Thermoregulation in rabbits
Fayez I., Marai M., Alnaimy A., Habeeb M.
in
Baselga M. (ed.), Marai I.F.M. (ed.).
Rabbit production in hot climates
Zaragoza : CIHEAM
Cahiers Options Méditerranéennes; n. 8
1994
pages 33-41
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-------------------------------------------------------------------------------------------------------------------------------------------------------------------------Fayez I., Marai M., Alnaimy A., Habeeb M. Th ermoregu lation in rabbits. In : Baselga M. (ed.), Marai
I.F.M. (ed.). Rabbit production in hot climates. Zaragoza : CIHEAM, 1994. p. 33-41 (Cahiers Options
Méditerranéennes; n. 8)
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CIHEAM - Options Mediterraneennes
Thermoregulation in rabbits
1. Fayez, M. Marai" andA. Alnaimy, M. Habeeb""
*
Faculty of
of Animal
Zagazig
Egypt.
**
of
13759.
Temperature of 21 OC is the "comfort zone" inrabbits. When the
animals are exposed to higher or lower temperature, the heat dissipation orheat
production must be carried out to maintain its body temperature. Thermoregulation
mechanism is conducted by different
the nasal mucose and the
ear are the important heat dissipation pathways in rabbits.
Heat dissipation, respiration rate, nasal mucosa, ear, rabbits.
Introduction:
induced by
The wild
much of
is
than those that of the domestic
The
body
climatic conditions and the means
will
discussed.
body
goes up
goes up
at
till noon then
night indicating that body
was not affected instantly by changes in
day.
body
within a
(0.2-0.3 O C )
efficiency of body heat
in
to
of
be
Diurnalandseasonalvariationsin
body heat regulation:.
(Shafie
1970)
b.
a.
physiological
ol
(Finzig&A, 1994).
to
of
body
is about 39.5'C,
is
-
33 -
of
CIHEAM - Options Mediterraneennes
168 and 235,
in New Zealand White
(Lee et al., 1976 and
1960), while in White Egyptian "Giza"
.a
vasodilation
that,
and 137 cpm
conditions of Egypt (Shafieet
al., 1982). Shafie al. (1982)
that when
to
by 70% of
its
while Johnson
al. (1957) noticed that
of New Zealand
physiological
body
39.4'C,
85
doubled
value at
Specially,
value
by 5-6
et al. (1957) and Shafie
to
cooling. The
by
at the
loss
above
and these
in a hot
the
1976)
could
of metabolizable
thus
goes up
each l'C
1985).
Response of rabbits to the climatic
conditions:
(1970)
that
lobe
highly effected
by
monthly
changes, due to the fact
physiological
the
means which
can keep body
added thatthe
which
changes. At
lobe
by 70% of its
(15OC
(1945)
that,
at
to
lobe, indicating
the two
lobe
The main components of climate
movement
the most
ones. The
of
each of these
components is as follows:
maximum values of
(1945)
that the slight change in pulse
due to
as the
is
- 34
the animal has
-
of 2loC is known
At
to expend
CIHEAM - Options Mediterraneennes
maintain
its body
heat
and
losses
body
by modifying
feed
intake level and using
devices to
mod@ heat loss:
body
position,
especially
ambient
is below 10°C, animals
minimize
loosing heatand
is
above 25 - 3OoC,
out so they can loose as much heat as
possible by
convection
(Lebas
much
1986).
to
low
high
of
(Lebas and
1982). Lebas (1989)
theheat
1963).
that the
low
is that feed consumption
so animals can maintain
is
a high
load on animals
to
30oC elevates body
39.67 to
and pulse
to 156 pulses/ minutein New
Zealand White
et
1957). The
69 to 190
by
18.3
to 33.3'~.
of
by
to
above 24OC
(Lee et
1976).
body
With continuous
conditions (e.g.
lines) w
l
l
i
than its
at
some
as the
Siames Satin and Sable, if
on
an adultis shaved and then exposed to
cold,
will
in
black in
it is
white. Fluctuations
may
of
especially, following the
of a cold
snap. One possibility to account
this is that a sudden
in
an
in
feed intake.
