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Vitamin E and Linolenic Acid Content of Hay as Related to Different Drying Conditions1

  • B. Thafvelin
    Affiliations
    National Veterinary Institute, Stockholm, Sweden, and Department of Medicine, College of Veterinary Medicine, Helsinki, Finland
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  • H.E. Oksanen
    Affiliations
    National Veterinary Institute, Stockholm, Sweden, and Department of Medicine, College of Veterinary Medicine, Helsinki, Finland
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  • Author Footnotes
    1 This investigation was made possible by grants from Jordbrukets forskningsråd. The α-tocopherol assays were carried out by B. Cederquist of AB Ewos, Södertälje.
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      Abstract

      During the harvesting season of 1964 the contents of vitamin E and linolenic acid were determined in three different grass species, viz., timothy grass, red clover, and tufted hair grass. The influence on the two components in timothy grass of stage of development, harvesting methods, and climatic factors was studied.
      In timothy grass having reached the flowrering stage the tocopherol content was 108 µg/gram and the linolenic acid content of its fat 49.1%, as compared to 52 µg/gram and 21.8%, respectively, in a late stage of development.
      The losses of vitamin E in timothy grass hay, dried on hay poles, were remarkable even under favorable weather conditions, whereas the fatty acid composition of the fat remained largely unchanged. In cocked hay a decrease in vitamin E content could be demonstrated as early as within ten days, in spite of favorable drying conditions; whereas, the linolenic acid content did not decrease until later, following a change towards rainy weather. In hay, dried as a swath, there was a rapid decrease in both vitamin E and linolenic acid content even under favorable weather conditions. The rate of vitamin E destruction was greatest (nearly 60% within four days) in hay, dried in a swath and artificially moistened.
      The investigations also included studies on changes in iodine value and degree of oxidation of the hay fat as related to different methods for haymaking.

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