Magnesium absorption by lactating dairy cows on a grass silage-based diet supplied with different potassium and magnesium levels

被引:17
|
作者
Holtenius, K. [1 ]
Kronqvist, C. [1 ]
Briland, E. [1 ]
Sporndly, R. [1 ]
机构
[1] Swedish Univ Agr Sci, Dept Anim Nutr & Management, SE-75323 Uppsala, Sweden
关键词
magnesium; potassium; absorption; dairy cow; EXCRETION; BICARBONATE; MINERALS; SITE;
D O I
10.3168/jds.2007-0309
中图分类号
S8 [畜牧、 动物医学、狩猎、蚕、蜂];
学科分类号
0905 ;
摘要
The objective of the present study was to investigate the interactions of dietary K intake typical for forage-based diets on Mg balance in lactating dairy cows. Six lactating multiparous cows of the Swedish Red and White breed in midlactation were used. Two concentrations of Mg (1.9 and 4.3 g/kg of dry matter) and 3 concentrations of K (19, 28, and 37 g of K/kg of dry matter) were obtained by adding appropriate amounts of MgO and KHCO3 to the diet. The experimental setup was a 6 x 6 Latin square design with a 2 x 3 factorial arrangement of treatments. Each experimental period lasted 14 d (9-d treatment adaptation period and 5-d data collection). There was no effect of Mg or K dietary supplementation on milk yield. Supplementing the ration with K did not significantly affect the Mg apparent absorption, urinary Mg excretion, or plasma Mg concentration. The Mg balance, estimated as the Mg losses in milk and urine, was positively related to Mg intake but not affected by K intake. The amount of apparently digested Mg was related to the Mg balance. The apparent digestibility ranged from 0.12 to 0.24 with no effect of mineral supplementation. There was a significant curvilinear relationship between plasma Mg and urinary Mg excretion, with a more marked increase in urinary Mg excretion at higher plasma levels of Mg.
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页码:743 / 748
页数:6
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