A 5-month-old 172-kg (378-lb) female Brahman-cross calf was evaluated after a sudden onset of ataxia and possible blindness. The calf's dam was also reported to have developed acute blindness 2 days prior to the onset of clinical signs in the calf. However, the cow had escaped its holding pen, and its clinical status was not known.
Clinical and Gross Findings
At the evaluation, the calf was laterally recumbent and unresponsive. On physical examination of the calf, the menace reflex was absent bilaterally, and the cranial nerve and patellar reflexes were bilaterally hyporeflexive. The calf was treated with thiamine (10
Objective—To evaluate the effect of an indwelling
nasogastric tube on gastric emptying of liquids in
Animals—9 healthy adult horses.
Procedure—A randomized block crossover design
was used. For treatment group horses, a nasogastric
tube was placed and 18 hours later, acetaminophen
was administered; the nasogastric tube remained in
place until the experiment was complete. For control
group horses, a nasogastric tube was passed into the
stomach, acetaminophen was administered, and the
nasogastric tube was removed immediately. Serial
blood samples were collected 15 minutes before and
after administration of acetaminophen. Serum concentration
of acetaminophen was determined by use
of fluorescence polarization immunoassay. The variables,
time to maximum acetaminophen concentration
(Tmax) and the appearance constant for acetaminophen
(Kapp), were determined. The values for
Kapp and Tmax in horses with and without prolonged
nasogastric tube placement were compared.
Results—No significant difference was found in Kapp
between horses with and without prolonged nasogastric
tube placement; the median difference in Kapp
was 0.01 min–1 (range, –0.48 to 0.80 min–1). No significant
difference was found in Tmax between horses
with and without prolonged nasogastric tube placement;
the median difference in Tmax was 5 minutes
(range, –30 to 50 minutes). Reanalysis of data following
the removal of possible outlier values from 1
horse resulted in a significant difference in Tmax
between horses with and without prolonged nasogastric
Conclusions and Clinical Relevance—Although no
clinically important impact of 18 hours of nasogastric
intubation was found on gastric emptying in healthy
horses, considerable variability in Kapp and Tmax was
found among horses. (Am J Vet Res 2005;66:642–645)
Objective—To assess signalment, history, results of
clinical and laboratory testing, and outcome for beef
cattle with a left displaced abomasum (LDA), right displaced
abomasum (RDA), or abomasal volvulus (AV).
Animals—19 beef cattle with an AV, LDA, or RDA.
Procedure—Signalment; history; results of physical
examination, diagnostic testing, and surgical exploration;
and condition of the animal at discharge were
obtained from medical records.
Results—Fourteen cattle had an AV, 4 had an RDA,
and 1 had an LDA. Duration of clinical signs ranged
from 1 to 21 days. Eighteen cattle had an AV or RDA;
7 were Brahmans, 12 were males, and median age
was 10 months. Abdominal distention was observed
in 11 cattle, heart rate of ≥ 100 beats/minute was
detected in 14, and the abomasum was palpable per
rectum in all cattle in which per rectal examination
was performed. Leukocytosis, neutrophilia, hyperglycemia,
azotemia, hypochloremia, and hypokalemia
were common laboratory findings. At surgery, 3 cattle
with an AV or RDA had a ruptured abomasum. Of the
remaining 15 cattle, 12 survived.
Conclusions—Clinical course in beef cattle with an
AV or RDA was more protracted than that typically
associated with these conditions in dairy cattle, but
survival rate in beef cattle that did not have rupture of
the abomasum was sim ilar to that of dairy cattle.
Clinical Relevance—Abomasal displacement should
be considered for beef cattle with abdominal distention.
Prognostic indicators recommended for use in
dairy cattle may not be useful for beef cattle. (J Am
Vet Med Assoc 2000;216:730–733)
Objective—To identify potential bacterial pathogens
in normal and telangiectatic livers of mature cattle at
slaughter and to identify consumer risk associated
with hepatic telangiectasia.
Sample Population—50 normal livers and 50 severely
Procedure—Normal and telangiectatic livers were
collected at slaughter for aerobic and anaerobic bacterial
culture. Isolates were identified, and patterns of
isolation were analyzed. Histologic examination of all
livers was performed.