this could cause
i.e.
of pathogens in the gut
with the
of lethal toxins.
in
a
is used to
quantity of feed
maintain body
feed .
in cold
feed
must be
is also expected
consumption
as
because of the
in feed
availability of
cold
Above 35OC,
-
-
no
CIHEAM - Options Mediterraneennes
'
in (Lebas &
Latentheatcan
no
dissipated when
is too
high and humidity is also high.
case
is
which can be followed by
sets
1986). At 4OoC
of the
metabolic
and enzymes
as a function of
by animals
to diminish heat
to
the
heat load
(Johnson, 1980).
animals
with
develop metabolic mechanisms to
adapt to
since it is
thatinthe
new
successfully
conditions in which the
is consistently 32 - 35OC,
while
of the same
adapted to cool conditions of the
West of the United
States may dieof
when the
on
occasions exceeds
35OC (Cheeke
1982).
100% humidity which often
seasoncan
while
which is too
(below 60%
and
hot is
it do
not only upset the
of mucus,
but the
the size of
infection
agents, ending then to
easily the
humidity level does not
in
seem to
c. Ventilation:
much
sensitive
to
of noxious gases and
movement) than
a high
of noxious gases
(especially
and high
speed in
the vicinity of
diseases of
contagious
snuffles
1985).
a
minimum ventilation is needed in the
to evacuate l h e
(COz,
given off by
and so on)
of excess
humidity
of
access heat given
b.
sensitive to
high humidity and may be affected by
changes in humidity, but not
with constant humidity
which depends
on housing design. This may be due to
the fact that wild
much
of
lives in
withhumidity level
point (100%). Lebas et
(1986)
that
found
that adequate humidity level is 60 65%,
'
-
-
CIHEAM - Options Mediterraneennes
significance
of the
in
is that it enables the
animal to dissipate heat by
the
which accounts
about 30% of
the
total
heat
dissipation.
These
systems
between O°C and 3OoC,
but when
exceeds,
out so it
can loose heat as much as possible by
convection and a
in each of
may
and
Thus the appetite is
the
and
off by
ventilation
depending
especially on climate, cage typeand
population density.
The most
attaining
of noxious gases in closed sheds
the
of dung and
by a
of
the
if it
dung
with
shed
in the
of
a long
in the shed(no
- nipples, no flushing and
of
... etc.), no adjoining
pits, gullies
between the
of the shed, help in
of pathologenic
(1985) indicated that
efficient ventilation systems closed
those
with
a
of
of about 2/ kg live weight/
the
movement in
the
vicinity of the
animals must not exceed 0.5
/
second.
to disease is
b. Nasal mucosa
medium
sized (such as
heat
is
blood and when animals
exposed to heat,panting occurs
and
nasal
mucosa
as an
of heat dissipation.
The
conicha seees as a
good heat
due to its
extensive and highly
of
which is in
contact with the
(Caputa'&
1976 a and b).
-
Means of heat dissipation:
a.
The only
means of
latent heat evacuation is by
since most of sweat
glands in
notfunctional
(the evacuation of
the skin)is
because of
1963). The
Cooling of exhaled
complex
nasal cavity is an
heat
-
37
-
.
the
of the
of
(Caputa,
CIHEAM - Options Mediterraneennes
et al., 1976a).
mucosal
the
cooled because
added to the incoming
which leaves
the
&th
at body
passes
th'ese cool
giving up heat, but
a
of its
content is
on the mucosal
(Caputa &
1976b).
along
The
nasal conicha of
influenced
by ambient
The exchange of both
heat
between the
and nasal
mucus is facilitated by the
of
the
nasal conicha
which
the
passes.
The nasal conicha is about 25
long and consists of a
system of
a
pathway
movement which has
a
with a
distance
the
of
to the mucosal wall(Caputa et al.,
nasal cooling is
1976a).
