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The objective of this study was to investigate the metabolism of inorganic and organic Se sources at different dietary Se levels in lactating goats and dairy cows. The study consists of two experiments on goats dosed singly, either orally with grass sprayed with Na275SeO3 one week before cutting, intraruminally (I.R.) with Na275SeO3, or intravenously (I.V.) with Na275SeO3 or 75Se-selenomethionine. Follow-up periods were from 15 to 28 d long. Dietary Se levels were 0.05, 0.22 and 0.34 mg/kg DM. Values for 75Se absorption, excretion in milk, urine and faeces, 75Se activity in plasma, erythrocytes and hair are presented. In another experiment lasting 539 d, 48 dairy cows were fed either Na275SeO3 or grass silage sprayed with Na275SeO3 one week before cutting. Dietary Se levels were from 0.03 to 1.8 mg/kg DM. Se content in milk, plasma and erythrocytes, and GSH-Px activity in erythrocytes and plasma are given. True absorption of 75Se was 63 % and 65 %, and excretion of 75Se in milk 4 % and 7 % in the goats dosed I.R. with Na275SeO3 and orally with 75Se-labeled grass. The effect of dietary Se content was non-significant. After I.V. dose, 3.6 % and 33 % of 75Se was excreted in milk in goats dosed with Na275SeO3 and 75Se-selenomethionine, respectively, Na275SeO3 being eliminated mainly via urine. In cows receiving selenium as Na275SeO3, milk contained 0.011, 0.011, 0.016 and 0.020 mg Se/l at dietary Se levels 0.11, 0.17, 0.42 and 0.68 mg/kg DM, respectively. In cows receiving Se-sprayed silage, milk Se content was 0.023, 0.020, 0.029 and 0.040 mg/l when the diet contained 0.09, 0.20, 0.45 and 1.20 mg Se/kg DM. Se incorporated into silage was more efficient (p

Selenium is unevenly distributed in soils worldwide. For climatic and geochemical reasons, Finland is one of the low-selenium regions in the world. To improve the quality of Finnish foods and animal health and to increase the selenium intake of the population, an official decision was made in 1984 to supplement compound fertilizers with selenium. Practically all fertilizers used in Finland have contained selenium since 1985. The objective of this chapter is to report the effects of the supplementation of selenium to commercial fertilizers on soils, feeds, basic foodstuffs, dietary selenium intake, human tissues and the environment. Within a monitoring programme, sampling of cereals, basic foodstuffs, feeds, fertilizers, soils and human tissues has been carried out at least annually since 1985. The systematic error in selenium analyses has been followed annually by a quality assessment scheme involving seven participating laboratories. The selenium concentration of spring cereals increased on average 15-fold compared with the level before the selenium fertilization practice. The mean selenium concentration in beef and pork increased six- and twofold, respectively, and in milk threefold, compared with levels before selenium fertilization. The average dietary intake increased from 0.04 mg Se/day to a plateau of 0.07 mg Se/day in the mid-2000s. Foods of animal origin in 2006 contributed over 75% of the total daily intake of selenium. The mean human plasma selenium concentration increased by 60% and the selenium status is optimal. Evident signs of selenium transport into natural waters have not been found. In Finland, where the geochemical conditions are relatively uniform, the nationwide supplementation of fertilizers with selenium has proved to be an effective, safe and controlled way of bringing the selenium intake of the whole population to the recommended level. Moreover the well-being of animals has been secured.

The effects of different types of Se supplementation on the selenium concentration of beef, bovine internal organs and some other tissues were studied. The animals (thirty-two bulls) were kept in four dietary groups from birth until to the age of 13-14 months, and fed on rations containing either 0.03 mg Se/kg (basic level in local feeds), 0.25 mg inorganic Se supplemented as sodium selenite, or 0.25 or 0.4 mg/kg plant Se in dry matter from feed produced by spraying with sodium selenite. Samples of four muscles and ten other tissues and organs were taken at slaughter. Se was determined by an electrothermal atomic absorption method. Se supplementation significantly increased the Se concentration of all tissue samples. The maximum response was caused by the diet containing 0.40 mg/kg plant Se. In muscles, this diet raised the Se concentration by a factor of 10-12. In other samples, the increment was 15-75 fold, depending on the type of tissue. In general, plant Se raised the Se level more effectively than inorganic Se. Se supplementation did not affect the vitamin E status of muscle tissue.

The present study evaluated the effects of feeding strategies with alternative feeds on the performance of mature suckler cows and their progeny during indoor feeding and subsequent grazing. In both experiments, a 2 × 2 factorially arranged design consisted of two feeding strategies (Step-up, S; Flat-rate, F) and two diets (Control, C; Alternative, A). The aim of Strategy F was to offer the cows the same amount of energy as offered on Strategy S, but at a constant daily level. In Experiment 1, cows on Diet C were offered grass silage and straw and on Diet A grass silage and a fl our-mill industry by-product. On Strategy S, feeding was stepped with barley (0, 1.5 and 3.5 kg d -1 ). On Strategy F, barley was offered 1.43 kg per head daily. In Experiment 2, cows were offered either grass silage (C) or whole-crop barley silage (A) as a sole feed. Strategy S was carried out by offering 68, 95 and 119 MJ metabolizable energy (ME) per cow daily. On Strategy F, roughage was given daily 97 MJ ME. In both experiments, there were no signifi cant differences between treatments in the cow live weight, body condition score, calf pre-weaning live weight gain and cow reproduction. Strategy F can be practised in the nutrition of mature suckler cows in marginal circumstances. Flour-mill industry by-product can partly replace grass silage and straw in the winter diet. Wholecrop barley silage can be offered as a sole feed to suckler cows with good body condition score in autumn.