【目的】试验旨在研究叶酸、B₁₂(钴胺素)、B族维生素混合物(简称BV混合物)及其与过瘤胃赖氨酸、过瘤胃蛋氨酸联用对奶牛采食行为、血细胞参数指标的影响。【方法】选取日均产奶量(44.1±5.9)kg/d和泌乳日龄(60±38)d相近的50头荷斯坦奶牛，随机分为五组：Ⅰ组(空白对照组)、Ⅱ组(叶酸100 mg/头/d)、Ⅲ组(B₁₂175 mg/头/d)、Ⅳ组[(BV混合物：硫胺素150 mg+核黄素150 mg+烟酸3 000 mg+泛酸475 mg+吡哆素120 mg+生物素20 mg+叶酸100 mg+B₁₂175 mg)/头/d]和Ⅴ组[BV混合物+过瘤胃赖氨酸20 g+过瘤胃蛋氨酸10 g)/头/d]。通过T检验，各组间产奶量无显著差异(P>0.05)。【结果】结果表明，与对照组相比，各组间饮水、反刍、行走及静卧行为未见异常，Ⅴ组采食量明显提高；Ⅱ、Ⅲ、Ⅳ、Ⅴ组的白细胞、单核细胞数量无显著差异，但在数值上均有提高(P>0.05)；Ⅱ、Ⅳ、Ⅴ组淋巴细胞、中性粒细胞、血小板数量无显著差异，但在数值上均有提高，淋巴细胞分别提高14.63%、12.86%、16.72%，中性粒细胞分别提高19.85%、16.85%、10.67%，血小板分别提高2.96%、8.11%、5.21%(P>0.05)；Ⅱ组红细胞数量无显著差异(P>0.05)，但在数值上提高0.15%；Ⅱ组较Ⅲ组血红蛋白浓度显著提升21.74%，差异显著(P<0.05)，其余各组间均无显著差异(P>0.05)。【结论】综上所述，在本试验条件下，饲喂叶酸、B₁₂、BV混合物、BV混合物+过瘤胃赖氨酸+过瘤胃蛋氨酸，奶牛采食行为未见异常，且均对奶牛血细胞参数指标有不同程度的积极影响。

【Objective】The experiment was conducted to investigate the effects of folic acid,vitamin B₁₂(cobalamin),B vitamin complex,and their combination with lysine and methionine on feeding behavior and blood cell parameter of dairy cows.【Methods】Fifty Holstein dairy cows with similar daily milk production(44.1±5.9)kg/d and lactation days(60±38)d were randomly divided into five groups: Group I(blank control group),Group II(folic acid 100 mg/cow/day),Group III(vitamin B₁₂175 mg/cow/day),Group IV [(thiamine 150 mg+riboflavin 150 mg+niacin 3 000 mg+pantothenic acid 475 mg+pyridoxine 120 mg+biotin 20mg+folic acid 100 mg+cyanocobalamin 175 mg)/cow/day] and Group V [(thiamine 150 mg+riboflavin 150 mg+niacin 3 000 mg+pantothenic acid 475 mg+pyridoxine 120 mg+biotin 20 mg+folic acid 100 mg+cyanocobalamin 175 mg+rumen escape lysine 20 g+rumen escape methionine 10 g)/cow/day].The T-test results showed no significant difference in milk production among the groups(P>0.05). 【Results】The results showed that: compared with the control group,there were no abnormalities in drinking,ruminating,walking,and resting behaviors among the groups,but the feed intake of dairy cows in Group V increased obviously;there were no significant differences in the number of white blood cells and monocytes in Groups II,III,IV,and V,but the numerical values had enhanced(P>0.05); there were no significant differences in the number of lymphocytes,neutrophils and platelets in Groups II,IV and V,but the numerical values had also enhanced,specifically,lymphocytes increased by 14.63%,12.86% and 16.72% respectively,neutrophils increased by 19.85%,16.85% and 10.67% respectively,and platelets increased by2.96%,8.11% and 5.21% respectively(P>0.05); there were no significant differences in the number of red blood cells in Groups II,but the numerical value increased by 0.15%(P>0.05); the hemoglobin concentration in Group II was significantly higher than that in Group III,with an increase of 21.74%(P<0.05),while there were no significant differences among the other groups(P>0.05).【Conclusion】In conclusion,under the conditions of this experiment,the dairy cows in treatment groups fed with folic acid,vitamin B₁₂,B vitamin complex,and their combination with rumen escape lysine and rumen escape methionine,showed no abnormalities on feeding behavior,and the various treatments all had positive effects on blood cell parameters of dairy cows to some extent.