The
only by
of
nasal cavity but also by
of
blood. flow
it, The
nasal conicha is
by many
the
to dista1
of the
1968 and Godynicki,
conicha
1975).
anastomoses
found in the conicha
1968). The blood supply is
advantageous
loss,
blood
et
exchange between the
Caputa
(197613)
that the
of
nasal
mucosal
in
mild
(35OC) is indicative. of
loss due
to
conditions, the
nasal conicha had the function
of a
On
hand,
of thenasal
vessels in cold
mucosal
blood
and,
heat loss.
and
(1969) and
Caputa et al. (1976 a)
that
spontaneous
activity is
accompanied by
cooling
of nasal
mucosa due
to
of its
vessels.
exchange between
is
leaves the
complete when
conicha, because the
of
of the
the conicha is not much
than
deep body
even in cold
exposed
.
the
conicha is
as
of
both heat
and
heat
dissipation.
c. The
The
function in
is like
a
(Lebas &
1986).
The physiological pathway of the
- 38 -
CIHEAM - Options Mediterraneennes
lobe
'
than at
is
of blood
the
body
to special blood vessels bed
lobes. The lobes of
supplied with a
big
of
blood
and
which could be
by
mechanism ( Johnson
1957). The tip
of the
lobe wasalways of
than the middle
because the
blood vessels of
less
abundant and of
than
those of the middle, so the blood
in vasodilation is
effective on the
of
the middle
lobe
The
of
of
lobe is
than that of
of the same
the animal
pimae and
it
the
body, exposing
to the ambient
dissipation by convection,
and
to maximum, while
the
pimae
folded
to cut-away its
contact with
at the same time, it
to
it
to the
body (Shafie
1970).
Conclusion
not functional and
evacuation of
is not
dissipation is
(the
the skin)
fur.
by
to
of the
the
addition the nasalmucosa
in that
play a big
References
S. (1945).
and
J. (1968) The
supply of
nose
cavity, Acta Anat. 70,168-183.
J.
W.
(1976a)
J.
W.
(1976b)
Significance of
blood
Acta
36~613-624.
Skin
was
stable
dueto
the
efficient insulation by
coat.
Johnson et al. (1957)
d.,
(1959)
that the coat was
at
Significance of
The
of
defence
-
-
in
venous lakes in the
Acta
CIHEAM - Options Mediterraneennes
G.S. (1982).
of high
of
J.N.
the
of the
in the
of
in five mammals.
417-440.
edited by
Cheeke,
and G.S. Templeton, 5th Edition. pp.
85-86.
by
(1960) A text book
.of
physiology.
5 , J.
and A.
.l04
place ,W. London.
16,
C.S. (1957).
of
on
(1985) "A text book
of a compenduim of
condition in developing
3 and 4,
Gesells
chaft
fur
technische
- wag
1,
study of
blood
physiological
cattle.
No 648.
and
of
Sta.
to minimize
change.
(1980)
of cattle
of climatic
of
of
'
(1994)
cycle of
body
in the hot season.
1st
on
in
Climate"
G.
and
health
and
United
Nations,
Egypt
S. (1975)
vessels of nasal cavity in
Folia
Food and
of the
Animal
21,6042.
.
J.S. (1959). The
in weight and tail length of
mice
at two
Livestock
and
.Livestock
9~235-250.
G,
- 40 -
(1982)
science,
CIHEAM - Options Mediterraneennes
in
,
LEE,
Effect
on bovine
(1976).
function,
imdantation. Animal
Science, 17,259-270.
Of
and
milk
Science, 59:104-109.
of
(1963). The
of cutaneous
in the
61:275.
calf. J.
fowls and its
S. A. (1976).
loss in domestic
to
Agric. Sci.
87527-532
F.
(1979). Effect of
on
physiological body
of
conditions.
Egyptian
of
Animal
10,133-149.
(1982).
conditions.
and
Egypt. 21-23.
development,
O . (1988)
conception
et
Cuni-Sciences, 2,l-28.
of 6th
on Animal
Zagazig,
- 41
-