bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantification, risk factors, and health impact of natural congenital infection with bovine viral diarrhea virus in dairy calves
Authors: Muñoz-Zanzi Claudia A. , Hietala Sharon K. , Thurmond Mark C. , Johnson Wesley O.
Published: January 2006

Objective—To estimate risk and identify risk factors
for congenital infection with bovine viral diarrhea virus
(BVDV) not resulting in persistent infection and examine
effect of congenital infection on health of dairy
calves.

Animals—466 calves.

Procedures—Calves from 2 intensively managed drylot
dairies with different vaccination programs and
endemic BVDV infection were sampled before ingesting
colostrum and tested with their dams for BVDV
and BVDV serum-neutralizing antibodies. Records of
treatments and death up to 10 months of age were
obtained from calf ranch or dairy personnel. Risk factors
for congenital infection, including dam parity and
BVDV titer, were examined by use of logistic regression
analysis. Effect of congenital infection on morbidity
and mortality rates was examined by use of survival
analysis methods.

Results—Fetal infection was identified in 10.1% of
calves, of which 0.5% had persistent infection and
9.6% had congenital infection. Although dependent
on herd, congenital infection was associated with
high BVDV type 2 titers in dams at calving and with
multiparous dams. Calves with congenital infection
had 2-fold higher risk of a severe illness, compared
with calves without congenital infection.

Conclusions and Clinical Relevance—The unexpectedly
high proportion of apparently healthy calves found
to be congenitally infected provided an estimate of the
amount of fetal infection via exposure of dams and
thus virus transmission in the herds. Findings indicate
that congenital infection with BVDV may have a negative
impact on calf health, with subsequent impact on
herd health. (Am J Vet Res 2003;64:358–365)
Computerized ultrasonographic tissue characterization of equine superficial digital flexor tendons by means of stability quantification of echo patterns in contiguous transverse ultrasonographic images
Authors: Schie Hans T. M. van , Bakker Erwin M. , Jonker A. Mieke , Weeren P. Rene van
Published: January 2006

Objective—To describe a method of computerized ultrasonographic tissue characterization that includes structures below the size limits of resolution in equine superficial digital flexor tendons.

Sample Population—2 damaged and 2 structurally normal superficial digital flexor tendons.

Procedure—Transverse ultrasonographic images were collected along the tendon long axis. Stability of echo pattern was quantified by means of variation in gray levels of each pixel in contiguous images and expressed as correlation, entropy, and waviness ratios.

Results—Normal young and normal old tissues were characterized by high correlation and low entropy and waviness ratios. In necrotic tissue, collapsed intratendinous septa resulted in high correlation, moderate entropy, and high waviness ratios. In early granulation tissue, complete lack of bundle formation resulted in values of zero for correlation and waviness ratios; loose connective tissue matrix resulted in a high entropy ratio. In late granulation tissue, formation of new bundles resulted in a high correlation ratio; swollen intratendinous septa and incomplete organization of connective tissue matrix were reflected in high entropy and waviness ratios. In early fibrotic tissue, rearrangement of tendon bundles resulted in a correlation ratio within reference range and a slight increase in the waviness ratio; an increase in cellularity and lack of fibrillar arrangement led to an increase in the entropy ratio. In late fibrotic and scar tissues, inferior quality of repair with almost complete lack of organization was reflected in low to moderate correlation, low waviness, and high entropy ratios.

Conclusions and Clinical Relevance—Stability of echo patterns accurately reflects homogeneity of tendons in horses. (Am J Vet Res2003;64:366–375)
Analgesic and systemic effects of ketamine, xylazine, and lidocaine after subarachnoid administration in goats
Authors: DeRossi Rafael , Junqueira Alexandre Lopes , Beretta Marcelo Paixão
Published: January 2006

Objective—To determine the effects of ketamine hydrochloride, xylazine hydrochloride, and lidocaine hydrochloride after subarachnoid administration in goats.

Animals—6 healthy goats.

Procedure—In each goat, ketamine (3 mg/kg), xylazine (0.1 mg/kg), lidocaine (2.5 mg/kg), and saline (0.9% NaCl) solution were injected into the subarachnoid space between the last lumbar vertebra and first sacral vertebra (time 0). Analgesic, ataxic, sedative, cardiovascular, and respiratory effects and rectal temperature were evaluated before (baseline) and 2, 5, 10, 15, and 30 minutes after administration and at 30-minute intervals thereafter as needed.

Results—Administration of anesthetics induced varying degrees of analgesia. Onset of the analgesic effect was more delayed for xylazine (mean ± SD, 9.5 ± 2.6 minutes) than for ketamine (6.7 ± 2.6 minutes) or lidocaine (3.5 ± 1.2 minutes). Duration of analgesia induced by xylazine (88.3 ± 15 minutes) was twice as long as the duration of analgesia induced by ketamine (48.8 ± 13.5 minutes) but similar to that induced by lidocaine (66.5 ± 31 minutes). Xylazine induced bradycardia, whereas ketamine caused a nonsignificant increase in heart rate. Xylazine induced a reduction in arterial pressure, whereas ketamine or lidocaine did not affect arterial pressure.

Conclusion and Clinical Relevance—Subarachnoid administration of xylazine in goats resulted in longer duration of analgesia of the tail, perineum, hind limbs, flanks, and caudodorsal rib areas than administration of ketamine or lidocaine. However, xylazine caused bradycardia and respiratory depression. Additional studies are needed to determine whether the analgesia would be sufficient to allow clinicians to perform surgical procedures. (Am J Vet Res2003;64:51–56)
Regional risk of exporting cattle seropositive for bluetongue virus from the United States
Authors: Hoar Bruce R. , Carpenter Tim E. , Singer Randall S. , Gardner Ian A.
Published: January 2006

Objective—To create a stochastic model to quantify
the risk that shipments of cattle from regions within
the United States would contain animals seropositive
for bluetongue virus and to determine shipment-level
accuracy of serologic testing by use of a competitive
ELISA (c-ELISA).

