Paper-Lecture51 - Dietary vitamin E and selenium affect...

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K. L. Smith, J. S. Hogan and W. P. Weiss Dietary vitamin E and selenium affect mastitis and milk quality 1997. 75:1659-1665. J Anim Sci http://jas.fass.org the World Wide Web at: The online version of this article, along with updated information and services, is located on www.asas.org by on April 10, 2008. jas.fass.org Downloaded from Copyright © 1997 American Society of Animal Science. All rights reserved. For personal use only. No other uses without permission.
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1659 1 Invited paper presented at the 29th Midwestern Section ASAS mtg., Des Moines, IA, 1996. 2 Salaries and research support were provided by state and federal funds appropriated to the Ohio Agricultural Research and Development Center, The Ohio State University. Manuscript 46 - 96. Received April 12, 1996. Accepted January 6, 1997. Dietary Vitamin E and Selenium Affect Mastitis and Milk Quality 1,2 K. Larry Smith, J. S. Hogan, and W. P. Weiss Department of Animal Sciences, The Ohio State University, Ohio Agricultural Research and Development Center, Wooster 44691 ABSTRACT: Vitamin E and selenium (SE) are essential nutrients that are integral components of the antioxidant defense of tissues and cells. Soils in many of the important dairy regions of the world are Se- deficient, and feedstuffs grown on these soils will not provide adequate dietary Se. Cattle consuming stored forages are likely to be low in vitamin E unless supplemented, and vitamin E deficiencies are fre- quently observed in peripartum dairy cows. Many new intramammary infections (IMI) occur in the 2 wk before and after calving. Deficiencies of either vitamin E or Se have been associated with increased incidence and severity of IMI, increased clinical mastitis cases, and higher somatic cell counts (SCC) in individual cows and bulk tank milk. Somatic cell counts are a primary indicator of mastitis and milk quality in dairy herds. The polymorphonuclear neutrophil (PMN) is a major defensive mechanism against infection in the bovine mammary gland. A known consequence of vitamin E and Se deficiency is impaired PMN activity and postpartum vitamin E deficiencies are frequently observed in dairy cows. Dietary supplementation of cows with Se and vitamin E results in a more rapid PMN influx into milk following intramammary bac- terial challenge and increased intracellular kill of ingested bacteria by PMN. Subcutaneous injections of vitamin E approximately 10 and 5 d before calving successfully elevated PMN a -tocopherol concentra- tions during the periparturient period and negated the suppressed intracellular kill of bacteria by PMN that commonly is observed around calving. Key Words: Mastitis, Vitamin E, Selenium J. Anim. Sci. 1997. 75:1659–1665 Introduction Vitamin E and selenium are essential micronutrients that share a common biological role as antioxidants (Bendich, 1990; Hogan et al., 1993a,1996b). Both nutrients as well as b -carotene, vitamin C, zinc, and copper function to maintain low tissue concentrations of reactive oxygen species ( ROS ) and lipid hydroperoxides (Bettger et al., 1979; Diplock, 1981; Chew, 1987, 1993; Putnam and Com- ben, 1987; Harris, 1992).
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Paper-Lecture51 - Dietary vitamin E and selenium affect...

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