THE EFFECT OF TWO DIFFERENT DOSES OF SELENIUM YEAST AND SODIUM SELENITE ON SELENIUM LEVEL IN BLOOD, COLOSTRUM, MILK AND METABOLIC PROFILE IN DAIRY COWS

Abstract

The aim of the study was to compare effects of two levels of selenium yeast (SY) and sodium selenite (SS) supplementation on blood, colostrum and milk Se levels, blood chemistry parameters in dairy cows under field conditions. The study included 36 Holstein cows from 5 weeks prepartum to 12 weeks postpartum. The cows were divided into 4 treatments (n = 9): 1. Negative Control (NC) – no Se supplement ; 2. Positive Control (PC) – 0.3 ppm Se (from sodium selenite) ; 3. S1 – 0.3 ppm Se (from selenium yeast – SELSAF ® , Lesaffre Feed Additives, France ) ; 4 . S2 – 5 ppm Se ( SELSAF ® , Lesaffre Feed Additives, France ). At 5 and 1 weeks prepartum, on the calving day, and 4, 8, 12 weeks postpartum, blood samples were taken . Colostrum and milk were collected on the calving day and 4, 8 and 12 weeks postpartum and analysed for Se content. Initial Se status in all the cows was marginal. Negative Control cows showed suboptimal blood Se levels for the whole period under study. S1 and S2 showed significantly (P < 0.01) higher values than NC and PC cows. Colostrum Se levels were significantly higher in S1 (128.17 ug/L) and S2 (155.58 ug/L) than in NC (94.68 ug/L) and PC (99.3 ug/L) cows. Overall mean milk Se levels in S1 (20.4 ug/L) and S2 (50.0 ug/L) were higher than in NC (10.9 ug/L) and PC (16.6 ug/L). Biochemical indicators of blood did not significantly differ between the treatments and were within the physiological ranges. Se levels in whole blood, colostrum and milk, and GSH-Px activity were significantly increased by selenium yeast supplementation. The response was dose dependent and consistent. Selenium from organic source was more bioavailable than selenium from sodium selenite. Dietary Se at a tolerance dose (5 ppm) had no detrimental effect on the blood chemistry parameters analysed.