Ketorolac Is Not More Effective Than Flunixin Meglumine or Phenylbutazone in Reducing Foot Pain in Horses.

The objective was to compare the analgesic efficacy of ketorolac tromethamine (KT) and two other nonsteroidal anti-inflammatory drugs (NSAIDs), including flunixin meglumine (FM) and phenylbutazone (PB), using a heart bar shoe (HBS) model of reversible foot lameness in horses. Nine adult horses were used in a blinded, randomized, placebo-controlled crossover study. After induction of left front limb lameness using a modified HBS model, one of three NSAIDs (KT, 2.0 mg/kg IV; FM, 1.1 mg/kg IV; PB, 4.4 mg/kg IV) or saline (placebo) was administered IV as a single dose. Lameness was assessed every 30 minutes for 2 hours, then every hour up to 12 hours using both a lameness grading scale (lameness score; LS) and a body-mounted inertial sensor system (lameness locator; LL). High-performance liquid chromatography and mass spectrometry were used to measure plasma drug concentration at various time points. There was no difference in percent reduction of LS or LL value between KT and any other group, or between FM and placebo. The PB group showed a significantly higher percentage in LS reduction than the placebo and FM groups. The mean percent reduction in LL value was greater for the PB group than that for the placebo and FM groups. Plasma drug concentration was similar among horses for each drug at each time point, with drug concentrations decreasing over time. Thus, variation in plasma drug concentration did not influence lameness reduction for any drug. Ketorolac tromethamine was not superior to FM or PB in reducing lameness using a HBS model.

Induction of Noninflammatory Pain in an Experimental Foot Lameness Model in Horses.

The mechanism by which nonsteroidal anti-inflammatory drugs mitigate pain caused by a heart bar shoe (HBS) model of lameness is unknown. The purpose of this study was to determine if this HBS model of lameness induces inflammation in horses. Five healthy adult horses from a university teaching herd were enrolled. A custom HBS was applied to the left front foot of each horse, followed by induction of the American Association of Equine Practitioners Lameness Score of 4. Inflammatory markers including serum amyloid A (SAA) concentration, local venous tumor necrosis factor alpha and prostaglandin E2 (PGE2) concentrations, and foot temperature were measured before lameness induction and 1, 3, and 13 hours after lameness induction. Lameness induction using the HBS model did not significantly increase production of plasma SAA, tumor necrosis factor alpha, or PGE2 concentrations at measured time points. Immediately and 1 hour after lameness induction, dorsal coronary band temperatures were higher in the left front foot compared with the right front foot, but there was no difference at 3 or 13 hours. In conclusion, the HBS model did not induce inflammation as assessed by select inflammatory markers, suggesting that the HBS model induces mechanical rather than inflammatory pain. This should be considered when using the HBS model to assess analgesic drugs in horses.

Occlusion of the corpus cavernosum penis in bulls intended for estrus detection: 18 cases (2002-2016).

OBJECTIVE To report surgical and long-term postoperative outcomes of bulls undergoing surgical occlusion of the corpus cavernosum penis (CCP) by acrylic injection and epididymectomy with or without penile fixation as preparation for use in estrus detection. DESIGN Retrospective case series. ANIMALS 18 client-owned bulls. PROCEDURES Medical records of bulls that underwent CCP occlusion between December 2002 and March 2016 were identified. Signalment, surgical data, and reported complications were recorded. Long-term (> 6 months after surgery) follow-up data were obtained from medical records or by telephone interview of bull owners with a questionnaire focused on postoperative outcome, use of the bull for estrus detection, and overall satisfaction with the procedure. RESULTS Intraoperative complications included difficulty isolating the penis, polymerization of the acrylic prior to injection, incomplete anesthesia of the surgical site, and fecal contamination of the site. Deposition of acrylic in an improper location led to urethral obstruction and euthanasia of 1 bull; another developed an abscess that was treated successfully. One bull was euthanized because of orchitis. Most (15/18) bulls were used for estrus detection (mean duration, 17.9 months). Libido was considered good or very good for 14 of 15 bulls; 1 was culled for loss of libido after 14 months. Ten of 12 bulls were reportedly unable to protrude the penis; 2 had or developed partial protrusion ability. Overall client satisfaction was high. CONCLUSIONS AND CLINICAL RELEVANCE In this population of healthy young bulls, CCP occlusion was generally well tolerated. Most bulls that underwent CCP occlusion (and epididymectomy with or without penile fixation) had adequate libido, and none were reported able to achieve intromission.

Comparison of the racing performance of Thoroughbreds with versus without osteochondral fragmentation of the accessory carpal bone identified on yearling sales repository radiographs.

OBJECTIVE To evaluate 2- and 3-year-old and career race performance of Thoroughbred racehorse prospects with and without osteochondral fragmentation of the accessory carpal bone (ACB) identified on yearling presale radiographs. DESIGN Retrospective, matched cohort study. ANIMALS 47 nonlame Thoroughbreds with (exposed cohort) and 94 nonlame Thoroughbreds without (unexposed cohort) osteochondral fragmentation of ACB facture identified on yearling sales repository radiographs. PROCEDURES Repository radiographic interpretation reports for September yearling sales of a large Kentucky auction house from 2005 through 2012 were reviewed, and race records were collected and analyzed. Race performance was compared between horses with and without ACB fracture chosen from the same sale to identify associations between racing performance and ACB fracture. RESULTS No significant differences were identified between horses with or without ACB fracture in their incidence of starting a race as a 2- or 3-year-old and the number of races started, earnings, or earnings per start for 2- or 3-year-old or career race performance. There was no significant difference in performance between horses with or without concurrent carpal osteoarthritis, nor did performance differ between horses with ACB fracture alone and those with ACB fracture and other radiographic abnormalities found to be associated with poorer performance in previous studies. CONCLUSIONS AND CLINICAL RELEVANCE ACB fracture with or without carpal osteoarthritic changes identified on repository radiographs of Thoroughbred yearlings was not associated with poorer racing performance or lower likelihood of starting a race as a 2- or 3-year-old, compared with outcomes for unaffected horses.