Results—Human pathogens isolated from normal
and telangiectatic livers included Escherichia coli
O157:H7 and group-D streptococci. Most livers in
both groups contained bacteria in low numbers; however,
more normal livers yielded negative culture
results. More group-D streptococci were isolated
from the right lobes of telangiectatic livers than from
the left lobes, and more gram-negative anaerobic bacteria
were isolated from left lobes of telangiectatic livers
than from right lobes. All telangiectatic lesions
were free of fibrosis, active necrotizing processes,
Conclusions and Clinical Relevance—The USDA
regulation condemning telangiectatic livers is justified
insofar as these livers contain more bacteria than normal
livers do; however, normal livers contain similar
species of microflora. Development of telangiectasia
could not be linked to an infectious process. The finding
of E coli O157:H7 in bovine livers suggests that
information regarding bacterial content of other offal
and muscle may identify sources of this and other
potential foodborne pathogens and assist in establishing
critical control points for the meat industry. (J
Am Vet Med Assoc 2001;219:36–39)
Objective—To evaluate the seroprevalence of paratuberculosis by use of 2 commercial ELISAs in association with prevalence of fecal shedding of mycobacteria within beef cattle herds.
Design—Cross-sectional field study.
Animals—Six beef herds (affected herds; 522 cattle) with and 3 geographically matched herds (181 cattle) without high seroprevalence of paratuberculosis.
Procedures—Blood and fecal samples were collected from adult cattle and assessed for serum anti–Mycobacterium avium subsp paratuberculosis (MAP) antibodies with 2 commercial ELISA kits and submitted for bacterial culture for MAP and environmental bacteria (termed environmental mycobacteria) via a radiometric method, respectively. Species of mycobacterial isolates were identified, and sensitivities and specificities of the 2 ELISAs were compared.
Results—Compared with comparison cattle, cattle from affected herds were 9.4 times as likely to have environmental mycobacteria isolated from feces. Among the 6 affected and 3 comparison herds, the proportions of cattle shedding environmental mycobacteria were 0.225 (range, 0.1 to 0.72) and 0.04 (range, 0 to 0.06), respectively. Although relative MAP-detection specificities (compared with bacterial culture of feces) were different between the 2 ELISAs, sensitivities were not. Nine environmental mycobacterial species were iden-tified from participating herds. All affected herds apparently had ≥ 1 bovid infected with MAP, although MAP was not isolated from any cattle in comparison herds.
Conclusions and Clinical Relevance—In beef herds with persistently high rates of false-positive ELISA results, which may be associated with recovery of environmental myco-bacteria from feces, organism detection via bacterial culture of feces or PCR assay should direct paratuberculosis control measures.
Objective—To determine risk factors associated with
development of postoperative ileus in horses undergoing
surgery for colic.
Animals—69 horses that developed ileus after
surgery for colic and 307 horses that did not develop
Procedure—Signalment, history, clinicopathologic
data, treatment, lesions, and outcome were obtained
from medical records.
Results—Variables associated with increased risk of
postoperative ileus included age > 10 years, Arabian
breed, PCV ≥ 45%, high serum concentrations of protein
and albumin, anesthesia > 2.5 hours' duration,
surgery > 2 hours' duration, resection and anastomosis,
and lesions in the small intestine. Enterotomy
reduced the risk of postoperative ileus. After multivariate
logistic regression, the final model included
the variables Arabian breed, PCV ≥ 45%, lesion type,
duration of surgery (> 2 hours vs ≤ 2 hours), and
pelvic flexure enterotomy.
Conclusions and Clinical Relevance—Results suggest
that by evaluating certain factors, horses at
increased risk of postoperative ileus may be recognized
before the condition develops. Preventative
treatment and early intervention may be instituted in
these horses. Shortening surgery time and performing
an enterotomy may decrease the probability of
horses developing postoperative ileus. (J Am Vet Med
Objective—To determine concentrations of 2 acute-phase
proteins (serum amyloid A [SAA] and
lipopolysaccharide-binding protein [LBP]) in serum
samples obtained from horses with colic and identify
relationships among these acute-phase proteins and
Animals—765 horses with naturally developing gastrointestinal
tract diseases characterized by colic (ie,
clinical signs indicative of abdominal pain) and 79
healthy control horses; all horses were examined at 2
university teaching hospitals.
Procedure—Serum concentrations of SAA and LBP
were determined by immunoturbidometric and dotblot
Results—SAA and LBP concentrations were determined
for 718 and 765 horses with colic, respectively.
