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Function of thyroid gland in working dogs
The purpose of this study was to analyze the results of thyroid gland function research in working dogs (German Shepherd, Spaniel, Malinois). The concentration of Thyroid-Stimulating Hormone (TSH), Thyroxine (total T4 and fT4), Triiodothyronine (total T3 and fT3), and Autoantibodies to Thyroglobulin (AATg) was measured.
The TSH and total T4 were higher than physiological limits, respectively, in 47,8 % and 52,2 % of German Shepherds, about 16,7 % of Spaniels and 25 % of Malinoises for both indices. The fT3 was decreased in the blood plasma in working dogs, but AATg were higher than 100 IU/l in 21,7 % of German Shepherds and 50% of Spaniels.
Thyroid gland takes an important place in the organism function. Examination of it function helps to determinate subclinical dysfunction, when there is no clinical signs.
During the clinical examination the authors register 81,8 % of working dogs with coat changes (coat was dry, tousled, dull). The molt was too long in time, the skin had low elasticity.
As a result of research, authors have found that the TSH rations were 0,12±0,027 mIU/l in German Shepherd dogs, 0,06±0,008 mIU/l in Spaniels and 0,06±0,010 mIU/l in Malinois. About 47,8 % of German Shepherds, 16,7 % of Spaniels and 25,0 % of Malinois had increased level of TSH. The TSH is the hormone of Anterior Pituitary. The decreased or increased TSH could be an indicator of Thyroid gland or/and Pituitary dysfunction.
The total Thyroxine increases metabolism and usage of Oxygen. It regulates energy metabolism and tissue differentiation.
The total Thyroxine (T4) rations were 91,1±16,7 nmol/l in German Shepherds, 46,8±2,8 nmol/l in Spaniels and 48,9±14,4 nmol/l in Malinois. 52,2 % of German Shepherd dogs, 16,7 % of Spaniels and 25,0 % of Malinois had increased level of total T4.
The fT4 rations were 1,8±0,08 ng/dl in German Shepherd dogs, 1,8±0,12 ng/dl in Spaniels and 1,5±1,177 ng/dl in Malinois. These rations were in the physiological limits for dogs.
The total T3 ranged in German Shepherds 0,8−4,6 ng/ml, in Spaniels 0,3−1,4 ng/ml, in Malinois – 0,7−1,1 ng/ml. About 70,0 % of German Shepherd dogs and 16,7 % of Spaniels had increased level of total T3. The 33,3 % of Spaniels and 20 % of Malinoises had decreased level of this hormone.
The fT3 is an active form of T3. It regulates the speed of oxygen usage by different tissues, increases Cholesterol catabolism, stimulates protein synthesis, sexual hormones, etc.
The fT3 was within 2,7−6,9 pg/ml in German Shepherds, 3,6−5,3 pg/ml in Spaniels and 2,3−4,2 pg/ml in Malinois. About 91,3 % German Shepherds, 100 % of Spaniels and Malinois had decreased level of fT3.
The autoantibodies to Tg were within 66,0±10,7 IU/l in the German Shepherd, 86,1±29,5 IU/l in the Spaniels and 44,0±5,7 IU/l in the Malinois. About 21,7 % of German Shepherds and 50 % of Spaniels had AATg above 100 IU/l.
Conclusions. 1. The increased level of TSH, total T4 was detected, respectively, in 34,8 % and 52,2 % of German Shepherds, 16,7 % of Spaniels and 25,0 % of Malinois.
2. The total T3 was increased in 70 % of German Shepherds and 16,7 % of Spaniels. It was lower of physiological limits in 33,3 % of Spaniels and 20 % Malinoises. It means, that hypofunction of thyroid gland is progressing.
3. The fT3 level was decreased in 91,3 % of German Shepherds and 100 % of Spaniels and Malinois.
4. The AATg level was higher than 100 IU/l in 21,7 % of German Shepherds and 50 % of Spaniels.
5. These indices of thyroid hormones in working dogs could be used as referent tests in hypothyroid dogs.
Key words: dogs, blood, thyroid gland, autoantibodies.
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