SEASONAL OCCURRENCE AND ITS EFFECT ON THY ROID-HORMONE CONCENTRATIONSIN BLOOD-SERUM OF GERMAN-SHEPHERD, DACHSHUNDS AND THEIR HEALTH-STATUS

A relatively frequent prevalence of dermatoses in summer has drawn our attention. Dermatoses of endocrine origin occur very often. We have n oticed the deterioration of skin changes in animals with hypothyroidis m. Bubenik et al. (1983), Webster et al. (1991), Reiter et al. (1988) reported that changes in concentrations of thyroid hormones were found in fallow-deer, sheep and hamsters due to the effect of temperature a nd season. Based upon this knowledge we have decided to observe the he alth status and function of the thyroid gland in two randomly selected groups of various size dogs - German shepherd and dachshund during fo ur seasons. We observed following parameters: concentration of triiodo thyronine (T-3), thyroxine (T-4), cholesterol (Chol) and total lipids (TL) in the blood serum, average temperatures in individual seasons. B lood was always withdrawn fasting in the morning from vena antebrachii . Concentrations of T-3 and T-4 were determined by the commercial kits RIA-test-T-4 and RIA-test-T-3 (Huma-Lab, Kosice, Slovak Republic). Th e levels of cholesterol and total lipids were determined by the BIO-LA -tests (Lachema, Brno, Czech Republic). March, April, May were include d into spring season; June, July, August into summer; September, Octob er, November into autumn; and December, January, February into winter. The Slovak Hydrometeorologic Institute in Kosice provided the values of average temperatures in observed seasons. The average temperatures in individual seasons were the following: spring +9.8 degrees C, summe r +18.4 degrees C, autumn +8.5 degrees C, winter -1.2 degrees C. Durin g the observed period concentrations of cholesterol and total lipids r anged within the reference values in both breeds. The different values were measured in German shepherds; the TL concentration in autumn (4. 58 +/- 1.13 mmol/l) was outside the reference range. Similarly, in the group of dachshunds the TL concentration in summer (7.64 +/- 2.85 mmo l/l) was higher than the reference value. Concentrations of hormones T -3 and T-4 varied during seasons in both breeds. The lowest values of T-3 and T-4 were measured in summer. In German shepherds and dachshund s the T-3 concentrations were 0.40 +/- 0.11 and 1.48 +/- 0.37 nmol/l, respectively. The T-4 concentrations in German shepherds and dachshund s in this season were 18.06 +/- 7.04 and 29.70 +/- 15.34 nmol/l, respe ctively. The highest concentrations of T-3 in German shepherds and dac hshunds were found in winter (1.63 +/- 1.93 and 2.22 +/- 0.34 nmol/l, respectively). The highest T-4 concentration in both breeds of dogs wa s found in autumn (German sheepherds 21.90 +/- 13.67 and dachshunds 44 .64 +/- 8.62 nmol/l). In the group of 8 dachshunds, marked skin change s - dry, rugose, coarse, inelastic skin with conspicuous hair Loss and pruritus - occurred in two of them. In these animals an increased con centration of serum TL (9.53 and 8.22 mmol/l) and low values of serum T-3 (0.93 nmol/l) and T-4 (3.45 nmol/l) also occurred. In the group of 59 German shepherds dermatosis was in 11 cases. The skin changes were similar to those in dachshunds. In no case the T-3 concentration was lower than 0.3 nmol/l. The T-4 concentrations in sick dogs were within the range of 0.3 to 38.2 nmol/l. In sick animals of both breeds a pro nounced deterioration of skin changes in summer was observed. Our resu lts confirm the need of observing the levels of given hormones during the whole year in sick animals, As well, it is necessary to increase i ndividually the dose of hormonal preparations administered to these an imals in summer.