SEARCH

SEARCH BY CITATION

Keywords:

  • horse;
  • laminitis;
  • obesity;
  • cresty neck;
  • insulin;
  • leptin

Summary

  1. Top of page
  2. Summary
  3. References

Reasons for performing study: The ability to predict ponies at increased risk of laminitic episodes, when exposed to nutrient dense pasture, would facilitate management to avoid disease.

Objectives: To identify variables and clinically useful cut-off values with reproducible diagnostic accuracy for the prediction of ponies that subsequently developed laminitis when exposed to nutrient dense pasture.

Methods: A cohort of predominantly Welsh and Dartmoor ponies from a closed herd was evaluated in March 2006 (n = 74) and March 2007 (n = 57). Ponies were categorised as never laminitic or previously laminitic according to reported laminitic history and as clinically laminitic (CL) if laminitis was observed within 3 months following evaluation. Body condition score (BCS), cresty neck score (CNS), girth and neck circumferences (NC), withers height, blood pressure and hoof surface temperature, and plasma insulin, glucose, triglyceride, leptin, cortisol, ACTH, uric acid and TNF-α concentrations were measured. Analysis of sensitivity, specificity and receiver operating characteristic curves was used to evaluate the diagnostic accuracy for a variable to predict CL ponies.

Results: Variables with diagnostic accuracy for the prediction of CL ponies included insulin, leptin, BCS, CNS, and NC:height ratio. Specific cut-off values of insulin (>32 mu/l), leptin (>7.3 ng/ml), BCS (≥7), CNS (≥4) and NC:height ratio (>0.71) had reproducible diagnostic accuracy for the prediction of laminitis. Combining tests did not result in higher diagnostic accuracy than individual tests of insulin or leptin during either evaluation.

Conclusions: Tests of insulin and leptin concentrations and measures of generalised (BCS) and localised (CNS or NC:height ratio) obesity were beneficial in the prediction of laminitic episodes.

Potential relevance: These results highlight the importance of monitoring and reducing insulin concentration, and generalised and regional obesity in ponies to reduce risk of laminitis.

