This publication was written by Dr. Joe Rook from Michigan State University. It was published by Shepherd Magazine.

1. ~ ~
Hypothermia
, and Starvation in Michigan Lambs~
By J. S. Rook, DVM
Michigan State University
Hypothermia and starvation account for nearly 30% of all pre-weaning lamb losses. The majority of these losses
occur prior to 3 weeks of age and producers should realize that starvation and hypothermia account for 50% of all
losses during week one and on day one of life. Management practices greatly affect hypothermia and starvation rates
within given flocks. In large flocks averaging 10-20% total lamb death losses, hypothermia and starvation may account
for as much as 49% or as little as 2% of those losses. Producers and their veterinarians should routinely examine
numerous dead lambs to identify trends within a given flock and use this information as a basis for management deci-
sions. Lamb loss patterns within a given flock will vary from year to year and, thus, mortality surveillance should be
an ongoing process just as dynamic as are decisions concerning management. This removable series of color prints
and accompanying narrative should help producers to identify the most common mortality problems affecting their flock.
For most lambs, a quick gross postmortem examination can determine the cause of their death. In some cases it
...../ may be necessary to send lambs or their tissue samples to a diagnostic laboratory for testing. All producers, and especial-
ly women of childbearing age, should exercise caution while handling dead lambs. Wearing rubber gloves and not
allowing pregnant women to handle aborted lambs or placenta is just common sense.
The Shepherd

2. Weigh the lamb to determine the ap- and lift up (away from the rib cage) cut- vation problems so don't be surprised
proximate death weight. Small newborn ting the skin under the armpit. thus to observe both problems in the same
lambs are extremely prone to hypo- reflecting the front limb away from you ex- lamb.
thermia because they chill more quickly posing the entire rib cage. Look for signs Hypothermia lambs that die very
than larger lambs. Low birth weight of bruising over the ribs as fractured ribs shortly after birth may also have a smafl --J
lambs, that die from hypothermia and are a common result of trauma. Also look amount of clear amber-colored fluid in
starvation, may indicate a nutritional prob. for signs of pale discoloration of the mus- the chest.
lem in the ewes during late gestation. cle which might indicate vitamin E and 2. IS THERE FAT IN THE HEART
Older lambs that die of starvation and selenium problems or hemorrhage. Do GROOVES? While looking at the lungs,
hypothermia may also weigh less due to not mistake injection stains (yellow LA200 cut through the heart sac and expose the
simple starvation. Death weights for these or white penicillin) under the elbow for bare heart muscle. Normal stillborn lambs
2- to 3-week-old lambs are often similar abscesses as this is a common site for in- have a good supply of tan fat in the
or less than typical birth weights for the jections. grooves on the external surface of the
flock. It is important to connect this loss Normal newborn lambs have a layer heart. This fat is lacking in starvation
of weight to the mothering and milking of tan fat which follows the junction of the lambs who have metabolized it for energy.
ability of the ewe. Did she own the lamb? ribs to the cartilage of the sternum and 3. IS THERE MILK IN THE STOMACH
Was she fed enough to milk properly? the junction of the ribs with the spine. This AND INTESTINES? Normal newborn
Mastitis? Blocked teat? fat is readily apparent in stillborn lambs lambs have a very large true stomach
Examine the external surface of the but totally absent in starvation animals. filled with a clear mucus and small
lamb to give you an idea of what that lamb After necropsying starvation and hypo- rudimentary forestomachs. The absence.
