[Jacob-list] pregnancy toxemia

[iseespots]

Hi Carl and all,

Here is what the Merck Vet manual says about it----long.
PREGNANCY TOXEMIA IN EWES (Ovine ketosis)

A disease of preparturient ewes, characterized primarily by impaired nervous
function.

Etiology:  The primary predisposing cause is undernutrition in late
pregnancy.  Overfed ewes carrying twins or triplets are more susceptible
than ewes in poor condition and those carrying single lambs.  Anything that
interrupts feed intake (eg. storms, transport, other disease conditions) may
induce the disease.  The primary lesion is hypoglycemic encephalopathy, the
result of inability of the ewe to supply sufficient glucose (from products
of digestion or catabolized tissues) to meet the carbohydrate demands of
large multiple fetuses and herself.  The defect appears to be in maintaining
the blood glucose level, since utilization of available glucose is
unimpaired.  As the disease progresses, severe ketosis and acidosis may
develop, together with hepatic, renal, and possibly endocrine disorders.
The blood glucose may rise without alleviating the signs of encephalopathy.
At this stage, the ewe is refractory to treatment.

Clinical Findings and Diagnosis:  Early clinical signs may be erratic and
difficult to detect.  The usual course, lasting 2-5 days, includes
listlessness, inappetence, aimless walking, "propping" against any kind of
obstruction, muscle twitching (of the ears, around the eyes, and perhaps of
other parts), unusual postures, grinding of the teeth, progressive loss of
reflexes, blindness, ataxia, and finally sternal decubitus, coma, and death.
Laboratory test usually reveal hypoglycemia early, with normoglycemia or
hyperglycemia later, and hyperketonemia.  Acidosis and high blood nonprotein
nitrogen are variable concomitant findings.  Necropsy findings include fatty
livers, indistinguishable from those found sometimes in apparently healthy
ewes underfed near term.  The adrenal glands may be swollen, hyperemic, or
grayish.  Pulmonary changes are associated with recumbency.
Acute hypocalcemia before lambing is the main differential diagnosis.  In
this, the course is shorter (deaths occur within 24 hr), and usually there
is a marked, immediate, and persistent response to IV calcium therapy.

Treatment:  Once signs are advanced, no treatment is highly effective.
Mortality of untreated cases is ~80%.  With early diagnosis, such as may be
made by gentle driving of the flock, particularly when the disease has been
induced by relatively sudden fasting, glyceroll or propylene glycol (PO, 4
oz bid) decreases mortality.  Best results are obtained by the combination
of one of these with an anabolic steroid and fluid therapy to counter
acidosis, but the mortality is still likely to be ~50%.  Cesarean section or
induced abortion early in the course of the disease usually leads to
recovery and, if near term, the offspring may be saved.  Palatable feed and
water and protection from extremes of weather should be provided.
Force-feeding bid with soaked alfalfa pellets given by stomach tube may be a
worthwhile practice with especially valuable animals; treatment should be
continued until the appetite returns.

Prophylaxis:  Obesity should be avoided in early pregnancy, and adequate
good feed supplied during the last 6 wk of pregnancy.  Feed supplementation
depends on the condition of the pastures and weight of the ewes.  When the
pastures become poor, heavy feeding may be necessary.  If adequate and
suitable feed is not available for the whole flock during late pregnancy,
early cases can be identified by gentle driving.  These can be separated
from the flock and given special care and nourishment, but any interruption
of feed intake should be avoided.
When the disease occurs in fat ewes on good pastures, perhaps associated
with mild foot conditions, gentle driving for 30 min may prevent incipient
cases from developing by elevating the blood glucose for a period.  When
supplementary feeding can be provided as prophylaxis, it is important to
prevent overeating, which may cause lactic acidosis and laminitis.  Both
diseasese are probable if grain is made available ad lib.

MEH
ISeeSpots Farm www.iseespots.com
Home of Jacob Sheep, and German Angora Rabbits,
colored German Angora crosses and a few French.
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