Sample Population—19,216 shipments containing
528,918 cattle and calves.

Procedure—Data were obtained on number of animals
and state of origin of cattle in export shipments
originating within the United States between January
1994 and March 2002. Probability distributions for
size of export shipments were determined for all
states within the United States, and distributions for
agar gel immunodiffusion and c-ELISA accuracy (sensitivity
and specificity) were determined from expert
opinion and review of the literature. The model simulated
selection of a shipment and then determined
the probability that a threshold number or percentage
of cattle within that shipment would have a positive
c-ELISA result. Shipment-level sensitivity, specificity,
positive-predictive value, and negative-predictive
value were calculated.

Results—Substantial differences were evident in the
regional probability of a shipment being declared positive,
with shipments from northeastern states having
the lowest probability and shipments from southwestern
states having the highest probability. The c-
ELISA had variable predictive values at the shipment
level, depending on the threshold used and the prevalence
of antibody-positive cattle within the region.

Conclusions and Clinical Relevance—Results from
this study will aid importers in making scientifically
based decisions regarding risk of importing antibodypositive
cattle. ( Am J Vet Res 2003;64:520–529)
Development of a multiple-marker polymerase chain reaction assay for detection of metastatic melanoma in lymph node aspirates of dogs
Authors: Catchpole Brian , Gould Sara M. , Kellett-Gregory Lindsay M. , Dobson Jane M.
Published: January 2006

Objective—To develop a reverse transcriptase-polymerase chain reaction (RT-PCR) assay to detect canine melanoma-associated antigens (MAAs) and to use this technique to screen aspirates of lymph nodes (LNs) for evidence of metastatic spread of oral malignant melanoma.

Animals—7 dogs with oral malignant melanoma and 4 dogs with multicentric lymphosarcoma.

Procedures—We prepared cDNA from melanoma tumor biopsies and fine-needle aspirates obtained from submandibular LNs of dogs with oral malignant melanoma or multicentric lymphosarcoma. The RTPCR assay was performed by use of tyrosinase, Melan-A, gp100, tyrosinase-related protein 2 (TRP-2), or melanoma antigen-encoding gene B (MAGE-B)- specific primers.

Results—We detected MAGE-B mRNA in canine testicular tissue but not in melanoma biopsy specimens. Tyrosinase, Melan-A, gp100, and TRP-2 mRNAs were detected in tumor biopsy specimens and in 2 of 5 LN aspirates from dogs with melanoma, suggesting metastatic spread in those 2 dogs. We did not detect MAAs in LN aspirates obtained from dogs with multicentric lymphosarcoma. Sequencing of canine Melan- A and gp100 PCR products confirmed the specificity of the assay for these genes.

Conclusions and Clinical Relevance—Clinical staging of dogs with oral malignant melanoma is useful to assist in designing appropriate treatments. However, results of histologic examination of LN biopsy specimens can be inconclusive and, in humans, can underestimate the number of patients with metastatic disease. Molecular staging of melanomas in dogs can be achieved by screening LN aspirates for MAA mRNA, and this can be performed in combination with cytologic examination to aid in detection of metastatic disease. (Am J Vet Res2003;64:544–549)
Coughing, mucus accumulation, airway obstruction, and airway inflammation in control horses and horses affected with recurrent airway obstruction
Authors: Robinson N. Edward , Berney Cathy , Eberhart Sue , deFeijter-Rupp Heather. L. , Jefcoat Andrew M. , Cornelisse Cornelis J. , Gerber Vincent M. , Derksen Frederik J.
Published: January 2006

Objective—To investigate relationships between cough frequency and mucus accumulation, airway obstruction, and airway inflammation and to determine effects of dexamethasone on coughing and mucus score.

Animals—13 horses with recurrent airway obstruction( RAO and 6 control horses.

Procedure—6 RAO-affected and 6 control horses were stabled for 3 days. Coughing was counted for 4 hours before and on each day horses were stabled. Before and on day 3 of stabling, tracheal mucus accumulation was scored, airway obstruction was assessed via maximal change in pleural pressure (ΔPplmax), and airway inflammation was evaluated by use of cytologic examination of bronchoalveolar lavage fluid (BALF). Effects of dexamethasone (0.1 mg/kg, IV, q 24 h for 7 days) were determined in 12 RAO-affected horses.

Results—To assess frequency, coughing had to be counted for 1 hour. In RAO-affected horses, stabling was associated with increases in cough frequency, mucus score, and ΔPplmax. Control horses coughed transiently when first stabled. In RAO-affected horses, coughing was correlated with ΔPplmax, mucus score, and airway inflammation and was a sensitive and specific indicator of ΔPplmax> 6 cm H2O, mucus score > 1.0, and > 100 neutrophils/µL and > 20% neutrophils in BALF. Dexamethasone reduced cough frequency, mucus score, and ΔPplmax, but BALF neutrophil count remained increased.

