OBJECTIVE To compare bony changes of the third metacarpal bone (MC3) of Thoroughbred racehorse cadavers with (cases) or without (controls) catastrophic condylar fracture by use of standing MRI.
SAMPLE 140 forelimbs from 26 case horses (both forelimbs) and 88 control horses (single forelimb).
PROCEDURES Bone marrow lesions (BMLs), identified as a decrease in T1-weighted (T1W) signal and increases in T2*-weighted (T2*W) and short tau inversion recovery (STIR) signals, and dense bone volume percentage (DBVP), identified as decreases in T1W, T2*W, and STIR signals, in the distopalmar aspect of MC3 were recorded. Logistic regression was used to compare fractured and nonfractured limbs of cases and fractured limbs of cases with randomly selected limbs of controls.
RESULTS Among cases, fractured limbs were significantly more likely to have BMLs (26/26 [100%]) than were nonfractured limbs (7/26 [27%]). Fractured limbs of cases were significantly more likely to have BMLs (26/26 [100%]) than were limbs of controls (6/88 [7%]). Among cases, there was no significant difference in DBVP between fractured and nonfractured limbs in lateral (26% vs 21%, respectively) or medial (25% vs 20%, respectively) condyles. However, DBVP was significantly greater in fractured limbs of cases than in limbs of controls for lateral (26% vs 16%, respectively) and medial (25% vs 18%, respectively) condyles.
CONCLUSIONS AND CLINICAL RELEVANCE Standing MRI revealed a significantly greater degree of bone change in racehorses with condylar fracture when comparing fractured and nonfractured limbs of case horses and fractured limbs of case horses with randomly selected limbs of control horses.
Objective—To evaluate the correlation between the
half-time of liquid-phase gastric emptying (T50) determined
by use of nuclear scintigraphy, using technetium
Tc 99m pentetate, and absorption variables of
orally administered acetaminophen in horses with
experimentally delayed gastric emptying.
Animals—6 mature horses.
Procedure—Delayed gastric emptying was induced
by IV injection of atropine sulfate. Twenty minutes
later, acetaminophen and technetium Tc 99m pentetate
were administered simultaneously via nasogastric
tube. Serial lateral images of the stomach region
were obtained, using a gamma camera. Power exponential
curves were used for estimation of T50 and
modified R2 values for estimation of goodness-of-fit of
the data. Serial serum samples were obtained, and
acetaminophen concentration was determined, using
fluorescence polarization immunoassay. Maximum
serum concentration (Cmax), time to reach maximum
serum concentration (Tmax), area under the curve for
480 minutes, and the appearance rate constant were
determined, using a parameter estimation program.
Correlations were calculated, using a Spearman rank
Results—A significant correlation was detected
between T50 determined by use of scintigraphy and
Tmax determined by use of acetaminophen absorption.
Correlation between T50 and other absorption
variables of acetaminophen was not significant.
Conclusions and Clinical Relevance—The acetaminophen
absorption method was a valid technique in
this model of delayed gastric emptying in horses. The
method may be a valuable tool for use in research as
well as in clinical evaluation of gastric emptying in
horses. (Am J Vet Res 2002;63:170–174)
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 whether specific feeding
practices were associated with development of colic
Design—Prospective matched case-control study.
Animals—364 horses examined by veterinarians in
private practice in Texas because of colic (cases; n =
182) or any other reason (controls; 182).
Procedure—Participating veterinarians were sent
forms at the beginning of the study to collect information
on signalment, feeding management practices,
farm management practices, and preventive
medical treatments. Case and control horses were
compared by use of conditional logistic regression to
identify factors associated with colic.
Results—Risk factors for colic were a recent change
in batch of hay, decreased exposure to pasture, a
recent change in type of grain or concentrate fed,
feeding > 2.7 kg (6 lb) of oats/d, feeding hay from
round bales, and Thoroughbred breed. Recent
anthelmintic administration decreased the risk of colic.
Conclusions and Clinical Relevance—Results suggest
that certain changes in diet (eg, change in batch of
hay, change in type of grain or concentrate, feeding hay
from round bales) and management (eg, decreased
availability of pasture) increase the risk of colic in horses.
