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.
To compare soil concentrations of macrolide- and rifampicin-resistant Rhodococcus equi strains (MRRE) on horse-breeding farms that used thoracic ultrasonographic screening (TUS) to identify foals with subclinical pneumonia combined with subsequent administration of macrolides and rifampin to affected foals (TUS farms) versus soil concentrations on farms that did not (non-TUS farms), determine whether the combined use of TUS and antimicrobial treatment of subclinically affected foals was associated with soil concentration of MRRE, and assess whether there were temporal effects on soil concentrations of MRRE during the foaling season.
720 soil samples and 20 completed questionnaires from 20 horse-breeding farms (10 TUS farms and 10 non-TUS farms) in central Kentucky.
A questionnaire was used to gather information from participating farms about their 2019 foaling season. Soil samples were collected during January, March, May, and July 2019 for bacterial culture and antimicrobial susceptibility testing to identify any isolates of MRRE. Results were compared for TUS farms versus non-TUS farms. Linear mixed-effects modeling was used to evaluate for potential associations between the soil concentration of MRRE and the use of TUS.
Overall, the sum of the mean soil concentrations of MRRE was significantly higher for TUS farms (8.85 log10-transformed CFUs/g) versus non-TUS farms (7.37 log10-transformed CFUs/g).
CONCLUSIONS AND CLINICAL RELEVANCE
Our findings indicated that farms that use TUS to identify foals with subclinical pneumonia for antimicrobial treatment select for antimicrobial-resistant R equi strains. Because prognosis is worse for foals infected with resistant versus nonresistant strains of R equi, prudent use of antimicrobials to treat foals with subclinical pulmonary lesions attributed to R equi is recommended.
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 estimate spatial risks associated with
mare reproductive loss syndrome (MRLS) during
2001 among horses in a specific study population and
partition the herd effects into those attributable to
herd location and those that were spatially random
and likely attributable to herd management.
Animals—Pregnant broodmares from 62 farms in 7
counties in central Kentucky.
Procedure—Veterinarians provided the 2001 abortion
incidence proportions for each farm included in the
study. Farms were georeferenced and data were analyzed
by use of a fully Bayesian risk-mapping technique.
Results—Large farm-to-farm variation in MRLS incidence
proportions was identified. The farm-to-farm
variation was largely attributed to spatial location
rather than to spatially random herd effects
Conclusions and Clinical Relevance—Results indicate
that there are considerable data to support an
ecologic cause and potential ecologic risk factors for
MRLS. Veterinary practitioners with more detailed
knowledge of the ecology in the 7 counties in
Kentucky that were investigated may provide additional
data that would assist in the deduction of the
causal factor of MRLS via informal geographic information
systems analyses and suggest factors for
inclusion in further investigations. (Am J Vet Res 2005;66:17–20)
Objective—To characterize the temporality of dates
of breeding and abortion classified as mare reproductive
loss syndrome (MRLS) among mares with abortions
during early gestation.
Animals—2,314 mares confirmed pregnant at
approximately 28 days after breeding from 36 farms in
central Kentucky, including 515 mares that had earlyterm
Procedure—Farm veterinarians and managers were
interviewed to obtain data for each mare that was
known to be pregnant to determine pregnancy status,
breeding date, last date known to be pregnant, and
date of abortion.
Results—Mares bred prior to April 1, 2001,
appeared to be at greatest risk of early-term abortion,
both among and within individual farms.
Mares bred in mid-February appeared to be at
greatest risk of abortion, with an estimated weekly
incidence rate of abortion of 66% (95% CI, 52% to
Conclusions and Clinical Relevance—Mares in
central Kentucky bred between mid-February and
early March were observed to be at greatest risk of
early-term abortion, and risk gradually decreased to
a background incidence of abortion of approximately
11%. Mares bred after April 1, 2001, appeared to
be at markedly less risk, indicating that exposure to
the cause of MRLS likely occurred prior to this
date. (Am J Vet Res 2005;66:1792–1797)
Objective—To determine the pharmacokinetics of gallium maltolate (GaM) after intragastric administration in healthy foals.
Animals—6 healthy neonatal foals.
Procedures—Each foal received GaM (20 mg/kg) by intragastric administration. Blood samples were obtained before (time 0) and at 0.25, 0.5, 1, 2, 4, 8, 12, 24, 36, and 48 hours after GaM administration for determination of serum gallium concentrations by use of inductively coupled plasma mass spectroscopy.
Results—Mean ± SD pharmacokinetic variables were as follows: peak serum gallium concentration, 1,079 ± 311 ng/mL; time to peak serum concentration, 4.3 ± 2.0 hours; area under the serum concentration versus time curve, 40,215 ± 8,420 ng/mL/h; mean residence time, 39.5 ± 17.2 hours; area under the moment curve, 1,636,554 ± 931,458 ng([h]2/mL); and terminal half-life, 26.6 ± 11.6 hours. The mean serum concentration of gallium at 12 hours was 756 ± 195 ng/mL.
Conclusions and Clinical Relevance—Gallium maltolate administered via nasogastric tube at a dose of 20 mg/kg to neonatal foals resulted in gallium serum concentrations considered sufficient to suppress growth or kill Rhodococcus equi in macrophages and other infected tissues.
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 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 determine whether administration of
killed West Nile virus vaccine was associated with
pregnancy loss among broodmares.
Design—Retrospective cohort study.
Procedure—Records of pregnant mares with known
vaccination history from 4 farms were reviewed.
Information obtained from 595 mares included mare's
identification; farm; age; breed; reproductive status;
last breeding date; date last known pregnant; vaccination
date; age of conceptus at vaccination; vaccination
during the early embryonic, early fetal, and late fetal
periods; and whether an early embryonic death (EED),
early fetal loss (EFL), or late fetal loss (LFL) occurred.
The relationships between the dichotomous outcomes
of loss (eg, EED, EFL, LFL) and independent categoric
variables (eg, vaccination during the early embryonic,
early fetal, or late fetal periods) were examined.
Results—Vaccination of pregnant mares during any
period of gestation was not associated with increased
incidence of pregnancy loss.
Conclusions and Clinical Relevance—Many mares
are already pregnant at the onset of mosquito season,
when mares are more likely to be vaccinated than at
other times. Our findings provide evidence that vaccine
administration will not compromise pregnancy in
horses. (J Am Vet Med Assoc 2004;225:1894–1897)
Objective—To determine factors associated with
development of postoperative ileus (POI) in horses
undergoing surgery for colic.
Design—Prospective case-control study.
Animals—251 horses undergoing colic surgery, of
which 47 developed POI.
Procedure—Signalment, history, clinicopathologic
data, pre- and postoperative treatments, lesions,
complications, costs, and outcome were recorded for
all horses during hospitalization.
Results—Variables associated with increased odds of
POI included small intestinal lesion, high PCV, and
increased duration of anesthesia. There was modest
evidence that pelvic flexure enterotomy and intraoperative
administration of lidocaine may have reduced
the odds of developing POI.
Conclusions and Clinical Relevance—Findings during
the preoperative and intraoperative periods can be used
to identify horses at increased risk of POI. Reducing surgical
and anesthetic duration should decrease the incidence
of POI. ( J Am Vet Med Assoc 2004;225: