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The objective of the study was to evaluate the influence of high iodine intake in ewes on haematological and biochemical parameters of the blood of ewes and their lambs. Twelve pregnant ewes of the Sumava sheep breed and their newborn lambs were included in the experiment. Control group (A) consisted of 6 ewes with 7 lambs and experimental group (B) comprised 6 ewes with 6 lambs. The feed ration was enriched with calcium iodate by addition of 3 and 5 mg/kg in group A and group B, respectively. The studied parameters in ewes and lambs were haematocrit value, red blood cell count and haemoglobin concentration in blood, concentration of urea and total proteins, and alkaline phosphatase activity in blood plasma. No differences were found out in haematocrit value, red blood cell count, concentration of haemoglobin and total proteins between groups of ewes A and B with their lambs. Urea concentration and alkaline phosphatase activity were higher in ewes of group B and their lambs during the entire experimental period. An increase in the values of urea and alkaline phosphatase in the group of ewes and lambs with higher iodine intake indicates a potential risk of high iodine intake associated with changes in the thyroid activity in ewes and their lambs.

In 2010 and 2011 two experiments on gimmers of Šumava mountain sheep were performed. The first experiment was carried out on 12 animals (experimental period was 11 months); control group was fed with 3 mg I*kg−1 in dry matter per day and experimental group was fed with 5 mg I*kg−1 in dry matter per day. The second experiment lasted 10 months and it was carried out on 12 animals. Feed ration for control group contained 10 mg I*kg DM−1. Feed ration for experimental group contained 10 mg I*kg DM−1 too; moreover it included rapeseed meal and 1 g of sodium nitrate. The aim of the first experiment was focused on impact of high iodine intake on structure of thyroid gland. The aim of the second experiment was to discover effect of strumigens during high iodine intake on structure of thyroid gland. The animals were slaughtered after the experiment and there was executed the dissection of thyroid gland. The samples of thyroid gland were processed during classic paraffin method and dyed with haematoxylin and eosin. For finding of histometrical parameters was used program Leica IM 500 Version 4.0. The length, the width and the area of follicles were measured. The follicles were divided into three groups after this procedure (by the length); in each group were measured 20 thyreocytes. In group with intake 5 mg I*kg DM−1 (experiment from year 2010): higher weight of thyroid (p < 0.01), significant higher (p < 0.05) proportional representation of large and medium follicles, significantly (p < 0.05) higher average size of follicles, demonstrably lower (p < 0.05) height of epithelium were found. There were not found any differences in monitored parameters between the groups from experiment which was carried out during the year 2011. After comparing results from the both experiments significantly higher percentage representation of large follicles a significantly lower representation of small follicles, distinctly higher average size and higher height of epithelium in all size categories, in groups with iodine intake 10 mg I*kg DM−1was found (from second experiment – year 2011).

The aim of this study was to analytically determine the content of iodine, copper, zinc and manganese in the yolk of consumer eggs in Bohemia in 2007 and 2008. Investigated eggs originated from six so called intensive farms with large flocks (118 eggs) and twelve backyard farms or small-flock establishments (136 eggs) from three administrative regions in Czech Republic. Eggs from intensive farms were obtained directly from the establishments, while eggs from backyard farms were purchased from private farmers. Spectrophotometric Sandell-Kolthoff method was used for determination of iodine content in egg yolk, while Cu, Zn and Mn levels were determined by the flame absorption spectrophotometric method (AAS). The average content in fresh egg yolk from intensive farms was determined to 0.9 ± 0.2 for iodine, 8.4 ± 2.1 of copper, 29.8 ± 6.9 of zinc and 1.2 ± 0.3 of manganese, all in mg·kg−1, as compared to yolk content from backyard farms with 0.4 ± 0.04 mg·kg−1 of iodine, 10.8 ± 2.9 of copper, 32.5 ± 6.9 of zinc and 1.5 ± 0.3 of manganese. Average content of copper, zinc and manganese was lower in egg yolks from intensive farms (P < 0.01) as compared to the egg yolks from backyard farms, while iodine content on the other hand was lower in eggs from backyard farms (P < 0.01).