McAdam P A, O'Dell G D
J Dairy Sci. 1982 Jul;65(7):1219-26. doi: 10.3168/jds.S0022-0302(82)82333-3.
Each of 20 Holstein cows was assigned randomly to a salt treatment upon calving. The experimental design was a 2 x 2 factorial having age (young versus mature) and salt treatment (plain versus mineralized) as factors. Salt was fed ad libitum. All animals were maintained on a balanced ration of corn silage fed ad libitum and concentrate fed in the barn in a ratio of .45 kg concentrate per 1.36 kg actual milk production. Concentrations in blood plasma of calcium, magnesium, sodium, potassium, cobalt, bicarbonate, chloride, phosphorus, total serum protein, sulfur, and fluoride were monitored throughout lactation and gestation. Statistical evaluation of weekly means for each treatment group for each element by analysis of variance showed when concentrations were different. Concentrations of calcium and magnesium were higher in younger animals than in mature animals during much of the lactation cycle. Magnesium concentration was higher in cows fed trace-mineralized salt. Concentration of phosphorus was higher in younger animals throughout the lactation cycle. Total serum protein was higher in mature cows throughout lactation, and concentrations of sulfur and fluoride were higher in mature cows through much of the cycle.
20头荷斯坦奶牛在产犊时被随机分配到一种盐处理组。实验设计为2×2析因试验，以年龄（年轻与成熟）和盐处理（普通盐与矿化盐）作为因素。盐采用自由采食。所有动物均维持自由采食玉米青贮和在牛舍以每1.36千克实际产奶量饲喂0.45千克精料的平衡日粮。在整个泌乳期和妊娠期监测血浆中钙、镁、钠、钾、钴、碳酸氢根、氯、磷、总血清蛋白、硫和氟的浓度。通过方差分析对每个处理组每种元素的每周均值进行统计评估，以显示浓度何时存在差异。在泌乳周期的大部分时间里，年轻动物的钙和镁浓度高于成熟动物。饲喂微量矿化盐的奶牛镁浓度较高。在整个泌乳周期中，年轻动物的磷浓度较高。在整个泌乳期，成熟奶牛的总血清蛋白较高，并且在周期的大部分时间里，成熟奶牛的硫和氟浓度较高。