(J Am Vet Med Assoc 2001;219:1419–1425)
Objective—To evaluate quality of duodenal tissue
specimens obtained endoscopically from dogs and
cats and submitted to 1 of 2 diagnostic laboratories
Sample Population—Slides from 50 consecutive
canine and 50 consecutive feline endoscopically
obtained duodenal tissue specimens submitted to
laboratory 1 and 49 consecutive canine and 46 consecutive
feline specimens submitted to laboratory 2.
Procedure—Slides were examined independently by
3 investigators, and each tissue piece on each slide
was classified as clearly inadequate, questionable, or
clearly adequate on the basis of 4 criteria. An overall
score was then assigned to the slide.
Results—Slides from laboratory 1 were more likely to
be scored as clearly adequate and less likely to be
scored as clearly inadequate than slides from laboratory
2. Clearly adequate slides from laboratory 1 had
a higher number of clearly adequate pieces of tissue
than did clearly adequate slides from laboratory 2.
Slides scored as clearly adequate had a higher number
of individual tissue pieces than did slides scored
as clearly inadequate.
Conclusions and Clinical Relevance—Results suggest
that the quality of endoscopically obtained duodenal
tissue specimens submitted to laboratories can
vary, possibly because of differences in experience of
individuals collecting biopsy specimens. Results suggest
that at least 8 individual tissue pieces should be
submitted when performing endoscopic biopsy of the
duodenum in dogs and cats. (J Am Vet Med Assoc
Objective—To determine the association between
high-speed exercise and risk of injury while racing
among Thoroughbreds in Kentucky.
Design—Matched case-control study.
Animals—206 Thoroughbreds that sustained a musculoskeletal
injury while racing and 412
Thoroughbreds that were not injured during the same
Procedure—Data regarding official timed workouts
and races and the Beyer's numbers for the 3 races
before the race during which injury occurred were
extracted from past performance charts and compared
between injured horses and control horses.
Results—For injured horses, cumulative distance of
high-speed exercise during the 1- and 2-month periods
prior to the race in which injury occurred was significantly
less than that of control horses; for either
period, a difference of 10 furlongs was associated
with approximately 2-fold greater risk of injury.
Beyer's numbers were significantly higher for injured
horses than for control horses. These effects
remained significant after adjusting for age and
results of prerace physical inspection.
Conclusions and Clinical Relevance—In Kentucky,
injured horses had significantly less cumulative highspeed
exercise than did control horses during the 1-
and 2-month periods prior to the race in which injury
occurred. These results differ from those observed in
California. The association of injury with cumulative
high-speed exercise appears to vary among regions in
the United States. (J Am Vet Med Assoc 2000;
Objective—To quantify the number of horses with Corynebacterium pseudotuberculosis infection identified in the United States from January 2003 through December 2012.
Sample—State veterinary diagnostic laboratory records of 2,237 C pseudotuberculosis culture-positive samples from horses.
Procedures—44 state veterinary diagnostic laboratories throughout the United States were invited by mail to participate in the study. Data requested included the number of C pseudotuberculosis culture-positive samples from horses identified per year, geographic location from which the C pseudotuberculosis culture-positive sample was submitted, month and year of sample submission, breed and age of horses, and category of clinical manifestation (ie, internal infection, external infection, or ulcerative lymphangitis).
Results—Of the 44 invited laboratories, 15 agreed to participate and provided data on affected horses from 23 states. The proportion of C pseudotuberculosis culture-positive samples submitted during 2011 through 2012 (1,213/2,237 [54%]) was significantly greater than that for the period from 2003 through 2010 (1,024/2,237 [46%]). Corynebacterium pseudotuberculosis was recovered from horses in states where the disease has not been previously recognized as endemic. Affected horses were identified year-round. The greatest proportion of C pseudotuberculosis culture-positive samples was identified during November, December, and January (789/2,237 [35%]). No significant association between the clinical form of disease and age or breed of horse was observed.
Conclusions and Clinical Relevance—The occurrence of C pseudotuberculosis infection in horses increased during the 10-year period, and affected horses were identified throughout the United States. Further studies to determine changes in annual incidence and to identify potential changing climatic conditions or vector populations associated with disease transmission are warranted to help control the occurrence and spread of C pseudotuberculosis infection in horses.