Conclusions and Clinical Relevance—Because of its sporadic nature, coughing cannot be assessed accurately by counting during brief periods. In RAO-affected horses, coughing is an indicator of airway inflammation and obstruction. Corticosteroid treatment reduces cough frequency concurrently with reductions in ΔPplmaxand mucus accumulation in RAO-affected horses. (Am J Vet Res2003;64:550–557)
Effect of bone diameter and eccentric loading on fatigue life of cortical screws used with interlocking nails
Authors: Aper Rhonda L. , Litsky Alan S. , Roe Simon C. , Johnson Kenneth A.
Published: January 2006

Objective—To test the effects of bone diameter and eccentric loading on fatigue life of 2.7-mm-diameter cortical bone screws used for locking a 6-mm-diameter interlocking nail.

Sample Population—Eighteen 2.7-mm-diameter cortical bone screws.

Procedure—A simulated bone model with aluminum tubing and a 6-mm-diameter interlocking nail was used to load screws in cyclic 3-point bending. Group 1 included 6 screws that were centrally loaded within 19-mm-diameter aluminum tubing. Group 2 included 6 screws that were centrally loaded within 31.8-mmdiameter aluminum tubing. Group 3 included 6 screws that were eccentrically loaded (5.5 mm from center) within 31.8-mm-diameter aluminum tubing. The number of cycles until screw failure and the mode of failure were recorded.

Results—An increase in the diameter of the aluminum tubing from 19 to 31.8 mm resulted in a significant decrease in the number of cycles to failure (mean ± SD, 761,215 ± 239,853 to 16,941 ± 2,829 cycles, respectively). Within 31.8-mm tubing, the number of cycles of failure of eccentrically loaded screws (43,068 ± 14,073 cycles) was significantly greater than that of centrally loaded screws (16,941 ± 2,829 cycles).

Conclusions and Clinical Relevance—Within a bone, locking screws are subjected to different loading conditions depending on location (diaphyseal vs metaphyseal). The fatigue life of a locking screw centrally loaded in the metaphyseal region of bone may be shorter than in the diaphysis. Eccentric loading of the locking screw in the metaphysis may help to improve its fatigue life. (Am J Vet Res2003;64:569–573)
Validation and comparison of the use of diuresis cystometry and retrograde filling cystometry at various infusion rates in female Beagle dogs
Authors: Hamaide Annick J. , Verstegen John P. , Snaps Frédéric R. , Onclin Karine , Balligand Marc H.
Published: January 2006

Objectives—To compare retrograde filling cystometry at infusion rates of 5, 10, and 20 mL/min with diuresis cystometry for determination of an appropriate infusion rate and to confirm the reproducibility of measurements obtained by urethral pressure profilometry (UPP) and cystometry in female Beagles.

Animals—6 adult female Beagles.

Procedure—Successive UPP and cystometry were performed by use of a water perfusion catheter on dogs anesthetized with propofol. Dogs randomly underwent each of the following at 1-week intervals: retrograde filling cystometry at 5, 10, and 20 mL/min, and diuresis cystometry. The maximum urethral pressure and closure pressure, functional and anatomic profile lengths, threshold pressure, threshold volume, and compliance were measured.

Results—For each UPP variable, significant differences were found among dogs, but no significant differences were found in intra- or interstudy measurements for individual dogs. For retrograde filling cystometry, threshold pressure was not significantly different between a 5 and 10 mL/min infusion rate. Threshold pressure was significantly higher during retrograde filling cystometry at 20 mL/min, compared with 5 and 10 mL/min, and was associated with bladder wall damages. Threshold pressure was significantly lower during diuresis cystometry, compared with retrograde filling cystometries. Threshold volume and compliance were not significantly different among retrograde filling cystometries but were significantly higher during diuresis cystometry.

Conclusions and Clinical Relevance—Retrograde filling cystometry at 20 mL/min leads to unacceptable sudden increase in threshold bladder pressure. Retrograde filling cystometry at 10 mL/min can be recommended in a clinical setting, shortening the anesthesia time. However, diuresis cystometry approximates physiologic bladder filling most accurately. (Am J Vet Res2003;64:574–579)
Comparison of radiographic assessments of the tibial plateau slope in dogs
Authors: Baroni Ermenegildo , Matthias Richard R. , Marcellin-Little Denis J. , Vezzoni Aldo , Stebbins Martha E.
Published: January 2006

Objectives—To evaluate the accuracy of 2 radiographic methods used to assess tibial plateau slope (TPS) in dogs and evaluate effects of film digitization and radiographic beam placement on TPS measurements.

Sample Population—16 hind limbs from dog cadavers weighing > 20 kg.

Procedures—Radiographs of tibiae were made with the radiographic beam centered over the stifle joint and midshaft of the tibia. Tibiae were collected, the femorotibial contact area was determined, and slope of the medial tibial condyle in relation to the tibial shaft was measured. Radiographs were digitized. Slope of the medial tibial condyle was measured on printed and digitized radiographs read in random order by 6 examiners unaware of anatomic measurements. Three examiners used a conventional measuring technique, and 3 examiners used an alternative measuring technique.

Results—Anatomic measurements were significantly higher than radiographic measurements made by use of the conventional interpretation method but did not differ from radiographic measurements made by use of the alternate method. Measurements from printed radiographs were lower than measurements from digitized radiographs for the 4 most experienced examiners.

Conclusions and Clinical Relevance—Measurements made by use of a line tangential to the cranial, linear portion of the medial tibial condyle at the femorotibial contact point were accurate measurements of the anatomic TPS. Measurements made by use of the conventional TPS measurement method underestimated the anatomic TPS. Measurements made on digitized radiographs were typically more accurate than measurements made on printed radiographs. (Am J Vet Res2003;64:586–589)
Two-dimensional link-segment model of the forelimb of dogs at a walk
Authors: Nielsen Cheri , Stover Susan M. , Schulz Kurt S. , Hubbard Mont , Hawkins David A.
Published: January 2006

Objective—To calculate normative joint angle, intersegmental forces, moment of force, and mechanical power at elbow, antebrachiocarpal, and metacarpophalangeal joints of dogs at a walk.

