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Effects of Supplementary Selenium Source on the Blood Parameters in Beef Cows and Their Nursing Calves
- Gunter, Stacey A., Beck, Paul A., Hallford, Dennis M.
- Biological trace element research 2013 v.152 no.2 pp. 204
- Cynodon dactylon, beef cows, blood, blood chemistry, breeding season, calves, calving, dietary mineral supplements, enzyme activity, feed supplements, glutathione peroxidase, herds, insulin-like growth factor I, lactation, minerals, models, pastures, selenium, sodium selenite, triiodothyronine, yeasts
- Over 2 years, 32 beef cows nursing calves were randomly selected from a herd of 120 that were managed in 6 groups and were assigned to six 5.1-ha bermudagrass (Cynodon dactylon [L.] Pers.) pastures. Treatments were assigned to pastures (2 pastures/treatment) and cows had ad libitum access to 1 of 3 free-choice minerals: 1) no supplemental selenium (Se), 2) 26 mg of supplemental Se from sodium selenite/kg, and 3) 26 mg of supplemental Se from seleno yeast/kg (designed mineral intake = 113 g/cow daily). Data were analyzed using a mixed model; year and pasture were the random effects and treatment was the fixed effect. At the beginning of the calving and breeding seasons, cows supplemented with Se had greater (P < 0.01) whole blood Se concentrations (WBSe) and glutathione peroxidase activities (GSH-Px) than cows receiving no supplemental Se; cows fed seleno-yeast had greater (P </= 0.05) WBSe than cows fed sodium selenite, but GSH Px did not differ (P >/= 0.25) between the two sources. At birth and near peak lactation (late May), calves from cows supplemented with Se had greater (P < 0.01) WBSe than calves from cows fed no Se and calves from cows fed seleno-yeast had greater (P </= 0.01) WBSe and GSH-Px than calves from cows fed sodium selenite. Thyroxine (T4), triiodothyronine (T3), and the T4:T3 ratio in calves did not differ among treatments (P >/= 0.35). At birth, IGF-1 was greater (P = 0.02) in calves nursing cows with no supplemental Se than in ones with supplemental Se; in calves nursing cows with supplemental sodium selenite, IGF-1 did not differ (P = 0.96) from ones offered supplemental seleno-yeast. Selenium supplementation of gestating beef cows benefited cows and calves by increasing WBSe and GSH Px. The use of seleno yeast as a Se supplement compared to sodium selenite increased the WBSe and GSH-Px of both cows and their calves, yet had no effect on T4 conversion or IGF-1 concentrations.