Total and free iodothyronine changes in response to transport of Equidae (Equus asinus and Equus caballus)

In this study the effects of short distance road transport on total and free iodothyronine changes in 12 stallions (Equus asinus and Equus caballus) were evaluated. Donkeys (n = 6) and horses (n = 6) were transported for a distance of 50 km. Blood samples were collected 1week before transport in basal conditions, 1 week later immediately before loading, and after transport and unloading. After transport, donkeys showed significant increases in circulating T-4 (P <= 0.01), fT(3) (P <= 0.001), and fT(4) (P <= 0.01) levels; while horses had significant increases in circulating T-3, fT(3) and fT(4) (P <= 0.01) levels. Compared to donkeys' values, horses showed lower T-4 values in basal condition, before and after transport (P <= 0.001); higher fT(3) values in basal condition and before (P <= 0.001), and lower values (P <= 0.001) after transport; higher fT(4) values (P <= 0.001) in basal condition. The results indicate that short road transport of donkeys and horses induces the activation of the thyroid gland, with the same release of fT(3) and fT(4) iodothyronines, but with different preferential release of T-3 in horses and T-4 in donkeys after transport.