Objective—To determine and compare substrate
specificity and kinetic rate constants of feline and
canine alcohol dehydrogenase (ADH) with ethanol
(EtOH) and ethylene glycol (EG) as substrates in vitro,
with and without fomepizole.
Sample Population—Livers from 3 dogs and 3 cats.
Procedure—Canine and feline ADH activity, in
cytosolic fractions of homogenized liver, was determined
by use of various concentrations of nicotinamide
adenine dinucleotide (NAD), EtOH, or EG as
substrates. Initial reaction velocities were calculated,
and kinetic inhibition rate constants (Ki) for fomepizole
Results—Substrate specificity of canine and feline
ADH for EtOH or EG was not significantly different. A
2-fold difference was detected in the maximal velocity
of canine, compared with feline, ADH, using either substrate.
Fomepizole Ki in feline hepatic homogenates
was significantly greater than Ki in canine hepatic
homogenates when either EtOH or EG was used as
substrate (10- and 30-fold, respectively). A 6-fold
increase in the concentration of fomepizole was
required to achieve ADH inhibition, with feline
homogenates equivalent to those of canine
Conclusions and Clinical Relevance—Feline ADH
has lower enzymatic capacity for turnover or is less
concentrated in liver than canine ADH with regard to
EtOH and EG catalysis. Canine ADH was more effectively
inhibited by fomepizole than feline ADH.
Results suggest that higher dosages of fomepizole
may be more effective to treat cats with EG intoxication
than dosages reported to treat dogs. (Am J Vet Res 2000;61:450–455)
Objective—To assess heritability and mode of inheritance
for hereditary equine regional dermal asthenia
(HERDA) in Quarter Horses.
Animals—1,295 horses with Quarter Horse bloodlines,
including 58 horses affected with HERDA.
Procedure—Horses were classified as affected or
unaffected or as undetermined when data were insufficient
to assess phenotype. Pedigree data were analyzed
to determine the probable mode of inheritance.
Heritability was estimated by use of Bayesian statistical
Results—Heritability (mean ± SD) of HERDA was
estimated to be 0.38 ± 0.13, with both sexes having
an equal probability of being affected. Results for evaluation
of the pedigrees were consistent with a single
Mendelian autosomal recessive mode of inheritance.
Conclusions and Clinical Relevance—HERDA in
Quarter Horses is an inherited disease, and affected
horses are more likely to produce affected offspring.
An autosomal recessive mode of inheritance should be
considered by people making breeding decisions
involving Quarter Horses when a first-degree relative
has been confirmed with HERDA or has produced
affected offspring. In addition, breeders whose horses
have produced affected offspring can reduce the likelihood
of producing affected horses in the future by
avoiding inbreeding. (Am J Vet Res 2005;66:437–442)
Objective—To analyze the sulfur content of water
and forage samples from a geographically diverse
sample of beef cow-calf operations in the United
States and to estimate frequency and distribution of
premises where forage and water resources could
result in consumption of hazardous amounts of sulfur
Sample Population—709 forage samples from 678
beef cow-calf operations and individual water samples
from 498 operations in 23 states.
Procedure—Sulfur content of forage samples and
sulfate concentration of water samples were measured.
Total sulfur intake was estimated for pairs of
forage and water samples.
Results—Total sulfur intake was estimated for 454
pairs of forage and water samples. In general, highest
forage sulfur contents did not coincide with highest
water sulfate concentrations. Overall, 52 of the 454
(11.5%) sample pairs were estimated to yield total
sulfur intake (as a percentage of dry matter) ≥ 0.4%,
assuming water intake during conditions of high
ambient temperature. Most of these premises were
in north-central (n = 19) or western (19) states.
Conclusions and Clinical Relevance—Results suggest
that on numerous beef cow-calf operations
throughout the United States, consumption of forage
and water could result in excessively high sulfur
intake. All water sources and dietary components
should be evaluated when assessing total sulfur
intake. Knowledge of total sulfur intake may be useful
in reducing the risk of sulfur-associated health and
performance problems in beef cattle. (J Am Vet Med Assoc