Date Published: November 3, 2008
Publisher: BioMed Central
Author(s): Petr Slavik, Josef Illek, Michal Brix, Jaroslava Hlavicova, Radko Rajmon, Frantisek Jilek.
Selenium (Se) is important for the postnatal development of the calf. In the first weeks of life, milk is the only source of Se for the calf and insufficient level of Se in the milk may lead to Se deficiency. Maternal Se supplementation is used to prevent this.
Cows in late pregnancy received a mineral premix with Se (SS or SY, 50 mg Se per kg premix) or without Se (control – C). Supplementation was initiated 6 weeks before expected calving. Blood and colostrum samples were taken from the cows that had just calved (Colostral period). Additional samples were taken around 2 weeks (milk) and 5 weeks (milk and blood) after calving corresponding to Se supplementation for 6 and 12 weeks, respectively (Lactation period) for Se, biochemical and haematological analyses.
Colostral period. Se concentrations in whole blood and colostrum on day 1 post partum and in colostrum on day 3 post partum were 93.0, 72.9, and 47.5 μg/L in the SY group; 68.0, 56.0 and 18.8 μg/L in the SS group; and 35.1, 27.3 and 10.5 μg/L in the C group, respectively. Differences among all the groups were significant (P < 0.01) at each sampling, just as the colostrum Se content decreases were from day 1 to day 3 in each group. The relatively smallest decrease in colostrum Se concentration was found in the SY group (P < 0.01). Se-enriched yeast was much more effective than sodium selenite in increasing the concentration of Se in the blood, colostrum and milk, as well as the GSH-Px activity.
Selenium (Se) is extremely important for the proper postnatal development of the calf. Selenium deficiency compromises growth, health and fertility . During pregnancy, Se passes through the placental barrier, and even if the cow is moderately Se deficient, the calf receives a sufficient Se supply . In the first weeks of life, milk is the only source of Se for the calf, but the Se content in the milk is rather low . Therefore, calves from dams with insufficient Se supplementation may suffer from myodystrophic diseases  or other disorders related to Se deficiency.
Selenium-enriched yeast was much more effective than sodium selenite in increasing the concentration of Se in blood, colostrum and milk, as well as the GSH-Px activity. Cows fed selenium-enriched yeast also showed a slower decrease in colostral Se levels. The findings indicate a higher bioavailability of organic Se. This is possibly more pronounced when treating Se deficient animals. As milk is the only nutritional source of neonatal calves and later a supplementary source of nutrition, the use of organic Se may be of clinical significance.
The author(s) declare that they have no competing interests.
PS, MB and JH carried out the clinical trial and collected samples of blood, colostrum and milk. JI participated in the design of the study, supervised and participated in data collection. RR carried out the statistical analysis. PS wrote the manuscript. FJ coordinated the work. All the authors have read and approved the final manuscript.