Comparison of treatment outcomes for superficial digital flexor tendonitis in National Hunt racehorses.

Superficial digital flexor (SDF) tendonitis is a common injury in Thoroughbred racehorses. Injuries require prolonged rehabilitation, with unpredictable outcomes and a high incidence of re-injury. This observational case-control study aimed to compare race outcomes after commonly advocated treatments for tendon healing. Clinical and racing records were evaluated for 127 National Hunt racehorses treated between 2007 and 2011 for an SDF tendon injury. Two age- and sex-matched control horses were selected for each case horse to analyse the effect on post-injury racing outcomes of pre-injury data, lesion severity and treatment group [controlled exercise alone, bar firing, intralesional platelet-rich plasma (PRP), tendon splitting, tendon splitting combined with bar firing]. Control horses raced more often than case horses, with higher maximum racing post rating (RPRmax) and longer racing distances. Pre-injury racing performance was not associated with treatment group. Rate of return to racing was not associated with lesion severity or treatment group. Number of races, total distance raced post-injury and RPRmax were not associated with lesion severity or treatment group. Controlled exercise alone offered similar post-injury racing outcomes in National Hunt racehorses with SDF tendonitis to the other treatment options examined. Bar firing, either alone or in conjunction with tendon splitting, provided no additional benefit in rate of return to racing and race performance.

Association of owner-reported noise with findings during dynamic respiratory endoscopy in Thoroughbred racehorses.

REASONS FOR PERFORMING STUDY: To determine the association between owner-reported noise and findings during dynamic respiratory endoscopy (DRE) in a large case series. HYPOTHESIS: The sensitivity of owner-reported noise for dynamic upper respiratory tract obstructions in horses is low, and the specificity is high. METHODS: One hundred horses underwent DRE for the investigation of abnormal respiratory noise and/or poor performance. The association of abnormal noise with findings during DRE was evaluated. RESULTS: Eighty-five horses underwent DRE for the investigation of abnormal respiratory noise. Of these, 82% were found to have one or more obstructive upper respiratory tract abnormalities during DRE. Forty-eight percent of horses reported to gurgle, rattle or make a rough noise were diagnosed with solitary palatal dysfunction. A further 24% with this history showed palatal dysfunction in combination with an additional abnormality. Twenty-seven percent of horses with a history of whistling or roaring showed some degree of recurrent laryngeal neuropathy. Seven percent of horses with a history of whistling or roaring had vocal cord collapse as a solitary condition, whereas 40% had vocal cord collapse and another abnormality. The sensitivity of abnormal respiratory noise for any obstruction of the upper portion of the respiratory tract was high (84%), while the specificity was low (25%). Characteristic owner reported noise patterns showed moderate to low sensitivity for specific conditions. Whistling and roaring showed the highest specificity (≥80%) for laryngeal dysfunction. CONCLUSION: Diagnosis of upper respiratory tract obstructions based solely on owner-reported noise and performance history may result in incomplete diagnoses. CLINICAL RELEVANCE: DRE should be performed in horses with abnormal respiratory noise to rule out complex conditions of the upper portion of the respiratory tract.

Outgroup heteroduplex analysis using temperature gradient gel electrophoresis: high resolution, large scale, screening of DNA variation in the mitochondrial control region.

The ability of DNA screening techniques such as Temperature Gradient Gel Electrophoresis (TGGE) and Heteroduplex Analysis to provide resolution approaching that provided by DNA sequencing for a fraction of the time, effort and expense point to them as the logical successor to allozyme electrophoresis for population genetics. Here we present a novel alternative to the standard TGGE/Heteroduplex Analysis protocol - Outgroup Heteroduplex Analysis (OHA). We assess this technique's sensitivity in comparison to previous screening approaches using a known hierarchy of sequence differences. Our data show that Outgroup Heteroduplex Analysis has greatly increased sensitivity for screening DNA variants from that of TGGE used alone and is easily applicable to large numbers of samples. Using this technique we can consistently detect differences of as small as one base change in a 433-base-pair fragment of Control Region mitochondrial DNA from Melomys cervinipes (an Australian rodent). The approach should easily be extendable to nuclear loci and is not necessarily dependent on the use of a denaturing gradient. When combined with a targeted sequencing effort, OHA provides a sensitive and simple means of obtaining allele/haplotype frequencies and their phylogenies for population and phylogeographic studies in molecular ecology.