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 evaluate the effect of vaccination of calves with a killed Mycobacterium avium subsp paratuberculosis (MAP) vaccine on colonization of tissues following oral MAP exposure.
Animals—12 healthy Holstein calves.
Procedures—At 14 days after birth, calves received the MAP vaccine (1.0 mL, SC) or saline (0.9% NaCl) solution (1.0 mL, SC [control treatment]). Each calf received 1.2 × 109 CFUs of live MAP orally 21 and 22 days after vaccination. Prior to vaccination and at subsequent intervals, a blood sample was collected for ELISA detection of antibodies against MAP and for whole blood, antigen-specific, interferon (IFN)-γ–release assay. Nine weeks after MAP challenge, calves were euthanized and various tissue samples were collected for mycobacterial culture. Interferon-γ production in prescapular lymph node cells was measured following in vitro stimulation with MAP antigens.
Results—Calves were seronegative for anti-MAP antibodies at all times. Compared with the findings in control calves, antigen-specific IFN-γ production in circulating lymphocytes and prescapular lymph node cells from vaccinated calves was significantly higher. Culture of tissues from vaccinated calves yielded significantly fewer CFUs of MAP (2,417 CFUs/g), compared with tissues from control calves (15,709 CFUs/g). Furthermore, significantly fewer tissue samples from vaccinated calves yielded MAP in culture (21.8 tissues/calf), compared with findings in control calves (27.6 tissues/calf).
Conclusions and Clinical Relevance—Inoculation of calves with a killed MAP vaccine was associated with reduced colonization of intestinal tissues following experimental exposure to MAP. Use of the vaccine could potentially reduce transmission of MAP to calves in infected herds.
Objective—To evaluate concordance among veterinary
pathologists in the assessment of histologic findings
in the pars intermedia of pituitary gland sections
from aged horses with mild signs suggestive of pituitary
pars intermedia dysfunction (PPID).
Sample Population—10 pituitary glands from aged
Procedure—7 pathologists were provided with signalment,
clinical signs, and a single H&E-stained pituitary
gland section from 10 aged horses with mild
signs suggestive of PPID. Pathologists described histologic
findings for each section and stated whether
findings were consistent with PPID. Agreement
among pathologists and with antemortem diagnostic
test results was calculated.
Results—Overall, only fair agreement was found
among the pathologists as to which horses had histologic
findings consistent with disease (mean ± SE
kappa value, 0.34 ± 0.069). Interpretation of individual
sections varied, with minimal agreement (4 or 5/7
pathologists) for 5 of 10 sections evaluated.
Postmortem assessment was in agreement with an
antemortem endocrine diagnostic test result 79% of
Conclusions and Clinical Relevance—Validation of
antemortem diagnostic testing for PPID in horses
often relies on the results of postmortem histologic
evaluation. The lack of consensus in histologic interpretation
of pituitary glands from aged horses with
mild clinical signs in our study indicates that postmortem
histologic evaluation of pituitary glands is an
inappropriate standard in validation of antemortem
diagnostic tests for detection of early PPID. Caution
should be used when interpreting diagnostic test
results in horses in which early PPID is suspected.
(Am J Vet Res 2005;66:2055–2059)