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  • Author or Editor: Darko Stefanovski x
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Abstract

OBJECTIVE To develop a risk prediction model for factors associated with an SeM-specific antibody titer ≥ 3,200 in horses after naturally occurring outbreaks of Streptococcus equi subsp equi infection and to validate this model.

DESIGN Case-control study.

ANIMALS 245 horses: 57 horses involved in strangles outbreaks (case horses) and 188 healthy horses (control horses).

PROCEDURES Serum samples were obtained from the 57 cases over a 27.5-month period after the start of outbreaks; serum samples were obtained once from the 188 controls. A Bayesian mixed-effects logistic regression model was used to assess potential risk factors associated with an antibody titer ≥ 3,200 in the case horses. A cutoff probability for an SeM-specific titer ≥ 3,200 was determined, and the model was externally validated in the control horses. Only variables with a 95% credibility interval that did not overlap with a value of 1 were considered significant.

RESULTS 9 of 57 (6%) case horses had at least 1 titer ≥ 3,200, and 7 of 188 (3.7%) of control horses had a titer ≥ 3,200. The following variables were found to be significantly associated with a titer ≥ 3,200 in cases: farm size > 20 horses (OR, 0.11), history of clinically evident disease (OR, 7.92), and male sex (OR, 0.11). The model had 100% sensitivity but only 24% specificity when applied to the 188 control horses (area under the receiver operating characteristic curve = 0.62.)

CONCLUSIONS AND CLINICAL RELEVANCE Although the Bayesian mixed-effects logistic regression model developed in this study did not perform well, it may prove useful as an initial screening tool prior to vaccination. We suggest that SeM-specific antibody titer be measured prior to vaccination when our model predicts a titer ≥ 3,200.

Full access
in Journal of the American Veterinary Medical Association

Abstract

OBJECTIVE

To evaluate complication rates for various types of mastectomy procedures, identify factors associated with an increased risk of complications, and determine the consequences of such complications.

ANIMALS

140 female dogs that underwent 154 separate mastectomy procedures to treat mammary gland tumors.

PROCEDURES

Medical records of dogs in the Penn Vet Shelter Canine Mammary Tumor Program from July 2009 to March 2015 were reviewed. Data regarding signalment, tumor characteristics (ie, number and size, benign or malignant, and bilateral or unilateral), mastectomy type, anesthesia time, concurrent ovariohysterectomy or ovariectomy, surgeons’ qualifications, antimicrobial administration after surgery, postoperative placement of surgical drains, and complications (seroma, abscess, dehiscence, or infection) were collected. Complications that required hospitalization were recorded. Fisher exact tests were used to evaluate associations between variables of interest and complications. Multivariable analysis was used to identify factors independently associated with an increased risk of complications.

RESULTS

Complication rate following all mastectomy procedures was 16.9% (26/154); of these, 9 (34.6%) required hospitalization. High body weight, undergoing bilateral mastectomy, and postoperative antimicrobial administration were associated with significantly increased odds of complications. The odds of complications associated with postoperative antimicrobial administration, however, varied according to mastectomy type; dogs undergoing chain mastectomy that did not receive antimicrobials postoperatively had the highest odds of developing complications. Dogs undergoing concurrent ovariohysterectomy or ovariectomy had significantly decreased odds of complications.

CONCLUSIONS AND CLINICAL RELEVANCE

Previously spayed dogs with a large body size that underwent the most extensive mastectomy procedures had increased odds of having postoperative complications.

Full access
in Journal of the American Veterinary Medical Association

Abstract

OBJECTIVE To describe gastrointestinal histologic findings for horses with recurrent colic and evaluate possible associations between initial clinical signs, biopsy method, histologic diagnosis, and outcome 1 year after hospital discharge.

DESIGN Retrospective case series.

ANIMALS 66 horses with a history of recurrent colic for which gastrointestinal specimens had been submitted for histologic examination.

PROCEDURES Histologic diagnosis was categorized as inflammatory, neoplastic, ischemic, other, and undiagnosed. Relationships among initial clinical features, biopsy method, histologic diagnosis, and outcome 1 year after hospital discharge (ie, alive vs dead and persistent recurrent colic [yes vs no]) and between corticosteroid treatment and outcome were investigated. Odds ratios and hazard ratios (HRs) with 95% confidence intervals (CIs) were calculated.

RESULTS Inflammatory disease (36/66 [55%]) was the most common histologic diagnosis. Horses undergoing rectal biopsy alone were significantly (OR, 14.4; 95% Cl, 2.7 to 76.1) more likely to not have a histologic diagnosis than were horses in which other biopsy methods were used. In multivariable modelling, persistence of recurrent colic (HR, 15.2; 95% Cl, 1.9 to 121.2) and a history of weight loss (HR, 4.9; 95% Cl, 1.4 to 16.5) were significantly associated with outcome (alive vs dead) 1 year after surgery. Corticosteroid treatment was not significantly associated with either outcome.

CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that a high proportion (36/66 [55%]) of horses with recurrent colic had inflammatory gastrointestinal disease. Use of rectal biopsy alone to obtain biopsy specimens was more likely to result in no histologic diagnosis. Use of corticosteroids in horses with inflammatory gastrointestinal disease was not associated with outcome but warrants further investigation.

Full access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To evaluate predictor variables for and complications associated with Streptococcus equi subsp equi infection (strangles) in horses.

Design—Retrospective case-control study.

Animals—108 horses with strangles (cases) and 215 horses without strangles (controls).

Procedures—Medical records from January 2005 through July 2012 were reviewed. Cases were defined as horses with clinical signs of strangles (pyrexia, retropharyngeal lymphadenopathy, and mucopurulent nasal discharge) that were associated with a confirmed strangles outbreak or had positive results for S equi on PCR assay or bacteriologic culture. Controls were defined as horses with pyrexia that did not meet the other criteria for cases. Data compared between cases and controls included signalment, clinical signs, diagnostic test results, and disease complications and outcome. Logistic regression was used to identify variables associated with strangles and its complications.

Results—Clinical signs of strangles were not evident in 12 of 25 cases classified as S equi carriers (infected > 40 days). Predictor variables associated with strangles included mucopurulent nasal discharge and external abscesses in the pharyngeal region. Strangles was more likely to be diagnosed in the spring than in the summer. Cases with anemia were more likely to develop purpura hemorrhagica than were cases without anemia. No risk factors were identified for the development of guttural pouch empyema or metastatic abscesses.

Conclusions and Clinical Relevance—Results indicated that not all horses infected with S equi develop clinical signs of strangles. We recommend that guttural pouch endoscopy and lavage with PCR assay of lavage fluid samples be performed to identify S equi carrier horses.

Full access
in Journal of the American Veterinary Medical Association

Abstract

OBJECTIVE To determine interval (1-year) prevalence of and factors associated with colic in horses hospitalized for ocular or orthopedic disease.

DESIGN Cross-sectional study.

ANIMALS 105 horses with ocular disease and 197 horses with orthopedic disease admitted to a veterinary teaching hospital between July 1, 2011, and June 30, 2012.

PROCEDURES Medical records were reviewed to determine whether colic (abnormal behavior prompting abdominal palpation per rectum or nasogastric intubation) was observed during hospitalization. Data were collected on putative risk factors for colic, including reason for admission, signalment, and medical or surgical interventions received.

RESULTS No significant difference in interval prevalence of colic was identified between horses with ocular disease (8/105 [8%]) or orthopedic disease (9/197 [5%]). However, horses with ocular disease differed significantly from other horses in median age (10 vs 3 years, respectively); proportions of sexually intact males (3% vs 30%), Thoroughbreds (28% vs 62%), and those receiving general anesthesia (65% vs 80%); and median duration of hospitalization (3 vs 2 days). For every 1 mg/kg increase in daily NSAID dose, the odds of colic increased by 98%. No difference between groups was identified in median duration of colic (1 day), hospitalization (7 vs 3 days), or systemic NSAID administration (7 vs 5 days). Colic in both groups resolved with medical management for all but 1 horse with ocular disease.

CONCLUSIONS AND CLINICAL RELEVANCE Horses hospitalized for ocular disease were at no greater odds for colic than were horses hospitalized for orthopedic disease. Medical management of colic appeared adequate for most horses.

Full access
in Journal of the American Veterinary Medical Association

Abstract

OBJECTIVE

To assess the prevalence of tubular genital tract neoplasia in does evaluated at 2 veterinary teaching hospitals; describe the main clinical, surgical, and histopathologic or necropsy findings in affected does; and assess factors potentially associated with short-term prognosis in these animals.

ANIMALS

42 does.

PROCEDURES

Medical records of 2 veterinary teaching hospitals were searched to identify does with neoplasia of the tubular genital tract. Signalment; history; physical and diagnostic imaging results; biopsy, surgery, and necropsy findings; and short-term outcome were recorded. Age and breed frequencies for the sample were compared with those of the overall hospital population, and variables of interest were tested for associations with a diagnosis of adenocarcinoma and with short-term outcome by statistical methods.

