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compensate for the heat lost from
the lamb’s transition into the external
environment, lambs have to increase
their heat production by up to 15
times.
(3)
Even though sheep are normally quite
resistant to cold weather, cold stress
can cause significant discomfort to
lambs if they are not kept dry and
adequately nourished.
(2)
The resultant
hypothermia can cause a dramatic
rise in lamb mortalities and therefore,
protection and shelter from wet
weather and wind chill is vital.
(1,2)
Lambs rely almost entirely on their
physiological ability to utilise brown
adipose tissue to generate heat.
Interestingly, the development of these
brown adipocytes is regulated by
the thyroid hormones and variations
in these hormones are a reflection
of breed differences in lamb body
temperature.
(2)
Smaller lambs have less body
reserves, and are therefore generally
weaker, slower to stand and have
less drive to suckle.
(1,2,3)
The ability
of the lamb to stand up and suckle
is fundamental in ensuring that
sufficient colostrum is ingested on
time.
(2)
Standing also decreases heat
loss to the ground.
(1)
Lambs do not
receive antibodies from the ewe via
the placenta therefore, neonatal lambs
are very vulnerable to infectious
diseases until they have acquired
passive immunity through their dam’s
colostrum.
(1,2,3)
The window for
passive transfer of immunity is very
narrow, not only because of the lamb’s
intestinal closure to immunoglobulin
absorption between 24 and 36 hours
after birth, but also because the
concentration of immunoglobulins in
the colostrum decreases rapidly.
(1)
Insufficient intake of colostrum is a
major factor affecting neonate survival.
(1,3)
Early colostrum intake will also
enable the lamb to increase heat
production by 17 %, even if body
reserves are low, thereby providing
increased resistance to hypother-
mia.
(1)
In the first 18 hours of life, a
lamb needs approximately 50 ml
colostrum per kilogram bodyweight
at an environmental temperature
between 18 °C to 26 °C, which
increases to approximately 280 ml
colostrum/kg at 0 °C to 10 °C, however,
few ewes can meet their lamb’s
needs in these instances.
(1,3)
Even
though twin-bearing ewes produce
more colostrum, they do not have as
much colostrum per lamb, which has
serious implications for lambs already
born at lower birth weights and lower
energy reserves.
(1,3)
An estimated
10 % of single-bearing and 30 % of
twin-bearing ewes do not produce
enough colostrum for their lambs after
birth.
(3)
For this reason, it is imperative
to ensure that ewes receive good and
adequate nutrition, so that there will
be sufficient colostrum available and
subsequent milk produced to meet the
needs of the growing lamb.
(3)
Look out for Part 2 in the June issue.
References:
1. Dwyer CM, Conington J, Corbiere F,
Holmøy IH, Muri K, Nowak R et al.
Invited review: Improving neonatal
survival in small ruminants: science
into practice.
Animal.
2016 Mar 1;
10(03):449-459.
2. Dwyer CM. The welfare of the
neonatal lamb.
Small Ruminant
Research
. 2008 Apr 30; 76(1):31-
41.
3. Nowak R, Poindron P. From birth
to colostrum: early steps leading
to lamb survival.
Reproduction
Nutrition Development
. 2006 Jul 1;
46(4):431-446.
Zoetis South Africa (Pty) Ltd., Co. Reg.
No.: 2012/001825/07, 6th Floor, North
Wing, 90 Rivonia Road, Sandton,
2196. PO Box 783720, Sandton, 2146,
South Africa. Tel.:
+27 11 245 3300
or
0860 ZOETIS (0860 963847).
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African Wildlife Foundation decries ruling on
South Africa’s rhino horn trade ban
The following is an excerpt from a statement by Philip Muruthi,
vice-president for species protection from the African Wildlife Foundation,
issued after the ruling by the Constitutional Court
It is a sad day for Africa’s rhino. The dismissal was made on appropriate legal grounds but from a conservation
perspective, it is potentially disastrous for Africa’s imperilled rhino population. Africa’s rhino have already suffered record
levels of poaching to supply the illicit rhino horn trade. With the moratorium on domestic trade lifted in South Africa,
criminal gangs now have legal cover under which to operate. We have already seen the damage a legal market can
do with the elephant ivory trade over the past 25 years. The legal trade has muddied the waters for law enforcement
combating illegal ivory trafficking, while removing the stigma once attached to owning, buying and selling ivory. This
strategy has ultimately proven ineffective in stopping elephant poaching, and there is no reason to expect a different
outcome for Africa’s rhino. What’s more, a decision to legalise rhino horn trade could be interpreted as an endorsement
of the erroneous belief that the horn contains medicinal properties. If legalisation is perceived as an endorsement, it could
stimulate, rather than curtail, demand. As we’ve stated previously, legalising any rhino horn trade sends mixed messages
to the marketplace at a time when a single, unambiguous message needs to be communicated to the millions – possibly
billions – of existing and potential consumers of this product. The dismissal of the appeal is an indisputable setback for
those trying to protect Africa’s rhino. We at AWF despair for what this will mean for the survival of the species.
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