Animals—6 clinically normal mixed-breed dogs.

Procedure—Kinetic data were collected via a force platform, and kinematic data were collected from forelimbs by use of 3-dimensional videography. Length, location of the center of mass, total mass, and mass moment of inertia about the center of mass were determined for each of 4 segments of the forelimb. Kinematic data and inertial properties were combined with vertical and craniocaudal ground reaction forces to calculate sagittal plane forces and moments across joints of interest throughout stance phase. Mechanical power was calculated as the product of net joint moment and the angular velocity. Joint angles were calculated directly from kinematic data.

Results—All joint intersegmental forces were similar to ground reaction forces, with a decrease in magnitude the more proximal the location of each joint. Flexor moments were observed at metacarpophalangeal and antebrachiocarpal joints, and extensor moments were observed at elbow and shoulder joints, which provided a net extensor support moment for the forelimb. Typical profiles of work existed for each joint.

Conclusions and Clinical Relevance—For clinically normal dogs of a similar size at a walk, inverse dynamic calculation of intersegmental forces, moments of force, and mechanical power for forelimb joints yielded values of consistent patterns and magnitudes. These values may be used for comparison in evaluations of gait in other studies and in treatment of dogs with forelimb musculoskeletal disease. (Am J Vet Res2003;64:609–617)
Postnatal changes in bacterial populations in the gastrointestinal tract of dogs
Authors: Buddington Randal K.
Published: January 2006

Objective—To describe postnatal changes in the populations of bacteria in the gastrointestinal tract (GIT) of dogs.

Animals—110 Beagles ranging from neonatal to adult dogs.

Procedure—Contents of the stomach and proximal and distal portions of the colon and contents and mucosa of the mid region of the small intestine were collected from puppies at 1 day after birth and subsequent suckling; puppies at 21, 42, and 63 days after birth; and adult female dogs (ie, dams of the puppies) for enumeration of bacterial populations.

Results—The entire GIT was colonized at day 1 by all groups of bacteria studied; aerotolerant forms were dominant. During subsequent postnatal development, there were changes in the relative proportions of the various groups of bacteria with anaerobic groups increasing in absolute and relative numbers.

Conclusions and Clinical Relevance—Establishment of bacterial populations in the GIT of dogs is a gradual process that begins immediately after birth. Age-related changes in the relative proportions of bacterial groups coincided with changes in diet and physiologic processes of the host and can influence nutritional state and disease resistance of developing dogs. Differences among regions of the GIT suggest that fecal samples may have limited use for understanding the populations of bacteria and the age and diet-related changes in various regions of the GIT. (Am J Vet Res2003;64:646–651)
Efficacy of various concentrations of coumaphos to control adult, nymphal, and larval stages of an organophosphate-resistant strain of Boophilus microplus on infested cattle
Authors: Davey Ronald B. , George John E. , Miller Robert J.
Published: January 2006

Objective—To evaluate the efficacy of coumaphos,
an organophosphate (OP) acaricide, at concentrations
up to 2 times higher than the highest concentration
required by the US Eradication Program against all
stages of an OP-resistant strain of Boophilus
microplusin experimentally infested cattle.

Animals—16 tick-naïve 200-kg female Hereford
calves.

Procedure—Four groups of cattle (4 calves/group)
were all infested with Boophilus ticks 3 times before
treatment. Each group was treated with coumaphos
as follows: group 1, at 0.165% active ingredient (AI);
group 2, at 0.299% AI; group 3, at 0.566% AI; and
group 4, not treated. Following treatment, ticks were
collected for 21 days. Ticks collected 1 to 7, 8 to 14,
and 15 to 21 days after treatment were considered
adults, nymphs, and larvae, respectively, at time of
treatment.

Results—Overall control at 0.165, 0.299, and 0.566%
AI was 52.9, 75.8, and 89.7%, respectively. Control of
adults ranged from 4.3% at 0.165% AI to 73.5% at
0.566% AI. Control of nymphs ranged from 60.6% at
0.165% AI to 97.3% at 0.566% AI. Control of larvae
was > 98% at all coumaphos concentrations.

Conclusions and Clinical Relevance—All coumaphos
concentrations failed to provide acceptable control
for use in the US Eradication Program against OPresistant
ticks. Treatment was least effective against
adults and most effective against larvae. Even at
0.566% AI (2 times higher than required by the US
Eradication Program), ticks were not eradicated, placing
the United States at risk from dispersing cattle
harboring viable ticks to uninfested areas. (Am J Vet Res 2003;64:684–689)
Effects of isoeugenol on in vitro neuromuscular blockade of rat phrenic nerve-diaphragm preparations
Authors: Ingvast-Larsson J. Carina , Axén V. Charlotte , Kiessling Anders K.
Published: January 2006

Objective—To investigate in vitro effects of
isoeugenol on neuromuscular transmission in tissues
obtained from rats.

Sample Population—Tissues (phrenic nerve and
diaphragm) obtained from 15 male Sprague-Dawley
rats.

Procedure—Rats were euthanatized, and tissues
(phrenic nerves and diaphragm) were obtained.
Phrenic nerve-diaphragm preparations were examined
in vitro. The phrenic nerve was stimulated with
weak electrical impulses. Muscle-twitch responses
were recorded before and after the addition of drugs
(pancuronium, neostigmine, isoeugenol, and benzocaine).

Results—Pancuronium and isoeugenol in low concentrations
(10 to 206µM) caused a distinct decrease
in twitch response, which could be reversed by the
addition of neostigmine. The decrease in twitch
response caused by benzocaine or high concentrations
of isoeugenol could not be reversed by the addition
of neostigmine.

