Objective—To examine total protein concentration
and cell counts of sequentially collected samples of
CSF to determine whether blood contamination
decreases in subsequent samples and whether formulas
used to correct nucleated cell count and total
protein concentration are accurate.
Procedure—For each horse, 3 or 4 sequential 2-ml
samples of CSF were collected from the subarachnoid
space in the lumbosacral region into separate
syringes, and blood was obtained from the jugular
vein. Total protein concentration, nucleated cell
count, and RBC counts were determined in all samples.
Results—Among 3 sequential samples, total protein
concentration and RBC count were significantly lower
in samples 2 and 3, compared with sample 1.
Nucleated cell count was significantly lower in sample
3, compared with sample 1. Among 4 sequential samples,
total protein concentration and RBC count were
significantly lower in samples 2, 3, and 4, compared
with sample 1. Nucleated cell count was significantly
lower in samples 3 and 4, compared with sample 1.
For 3 correction formulas, significant differences in
corrected values for nucleated cell count and total
protein concentration were detected between sample
1 and sample 3 or 4.
Conclusion and Clinical Relevance—Because
iatrogenic blood contamination decreases in sequential
CSF samples, a minimum of 3 samples should be
collected before submitting the final sample for analysis.
Formulas to correct nucleated cell count and total
protein concentration are inaccurate and should not
be used to correct for blood contamination in CSF
samples. (J Am Vet Med Assoc 2000;217:54–57)
Objective—To characterize pneumothorax in horses
and to describe clinical signs, diagnostic testing, and
clinical outcome of horses with pneumothorax.
Procedure—Medical records of horses with pneumothorax
were reviewed to obtain information on signalment,
history, clinical signs, diagnostic testing,
treatment, and clinical outcome.
Results—Horses developed pneumothorax secondary
to pleuropneumonia (17 horses), open
wounds of the thorax (9), closed trauma to the thorax
(7), surgery on the upper portion of the respiratory
tract (3), and surgery involving the thoracic cavity (1);
3 horses had pneumothorax of unknown cause.
Clinical signs included tachypnea, dyspnea, cyanosis,
lack of lung sounds on auscultation of the dorsal
aspect of the thorax, fever, tachycardia, signs of
depression or anxiousness, and cough. Radiography
and ultrasonography were useful to definitively diagnose
pneumothorax. Pneumothorax was bilateral in
47.5% (19/40) and unilateral in 42.5% (17/40) of horses;
designation of unilateral versus bilateral was not
recorded in the remaining 4 horses. Horses with
pneumothorax secondary to pleuropneumonia more
commonly had unilateral pneumothorax (64.7% for
unilateral vs 29.4% for bilateral; not specified for 1
horse). Horses with pneumothorax secondary to
pleuropneumonia were less likely to survive than
horses with pneumothorax secondary to other causes
(35.3 vs 69.6% survived, respectively).
Conclusions and Clinical Relevance—Pleuropneumonia
is an important cause of pneumothorax in
horses. Classic clinical signs of pneumothorax may
not be evident. Radiography, ultrasonography, or both
may be required for diagnosis. Prognosis for survival
is better for horses with pneumothorax not associated
with pleuropneumonia. (J Am Vet Med Assoc
Objective—To evaluate the safety of sodium bisulfate
for use in horse barn environments by determining its
irritant effect on skin and hooves.
Animals—6 female mixed-breed ponies.
Procedure—Sodium bisulfate was applied to clipped
intact skin of 6 ponies to evaluate its irritant effect
after single (48 hours) and repetitive (6 h/d for 10 days)
applications; similar areas of skin were used as
untreated control sites. In addition, sodium bisulfate
was applied to the sole of both front hooves of each
pony and covered with wet gauze, and the entire hoof
was covered with adhesive tape for 48 hours.
Results—Contact with moistened sodium bisulfate
for 48 hours had no effect on pony skin. Contact with
sodium bisulfate for 6 hours on 10 consecutive days
did not cause gross changes but did cause mild to
moderate microscopic changes including epidermal
necrosis, hyperkeratosis, capillary congestion,
edema, and diffuse mixed inflammatory cell infiltrate.
All changes were limited to the epidermis and superficial
dermis. Gross changes in hoof sole, signs of
lameness, and increase in digital pulse pressure or
pulse intensity were not detected.
