Authors
Abstract
Objective: To compare and analyze the correlation between serum thyroid concentrations of 6 groups of horses (young females vs. young males; adult females vs. adult males; young females vs. adult females; young males vs. adult males; females vs. males, and young vs. adults). Materials and Methods: Blood samples were obtained from 99 horses in the fasting state, differentiated by gender and age (50 horses under two years: 25 females and 25 males, and 49 horses over two years: 25 females and 24 males). Levels of THS and free T4 were measured by enzymatic immunoassay. Results: For the FT4 by age group: significant difference for young vs. adults was found, with a p-value lower than 0.05 equal to 0.005, with 0.74 mg/dl and 0.59 mg/dl average ranks for young and adults respectively, with a confidence level of 95%. Similarly, statistically significant difference for young females vs. adult females was found in the FT4 fraction ranging from 0.74 mg/dl and 0.56 mg/dl respectively, with a p-value lower than 0.05 equal to 0.01. For the other groups, the differences in FT4 and TSH values ?? were not significant (P ≥ 0.05). Conclusions: The results suggest that young females present higher FT4 serum levels.
Keywords:
References
BARAGLI, P. et al., 2011. Early evidence of the anticipatory response of plasma catecholamine in equine exercise. Equine Vet J., 31: 85-88.
BOOSINGER, T.R.; BRENDEMUEHL, J.P.; BRANSBY, D.L. et al. 1995. Prolonged gestation, decreased triiodothyronine concentration, and thyroid gland histomorphologic features in newborn foals of mares grazing Acremonion coenophialum-infected fescue. Am J Vet Res, 56, 66-9
BREUHAUS, B.A., 2011. Disorders of the Equine Thyroid Gland. Vet Clin North Am Equine Pract., 27 (1): 115-128.
BREUHAUS, B.A. & LAFEVERS, D.H. 2005. Thyroid function in normal, sick and premature Foals [abstract]. J Vet Intern Med, 19, 445.
BUFF, P.R. et al., 2007. Seasonal and pulsatile dynamics of thyrotropin and leptin in mares maintained under a constant energy balance. Domestic Animal Endocrinol., 33: 430-436.
CHRISTENSEN, R.A. et al., 1997. Acute effects of short-term feed deprivation and refeeding on circulating concentrations of metabolites, insulin-like growth factor i, insulin-like growth factor binding proteins, somatotropin, and thyroid hormones in adult geldings. J Anim Sci., 75: 1351-1358.
CROCKFORD, S.J., 2003. Thyroid rhythm phenotypes and hominid evolution: a new paradigm implicates pulsatile hormone secretion in speciation and adaptation changes. Comp Biochem Physiol AMol Integr Physiol., 135: 105-129.
DIVERS, J.T., 2008. Endocrine Testing in Horses: Metabolic Syndrome and Cushing's Disease. Equine Vet J., 28 (5): 315-316.
DONALD E.G. GRIESDALE, RUSSELL J. DE SOUZA, ROB M. VAN DAM. et al., 2008. Intensive insulin therapy and mortality among critically ill patients: a meta-analysis including NICE-SUGAR study data. CMAJ. 180(8): 821–827.
DOUGLAS, R. 1999. Circadian cortisol rhythmicity and equine cushing's-like disease. Equine Vet J, 19(11), 684, 750-751, 753.
DUCKETT WM. 1989. Thyroid gland. Equine internal medicine. 917–923.
FAZIO, E. et al., 2007. Total and free iodothyronine levels of growing Thoroughbred foals: Effects of weaning and gender. Livestock Science, 110 (3): 207-213.
FRANK, N. et al., 2002. Equine thyroid dysfunction. Vet Clin Equine, 18: 305-319.
FURR, M.O.; MURRAY, M.J. & FERGUSON, D.C. 1992. The effects of stress on gastric ulceration, T3, T4, reverse T3 and cortisol in neonatal foals. Equine Vet J, 24, 37-40.
HALLERMEIER KM , WU SM, STRATAKIS CA, CHAN CHY, BOURDONY CJ, RENNERT OM, et al., 1998. Genetic heterogeneity of adrenocorticotropin (ACTH) resistance syndromes: identification of a novel mutation of the ACTH receptor genein hereditary glucocorticoid deficiency. Mol Genet Metab., 64:256-65.
HULBERT, A.J., 2000. Thyroid hormones and their effects: a new perspective. Biol. Rev., 75: 519-631.
HURCOMBE, S.D., 2011. Hypothalamic-Pituitary gland axis function and disfunction in horses. Vet Clin Equine, 27: 1-17.
KRATZSCH, J. & PULZER, F., 2008. Thyroid gland development and defects. Best Pract Res Clin Endocrinol Metab., 22 (1): 57-75.
MEDICA, P. et al., 2011. 24-hour endocrine profiles of quarter horses under resting conditions. Equine Vet J., 31: 35-40.
MESSER, N.T. et al., 1998. Thyroid Hormone Levels in Thoroughbred Mares and Their Foals at Parturition. Proceedings of the Annual Convention of the AAEP, 44: 248-251.
TORIBIO, R.E., 2011. Endocrine dysregulation in critically ill foals and horses. Vet Clin North Am Equine Pract., 27 (1): 35-47.
TORIBIO, R.E. & DUCKETT, W.M., 2004. Equine Internal Medicine. Estados Unidos de América: Saunders.