1) PREGNANCY TOXEMIA
Also known as pregnancy disease, ketosis or twin lamb disease.
Pregnancy toxemia is a metabolic disease of goats and sheep in late
pregnancy. Factors important in the development of the disease are: (1)
Presence of two or more fetuses; (2) Undernourishment during late
pregnancy when the fetuses have the most rapid growth; (3) Addition of
stress such as severe weather, sudden changes in feed, other disease or
transportation upon the previous factors. The disease usually appears
in the last 30 days of pregnancy and is more common after the first
pregnancy. The does show signs of ketonemia, ketonuria, acidosis and
central nervous system involvement. The mortality rate is high in
affected animals. Most information available is the result of studies
As pregnancy progresses, an increasing demand is on the
available blood glucose supply of the doe or ewe because of fetal
development. The principal source of energy to the fetus is glucose
and utilization by the fetus occurs at the detriment of the mother.
Glucose requirements during late pregnancy are increased 70-800ver
the nonpregnant state since 800f fetal growth occurs during the last
40 days of pregnancy. Blood sugar levels decrease as pregnancy
progresses (hypoglycemia) from a normal 35-45 mg per 100 ml blood to
20-25 mg per 100 ml blood in late pregnancy. Pregnancy toxemia may
develop when levels decrease to about 18 mg per 100 ml blood. The
severity of hypoglycemia will be directly affected by undernourishment
of the mother or by increased requirements of the fetus(es).
As the glucose supply diminishes from increasing fetal demands and
decreased glucose production due to undernourishment, energy
requirements are furnished by other metabolic pathways, i.e. from free
fatty acids and amino acids. Breakdown of the free fatty acids results
in increased production of ketones, acetoacetate and
B-hydroxybutyrate. As hypoglycemia becomes more severe, the ketone
level in the blood increases (ketonemia) and ketosis occurs.
As ketosis increases, the bicarbonate level in the blood decreases
and acidosis may result. When the bicarbonate level declines
sufficiently, the animal will become comatose. During the later stages
of pregnancy toxemia, water consumption decreases, urine output is
decreased and kidney function is impaired. The blood sugar level may
increase severely (hyperglycemia) during the late stages of the
disease as a result of the response of the adrenal glands to stress.
Circumstances which cause severe hypoglycemia will usually result
in pregnancy toxemia. Under-nourishment of the doe may not meet the
demands for glucose production. The level of nutrition should be
increasing as pregnancy progresses so that the doe will be able to
provide fetal requirements. The doe should be gaining weight during
pregnancy. As previously mentioned, multiple fetuses greatly increase
the glucose requirements. A gradual onset of undernourishment, as would
be seen if the feed intake was not increased during pregnancy, may be
tolerated by the doe and toxemia may not develop. However, if the
animal is starved for several days, pregnancy toxemia may develop
readily. Sudden changes in weather, infections or transport may result
in periods of inappetence and may trigger pregnancy toxemia.
Excessively fat animals may develop periods of poor appetite under
6) Clinical Signs
Clinical signs are those observed with involvement
of the central nervous system. Initially, the animal tends to separate
from others. There is mild depression. Evidence of blindness develops,
the animal runs into objects, shows little or no reaction when
approached, and wanders aimlessly. Dullness and depression become
progressively severe. There is reluctance to move. Eventually they go
down in sternal or lateral recumbency and show little or no response to
their environment. The does become comatose and eventually die.
Occasionally, animals may show a short period or intermittent
periods of hypersensitivity. There may be quivering, twitching of the
ears, muzzle or eyelids or spasms of certain muscles. Incoordination
may be evident. Recumbent animals may have convulsive paddling
Chewing, teeth grinding or vigorous licking movements may be seen.
Mild scouring may be present. A snuffling respiration due to excessive
nasal secretion may be common. Drooling of saliva is also seen.
Temperature and pulse are within normal limits. Respiration is
usually normal until the later stages when it may become labored. The
appetite is poor or absent. Ketones may be detected in the urine.
In some herds, 200r more may be affected. Mortality may reach
80 Some may recover spontaneously following parturition or abortion.
11) Post Mortem Findings
The liver is enlarged and has a pale yellow
to orange coloration. The adrenal glands may be enlarged. The uterus
contains two or more fetuses.
Oral administration of glycerol or propylene glycol or
intravenous administration of glucose may be effective in the early
stages of the disease. Insulin may be used with these treatments for
better utilization of glucose. During the late stages of the disease,
glucose administration may be ineffective or detrimental because the
blood glucose levels may be very high.
During the later stages of the disease, acidosis and dehydration
may be important factors. Intravenous administration of large volumes of
electrolyte solutions with sodium bicarbonate may be important.
Corticosteroids may not be effective in the later stages unless given
at dosages utilized to combat endotoxic shock.
Cesarean section or other methods of terminating pregnancy may be
effective in some cases.
An adequate nutritional level throughout the
pregnancy will prevent pregnancy toxemia. Protein and energy levels
during the last 30-40 days of pregnancy should meet the doe's
maintenance requirements as well as the growth requirements of the
fetuses. Allowing the animal to become excessively fat should be
16) Management during late pregnancy should be directed at avoiding
appetite problems in the animals. Avoid sudden feed changes, diminish
stresses of severe weather, delay or avoid transportation and prevent
concurrent disease problems.