Concentrations of SAA were significantly higher in
nonsurvivors than in survivors, and horses with
enteritis or colitis and conditions characterized by
chronic inflammation (eg, abdominal abscesses, peritonitis,
or rectal tears) had SAA concentrations significantly
greater than those for horses with other conditions.
Serum concentrations of LBP did not correlate
with outcome, disease process, or portion of the
gastrointestinal tract affected.
Conclusions and Clinical Relevance—Circulating
concentrations of SAA were significantly higher at
admission in horses with colic attributable to conditions
having a primary inflammatory cause (eg, enteritis,
colitis, peritonitis, or abdominal abscesses) and
were higher in horses that failed to survive the
episode of colic, compared with concentrations in
horses that survived. Serum concentrations of LBP
did not correlate with survival. Analysis of these findings
suggests that evaluation of SAA concentrations
may be of use in identifying horses with colic attributable
to diseases that have inflammation as a primary
component of pathogenesis. (Am J Vet Res
Objective—To determine the pharmacokinetics and clinical effects of a subanesthetic, continuous rate infusion of ketamine administered to healthy awake horses.
Animals—8 adult horses.
Procedures—Ketamine hydrochloride was administered to 2 horses, in a pilot study, at rates ranging from 0.4 to 1.6 mg/kg/h for 6 hours to determine an appropriate dose that did not cause adverse effects. Ketamine was then administered to 6 horses for a total of 12 hours (3 horses at 0.4 mg/kg/h for 6 hours followed by 0.8 mg/kg/h for 6 hours and 3 horses at 0.8 mg/kg/h for 6 hours followed by 0.4 mg/kg/h for 6 hours). Concentration of ketamine in plasma, heart rate, respiratory rate, blood pressure, physical activity, and analgesia were measured prior to, during, and following infusion. Analgesic testing was performed with a modified hoof tester applied at a measured force to the withers and radius.
Results—No signs of excitement and no significant changes in the measured physiologic variables during infusion rates of 0.4 and 0.8 mg of ketamine/kg/h were found. At 6 hours following infusions, heart rate and mean arterial pressure were decreased, compared with preinfusion measurements. An analgesic effect could not be demonstrated during or after infusion. Pharmacokinetic variables for 0.4 and 0.8 mg/kg/h infusions were not significantly different.
Conclusions and Clinical Relevance—Ketamine can be administered to awake horses at 0.4 or 0.8 mg/kg/h without adverse behavioral effects. The observed pharmacokinetic values are different than those reported for single-dose IV bolus administration of this drug.
Objective—To determine whether ether-a-go-go
(ERG) potassium channels are expressed in equine
gastrointestinal smooth muscle, whether ERG channel
antagonists affect jejunal muscle contraction in
vitro, and whether plasma cisapride concentrations in
horses administered treatment for postoperative ileus
(POI) are consistent with ERG channels as drug targets.
Sample Population—Samples of intestinal smooth
muscle obtained from 8 horses free of gastrointestinal
tract disease and plasma samples obtained from
3 horses administered cisapride for treatment of POI.
Procedure—Membranes were prepared from the
seromuscular layer of the duodenum, jejunum, ileum,
cecum, large colon, and small colon. Immunoblotting
was used to identify the ERG channel protein.
Isolated jejunal muscle strips were used for isometric
stress response to ERG channel blockers that included
E-4031, MK-499, clofilium, and cisapride. Plasma
concentrations of cisapride were determined in 3
horses administered cisapride for treatment of POI
after small intestinal surgery.
Results—Immunoblotting identified ERG protein in all
analyzed segments of the intestinal tract in all horses.
The selective ERG antagonist E-4031 caused a concentration-
dependent increase in jejunal contraction.
Clofilium, MK-499, and cisapride also increased jejunal
contraction at concentrations consistent with ERG
channel block; effects of E-4031 and cisapride were
not additive. Peak plasma cisapride concentrations in
treated horses were consistent with ERG block as a
mechanism of drug action.
Conclusions and Clinical Relevance—The ERG
potassium channels modulate motility of intestinal
muscles in horses and may be a target for drugs. This
finding may influence development of new prokinetic
agents and impact treatment of horses with POI.
(Am J Vet Res 2003;64:267–272)