不同钼铜水平下肉牛铜需要量的研究

A STUDY ON REQUIREMENT AND MONITORING OF COPPER STATUS UNDER DIFFERENT FEEDING LEVEL OF MOLYBDENUM AND COPPER IN BEEF CATTLE

选择年龄、体重相近,健康利木赞×鲁西黄牛杂交一代公牛4头,在不同钼铜水平下,研究肉牛血液铜的代谢规律和铜需要量。试验分低钼(基础日粮钼含量0.27mg/kg)和高钼(基础日粮+钼5 mg/kg)两个水平进行。研究结果表明:低钼水平下,日粮干物质中添加铜10、25和50mg/kg,血液铜水平在0.97～1.18mg/kg之间,各水平间无差异,证明日粮中添加10mg/kg铜即可满足肉牛的需要。高钼水平下,血液铜含量随着铜添加量的增加而变化较大,加10mg/kg铜时血液铜水平在0.8mg/kg以下,不能满足牛的需要;添加铜25和50mg/kg时,血液铜水平上升到1.0mg/kg左右,并能满足牛对铜的需要,而添加25和50mg/kg血液铜无差异,证明高钼时添加25mg/kg才能满足肉牛铜的需要量。本研究还证明,肉牛铜营养状况可用以下回归公式预测:低钼:Y=24.33X4.39(R=0.991,n=3);高钼:Y=61.84X2.58(R=0.923,n=3)。式中:Y-日粮铜水平;X-血液铜水平。

Selecting four bulls with similar age and weight, blood copper metabolism and copper requirement of beef cattle under different feeding level of molybdenum and copper were studied. The test included two periods, ie. lower dietary Mo level(the 0.27mg/ kg·DM of Mo concentration) and higher dietary Mo level (the 5.27mg/kg·DM of Mo concentration ) periods. The results were as follows: in the period of lower Mo, the blood copper content was 0.97- 1.18mg/kg and there was no significant among the different added Cu levels. In lower Mo diet copper added level of 10mg/kg could meet the needs of the cattle. In higher Mo period, blood copper content varied with the increase of copper added level. When the added copper level was 10mg/kg,the blood copper content was below 0. 8mg/kg, which indicated 10 mg/ kg level couldn' t meet the needs of copper of the cattle. When 25mg/ kg and 50mg/ kg were added, the blood copper content was about 1.0mg/ kg, which indicated in higher Mo diet the two added Cu levels could meet the needs of the cattle. The blood copper contents beween the two added Cu levels were no significantly different. The optimum Cu addition level was 25mg/ kg under higher Mo level. A regression equations for estimating dietary Cu level were established as follows: Under lower Mo level : Y=24.33X4.39(R = 0.991,n=3) ; Under higher Mo level : Y = 61. 84X2. 58(R = 0. 923 , n = 3). where: Y- Copper level in diet;X-Blood copper content.