To assess the presence of suspected pigment-associated deafness in North American yaks (Bos grunniens).
12 North American yaks, including 11 with the homozygous piebald Royal pigmentation phenotype and 1 with the heterozygous piebald Trim phenotype.
Hearing was assessed using the brainstem auditory evoked response (BAER) on yaks restrained in the head gate of a grooming chute.
Five of the Royal yaks and the Trim yak had hearing in both ears. Six Royal yaks were affected; 3 were deaf in 1 ear and 3 were deaf in both ears.
For the first time, probable sensorineural deafness has been confirmed to be present in Royal yaks. The disorder is assumed to be congenital and associated with white pigmentation, based on the pattern of occurrence in other species.
Objective—To evaluate physical methods for inducing death during the slaughter of American alligators (Alligator mississippiensis).
Animals—24 captive hatched-and-reared American alligators.
Procedures—Baseline electroencephalograms (EEGs) were obtained for awake and anesthetized alligators. Corneal reflex, spontaneous blinking, and EEGs were evaluated after severance of the spinal cord, severance of the spinal cord followed by pithing of the brain, application of a penetrating captive bolt, or application of a nonpenetrating captive bolt (6 alligators/group).
Results—Overall, alligators subjected to spinal cord severance alone differed from those subjected to the other techniques. Spinal cord severance alone resulted in postprocedure EEG power values greater than those in anesthetized alligators, whereas the postprocedure EEG power values were isoelectric for the other 3 techniques. Corneal reflex and spontaneous blinking were absent in all alligators immediately after application of a penetrating or nonpenetrating captive bolt. One of 6 alligators had a corneal reflex up to 1 minute after pithing, but all others within that group had immediate cessation of reflexes after pithing. Mean time to loss of spontaneous blinking and corneal reflex for alligators subjected to spinal cord severance alone was 18 minutes (range, 2 to 37 minutes) and 54 minutes (range, 34 to 99 minutes), respectively.
Conclusions and Clinical Relevance—Spinal cord severance followed by pithing of the brain and application of a penetrating or nonpenetrating captive bolt appeared to be humane and effective techniques for inducing death in American alligators, whereas spinal cord severance alone was not found to be an appropriate method.
Objective—To determine functional and morphologic
changes in palmar digital nerves after nonfocused
extracorporeal shock wave (ESW) treatment in horses.
Procedures—The medial and lateral palmar digital
nerves of the left forelimb were treated with nonfocused
ESWs. The medial palmar digital nerve of the
right forelimb served as a nontreated control nerve.
At 3, 7, and 35 days after treatment, respectively, 2
horses each were anesthetized and nerves were surgically
exposed. Sensory nerve conduction velocities
(SNCVs) of treated and control nerves were recorded,
after which palmar digital neurectomies were performed.
Morphologic changes in nerves were
assessed via transmission electron microscopy.
Results—Significantly lower SNCV in treated medial
and lateral nerves, compared with control nerves, was
found 3 and 7 days after treatment. A significantly lower
SNCV was detected in treated medial but not lateral
nerves 35 days after treatment. Transmission electron
microscopy of treated nerves revealed disruption of the
myelin sheath with no evidence of damage to Schwann
cell bodies or axons, 3, 7, and 35 days after treatment.
Conclusions and Clinical Relevance—Nonfocused
ESW treatment of the metacarpophalangeal area resulted
in lower SNCV in palmar digital nerves. This effect
likely contributes to the post-treatment analgesia
observed in horses and may result in altered peripheral
pain perception. Horses with preexisting lesions may be
at greater risk of sustaining catastrophic injuries when
exercised after treatment. (Am J Vet Res
Objective—To determine whether hyperbaric oxygen
treatment (HBOT) would affect incorporation of an
autogenous cancellous bone graft in diaphyseal ulnar
defects in cats.
Animals—12 mature cats.
Procedure—Bilateral nonunion diaphyseal ulnar
defects were created in each cat. An autogenous
cancellous bone graft was implanted in 1 ulnar
defect in each cat, with the contralateral ulnar
defect serving as a nongrafted specimen. Six cats
were treated by use of hyperbaric oxygen at 2
atmospheres absolute for 90 minutes once daily for
14 days, and 6 cats were not treated (control
group). Bone labeling was performed, using fluorochrome
markers. Cats were euthanatized 5
weeks after implanting, and barium sulfate was
infused to evaluate vascularization of grafts. Ulnas
were evaluated by use of radiography, microangiography,
histologic examination, and histomorphometric
Results—Radiographic scores did not differ
between treatment groups. Microangiographic
appearance of grafted defects was similar between
groups, with all having adequate vascularization.
Differences were not observed between treated
and nontreated groups in the overall histologic
appearance of decalcified samples of tissue in grafted
defects. Mean distance between fluorescent
labels was significantly greater in cats given HBOT
than in nontreated cats. Median percentage of bone
formation in grafted defects was significantly
greater in cats given HBOT.
Conclusions—Hyperbaric oxygen treatment
increased the distance between fluorescent labels
and percentage of bone formation when incorporating
autogenous cancellous bone grafts in induced
nonunion diaphyseal ulnar defects in cats, but HBOT
did not affect revascularization, radiographic appearance,
or qualitative histologic appearance of the
grafts. (Am J Vet Res 2000;61:691–698)