Abbreviations
BCS

Body condition score

CL

Clinically laminitic

CNS

Cresty neck score

LR

Likelihood ratio

MIRG

Modified insulin-to-glucose ratio

NL

Never laminitic

PL

Previously laminitic

PLMS

Prelaminitic metabolic syndrome

RISQI

Reciprocal of the square root of insulin

ROC

Receiver operating characteristic

gROC

Global ROC

1ROC

Local ROC

References

  1. Top of page
  2. Summary
  3. References
  • Altman, D.G., Machin, D., Bryant, T.N. and Gardner, M.J. (2000) Statistics with Confidence, 2nd edn., J.W. Arrowsmith Ltd, Bristol .
  • Anon (1999) Definition, Diagnosis, and Classification of Diabetes Mellitus and its Complications: Report of a WHO Consultation. World Health Organization, Geneva .
  • Anon (2000) Lameness and Laminitis in U.S. Horses, Ed: C. USDA:APHIS:VS, National Animal Health Monitoring System, Fort Collins , Colorado .
  • Anon (2001) Executive summary of the Third Report of The National Cholesterol Education Program (NCEP) Expert Panel on detection, evaluation, and treatment of high blood cholesterol in adults (Adult Treatment Panel III). J. Am. med. Ass. 285, 24862497.
  • Asplin, K.E., Sillence, M.N., Pollitt, C.C. and McGowan, C.M. (2007) Induction of laminitis by prolonged hyperinsulinaemia in clinically normal ponies. Vet. J. 174, 530535.
  • Bailey, S.R., Habershon-Butcher, J.L., Ransom, K.J., Elliott, J. and Menzies-Gow, N.J. (2008) Hypertension and insulin resistance in a mixed-breed population of ponies predisposed to laminitis. Am. J. vet. Res. 69, 122129.
  • Bailey, S.R., Menzies-Gow, N.J., Harris, P.A., Habershon-Butcher, J.L., Crawford, C., Berhane, Y., Boston, R.C. and Elliott, J. (2007) Effect of dietary fructans and dexamethasone administration on the insulin response of ponies predisposed to laminitis. J. Am. vet. med. Ass. 231, 13651373.
  • Biggerstaff, B.J. (2000) Comparing diagnostic tests: a simple graphic using likelihood ratios. Stat. Med. 19, 649663.
  • Buff, P.R., Dodds, A.C., Morrison, C.D., Whitley, N.C., McFadin, E.L., Daniel, J.A., Djiane, J. and Keisler, D.H. (2002) Leptin in horses: tissue localization and relationship between peripheral concentrations of leptin and body condition. J. anim. Sci. 80, 29422948.
  • Carter, R.A., Geor, R.J., Staniar, W.B., Cubitt, T.A. and Harris, P.A. (2008) Apparent adiposity assessed by standardised scoring systems and morphometric measurements in horses and ponies. Vet. J. doi:10.1016/j.tvjl.2008.1002.1029.
  • Carter, R.A., Treiber, K.H., Hess, T.M., Kronfeld, D.S. and Geor, R.J. (2006) Prelaminitic metabolic syndrome: Application to Connemara ponies. In: Proceedings of the 6th Annual Clinical Nutrition and Research Symposium of the American Academy of Veterinary Nutrition. p 17.
  • Cartmill, J.A., Thompson, D.L., Jr., Storer, W.A., Crowley, J.C., Huff, N.K. and Waller, C.A. (2005) Effect of dexamethasone, feeding time, and insulin infusion on leptin concentrations in stallions. J. anim. Sci. 83, 18751881.
  • Cartmill, J.A., Thompson, D.L., Jr., Storer, W.A., Gentry, L.R. and Huff, N.K. (2003) Endocrine responses in mares and geldings with high body condition scores grouped by high vs. low resting leptin concentrations. J. anim. Sci. 81, 23112321.
  • Coffman, J.R. and Colles, C.M. (1983) Insulin tolerance in laminitic ponies. Can. J. comp. Med. 47, 347351.
  • Donaldson, M.T., Jorgensen, A.J. and Beech, J. (2004) Evaluation of suspected pituitary pars intermedia dysfunction in horses with laminitis. J. Am. vet. med. Ass. 224, 11231127.
  • Frank, N., Elliott, S.B. and Boston, R.C. (2008) Effects of long-term oral administration of levothyroxine sodium on glucose dynamics in healthy adult horses. Am. J. vet. Res. 69, 7681.
  • Frank, N., Elliott, S.B., Brandt, L.E. and Keisler, D.H. (2006) Physical characteristics, blood hormone concentrations, and plasma lipid concentrations in obese horses with insulin resistance. J. Am. vet. med. Ass. 228, 13831390.
  • Freestone, J.F., Wolfsheimer, K.J., Kamerling, S.G., Church, G., Hamra, J. and Bagwell, C. (1991) Exercise induced hormonal and metabolic changes in Thoroughbred horses: effects of conditioning and acepromazine. Equine vet. J. 23, 219223.
  • Gibson, R.S. (1990) Principles of Nutritional Assessment, Oxford University Press, New York .
  • Harris, P., Bailey, S.R., Elliott, J. and Longland, A. (2006) Countermeasures for pasture-associated laminitis in ponies and horses. J. Nutr. 136, 2114S2121S.
  • Henneke, D.R., Potter, G.D., Kreider, J.L. and Yeates, B.F. (1983) Relationship between condition score, physical measurements and body fat percentage in mares. Equine vet. J. 15, 371372.
  • Hoffman, R.M., Boston, R.C., Stefanovski, D., Kronfeld, D.S. and Harris, P.A. (2003) Obesity and diet affect glucose dynamics and insulin sensitivity in Thoroughbred geldings. J. anim. Sci. 81, 23332342.
  • Jeffcott, L.B., Field, J.R., McLean, J.G. and O'Dea, K. (1986) Glucose tolerance and insulin sensitivity in ponies and Standardbred horses. Equine vet. J. 18, 97101.
  • Johnson, P.J. (2002) The equine metabolic syndrome peripheral Cushing's syndrome. Vet. Clin. N. Am.: Equine Pract. 18, 271293.
  • McFarlane, D., Beech, J. and Cribb, A. (2006) Alpha-melanocyte stimulating hormone release in response to thyrotropin releasing hormone in healthy horses, horses with pituitary pars intermedia dysfunction and equine pars intermedia explants. Domest. Anim. Endocrinol. 30, 276288.
  • Mcintosh, B., Kronfeld, D., Geor, R., Staniar, W., Longland, A., Gay, L., Ward, D. and Harris, P. (2007) Circadian and seasonal fluctuations of glucose and insulin concentrations in grazing horses. In: Proceedings of the 20th Equine Science Society. pp 100101.
  • McManus, C.J. and Fitzgerald, B.P. (2000) Effects of a single day of feed restriction on changes in serum leptin, gonadotropins, prolactin, and metabolites in aged and young mares. Domest. anim. Endocrinol. 19, 113.
  • Murphy, K.G. and Bloom, S.R. (2006) Are all fats created equal? Nat. Med. 12, 3233.
  • Perkins, G.A., Lamb, S., Erb, H.N., Schanbacher, B., Nydam, D.V. and Divers, T.J. (2002) Plasma adrenocorticotropin (ACTH) concentrations and clinical response in horses treated for equine Cushing's disease with cyproheptadine or pergolide. Equine vet. J. 34, 679685.
  • Pratt, S.E., Geor, R.J. and McCutcheon, L.J. (2005) Repeatability of 2 methods for assessment of insulin sensitivity and glucose dynamics in horses. J. vet. int. Med. 19, 883888.
  • Treiber, K.H., Kronfeld, D.S., Hess, T.M., Boston, R.C. and Harris, P.A. (2005) Use of proxies and reference quintiles obtained from minimal model analysis for determination of insulin sensitivity and pancreatic beta-cell responsiveness in horses. Am. J. vet. Res. 66, 21142121.
  • Treiber, K.H., Hess, T.M., Kronfeld, D.S., Boston, R.C., Geor, R.J. and Harris, P.A. (2007) Insulin resistance and compensation in laminitis-predisposed ponies characterized by the minimal model. Pferdeheilkunde 23, 237240.
  • Treiber, K.H., Kronfeld, D.S., Hess, T.M., Byrd, B.M., Splan, R.K. and Staniar, W.B. (2006) Evaluation of genetic and metabolic predispositions and nutritional risk factors for pasture-associated laminitis in ponies. J. Am. vet. med. Ass. 228, 15381545.
  • Vick, M.M., Adams, A.A., Murphy, B.A., Sessions, D.R., Horohov, D.W., Cook, R.F., Shelton, B.J. and Fitzgerald, B.P. (2007) Relationships among inflammatory cytokines, obesity, and insulin sensitivity in the horse. J. anim. Sci. 85, 11441155.
  • Zweig, M.H. and Campbell, G. (1993) Receiver-operating characteristic (ROC) plots: a fundamental evaluation tool in clinical medicine. Clin. Chem. 39, 561577.