The impact of high iodine intake on thyroid function in ewes and lambs.

Objectives: The objective of the study was to assess the metabolic risk of excessive dietary iodine intake in ewes and neonatal lambs.

Design: Pregnant Šumava ewes received an experimental diet containing 3.1 mg iodine per kg of dietary dry matter in Group A (control, n=13, 6 ewes and 7 lambs) and 5.

[Occurrence of struma in cattle in the Czech Republic].

In the years 1988 to 1995 among 1355 cattle examined in the frame of iodine deficiency studies in the Czech Republic 404 animals (30%) showed congenital struma. Clinical and postmortal findings are described. A monitoring of iodine content in milk showed lower values in herds with struma prevalence.

Osmotic and oxidative haemolysis of erythrocytes in calves with white muscle disease.

The stability of erythrocytes to both osmotic and oxidative haemolysis was studied in naturally occuring cases of white muscle disease of calves two to 14 weeks old. During clinical and subclinical disease the incidence of haemolysis when erythrocytes were exposed to 0-588 per cent NaCl was 74-3 +/-18-8 per cent and 76-6+/-18-6 per cent respectively, whereas in clinically healthy animals receiving 30 mg vitamin E per kg feedstuff the incidence of haemolysis was only 55-9+/-12-7 per cent. Erythrocytes of the calves receiving vitamin E supplements were completely resistent to peroxidative haemolysis whereas in the clinical and preclinical cases approximately 12-5 per cent of cells were lysed.

[Selenium content in cattle hair in areas with incidence of nutrition-induced muscular dystrophy].

In the South Bohemian Region which is an area of enzootic incidence of nutritional muscle dystrophy selenium content in the fur of dairy cows and young cattle was determined. In the breeds in which the "white muscle disease" appeared in the past years in young cattle, lambs and calves the lowest mean selenium values in the fur dry matter found were: 0.18 +/- 0.