was doing before it died. Most starvation thermia lambs, the comparison is obvi- of milk in the abomasum or true stomach
and hypothermia lambs die on day one. ous-look for it. is common in hypothermia and starvation
They are often thought to be stillborn Next make a long curved incision lambs. Normally, when a lamb nurses, the
lambs, and are tossed in the pile of "born from front to rear through the cartilage milk bypasses the forestomachs and goes
dead" lambs, when this is often not the junction of the ribs and sternum and con- directly to the abomasum where it forms
case. Stillborn lambs generally are coated tinue the cut up across the abdomen to cottage cheese-like curds during diges-
with thick mucus or bright orange-yellow the area just in front of the hip. Lift up on tion. Weak lambs tube fed by producers
fluid, have a wet, fresh looking umbilical the ribs and push them away from you often have fluid milk (lacking curds) pre-
cord, and often are still covered with (you may actually break the ribs at their sent in the forestomachs and abomasum
placenta. The bright yellow mustard- connection to the spine) allowing all the (since suckling did not take place) and
colored fluid covering them is uterine fluid internal organs of the chest and abdomen sometimes the extreme upper portion of
stained with the lamb's meconium to be viewed like an oyster on the half- the small intestine. Milk in the fore-
(manure) and indicates a difficult birth. shell. Trim any skin or muscle in your way. stomachs, lack of curdling and absence ......I
Also, look under the tail in the rectal area Finalfy, make a cut through the back of milk in the lower intestinal tract indicate
for any evidence of scouring and check of the muscles of the ham area to check tube feeding as a last resort. Do not rule
legs for any indication of fractures or for uneven, pale muscle discoloration out starvation simply by the presence
swollen joints. A quick check for major characteristic in this area for white-muscle or absence of milk. The presence of
congenital deformities shouid also be disease. large amounts of sltage. hay or grass
done. although these are rare. With the lamb opened in a routine man- In the stomach of very young lambs
Check feet and navel on all lambs to ner, the diagnosis of hypothermia and may also support starvation.
help determine the age of the lamb (if starvation and other common diseases 4. IS KIDNEY FAT PRESENT IN NOR-
unknown). Stillborn lambs have soft, can now be easily made while asking MAL AMOUNT AND COLOR? Kidney fat
rounded. clean soles. typical of newborn yourself several questions. color and consistency is probably the
animals. If manure is on the boltom of the 1. ARE THE WNGS NORMAL AND most remarkable change occurring in
feet and the soles are worn, the lamb was INFLATED? This is the first important starvation and hypothermia lambs. As you
strong enough to stand and was looking question to answer. especially in lambs examine stillborn lambs, look at the large
for nutrition and warmth. This is common- dying from hypothermia and starvation amount of light brown fat mother nature
ly the case with newborn lambs that pro- during day one. If the lamb is stillborn, the deposits around the kidney. This fat acts
ducers just find dead shortly after birth. lungs will be an even dark purple colora- as a source of energy for newborn lambs
These lambs were born alive and had a tion throughout-much the same color until they receive adequate nutrition. As
chance to survive. The umbilical cord also and feel as the liver. Normal aerated starvation ensues the fat changes from a
begins to dry and shrivel shortly after birth lungs, however, will be spongy to the light tan color to a dark purple gelatinous
and usually falls off between 3 to 10 days touch and an even colored pink. Varia- material (about the color of black cherry
of age. This will also help document age tions in color and feel with dark purple jello) as it is gradually metabolized for
if the time of birth is unknown. firm areas toward the bottom and front of energy. Kidneys in older starvation lambs
Routinely necropsy lambs no matter the lungs with normal feeling spongy pink are often totally devoid of any fat. In ex-
how sure you are of the cause of death areas toward the top and back might in- tremely cold weather, when the starving
since routine examination allows you to dicate pneumonia or some other cause lamb requires lots of calories for heat pro-
recognize normal structures and findings. of death. duction, this change in color may occur
You will not be prone to miss things if your over the 3-12 hours preceding death. In
exam is done the same way each time. Starvation and hypothermia lambs warmer weather, starvation may occur "-/
Lay the dead lamb on its right side with should have normal lungs unless some over several days and result in kidneys
the head to your left and feet towards you. compounding problem exists. Pneu- which are totally devoid of fat. If you look
Grab the front upper leg in your left hand monia is often found secondary to star- closely, a small gland known as the
The Shepherd

3. adrenal gland is also more obvious in
older starvation lambs.The adrenal is nor-
mally small and hidden under the renal
fat just in front of and to the inside of the
kidney. The adrenal enlarges to produce
more cortisone-like products in response
to the stress of starvation and becomes
more obvious due to the lack of fat.
