Objective—To compare the effectiveness of lincomycin and oxytetracycline for treatment of digital dermatitis (DD) in dairy cows through gross visual examination, histologic evaluation, and bacteriologic evaluation.
Design—Randomized controlled clinical trial.
Animals—25 cows with DD lesions from a commercial Holstein dairy herd.
Procedures—Cows with DD lesions were randomly assigned to 1 of 3 groups: topical treatment with 10 g of lincomycin hydrochloride (n = 11), topical treatment with 10 g of oxytetracycline hydrochloride (11), and no treatment (3) on days 1 and 2 (d1). Biopsy specimens were obtained for histologic examination from DD lesions prior to treatment and 28 or 31 days (d30) after treatment for histologic examination. Cows were clinically examined on d1, days 12 or 14 (d14), and d30.
Results—No difference was evident in clinical responses to lincomycin and oxytetracycline, so data were pooled; at d30, 8 of 11 of lincomycin-treated lesions and 7 of 11 oxytetracycline-treated lesions appeared visually healed, respectively. Gross visual examination suggested 73% (16/22) of treated cows were healed at d14 and 68% (15/22) of treated cows were healed on d30. Of the 15 lesions that appeared healed on d30, 7 of 15 were classified histologically as active (ulceration and bacterial invasion; 2/15) or incipient (5/15).
Conclusions and Clinical Relevance—Clinical responses to lincomycin and oxytetracycline did not differ. Agreement was good between gross visual and histologic assessments of DD lesions before treatment; agreement 1 month after treatment was variable. Histologic evaluation could not distinguish incomplete healing from lesion recurrence.
Objective—To determine risk factors for Clostridium
piliforme infection in neonatal foals on a Thoroughbred
breeding farm in California.
Design—Case-control and retrospective cohort studies.
Animals—322 neonatal Thoroughbred foals either
born on the study farm or born elsewhere but traveled
to the farm with their dam during the 1998,
1999, and 2000 breeding seasons.
Procedure—Mare and foal records from 1998, 1999,
and 2000 were examined, using case-control design
methods to determine variables associated with
increased risk of C piliforme infection in foals.
Important risk factors identified in the case-control
study were then reevaluated by use of a retrospective
cohort design, using data from all neonatal foals
present on the farm during the 3-year study period.
Results—Foals born between March 13 and April 13
were 7.2 times as likely to develop C piliforme infection
as were those born at any other time of the foaling
season. Foals of nonresident (visiting) mares were
3.4 times as likely to develop disease as were foals
born to mares that were permanent residents of the
study farm. Foals of mares < 6 years of age were 2.9
times as likely to develop disease as were foals born
to older mares.
Conclusions and Clinical Relevance—Results of
this research can be used to better understand the
epidemiologic factors of C piliforme infection in horses.
High-risk foals can be closely monitored to aid in
early diagnosis and treatment, resulting in the best
possible clinical outcome for affected individuals.
(J Am Vet Med Assoc 2002;220:785–790)
Objective—To determine major causes of death and the anatomic location of musculoskeletal injuries in Quarter Horse racehorses in California.
Design—Retrospective case series.
Animals—314 Quarter Horse racehorses with musculoskeletal injuries that were necropsied through the California Horse Racing Board Postmortem Program from 1990 to 2007.
Procedures—Postmortem pathology reports were retrospectively reviewed. Musculoskeletal injuries were categorized by anatomic region and described. The number of Quarter Horse starts and starters for the same period of time were obtained from a commercial database for determination of fatal injury incidence.
Results—Musculoskeletal injuries accounted for 314 of the 443 (71 %) Quarter Horse racehorses that died during the 18-year study period. Fatal musculoskeletal injuries occurred at a rate of 2.0 deaths/1,000 race starts and 18.6 deaths/1,000 horses that started a race. Musculoskeletal injuries occurred predominantly during racing (84%) and in the forelimbs (81%). The most common fatal musculoskeletal injuries were metacarpophalangeal and metatarsophalangeal joint (fetlock) support injuries (40%) and carpal (24%), vertebral (10%), and scapular (8%) fractures. Proximal interphalangeal (pastern) joint luxations resulted in death of 3% of horses. Fracture configurations of some bones were consistent with those of Thoroughbred racehorses. Evidence of preexisting stress remodeling of bone was reported for some fractures.
Conclusions and Clinical Relevance—Knowledge of common locations and types of fatal musculoskeletal injuries in racing Quarter Horses may enhance practitioners' ability to detect mild injuries early, rest horses, and help prevent catastrophic injuries.
Objective—To determine the distribution for limbs and bones in horses with fractures of the proximal sesamoid bones and relationships with findings on palmarodorsal radiographic images.
Sample Population—Proximal sesamoid bones obtained from both forelimbs of cadavers of 328 racing Thoroughbreds.
Procedure—Osteophytes; large vascular channels; and fracture location, orientation, configuration, and margin distinctness were categorized by use of high-detail contact palmarodorsal radiographs. Distributions of findings were determined. Relationships between radiographic findings and fracture characteristics were examined by use of χ2 and logistic regression techniques.
Results—Fractures were detected in 136 (41.5%) horses. Biaxial fractures were evident in 109 (80%) horses with a fracture. Osteophytes and large vascular channels were evident in 266 (81%) and 325 (99%) horses, respectively. Medial bones typically had complete transverse or split transverse simple fractures, indistinct fracture margins, > 1 vascular channel that was > 1 mm in width, and osteophytes in abaxial wing and basilar middle or basilar abaxial locations. Lateral bones typically had an oblique fracture and distinct fracture margins. Odds of proximal sesamoid bone fracture were approximately 2 to 5 times higher in bones without radiographic evidence of osteophytes or large vascular channels, respectively.
Conclusions and Clinical Relevance—Biaxial fractures of proximal sesamoid bones were common in cadavers of racing Thoroughbreds. Differences between medial and lateral bones for characteristics associated with fracture may relate to differences in fracture pathogeneses for these bones. Osteophytes and vascular channels were common findings; however, fractures were less likely to occur in bones with these features.