Conclusions and Clinical Relevance—Isoeugenol
caused a competitive blockade of neuromuscular
transmission. Neostigmine restored this transmission
by inhibiting acetylcholinesterase, which led to
increased concentrations of acetylcholine. Because
isoeugenol is used as an anesthetic in fish, further
investigations are necessary to determine whether
fish exposed to isoeugenol are sedated and unconscious
or whether they are only paralyzed but have
intact perception in afferent sensory nerves.
(Am J Vet Res 2003;64:690–693)
Use of scintigraphy for assessment of fracture healing and early diagnosis of osteomyelitis following fracture repair in rabbits
Authors: Southwood Louise L. , Kawcak Chris E. , McIlwraith C. Wayne , Frisbie David D. , Steyn Phillip F.
Published: January 2006

Objective—To evaluate use of technetium Tc 99m disodium hydroxymethylene diphosphonate (99m-Tc- HDP) for assessing fracture healing and 99m-Tc-HDP and technetium Tc 99m ciprofloxacin (99m-Tc-CIPRO) for early diagnosis of osteomyelitis in rabbits.

Animals—32 skeletally mature New Zealand White rabbits.

Procedure—A femoral fracture defect stabilized with bone plates and cortical screws was used. Scintigraphy was performed 4, 8, 12, and 16 weeks after surgery. The 99m-Tc-CIPRO scan was performed 48 hours after the 99m-Tc-HDP scan. The uptake ratio of the experimental limb to the normal limb was calculated by use of multiple regions of interest. Results of radiography performed to determine external callus and lysis grade and percentage defect ossification at 16 weeks were compared with scintigraphy results.

Results—Infected fractures had a higher uptake ratio for 99m-Tc-HDP and 99m-Tc-CIPRO than noninfected fractures. Infected fractures could be differentiated from noninfected fractures late in healing by use of 99m-Tc-HDP. Although 99m-Tc-CIPRO was better than 99m-Tc-HDP for identifying infection, there was a high incidence of false positive and negative results with 99m-Tc-CIPRO. There was an association between 99m-Tc-HDP uptake ratio and callus formation and a good correlation between 99m-Tc-HDP uptake ratio and defect ossification after 4 weeks.

Conclusions and Clinical Relevance—99m-Tc-HDP and 99m-Tc-CIPRO may be useful for diagnosing osteomyelitis late in fracture healing; however, false positive and false negative results occur. Technetium Tc 99m disodium hydroxymethylene diphosphonate may be useful for evaluating fracture healing. (Am J Vet Res2003;64:736–745)
Body weight, hematologic findings, and serum and plasma biochemical findings of horses competing in a 48-, 83-, or 159-km endurance ride under similar terrain and weather conditions
Authors: Barton Michelle H. , Williamson Lisa , Jacks Stephanie , Norton Natalie
Published: January 2006

Objective—To compare physiologic, hematologic, and selected serum and plasma biochemical variables obtained from horses competing in 48-, 83-, or 159- km endurance rides before competition and at the same cumulative distance points.

Animals—83 horses.

Procedure—Weight and rectal temperature measurements and blood samples were obtained from horses before, during, and after 1 of 3 rides conducted on the same day. Plasma protein (PP), lactate, WBC, serum electrolyte, and calcium concentrations; PCV; and creatine kinase (CK) activity were determined. Assessments were made to determine whether any differences among groups, with respect to total distance competed, could be explained by differences in lap speed or conditioning and to investigate the effect of time in transit or on-site prior to competition on results of blood analyses or competition outcome.

Results—Horses in the 159-km distance group had the lowest preride serum sodium, chloride, bicarbonate, and calcium concentrations. As hours in transit increased, preride PP concentration was significantly greater; serum sodium, chloride, and bicarbonate concentrations were lower; CK activity at 159 km was greater; and horses were more likely to be eliminated. The preride sodium was significantly greater in horses that completed the ride, compared with those eliminated.

Conclusions and Clinical Relevance—Among distance groups, distance ridden, speed, level of fitness, and years of experience of horses had little effect on the variables examined. Electrolyte and water supplementation and earlier arrival at the event may be beneficial for horses that are transported long distances to endurance competition. (Am J Vet Res2003;64:746–753)
Effects on plasma endotoxin and eicosanoid concentrations and serum cytokine activities in horses competing in a 48-, 83-, or 159-km endurance ride under similar terrain and weather conditions
Authors: Barton Michelle H. , Williamson Lisa , Jacks Stephanie , Norton Natalie
Published: January 2006

Objective—To determine plasma endotoxin concentration in horses competing in a 48-, 83-, or 159-km endurance race and its importance with regard to physical, hematologic, or serum and plasma biochemical variables.

Animals—83 horses.

Procedure—Weight and rectal temperature measurements and blood samples were obtained before, during, and after exercise. Blood samples were analyzed for plasma endotoxin concentration; serum antiendotoxin antibody titers; thromboxane B2(TxB2) and 6- keto-prostaglandin F1α(PGF1α) concentrations; tumor necrosis factor alpha (TNFα) and interleukin-6 (IL-6) activities; WBC, plasma protein, lactate, serum electrolyte, and calcium concentrations; PCV; and creatine kinase activity.

