TOXICITY OF LITHIUM GREASE
Is "lithium grease" toxic to cattle? A good
question and one to stir the gray cells into action! What
is lithium grease? Is tithi'um in the grease toxic? What
other contents in lithium grease could cause a disease
A chemical dictionary describes lithium greases as greases
using lithium soaps of the higher fatty acids
as a base. They are water resistant and are stable when
heated above their melting point and cooled again. They
are used in aircraft and other low temperature service.
They are also in common use on farms as lubricants for machinery.
Lithium hydroxystearate from hydrogenated castor oil is
widely used. (Rose's Condensed Chemical Dictionary, 7th
Lithium carbonate (tablets or capsules) and lithium citrate
(syrup) are used in human medicine to treat some mental
conditions. Preclinical studies have shown that lithium
alters sodium transport in nerve and muscle cells and effects
a shift toward intraneuronal metabolism of catecholamines.
Lithium toxicity may develop in patients with significant
renal or cardiovascular disease, severe debilitation or
dehydration, or sodium depletion. Toxic levels of lithium
are close to therapeutic levels in humans (PDR, 1989).
The good news to the animal world is that lithium carbonate
is not very. toxic. The oral ld90 for rats is 710 mg/kg.
Intravenous toxic doses to animals are cardiotoxic, causing
ECG changes, and in high doses may cause renal failure (Gosselin's
Clinical Toxicology of Commercial Products: Acute Poisoning,
5th ed., 1984).
So what about the toxicity of lithium grease
in cattle? I have not found any specific studies on the
subject (they may exist), so I have to rely on conventional
wisdom and say that it seems very unlikely that a cow could
ingest enough lithium grease to cause a toxic response.
I would expect diarrhea to occur because of thegreasy nature
of the substance and caution about the possibility of
inspiration (foreign body) pneumonia, similar to that sometimes
seen in cattle following ingestion of waste oils and petroleum
It was suggested to me that lithium grease may contain
molybdenum, and again I know of no reports of molybdenum
toxicosis (secondary hypocuprosis) in cattle due to ingestion
of lithium grease. Molybdenum toxicosis in cattle is seen
clinically as a chronic toxicosis characterized as fading
of the haircoat(hypotrichromia), diarrhea and anemia.
If the reader is aware of specific information on the toxicity
of lithium grease, I would appreciate a letter or telephone
F.R. ROBINSON D.V.M.,PhD
CHIEF OF TOXICOLOGY