食土奶牛和健康奶牛行为与饲粮、粪便、土壤和血液中矿物元素含量关系的比对研究

Comparative study on behaviors of soil-feeding dairy cows and healthy dairy cows and mineral elements content in diet, feces, soil and blood

试验旨在研究奶牛食土原因与饲粮、粪便、土壤和血液中矿物元素的关系。通过对食土奶牛进行观察和分组,按照产奶量、泌乳天数等条件分组,食土奶牛为试验组,正常奶牛为对照组,每组6头奶牛。采集饲粮、粪便及土壤样品,测定样本中微量元素(Fe、Zn、Mn、Cu)、常量元素(K、Ca、Mg、P)和粗蛋白质(CP)的含量。结果表明:1)饲粮中P、Zn、Mn、Cu的含量能满足奶牛营养需要量,其中Zn、Cu显著高于营养需要量(P<0.05);Mg和CP显著低于奶牛营养需要量(P<0.05),K、Ca、Fe极显著低于奶牛营养需要量(P<0.01)。2)食土组土壤样品中K、Mg、Mn含量均低于对照组,差异不显著(P>0.05),Ca、Fe、Zn、Cu、P含量均高于对照组,差异不显著(P>0.05)。3)食土组奶牛粪便中各元素含量均高于对照组;其中K、Ca、Mg显著高于对照组(P<0.05)。4)血液中K、Fe、Zn、Cu元素含量均高于对照组;其中K和Fe显著高于对照组(P<0.05)。结论:奶牛饲粮中K、Ca、Mg、Fe和CP不能满足奶牛的营养需要量时可能会导致奶牛食土。

This experiment was to determine the relationship between soil eating of cows, and mineral elements in their feed, feces, and blood and in soil. By observing and based on the milk yield and lactating time, soil eating cows were identified and had them form an experimental group(n=6), and the same number of healthy cows were used to form a control group. Then, samples were collected form the feeds, feces, blood of the cows and from related soil to test the contents of the trace elements of Fe、Zn、Mn and Cu, and the contents of the macroelements of K, Ca, Mg, total phosphorus(P) and crude protein. The results were as follows: 1) The contents of P, Zn, Mn and Cu in the diet met the nutritional requirements of dairy cows, and Zn and Cu were significantly higher than the nutritional requirement(P<0.05);Mg and CP were significantly lower than the nutritional requirements of dairy cows(P<0.05), and K, Ca and Fe were significantly lower than required(P<0.01). 2) The contents of K, Mg and Mn in the related soil samples of the control group were higher than those in the re lated soil of the experimental group,but the difference was not significant( P>0. 05). The contents of Ca,Fe,Zn,Cu and P in the soil samples of the control group were lower than those in the soil of the experimental group,and the difference was not significant,either( P>0. 05).3) The contents of all the above-mentioned elements in the feces of the dairy cows in the experimental group were higher than those in the feces of the control group;and K,Ca and Mg in the feces of the experimental cows were significantly higher( P<0. 05). 4) The contents of K,Fe,Zn and Cu in the blood of the experimental group were higher than in those of the control group;and K and Fe were significantly higher( P<0. 05). In conclusion,when K,Ca,Mg,Fe and crude protein in the diet of dairy cows could not meet their nutritional requirement the animals would have to feed on soil which contain those elments.