Effects of fence height on total and free iodothyronine changes in horses after experimental show jumping sessions

Abstract

SummaryReasons for performing study: Involvement of thyroid function on performance warrants further investigation as limited data exists on the effects of showjumping on the dynamics of total and free iodothyronines.

Dynamics of Total and Free Iodothyronines of Jumping Horses on the Responses to Competition and Transport

“…The absence of significant changes of total and free iodothyronines at 5 and 30 minutes after competition (session t2) confirmed previous data observed in experienced jumpers [3] and in trained horses after experimental show jumping session with fences of 1.00 m of height [6].…”

“…Serum total and free iodothyronine (T 3 , T 4 , fT 3 , fT 4 ) concentrations were determined in duplicate using EIA Kits that had been validated for equine serum [6]. Assays were carried out according to the manufacturer's instructions.…”

“…The effect of diet composition and feeding state on the response to exercise in feed-restricted horses, with an increase of T 3 concentrations in response to exercise, was described [13]. Experimental show jumping sessions induced significant increased values at 30 minutes for T 3 , T 4 , and fT 4 [6]. Because limited information exists about the specific effects of show jumping competition, or transport, or competition plus transport on the thyroid hormones changes in sport horses, the aim of the research was to study the total and free iodothyronine changes of trained horses transported before and/or after competition, or performing in show jumping competition, respectively.…”

“…Free T 3 (fT 3 ) is the most potent and active thyroid hormone in circulation, and its measurement can give a clearest picture of true contribution of extrathyroidal tissues, such as the musculoskeletal system, as a consequence of the thyroid stimulation and/or changes in capacity to bind iodothyronines [4][5][6]. Thyroid hormones are considered as markers of stress in horses, showing changes according to training [7], pretraining status and circadian changes [8], exercise [5,6,9], and transport and previous experience [3]. A sudden increase in plasma T 3 levels 5 minutes after exercise was obtained in Thoroughbred horses [9]; in addition, endurance exercise resulted in transient decreases in serum total and free iodothyronines [10].…”

Science in brief: Clinical news from the 8th ICEEP conference 2010: What more can we learn from haematology and serum biochemistry in athletic horses?

“…2010); however, an increase in circulating concentration of thyroid hormone has been demonstrated in showjumping horses (Ferlazzo et al . 2007) and appears related to the intensity (fence height) of the work (Ferlazzo et al . 2010).…”