How Herbicide Phenoxy acids affects dogs
(Check out LINKS to epidemiological
studies)
MCPA, Phenoxy Acids: Effects in humans
The lowest published lethal oral dose for MCPA in humans is 814 mg/kg bw
(RTECS, 2005). Symptoms of acute exposure to large doses of MCPA have been
reported as a result of poisoning from accidental ingestion and accidental
exposure during manufacturing or application in the field. The symptoms
include fatigue, weakness,
anoxia,
nausea, vomiting and diarrhoea, lowering of the blood pressure, body temperature
disturbance, progressive hypotension
9.2.2 Short-term exposure studies Short-term studies were conducted on
the effects of MCPA, MCPA-DMAS and MCPA- in mice, rats and
dogs.
Adverse health effects were noted in the liver and kidney.
In general,
dogs appear to be more
sensitive than rats to the adverse
effects of MCPA after repeated exposure. According to the
U.S. EPA (2003, 2004e), this increased sensitivity appears to be a consequence
of reduced capacity in the elimination of MCPA in dogs relative to rats.
In a 28-day oral range-finding toxicity study, MCPA (94.8%) was administered
to mice (4–6 per sex per dose) in the diet at dose levels of 0, 100,
300, 900 or 2700 ppm (equivalent to 0,
19.1–22.0, 56.3–67.7, 173.4–184.8 and 453.7–820.1 mg/kg
bw per day for males and 0, 20.7–26.2, 69.2–73.9, 193.4–223.9
and 442.3–956.3 mg/kg bw per day for females).
Observed effects at the highest dose in both sexes included motor
disturbances, significant cumulative body weight loss, hepatotoxicity (increased
serum alanine aminotransferase [ALT] and alkaline phosphatase [ALP] activities,
increased liver weight and related histopathological findings), spleen effects
(decreased mean spleen weights, gross observation of involution, increased
neutrophil counts and decreased lymphocyte counts) and decreased kidney weights.
High-dose males had decreased mean testicular weight with histopathological
findings of testicular atrophy, whereas females had atrophy of the ovaries
and uterine glands. At necropsy, high-dose animals were shown to be cachectic
(state of general ill health characterized by malnutrition, weakness and
emaciation). Liver effects (cloudy swelling) were observed in one mid-dose
female.
dogs
(four per sex per dose) at dose levels of 0,
3, 12 or 48 mg/kg bw per day and at dose levels of 0, 0.3, 1 or 12 mg/kg
bw per day, respectively. Severe toxicity and mortality were seen at the
highest dose (48 mg/kg bw per day): one female died during week 5, and the
remaining three females and three out of four males were sacrificed moribund
during weeks 7–8.
A decrease in kidney and liver function,
characterized by an increase in blood urea, ALT and creatinine levels,
was noted...
See Moose's final Complete Blood Count --February 21, 2007, taken three
days before death.
Blood work page
1
Blood work page
2
Acute: 2,4 D
Early symptoms of exposure include gastritis, vomiting and loss of
consciousness. General types of effects noted upon acute ingestion of 2,4-D
include irritation of the mouth, throat and gastrointestinal tract,
chest pain (from esophagitis), abdominal pain, diarrhea, fibrillary muscle
twitching, skeletal muscle tenderness, myotonia, metabolic acidosis,
fever, tachycardia, hyperventilation, vasodilation and sweating; some
cases have been characterized by coma and convulsions (USEPA, 1988;
HSDB, 1995).
Death is usually preceded by muscular paralysis (USEPA, 1988). Several
cases were also reported in which an unspecified amount of 2,4-D ester was
absorbed through the skin, producing polyneuritis but not affecting the eyes
or vision (HSDB, 1995). In addition, acute symptoms reported among workers
using various esters and salts of 2,4-D include rapid fatigue, headache,
loss of appetite, pain in the region of the liver and stomach and reduced
sensitivity to taste and smell (HSDB, 1995).
(Amazing! All the above descriptions that
I've emboldend are exactly the affects that herbicide poisoning had on Moose!)
Observations in laboratory animals indicate that acute oral or injection
exposure to 2,4-D by various routes of exposure has resulted in vomiting,
diarrhea, anorexia, weight loss, ulcers in the mouth, as well as liver and
kidney effects, progressive symptoms of muscular incoordination, hindquarter
paralysis, stupor and coma in various laboratory animals.
Death has been ascribed to ventricular fibrillation and cardiac arrest.
The dominant effect consistently noted in a variety of species, regardless
of the route of exposure, is myotonia.
Acute exposure to high 2,4-D levels has resulted in kidney and skeletal
muscle damage in rodents but liver effects
were only described in dogs.
.... A canine epidemiologic study suggests that pet dogs may be
at risk [for cancer] from exposure to 2,4-D or to areas treated by
a lawn care service.
How Herbicide Phenoxy acids affects
dogs
Links