Results—Detection of plasma endotoxin increased during exercise for horses competing at all distances but occurred more frequently in the 48- and 83-km groups. Plasma lactate concentration was significantly greater when endotoxin was concurrently detected. Endotoxin in plasma was not significantly associated with success of race completion. Plasma TxB2and PGF1αconcentrations and serum IL-6 activity significantly increased with exercise. Horses that had an excellent fitness level (as perceived by their owners) had greater decreases in serum antiendotoxin antibody titers during exercise than did horses perceived as less fit. In horses with better finish times, TxB2and PGF1αconcentrations were significantly greater and TNFαactivity was significantly less than that of slower horses.

Conclusions and Clinical Relevance—Endotoxemia developed during endurance racing, but was significantly correlated with increased plasma lactate concentration and not with other variables indicative of endotoxemia. Plasma TxB2and PGF1αconcentrations and serum TNFαactivity may be associated with performance success. (Am J Vet Res2003;64:754–761)
Evaluation of skin test reactivity to environmental allergens in healthy cats and cats with atopic dermatitis
Authors: Schleifer Sebastian G. , Willemse Ton
Published: January 2006

Objective—To evaluate skin test reactivity to environmental allergens in healthy cats and in cats with atopic dermatitis (AD).

Animals—10 healthy cats and 10 cats with AD.

Procedure—10 allergens in serial dilutions were injected ID on the lateral aspect of the thorax of sedated cats. Histamine (0.01% solution) and buffer solutions were used as positive and negative controls, respectively. Immediately after the last injection, 10% fluorescein solution was administered IV. Skin test results were evaluated with ultraviolet light after 15 to 30 minutes and at 4 and 6 hours by 2 independent observers. In the control group, skin tests were repeated after 6 weeks. Skin test reactivity and the nature of the immunoglobulin involved were investigated by use of the Prausnitz-Küstner test with untreated and heat-treated cat sera.

Results—Intertest and interobserver agreement were high when measurement of the diameter of the fluorescent wheal was used to evaluate skin test responses, compared with assessment of its intensity. In both groups of cats, immediate skin test reactivity was observed as an IgE-mediated reaction, as an IgG-mediated reaction, and as a result of nonspecific mast cell degranulation. There was no correlation between allergen concentration and the type of reaction observed.

Conclusions and Clinical Relevance—Skin test reactivity in cats should be evaluated after IV administration of 10% fluorescein solution by means of a Prausnitz-Küstner test to differentiate among IgEmediated, IgG-mediated, and nonspecific reactions. (Am J Vet Res2003;64:773–778)
Effect of histamine on lung contractile elements in growing cattle
Authors: Jolly Sandra , Robinson N. Edward , Desmecht Daniel J.
Published: January 2006

Objective—To determine the effect of histamine on
the contractile elements of the respiratory tract in
neonatal calves and young adult cattle.

Sample Population—Samples of trachealis muscle,
bronchi, and intrapulmonary arteries and veins dissected
from the respiratory tracts of healthy bovids (2
to 8 days and 16 to 20 months old).

Procedure—Histamine cumulative concentrationeffect
curves (10–8 to 10–3M) were constructed in duplicate
smooth muscle samples mounted in organ
baths. Contractile responses to histamine were compared
with reference contractions elicited by methacholine
(10–5M) for airways or KCl (127mM) for vessels.

Results—In young adult cattle, trachealis muscle had
a substantial contractile response to histamine (84%
of methacholine-induced contraction), whereas
bronchi reacted slightly (15 and 20% for large and
small bronchi, respectively). Although contractile
responses to KCl were comparable in arteries and
veins, histamine-induced contractions were greater
for intrapulmonary veins than for arteries (202 vs 48%
of KCl-induced contraction). In neonatal calves, histamine-
induced contraction of veins also exceeded that
of arteries (230 vs 54% of KCl-induced contraction);
however, unlike in young adult cattle, histamine produced
notable contraction of large and small bronchi
(48 and 60% of methacholine-induced contraction,
respectively).

Conclusions and Clinical Relevance—Compared
with intrapulmonary arteries, intrapulmonary veins
have greater contractile responses to histamine in
neonatal and young adult cattle. Data suggest loss of
histamine responsiveness in bronchial smooth muscle
as neonatal calves grow to young adults.
Venodilation may be useful in treatment of lung
edema in cattle. (Am J Vet Res 2003;64:819–822)
Submural histopathologic changes attributable to peracute laminitis in horses
Authors: Morgan Sherry J. , Hood David M. , Wagner Ilka P. , Postl Steve P.
Published: January 2006

Objective—To describe submural histopathologic changes attributable to peracute laminitis in horses.

Animals—20 adult horses.

Procedure—A concurrent-control design was used to compare laminar lesions in 10 horses subjected to carbohydrate-induced laminitis with laminar characteristics of 10 sex- and aged-matched control horses with normal feet. Horses in the treatment group were administered an overload of carbohydrate. Tissues were obtained by biopsy 4 to 8 hours after onset of lameness or 72 hours after administration of the carbohydrate overload when lameness did not develop. Sections were stained with H&E, Masson's trichrome, and periodic acid-Schiff stains. Histopathologic changes were analyzed to detect differences between groups and to correlate epidermal changes with severity and duration of lameness.

Results—Analysis indicated that dermal and epidermal lesions were evident despite lack of visible separation of the epidermal basement membrane, can be found in horses without detectable lameness, and were nonspecific and progressive following onset of lameness. Furthermore, severity and location of lesions were associated with severity and duration of lameness.