Objective—To compare bony changes in the metacarpophalangeal joint (MCPJ) of racehorses with (cases) and without (controls) biaxial proximal sesamoid bone (PSB) fracture as determined by 2 grading scales applied to images of cadaveric forelimbs obtained by means of standing MRI (sMRI).
Sample—Forelimbs from 74 Thoroughbred racehorses (21 cases and 53 controls) that were euthanized at a Florida racetrack.
Procedures—Both forelimbs were harvested from cases and controls. Each forelimb underwent sMRI to obtain images of the MCPJ. Two grading scales were described and used for image evaluation; one assessed the density of the PSBs, and the other assessed the integrity of the subchondral bone (SCB) plate at the distopalmar aspect of the third metacarpal bone (MC3). Logistic regression was used to compare the grades between case and control limbs.
Results—Biaxial PSB fracture was associated with a total PSB grade (sum of lateral and medial PSB grades) ≥ 5 for the fractured limb, total MC3 SCB grade (sum of lateral and medial MC3 SCB grades) ≥ 5 for the contralateral limb, and the presence of orthopedic disease in the contralateral MC3.
Conclusions and Clinical Relevance—For cases with biaxial PSB fracture, the density of the PSBs in the affected limb was greater and the MC3 of the contralateral limb was more likely to have orthopedic disease, compared with those for controls. Further evaluation of sMRI as a screening tool for identification of racehorses at risk of biaxial PSB fracture is warranted. (J Am Vet Med Assoc 2015;246:661–673)
OBJECTIVE To describe the chief complaints by owners and the types and prevalences of musculoskeletal problems associated with lameness or poor performance in cutting horses.
DESIGN Retrospective case series.
ANIMALS 200 client-owned cutting horses examined at the Texas A&M University Veterinary Medical Teaching Hospital between January 1, 2007, and December 31, 2015, because of lameness or poor performance.
PROCEDURES Medical records were reviewed, and data were collected regarding signalment, history, findings on physical and lameness examinations, results of diagnostic procedures performed, diagnosis, and treatment. Distribution of observed proportions of forelimb and hind limb involvement was compared with a hypothetical distribution of 50% by means of a χ2 test.
RESULTS More horses were examined because of a recent decrease in performance (116/200 [58%]) than for lameness (84 [42%]). All horses had at least 1 lame limb, with lameness affecting a total of 281 limbs. Of the 281 lame limbs, 189 (67%) were hind limbs and 92 (33%) were forelimbs. These proportions were substantially different from a hypothetical distribution of 50% hind limbs and 50% forelimbs. The most common performance change was that horses would not reverse direction to follow prespecified individual cattle, and the most common cause of lameness was pain localized to the stifle joint region (69 [35%]).
CONCLUSIONS AND CLINICAL RELEVANCE Cutting horses sustained more hind limb than forelimb musculoskeletal problems, and although these horses were more likely to be examined for decreased performance than lameness, veterinarians should be vigilant for problems affecting the stifle joint region.
Objective—To identify farm characteristics and management
practices associated with development of
Rhodococcus equi pneumonia in foals.
Design—Prospective case-control study.
Animals—5,230 foals on 138 breeding farms with
Procedure—During 2003, participating veterinarians
provided data from 1 or 2 farms with ≥ 1 foal with
R equi pneumonia and unaffected farms. Data from
affected and unaffected farms were compared by use
of logistic regression analysis.
Results—A number of variables relating to farm size
and desirable management practices were significantly
associated with increased odds of farms being
affected with R equi pneumonia. By use of multivariate
logistic regression, affected farms were determined
significantly more likely to have raised Thoroughbreds,
housed ≥ 15 foals, used concrete floors in foaling stalls,
and tested foals for passive transfer of immunity than
unaffected farms. These results remained significant
even after accounting for exposure of foals to other
breeding farms during the first month of life.
Conclusions and Clinical Relevance—Breeding
farms with large acreage and a large number of mares
and foals have greater odds of being affected by
R equi pneumonia. Clinical relevance of associations
with Thoroughbred breed and concrete flooring in
foaling stalls remains uncertain. Desirable management
factors commonly used on farms were not
effective for controlling or preventing development of
R equi pneumonia. This finding indicates a need to
focus on host factors that influence disease development.
(J Am Vet Med Assoc 2005;226:404–413)