 et 20°C et est minimal vers 25°C. En tenant compte des objectifs de réduction du coût alimentaire et de l’état d’engraissement des carcasses, la température optimale pour le porc en croissance-finition élevé sur caillebotis béton est de 24-25°C. Les études d’interaction avec l’alimentation ont montré qu’au froid les animaux valorisent bien les aliments riches en fibres alors qu’au chaud les meilleures performances sont obtenues avec des rations concentrées en énergie. Ces études ont également permis d’estimer l’accroissement du besoin énergétique à 25 EM/kg0.75/j/°C entre 20 et 12°C et de montrer que, pour un même gain de poids ou de muscle, le besoin journalier en acides aminés est indépendant de la température ambiante.
Pigs (33-66 days old) were exposed to temperatures of 15, 20, 25, 30, 35 and 37. 5 degree C in 88 experiments. Data collected includes hypothalamic rectal and 8 skin surface temperatures, oxygen consumption, carbon dioxide production, respiratory evaporative water loss, respiration rate and regional skin surface areas. Metabolic respiratory and vasomotor thermoregulatory defenses are presented and discussed.
Eighty-eight first-litter sows were used in a factorial experiment to examine the effects of energy and protein intakes during lactation on subsequent performance. Some received either 45 MJ (E,) or 60 to 63 MJ (E 2 ) digestible energy per day and either 508 to 511 (P,) or 703 to 815 (P 2 ) g crude protein per day during a 28-day lactation. Sows on the E 2 P 2 treatment lost less body weight during lactation than sows on the other three treatments ( P < 0·05). Average live-weight losses during lactation were 21·8, 20·8, 17·8 and 9·6 kg for the E 1 P 1 , E 1 P 2 , E 2 P 1 , and E 2 P 2 sows, respectively. The corresponding reductions in backfat measurements during lactation were 5·5, 7·9, 3·2 and 4·0 mm. Backfat losses were greater for sows given either moderate energy intakes or high protein intakes ( P < 0·01). Neither protein intake nor energy intake during lactation affected subsequent ovulation rate, but piglets sucking sows given high protein intakes grew faster, particularly during the last week of lactation, than piglets sucking sows receiving low protein intakes ( P < 0·05). Within 8 days of weaning, more sows given high intakes of protein during lactation exhibited oestrus than did sows which received lower intakes of protein (27/44 v. 14/44, x ² = 7·7, P < 0·01). Protein intake during lactation affected the nitrogen balance of sows in a similar way. The nitrogen balances were estimated during the 3rd week of lactation, and for sows given rations E 1 P 1 , E 1 P 2 , E 2 P 1 , and E 2 P 2 were -20·2, -11·5, -17·5 and -7·2 g/day respectively.