Selenium in milk from feeding small supplements

Improving the quantity, quality and transparency of data used to derive radionuclide transfer parameters for animal products. 2. Cow milk

Under the International Atomic Energy Agency (IAEA) MODARIA (Modelling and Data for Radiological Impact Assessments) Programme, there has been an initiative to improve the derivation, provenance and transparency of transfer parameter values for radionuclides from feed to animal products that are for human consumption. A description of the revised MODARIA 2016 cow milk dataset is described in this paper. As previously reported for the MODARIA goat milk dataset, quality control has led to the discounting of some references used in IAEA's Technical Report Series (TRS) report 472 (IAEA, 2010). The number of Concentration Ratio (CR) values has been considerably increased by (i) the inclusion of more literature from agricultural studies which particularly enhanced the stable isotope data of both CR and F_m and (ii) by estimating dry matter intake from assumed liveweight. In TRS 472, the data for cow milk were 714 transfer coefficient (F_m) values and 254 CR values describing 31 elements and 26 elements respectively. In the MODARIA 2016 cow milk dataset, F_m and CR values are now reported for 43 elements based upon 825 data values for F_m and 824 for CR. The MODARIA 2016 cow milk dataset F_m values are within an order of magnitude of those reported in TRS 472. Slightly bigger changes are seen in the CR values, but the increase in size of the dataset creates greater confidence in them. Data gaps that still remain are identified for elements with isotopes relevant to radiation protection.

Effect of selenium in soluble glass bolus on selenium content of milk and blood of goats

Soluble glass bolus (SGB) with selenium (Se) was administered intraruminally to Se-deficient Philippine does to determine its effect on milk Se and to correlate the Se contents of does' milk and blood of does and kids. Five months after the Se administration, the does in the treated group (n = 14) had higher (p < 0.01) Se content in their blood (62.2 vs 25.7 micrograms/L) and milk (5.1 vs 2.5 micrograms/L) than does in control group (n = 13). Consequently, the blood Se of the kids (n = 14) from the treated does was higher (p < 0.05) than those kids (n = 13) in the control group (28.0 vs 5.1 micrograms/L). Blood and milk Se of does and blood Se of their kids correlated (p < 0.01) with each other. The increased Se level of does' milk because of Se supplementation was not regarded as a health hazard to humans.

Responses of dairy cattle to long-term and short-term supplementation with oral selenium and vitamin E1

In a two-lactation-gestation cycle experiment, 152 Holstein cows with low serum Se and vitamin E were fed total mixed rations and assigned at parturition to four groups (1, control; 2, 500 IU vitamin E/d; 3, 2 mg Se/d; 4, 500 IU vitamin E plus 2 mg Se/d). Supplements were not fed during dry periods. Serum Se and vitamin E were increased within 1 mo by oral supplements. Maximal mean serum Se in cycles 1 (67 ng/ml at 7 mo) and 2 (74 ng/ml at 4 mo) occurred in groups 3 and 4, respectively. Maximal mean serum vitamin E in cycle 1 (3.3 micrograms/ml at mo 8) and 2 (3.03 micrograms/ml at mo 2) occurred in groups 4 and 2, respectively. Selenium treatment of the dams increased Se in colostrum and in serum of presuckle calves. Vitamin E supplementation of dams did not affect vitamin E in serum of presuckled calves. Reproductive performance was not affected by supplement. In an 8-wk study, 24 lactating cows with low serum Se were assigned (6/group) to 0, 2.5, 5, and 10 mg supplemental Se/d. Maximal mean serum Se concentrations of 23, 56, 71, and 79 ng/ml were attained by wk 4 in the above respective groups. These data indicate that 2 to 2.5 mg supplemental Se/cow per d were inadequate for desirable serum Se concentrations and support recent changes in allowed Se supplementation for dairy cattle.

Prepartum supplementation of selenium and vitamin E to dairy cows: assessment of selenium status and reproductive performance

Incidence of retained placenta in dairy cows was evaluated in 627 parturitions. The herd was divided prepartum into three groups: 1) control, no treatment (n = 217 cows); 2) cows injected intramuscularly (n = 190) 21 to 10 d prior parturition with 45 mg Se and 2040 IU of vitamin E; and 3) cows intraruminally administered (n = 220) with two 30-g pellets containing 10% elemental selenium 2 mo prior to expected calving. Incidence of retained placenta (22.1%) was not reduced by Se in combination with vitamin E injection or intraruminal Se pellet nor were other measures of reproduction improved for cows fed a prepartum diet adequate in Se. At parturition the blood plasma Se concentrations were higher in treated postpartum with Se than in untreated cows. No difference in blood plasma Se was observed at parturition between cows with or without placenta retention. Cows dosed intraruminally with Se had a significant increase in milk Se, but this was too small to be a danger to human health. The present results on placenta retention suggest that this disorder is not a Se responsive disease in the dairy cow.

Mineral content of milk, colostrum, and serum as affected by physiological state and mineral supplementation

A 22-mo experiment was conducted to determine effects of mineral supplementation of cows on mineral elements in milk, colostrum, and blood serum. Purebred Brahman beef cows grazing pastures grown on sandy and well-drained soils were allotted to three treatments of 12 cows each as follows: control, a complete commercial mineral mixture, control plus dietary and injected Se, and control plus fortified mineral mixture. Milk and serum were analyzed for minerals 2 consecutive yr at parturition and 3 mo postpartum. Mean cow serum, Ca, Mg, P, and packed cell volume values were higher at parturition than 3 mo later, whereas serum Cu was highest at 3 mo. Mean serum concentrations were affected by year with higher Ca and hemoglobin and lower Cu concentrations in 1982 than in 1981. Increasing dietary Se resulted in higher serum Se. Colostrum was higher in Mg, P, Cu, Fe, Se, and Zn than milk, whereas milk was higher than colostrum in Mn. Means for treatment X time showed cows fed dietary and dietary plus injected Se and vitamin E had more Se in milk than milk from cows fed no supplemental Se.

Maternal transfer and retention of supplemental selenium in neonatal calves

Selenium concentrations in blood serum of heifer calves from dams fed 0, 1, or 5 mg supplemental selenium daily during the dry period were compared. Dry cows were fed corn silage top dressed with a soybean meal mineral mix containing the desired amount of selenium. At birth, calves were assigned to one of six treatments in a 3 x 2 factorial arrangement. Calf treatments were 0, 1 (at birth), or 2 (at birth and 14 days of age) injections of selenium/vitamin E with feeding of starter commencing at 14 or 28 days of age. Dosage per injection was .078 mg selenium and 5.4 IU vitamin E per kilogram body weight. Selenium concentrations of blood serum of cows at parturition were 14, 32, and 58 ppb for cows fed 0, 1, and 5 mg selenium per day. Amount of selenium fed to cows affected selenium concentrations in blood serum of their calves with those from cows fed 5 mg selenium having the greatest concentrations. Calves from cows fed no supplemental selenium showed increased selenium in serum at day 28 and 42 when given one or two injections of selenium. Two injections, however, were necessary to elicit a response in calves from cows fed 1 mg per day. Selenium in blood serum of calves from cows fed 5 mg per day was not elevated when calves were given one or two injections of selenium. Prepartum selenium supplementation of the dam elevated selenium of blood serum in the calf at birth.(ABSTRACT TRUNCATED AT 250 WORDS)