RESULTS

Median age at hospital admission (10 years) was greater for the study sample than for the general hospital population (2 years). Pygmy goats were overrepresented (22/42 [52%]). Common reasons for evaluation were bloody vaginal discharge or hematuria and abdominal straining. Adenocarcinoma (13/42 [31%]), leiomyoma (13 [31%]), and leiomyosarcoma (11 [26%]) were the most common tumors. Does with distant metastasis had greater odds of a diagnosis of adenocarcinoma (OR, 40.5) than does without distant metastasis. In the analysis adjusted for hemorrhagic discharge, odds of euthanasia for does with straining were 13 times those for does without straining. In the analysis adjusted for straining status, does with hemorrhagic discharge had almost 7 times the odds of euthanasia for does without this finding. The survival-to-discharge rate was low (13/42 [31%]).

CONCLUSIONS AND CLINICAL RELEVANCE

The frequency of adenocarcinomas in the study sample was unexpectedly high. Further research is needed to confirm the study findings.

Full access
in Journal of the American Veterinary Medical Association

Abstract

OBJECTIVE

Measure 18F-FDG uptake in digital tissues of healthy horses subjected to different ambulatory conditions between the time of injection and positron emission tomography (PET) scan acquisition.

ANIMALS

8 healthy adult horses.

METHODS

Horses were walked (AMB) or tied in stalls (NONAMB) immediately after injection with ∼1.5 MBq/kg 18F-FDG until scan acquisition using a randomized crossover design. Steps were quantified using accelerometers. Standardized uptake values (SUV; mean and maximum) in digital tissues including the dorsal lamellae (proximal, middle, and distal), quarter lamellae (medial and lateral), and coronary band were analyzed using a mixed-effects linear regression model.

RESULTS

Mean (95% CI) step count for AMB (569[484–653]) was higher than NONAMB (88[24–152]) P = <.001. The SUVmax (but not SUVmean) was increased in AMB compared with NONAMB in the proximal (2.74[2.52–2.98] vs 2.42[2.05–2.78]; P = .04) and middle (2.74[2.37–3.11] vs 2.36[2.05–2.68]; P = .03) dorsal lamellae but was not different in the distal lamellae or coronary band. In the medial quarter lamellae, both SUVmax (2.53[1.58–3.48] vs 2.07[0.81–3.33]; P = .01) and SUVmean (1.90[1.55–2.25] vs 1.49[0.91–2.06]; P = .007) were increased in AMB compared with NONAMB. The medial quarter lamellae also had lower SUVmax (P = .002) and SUVmean (P = .04) compared with the lateral quarter and lower SUVmax compared with the mid-dorsal lamellae (P = .01).

CLINICAL RELEVANCE

Lamellar 18F-FDG uptake was affected by ambulatory activity mostly in the medial quarter; however, this effect was relatively small and unlikely to interfere with clinical detection of laminitis.

Open access
in American Journal of Veterinary Research

Abstract

OBJECTIVE

To determine the effect of stage of estrus cycle (day after ovulation) at the time of transvaginal ultrasound-guided follicle aspiration (TVA) on parameters related to the success of in vitro equine embryo production.

ANIMALS

14 healthy mares were used; 11 completed the study and were included for analysis.

PROCEDURES

Mares underwent TVA of all follicles ≥ 5 mm diameter at each of 3 timepoints: 7 days after ovulation, 14 days after ovulation, and S-DSF (subordinate to a dominant stimulated follicle), during estrus at 24 hours after gonadotropin administration. The 3 treatments were assigned to each mare in random order; mares underwent follicle growth and ovulation between treatments. Recovered oocytes were matured in vitro, subjected to intracytoplasmic sperm injection (ICSI), and cultured to the blastocyst stage in vitro.

RESULTS

Total follicle numbers differed significantly between individual mares but did not differ between treatments. The number of follicles of different sizes significantly (P < 0.05) differed between treatments, with mares in the Day 7 treatment having more follicles 5 to 9 mm in diameter and fewer follicles 20 to 24 mm in diameter than mares in the other 2 treatments. After in vitro maturation culture, there were significantly more mature oocytes in the S-DSF treatment than in the other 2 treatments. There were no differences in blastocyst rate after ICSI among treatment groups.

CLINICAL RELEVANCE

Timing of TVA for aspiration of S-DSFs may increase the number of mature oocytes available for ICSI. Understanding of the effects of timing of TVA will help veterinarians to maximize the efficiency of this procedure.

Full access
in Journal of the American Veterinary Medical Association