Evaluation of videoendoscopic examinations of arytenoid function in the 2‐year‐old Thoroughbred: Can we all agree?

Stakeholder perceptions of thoroughbred yearling sales endoscopy in Australia: can we do better?

OBJECTIVE

To identify thoroughbred industry stakeholders' views on the yearling sales endoscopy in Australia.

DESIGN

Semi-structured qualitative group interviews with equine veterinarians, thoroughbred breeders and yearling purchasers.

METHODS

Twenty-nine experienced thoroughbred industry stakeholders participated in online focus groups: (1) equine veterinarians involved in yearling endoscopy; (2) thoroughbred breeders; and (3) yearling buyers. The focus groups were audio and video recorded and digital whiteboards were available. Data was transcribed, live-coded and analysed thematically.

RESULTS

The main themes identified included the uncertainty surrounding the relationship between yearling laryngeal function and future performance, especially the significance of yearlings with grade 3 out of 5 laryngeal function; interobserver variability in the laryngeal function grade assigned by veterinarians to the same endoscopic exam; and the presence of intra-horse variability in laryngeal function over different time points.

DISCUSSION

Stakeholders raised multiple concerns about the current yearling sales endoscopy process in Australia. Recommendations to address these concerns include further investigation into the race performance of yearlings identified with grade 3 laryngeal function; training of veterinarians to reduce inter-observer variability; and the need to determine the most appropriate grading system to use in yearlings. Future research should evaluate the significance of intra-horse variability in a yearling population.

Subchondral lucencies of the medial femoral condyle in yearling and 2-year-old Thoroughbred sales horses: Prevalence, progression and associations with racing performance

BACKGROUND

Subchondral lucencies (SCLs) in the distal aspect of the medial femoral condyle (MFC) of young Thoroughbred horses are a source of controversy on presale radiographs. There is limited scientific evidence regarding the risk of progression and impact on future racing performance.

OBJECTIVES

To (1) identify the prevalence of MFC SCLs on sales repository radiographs in yearling and 2-year-old Thoroughbreds; (2) identify any association between grade of MFC SCL and future racing performance and (3) monitor changes in MFC SCL grades between yearling and 2-year-old sales.

STUDY DESIGN

Prospective cohort study.

METHODS

Radiographs were obtained with consignor permission from a 2016 yearling sale and five 2017 2-year-old sales. Stifle radiographs were evaluated and MFC SCLs graded on a scale of 0-3. Axial MFC lucencies were recorded separately. Maximum MFC grades per horse were analysed for associations with racing performance outcomes, adjusted for sex, to the end of the horses' 4-year-old racing year. Analysis was via logistic, negative binomial or linear regression as appropriate, with the threshold for significance set at α = 0.05.

RESULTS

Radiographs from 2508 yearlings (5016 stifles) and 436 2-year-olds (872 stifles) were included in the study. MFC SCLs of grades 1-3 were observed in 242 (9.65%) yearlings and 49 (11.2%) 2-year-olds. Bilateral MFC SCLs of grades 1-3 were observed in 54 (2.2%) yearlings and 12 (2.8%) 2-year-olds. Grade 1 MFC SCLs in yearlings either remained unchanged (14/31), progressed to a grade 2 (6/31) or resolved (11/31) by the 2-year-old sale. Grade 2 MFC SCLs in yearlings remained unchanged (6/10), progressed to a grade 3 (2/10) or improved to a grade 1 (2/10). Yearlings with a grade 3 MFC SCL had a 78% probability of starting a race (95% confidence interval [CI] 58.2-89.6%), compared with an 84% probability of racing for grade 0 yearlings (95% CI 82.7-85.8%). Six of the seven yearlings with axial MFC lucencies raced.

MAIN LIMITATIONS

This study may underestimate the prevalence of severe lesions in the general yearling population of U.S. Thoroughbreds. However, the convenience sample used is representative of the population of interest at sales. The study design could not address exclusions prior to sale.

CONCLUSIONS

Grade 1 MFC SCLs are the most common type seen in yearling and 2-year-old sales horses. The majority of yearling grade 1 MFC SCLs resolved or remained static by 2-year-old sales. It was also possible for grade 2 and 3 MFC SCLs to improve one grade between sales. Fewer sales yearlings with a grade 3 MFC SCL raced, but in those that did race there was no evidence of worse performance compared to unaffected peers. Axial MFC lucencies did not affect racing performance.

Inter-observer variability of two grading systems for equine glandular gastric disease

BACKGROUND

Equine glandular gastric disease (EGGD) is recognised as a separate entity to equine squamous gastric disease (ESGD) and it is recommended that lesions are graded differently. Currently, no validated scoring system exists for EGGD.

OBJECTIVES

To determine inter-observer reliability of two previously described grading systems for EGGD and to assess if agreement improved with gastroscopy experience, specialist training or familiarity with the descriptive system.

STUDY DESIGN

Cross-sectional survey.

METHODS

A link to an electronic questionnaire containing 20 images of glandular lesions was circulated. Respondents were asked to score lesions using descriptive terminology and a 0-2 verbal rating scale (VRS). Krippendorff's alpha reliability estimate was used to assess inter-rater agreement. A mixed effects model was used to determine which descriptive categories were associated with lesions being described as severe and decision to treat.

RESULTS

Eighty-two veterinarians responded, 49 diplomates and 33 non-diplomates. There was no agreement when all four descriptive variables were combined (α = 0.19). Agreement was fair to moderate for severity (α = 0.52), distribution (α = 0.44), appearance (α = 0.38) and shape (α = 0.32). Agreement for the VRS was similar to that for severity (α = 0.53). Agreement was better among diplomates across all categories. Lesion appearance and shape, but not distribution, were associated with both a decision to treat; and lesions being described as severe (P =< .05). A VRS score 2/2 was associated with a lesion being described as severe (OR 75.2, 95% CI 51.12-110.48, P =< .001).

MAIN LIMITATIONS

Intra-observer variability was not assessed. The number of images is relatively small, and the decision to treat is based on several factors in practice.

CONCLUSIONS

Overall, agreement for the descriptive system was poor. Better delineation of descriptive category boundaries and characteristics should be determined. Agreement was similar when comparing the severity category and the VRS. Extrapolation to a VRS based on lesion severity may therefore be possible.