[The horses of Giara: variation of the thyroid activity and certain blood parameters between winter and summer]

The changes of some parameters in the blood serum of six Giara horses (3 males and 3 females) were checked weekly, in relation to the environmental temperature throughout a one winter and summer. T3, total lipids, triglycerides, urea nitrogen, creatinine, total protein, albumin, beta and gamma globulin showed significant difference between winter and summer and, with the exception of triglycerides, urea nitrogen and total protein were correlated to the environmental temperature. T4, glucose, uric acid and alpha globulin showed no difference between the two seasons and no correlation with the temperature. The results indicate that the seasonal variations in thyroid activity affected the T3 only, and that the blood lipids were transported from the beta globulin and, perhaps, in a smaller quantity, from the albumin, while the alpha globulin was not affected.