Conclusion and Clinical Relevance—These observations are consistent with the concept that separation of the laminar epithelial basement membrane is a delayed step in the pathogenesis of acute laminitis, digital vascular hypoperfusion is an underlying cause for laminitis, and the potential for repeated episodes of subclinical laminitis may underlie the development of structural and mechanical changes consistent with chronic laminitis despite lack of clinical signs of acute laminitis. (Am J Vet Res2003;64:829–834)
New approach for quantitative assessment of articular cartilage degeneration in horses with osteoarthritis
Authors: Brommer Harold , Weeren P. René van , Brama Pieter A. J.
Published: January 2006

Objective—To evaluate a modified digital imaging technique for quantitative assessment of the grade of osteoarthritis across the proximal articular surface of the first phalanx in horses.

Sample Population—6 metacarpophalangeal (fetlock) joint specimens from 6 horses with various stages of osteoarthritis.

Procedure—First phalanx specimens, together with 4 gray scale reference calibration targets, were positioned in a bath with the proximal articular cartilage surface submerged in saline (0.9% NaCl) solution. Digital images were obtained from the articular surface before and after staining with Indian ink. Computer-controlled gray level analysis of the nonstained and Indian ink-stained cartilage surfaces and gray scale reference calibration targets was performed by use of the mean pixel value (based on 255-gray scale). An increase in the mean pixel value after staining was used to calculate the cartilage degeneration index (CDI).

Results—The CDI of the proximal articular cartilage surface of the first phalanx specimens ranged from 9.2 ± 5.7 (early stage osteoarthritis) to 41.5 ± 3.6% (late stage osteoarthritis). The effect of repeating the measurement 6 times in nonstained (including repositioning) and stained specimens (including repositioning and restaining) was not significant. Up to 10 measurements of nonstained specimens could be made without refreshing the bath solution. In stained specimens, mean gray level increased significantly after the sixth measurement.

Conclusion and Clinical Relevance—The modified digital imaging technique allowed quantitative assessment of cartilage degeneration across the articular cartilage surface. The CDI is the first quantitative measure for osteoarthritis-induced cartilage degeneration over an entire joint surface in horses. (Am J Vet Res2003;64:83–87)
Influence of topically applied cold treatment on core temperature and cell viability in equine superficial digital flexor tendons
Authors: Petrov Raina , MacDonald Melinda H. , Tesch Anthony M. , Hoogmoed Linda M. Van
Published: January 2006

Objective—To determine rate and degree of cooling for the superficial digital flexor tendon (SDFT) during a standard cryotherapy application in horses and evaluate in vitro effects of cooling on survival of tendon cells.

Sample Population—6 limbs of 5 adult horses and cultured cells obtained from SDFT of 3 adult horses during necropsy.

Procedure—In vivo data were acquired by use of a thermocouple temperature probe inserted into the SDFT of a forelimb of each standing sedated horse. After baseline temperatures were recorded, a commercial compression splint with circulating coolant was placed on each selected limb, which was then exposed to cold treatment for 60 minutes. Temperatures were recorded at 30-second intervals. Mean minimum core temperature was calculated and used to design a protocol for in vitro cold treatment of cells. Specimens were obtained from the SDFT of horses during necropsy; tendon cells were cultured in suspension and exposed to 1-hour of cold treatment that mimicked the in vivo procedure. Viability of cells after cold treatment was compared with viability of cells maintained at body temperature.

Results—After 1 hour of cold treatment, SDFT core temperature was reduced by a mean of 21.8°C, reaching a mean minimum temperature of 10oC. Viability did not differ significantly between cold-treated and control cells.

Conclusion and Clinical Relevance—Results indicated that topical application of cryotherapy significantly reduced core SDFT temperature in standing sedated horses. Temperatures achieved in vivo during cold treatment were not detrimental to the in vitro viability of tendon cells. (Am J Vet Res2003;64:835–844)
Replication of bluetongue virus and epizootic hemorrhagic disease virus in pulmonary artery endothelial cells obtained from cattle, sheep, and deer
Authors: McLaughlin Bridget E. , DeMaula Christopher D. , Wilson William C. , Boyce Walter M. , MacLachlan N. James
Published: January 2006

Objective—To compare replication of bluetongue virus (BTV) and epizootic hemorrhagic disease virus (EHDV) in pulmonary artery endothelial cells (ECs) obtained from juvenile cattle, sheep, white-tailed deer (WTD;Odocoileus virginianus), and black-tailed deer (BTD;O hemionus columbianus).

Sample Population—Cultures of pulmonary artery ECs obtained from 3 cattle, 3 sheep, 3 WTD, and 1 BTD.

Procedure—Purified cultures of pulmonary artery ECs were established. Replication, incidence of infection, and cytopathic effects of prototype strains of BTV serotype 17 (BTV-17) and 2 serotypes of EHDV (EHDV-1), and (EHDV-2) were compared in replicate cultures of ECs from each of the 4 ruminant species by use of virus titration and flow cytometric analysis.

Results—All 3 viruses replicated in ECs from the 4 ruminant species; however, BTV-17 replicated more rapidly than did either serotype of EHDV. Each virus replicated to a high titer in all ECs, although titers of EHDV-1 were significantly lower in sheep ECs than in ECs of other species. Furthermore, all viruses caused extensive cytopathic effects and a high incidence of cellular infection; however, incidence of cellular infection and cytopathic effects were significantly lower in EHDV-1-infected sheep ECs and EHDV-2-infected BTD ECs.

Conclusions and Clinical Relevance—There were only minor differences in replication, incidence of infection, and cytopathic effects for BTV-17, EHDV-1, or EHDV-2 in ECs of cattle, sheep, BTD, and WTD. It is not likely that differences in expression of disease in BTV- and EHDV-infected ruminants are attributable only to species-specific differences in the susceptibility of ECs to infection with the 2 orbiviruses. (Am J Vet Res2003;64:860–865)
Effects of topical application of antimicrobials and bandaging on healing and granulation tissue formation in wounds of the distal aspect of the limbs in horses
Authors: Berry II Douglass B. , Sullins Kenneth E.
Published: January 2006

Objective—To determine whether povidone iodine ointment or 2 forms of silver sulfadiazine applied topically to wounds of the distal aspect of the limbs in horses affect the rate of second intention healing and to evaluate the additional influence of bandaging with these antimicrobials on granulation tissue formation.

