Ársrit Ræktunarfélags Norðurlands - 01.01.1972, Side 43

HEIMILDIR
Agricultural Research Council. 1965. The Requirenients of Farm Livestock,
No. 2 Ruminants. Technical Reviews and Summeries. Agricultural Research
Council, London, bls. 67 og 73.
Crampton, E. W. og Lloyd. 1959. Nutrition of Farm Animals. W. H. Free-
man Co., San Francisco, bls. 237. (Tilvitnun úr Thompson, 1972).
Devlin, T. ]., W. K. Roberts og V. V. E. St. Omer. 1969.Effects of dietary
potassium upou growth, serum electrolytes and intraruminal environment of
finishing beef steers. J. Animal Sci., 28 : 557.
Langley, L. L. 1965. Outline of Physiology, önnur útgáfa. McGraw-Hill
Book Company, bls. 399.
Óskarsson, Magnús. 1965. Jarðræktarfræði, I. kafli. Áburðarfræði. Bænda-
skólinn á Hvanneyri, bls. 52.
Paquay, R., F. Lomba, A. Lousse og V. Bienfet. 1969. Statistical research on
the fate of dietary mineral elements in dry and lactating cows. V. Potassium.
J. Agric. Sci., Camb. 73 : 445.
Pradhan, K. og R. W. Hemken. 1968. Potassium depletion in lactating
dairy cows. J. Dairy Sci. 51 : 1377.
Roberts, W. K., og V. V. E. St. Omer. 1965. Dietary potassium requirement
of fattening steers (abstract). J. Animal Sci. 24 : 902. (Tilvitnun úr Thompson,
1972).
Sasser, L. B., G. M. Ward og J. E. Johnson. 1966. Variations in potassium
concentration of cow’s milk. J. Dairy Sci. 49 : 893.
Scott. M. L. 1968. Role of potassium in animal nutrition. Poultry and
Livestock Comment (Du Pont) 24 : 4.
Telle, P. P., R. L. Prestin, L. D. Kintner og W. H. Pfander. 1964. Defin-
ition of ovine potassium requriement. J. Animal Sci. 23 : 59, 1964.
Thompson, D. J. 1972. Potassium in Animal Nutrition. International Min-
erals & Chemical Corporation, Libertyville, Illinois, USA.
West, E. S., W. R. Todd, H. S. Mason og J. T. Van Bruggen. 1966. Text-
book of Biochemistry. Fjórða útgáfa. The Macmillan Company, New York,
bls. 703-727.
SUMMARY
The title of this paper is „The feeding of dairy cows with respect to
milk yield and potassium content of Icelandic hays“.
High yielding cows in northern Iceland have been cured o£ certain
symptoms, which have been concurrent with hay of low potassium con-
tent, by supplementing their diet with potassium. This led to a de-
tailed investigation by Northern Laboratories during the winter of
1971—’72, on the effects of feeding newly calved cows on hay contain-
ing varying amounts of potassium.
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