Hypothermia and starvation lambs dying
very early in life will not have obvious
adrenal enlargement due to the acute-
Figure 3-Stillborn lamb. Atter cutting
ness of their condition. Older starvation through the rib cartilage, 11ft the ribs and
lambs may. push them away from you, breaking the ribs
Remember to check kidney fat on all at their attachment to the spine. This should
dead lambs to appreciate normal open the chest and belly cavity for easy
viewing. Notice the dark purple non.inflated
amounts and color, and avoid missing
lungs typical of a lamb which never
starvation-related Infectious diseases. breathed. Also, notice the straw-colored
Conclusion mucus normally found in the newborn's
Remember that 50% of all Michigan stomach and the large deposits of tan.
colored fat surrounding the kidney. Inflated
lambs. that were born alive and died dur-
lungs ot a lamb which had breathed would
ing week one of life. died from hypother- be reddish-pink in color and spongy feeling FIgures 6 & 7-Not;ce the normal amounts
mia and starvation. Approaching the compared to these dark purple lungs which of tan fat covering the ribs and chest
nutritional, environmental and manage- are of similar consistency to raw liver. muscles of a newborn lamb (figure 6). Com-
ment factorscontributing to starvationand pare this to the lack of fat cover In a 5-day-
hypothermia after lambing has begun is old stalVatlon lamb (figure 7).
simply plugging the dike. Think about
your operation and where changes could
be made for next year.
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Figure 4-Notice the normal amount and
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color of the kidney fat In a newborn lamb. Figure 8-This picture illustrates the pro-
ThIs tan fat selVes as an energy source dur- gressive fat loss and color changes com-
ing the first few days at life. Compare this monly observed In hypothermia and stalVa-
to the pictures ot sfalVation and hypother. tlon lambs. In cold weather; progression
mla lambs. from the normal fat color and consistency
observed in the upper left kidney to the
black cherry }ello color of the lower left or
Figure 1-Typical stillborn lamb positioned
upper middle kidney may only span several
on Its right side and ready to be necropsied.
hours. Warm weather starvation lambs sur.
Notice the yellow meconium staining and
'lIving several days may totally deplete the
soH rounded hooves commonly seen in still.
kidney at tat as observed in the kidney In the
born lambs. lower center row or on the far right.
Figure 5-Non-lnflated lungs of a stillborn
lamb. Areas of hemorrhage (dark purple
spots) on the lung surface are commonly
observed.
FIgure 9-AII the components of hypother-
Figure 2-Cut the skin under the lront leg mia and starvation are present. Notice the
and fold the cut leg oller the back of the sharp, manure stained hooves Indicating
lamb. Next cut the cartilage Junction of the that this lamb was up and walking. Notice
ribs and sternum and continue this cut the Inflated lungs, empty stomach and in.
through the skin and muscle up the flank to testlnes and the typical color change in the
the point of the hlp. kidney tat.
The Shepherd

4. Figure 10-Trauma lambs often show blood
loss into the chest or abdominal cavity. This
is normally due to fractured ribs or ruptured
livers. Notice the clotted blood around the
liver of this traumatized lamb.
Figures 12 & 13-Lambs dying from pneu-
monia usually will have a sharp line of
demarcation between normal (pink and
spongy) and diseased lung tissue. The dark
reddish-purple, firm diseased area is usually
Figure 11-Many lambs die from more than located to the front and bottom of the lungs
one cause. Notice the fractured ribs and with the normal area usually positioned to
punctured lungs typical of a traumatized the top and back. This is obvious In both
lamb. The owne~ thought that this lamb had figures 12 and 13. Figure 12 shows the sud-
been crushed. However, further examination den severe pneumonia that often occurs In
revealed a starvation kidney and empty 1- to 2-day~old lambs. Figure 13 shows a
stomach. Starvation was the primary cause more chronic condition with round, yellow
of death. Starvation underlies many trauma abscesses distributed throughout the dis-
and pneumonia deaths. eased portions of the lung.
Figures 14, 15 & 16-Abortlon causes are
often difficult to document. Figure 14 /I~
The Shepherd sincerely thanks Dr. Joe Rook for aI/owing us to publish his slides on lustrates the circular, doughnut-shaped
areas on the liver sometimes noted with
the necropsy of lambs. With the assistance of dedicated veterinarians like Dr. Rook, the
vibrionic abortion. Figures 15 and 16 are
sheep industry may be able to defeat the scourges of lambing time, hypothermia and commonly seen with toxoplasmosis abor-
starvation. We hope that our readers will make good use of Dr. Rook's work and that tion. Figure 15 illustrates a typical set of
it will aid them in diagnosing problems in their own lambing sheds. Again, our thanks twins aborted from toxoplasmosis. Notice
to Dr. Rook. the mummified fetus and more normal look.
ing twin. Figure 16 illustrates the white,
Guy Flora, Editor
granular appearance to the buttons of the
The Shepherd placenta commonly seen with toxoplas-
mosis abortions.
THEG"s'iiEPHERD
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