Animals—6 healthy adult horses.

Procedure—Six standardized 2.5-cm2skin wounds/horse were distributed between the dorsomedial surfaces of the metacarpi and metatarsi. One of the following 6 treatments was applied to each wound: 1% silver sulfadiazine cream with bandage, 1% silver sulfadiazine slow-release matrix with bandage, 1% silver sulfadiazine slow-release matrix without bandage, povidone-iodine ointment with bandage, untreated control with bandage, and untreated control without bandage. Wound area, granulation tissue area, and perimeter were measured by use of planimetry software applied to digital images. Exuberant granulation tissue was excised when present. Days until healing, rate of healing parameter, rate of contraction, and epithelialization were compared among wound treatment groups.

Results—Healing parameters and mean days to healing did not differ significantly among any of the wound treatment groups. Percentage wound contraction and rate of epithelialization were similar among wound treatments. All bandaged wounds produced exuberant granulation tissue, which was surgically excised; none of the unbandaged wounds produced exuberant granulation tissue.

Conclusion and Clinical Relevance—When exuberant granulation tissue is removed, rates of epithelialization and wound contraction were not different among wound treatment groups, whether bandaged or unbandaged. Topical application of 1% silver sulfadiazine slow-release matrix on unbandaged wounds induced the same result as medications applied beneath bandages, but without exuberant granulation tissue formation. (Am J Vet Res2003;64:88–92)
Efficacy of ceftiofur for treatment of experimental salmonellosis in neonatal calves
Authors: Fecteau Marie-Eve , House John K. , Kotarski Susan F. , Tankersley Natalie S , Ontiveros Monica M. , Alcantar Carlos R. , Smith Bradford P
Published: January 2006

Objective—To evaluate therapeutic efficacy of a high extralabel dose of ceftiofur for treatment of experimental salmonellosis in neonatal calves.

Animals—Forty-two 1- to 4-day-old Holstein bull calves.

Procedure—36 calves were orally challenged withSalmonella enteriticaserovar Typhimurium (6.5 × 108colony-forming units). Six additional calves were retained as nonmedicated nonchallenged control calves. Four days followingSalmonellachallenge, surviving calves were randomly allocated to ceftiofurtreated (5 mg/kg, IM, q 24 h) or nonmedicated control groups. Calves assigned to the treated group were medicated daily for 5 days starting on day 4 after challenge. Calves were monitored for 18 days followingSalmonellachallenge. Outcome assessments included clinical parameters (attitude, appetite, fecal characteristics, and rectal temperature), mortality rate, and quantitativeSalmonellaculture of fecal samples, mesenteric lymph nodes, and cecal contents.

Results—Ceftiofur treatment was associated with a significant decrease in rectal temperature and diarrhea. Three of 15 medicated calves and 4 of 14 nonmedicated calves died or were euthanatized between days 4 and 18. A significant decrease in fecal shedding ofSalmonellaorganisms was observed in treated calves, compared with non-medicated calves.Salmonellaorganisms were isolated from all 10 nonmedicated calves at necropsy, whereas noSalmonellaorganisms were isolated from 5 of 12 medicated calves.

Conclusions and Clinical Relevance—Treatment of salmonellosis in neonatal calves with a high extralabel dose of ceftiofur (5 mg/kg, IM, q 24 h) promotes animal welfare, reduces fecal shedding ofSalmonellaorganisms, and may promote clearance ofSalmonellainfections when plasma ceftiofur concentrations are maintained above minimal inhibitory concentrations. (Am J Vet Res2003;64:918–925)
Comparison between invasive hemodynamic measurements and noninvasive assessment of left ventricular diastolic function by use of Doppler echocardiography in healthy anesthetized cats
Authors: Schober Karsten E. , Fuentes Virginia Luis , Bonagura John D.
Published: January 2006

Objective—To compare Doppler echocardiographic variables of left ventricular (LV) function with those obtained invasively via cardiac catheterization under a range of hemodynamic conditions.

Animals—7 healthy anesthetized cats (1 to 3 years of age).

Procedure—Cats were anesthetized and instrumented to measure the time constant of isovolumic relaxation (tau []), LV end-diastolic pressure (LVEDP), peak negative and positive rate of change of LV pressure, arterial blood pressure, and cardiac output. Echocardiographic variables of diastolic function (isovolumic relaxation time [IVRT], early LV flow propagation velocity [Vp], transmitral and pulmonary venous flow velocity indices, and LV tissue Doppler imaging indices) were measured simultaneously over a range of hemodynamic states induced by treatments with esmolol, dobutamine, cilobradine, and volume loading. Correlation between invasive and noninvasive measures of LV filling was determined by univariate and multivariate regression analyses.

Results—Significant correlations were found betweenand IVRT, peak Vp, peak late transmitral flow velocity, and peak systolic pulmonary venous flow velocity. A significant correlation was found between LVEDP and early diastolic transmitral flow velocity (peak E) and the ratio of peak E to peak Vp, but not between LVEDP and peak Vp.

Conclusion and Clinical Relevance—IVRT and Vp can be used as noninvasive indices of LV relaxation; Vp was independent of preload and heart rate in this study. The E:Vp ratio may be useful as an indicator of LV filling pressure. (Am J Vet Res2003;64:93–103)