New diagnostic tools helping poll breeding for sustainable beef production

Management of horns in beef cattle has major economic and welfare impacts, and therefore, breeding for naturally hornless (polled) cattle is widely practiced. Poll breeding can be significantly accelerated by using DNA diagnostic tools (Prayaga 2007), and the Australian beef cattle industry has adopted the available DNA poll testing assays, which are generally successful. However, issues of applicability in Bos indicus cattle has arisen due to a more complex mode of inheritance of the horn phenotype. This study has investigated these limitations and further optimized the poll gene testing to increase accuracy and informativeness across all breeds. We also investigated if polled genetics were different than horned animals for beef production

Epidemiological investigation of insulin dysregulation in Shetland and Welsh ponies in Australia

Background: Insulin dysregulation (ID) is central to equine metabolic syndrome. There are limited epidemiological studies investigating dynamic testing of ID in ponies. Objectives: To evaluate prevalence and risk factors for ID through dynamic testing of hyperinsulinaemia (DHI) and insulin resistance (IR). Study design: Cross-sectional. Methods: Sex, age, breed, height, cresty neck score (CNS), body condition score (BCS), laminitis, HMGA2:c.83G>A genotype and pituitary pars intermedia dysfunction (PPID) status were documented. Dynamic hyperinsulinaemia was diagnosed with an oral sugar test (OST) and IR with an insulin tolerance test (ITT). Owners completed surveys reporting activity, laminitis history and perception of body condition using a (1–9) visual analogue scale (VASo). Ordinal scores were converted to binary outcomes for CNS (≤2/5 or ≥3/5), BCS and VASo (≤6/9 or ≥7/9). Variables associated with insulin concentrations, glucose reduction after the ITT and laminitis were evaluated with mixed effects regression models accounting for random effects of farms. Results: Among 167 ponies tested, median (range) age was 9 (4–21) years and BCS was 6 (4–8). Prevalence (95% confidence interval [CI]) of ID was 61 (53–68)%. Factors associated with insulin concentrations (estimate [95% CI]; μIU/mL) 60 min post-OST were: age (1.07 [1.02–1.11]), CNS (≥3/5, 1.52 [1.04–2.23]) and VASo (≥7/9, 1.75 [1.09–2.79]); and 90 min post-OST were: age (1.08 [1.03–1.12]), CNS (≥3/5, 1.80 [1.22–2.64]), VASo (≥7/9, 2.49 [1.52–4.08]) and sex (male, 0.64 [0.45–0.91]). Factors associated with glucose reduction after the ITT (estimate [95% CI]; %) were: age (−1.34 [−2.01 to −0.67]), sex (female, −6.21 [−11.68 to −0.74]) and VASo (≥7/9, −1.74 [−18.89 to −4.78]). Factors associated with laminitis (odds ratio [95% CI]) were DHI (4.60 [1.68–12.58]), IR (3.66 [1.26–10.61]) and PPID (11.75 [1.54–89.40]). Main limitations: Single time-point sampling, laminitis definition and diet analysis. Conclusions: Ageing, being female and owner-perceived obesity were associated with ID. © 2024 The Authors. Equine Veterinary Journal published by John Wiley & Sons Ltd on behalf of EVJ Ltd.Open access articleThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]