Conclusions and Clinical Relevance—Duration of
contact with sodium bisulfate in this study was in
excess of that expected under typical husbandry conditions.
Despite this fact, gross changes in skin and
hooves were not detected. Microscopic lesions were
confined to the epidermis and superficial dermis.
Results suggest that contact with sodium bisulfate
under these conditions is safe. (Am J Vet Res
Objective—To determine application rate and effectiveness
of sodium bisulfate to decrease the fly population
in a horse barn environment.
Sample Population—12 privately owned farms in
Procedure—Application rates of sodium bisulfate
were approximately 2.3 kg/stall, 1.1 kg/stall, and 0.5
kg/stall. Two or 3 stalls were treated, and 1 or 2 stalls
were not treated (control stalls) at each farm. Farm
personnel applied sodium bisulfate in treated stalls
daily for 7 days. Fly tapes were hung from the same
site in treated and control stalls. After 24 hours, the
fly tape was removed, flies adhering to the sticky surface
were counted and recorded, and a new fly tape
was hung. This procedure was repeated daily during
each of the testing periods.
Results—Following the application of 2.3 kg of sodium
bisulfate/stall, the numbers of flies collected on
the fly tape were significantly decreased in treated
stalls, compared with control stalls during the same
time periods on 9 of the 12 farms evaluated.
Following the application of 1.1 kg of sodium bisulfate/
stall, fly numbers were significantly decreased in
treated stalls on 6 of the 9 farms evaluated. Following
the application of 0.5 kg of sodium bisulfate/stall, fly
numbers were significantly decreased in the treated
stalls on 3 of the 4 farms evaluated.
Conclusions and Clinical Relevance—Our findings
suggest that sodium bisulfate would be effective for
fly control in horse barns. (Am J Vet Res 2000;
Objective—To identify factors associated with an increased likelihood that horses would have a serum Streptococcus equi SeM-specific antibody titer ≥ 1:1,600.
Animals—188 healthy client-owned horses.
Procedures—A single serum sample from each horse was tested for SeM-specific antibody titer with an ELISA. Multivariate logistic regression was used to identify factors associated with having a titer ≥ 1:1,600.
Results—Age, breed, and vaccination status were significantly associated with the likelihood of having a titer ≥ 1:1,600. The odds of having a titer ≥ 1:1,600 increased by a factor of 1.07 with each 1-year increase in age. Quarter Horses and horses of other breeds were 4.08 times as likely as were Thoroughbreds and warmbloods to have a titer this high. Horses that had previously received an intranasal S equi vaccine were 4.7 times as likely as were horses without any history of vaccination to have a titer this high.
Conclusions and Clinical Relevance—Results indicated that older horses, horses other than Thoroughbreds and warmbloods, and horses that had been vaccinated with an attenuated-live intranasal S equi vaccine between 1 and 3 years previously had an increased likelihood of having a serum SeM-specific antibody titer ≥ 1:1,600.
Objective—To determine whether results of physical
or radiographic examination or biochemical analyses
in adult racehorses with primary lung abscesses were
associated with ability to race following treatment.
Design—Multiple-center retrospective study.
Animals—25 Standardbreds and 20 Thoroughbreds.
Procedure—Medical records of horses with a primary
lung abscess that were admitted to any of 4 veterinary
teaching hospitals were reviewed. Results of
physical examination, laboratory testing, and thoracic
radiography were reviewed. Racing performance after
treatment was compared with performance before illness
and with performance of the general population
of racehorses of similar age, sex, and breed.
Results—23 of 25 Standardbreds and 13 of 20
Thoroughbreds raced after diagnosis and treatment of
a lung abscess. Most horses had a solitary abscess in
the dorsal to caudodorsal lung fields. Results of initial
physical examination, biochemical analyses, and culture
and identification of the microbial isolate were
not associated with whether a horse returned to racing.
For horses that had raced prior to the illness, race
performance after treatment of the lung abscess was
not significantly different from performance before
Conclusions and Clinical Relevance—On the basis
of racing performance in those horses that resumed
racing after treatment, long-term residual lung damage
did not develop in horses with primary lung
abscesses that were treated appropriately. It is not
known whether horses that recovered would be more
likely to bleed from the site of a prior infection when
resuming strenuous exercise and whether lung
abscesses contributed to a failure to resume racing.
(J Am Vet Med Assoc 2000;216:1282–1287)