本文旨在研究硒和维生素E对奶牛生产性能及血液生化指标的影响。选用产后天数为60~100 d的荷斯坦奶牛54头,参照泌乳量和胎次按单位区组法分为9组,每组6头,试验分2期进行,每期分为8个试验组和1个校正组,2期的校正组固定。采用4×4双因素设计添加硒和维生素E,硒的4个添加水平分别是0、0.1、0.2和0.3 mg/kg,维生素E的4个添加水平分别是0、30、60和90 IU/kg,共形成16组饲粮,分别以0/0、0.1/0、……、0.2/90、0.3/90组表示。每期预试期7 d,正试期14 d。测定奶牛生产性能及血液生化指标的变化。结果表明:1)0.3/0、0.2/30、0.3/30、0.1/60、0.2/60、0.3/60和0.1/90组的泌乳量显著高于其余组(P<0.05);0/0组的乳脂率极显著低于0.3/30、0/60和0.3/60组(P<0.01),显著低于其余组(P<0.05);0.3/60、0/90和0.2/90组的乳总固形物率显著低于其余组(P<0.05);0.3/30、0.3/60、0.1/90、0.2/90和0.3/90组的乳中体细胞数显著低于0/0、0.1/0、0/30和0/60组(P<0.05)。2)硒和维生素E对血清白蛋白和促乳素浓度的影响不显著(P>0.05);0.3/0和0.3/30组的总蛋白和尿素氮浓度显著或极显著低于其余组(P<0.05或P<0.01);0.3/30和0.3/60组的胰岛素和胰高血糖素浓度极显著高于0/0组(P<0.01);0.3/0、0/30、0.3/30、0/60、0.1/60、0.2/60、0.3/60和0/90组的甲状腺素浓度极显著低于0/0组(P<0.01),显著低于其余组(P<0.05);0.3/30和0.3/60组的三碘甲腺原氨酸极显著高于其余组(P<0.01)。3)饲粮添加0~0.3 mg/kg硒和0~30 IU/kg维生素E的各组及0/60组的血清谷草转氨酶活性显著低于其余组(P<0.05);0.3/60组血清谷丙转氨酶的活性以及0.3/30和0.3/60组血清谷胱甘肽过氧化物酶的活性均极显著高于0/0、0.1/0、0/30、0/60、0/90和0.3/90组(P<0.01)。综上所述,奶牛饲粮中硒和维生素E的适宜添加水平分别为0.3 mg/kg和30~60 IU/kg。

This study was conducted to investigate the effects of selenium (Se) and vitamin E on performance and blood biochemical indices of dairy cows. Fifty-four Holstein dairy cows (60 to 100 days after calving) were selected and assigned to nine groups by unit block method based on milk yield and parity with 6 cows in each group. There were 2 stages with 8 experimental groups and 1 calibration group per stage, and the calibration group was fixed. Se and vitamin E were added according to a 4×4 two-factor design. Supplemental levels of Se were 0, 0.1, 0.2 and 0.3 mg/kg, and those of vitamin E were 0, 30, 60 and 90 IU/kg, respectively. There was 16 diets in all, and they were represented in 0/0, 0.1/0, ……, 0.2/90 and 0.3/90 groups, respectively. The pre-experimental and experimental periods lasted for 7 and 14 days, respectively. The performance and physiological biochemical indices of dairy cows were determined. The results showed as follows: 1) the milk yield in 0.3/0, 0.2/30, 0.3/30, 0.1/60, 0.2/60, 0.3/60 and 0.1/90 groups was significantly higher than that in the other groups (P<0.05); the milk fat percentage in 0/0 group was extremely significantly lower than that in 0.3/30, 0/60 and 0.3/60 groups (P<0.01), and significantly lower than that in the other groups (P<0.05); the milk total solid in 0.3/60, 0/90 and 0.2/90 groups was significantly lower than that in the other groups (P<0.05); the somatic cell count in milk in 0.3/30, 0.3/60, 0.1/90, 0.2/90 and 0.3/90 groups was significantly lower than that in 0/0, 0.1/0, 0/30 and 0/60 groups (P<0.05). 2) The serum total protein and urea nitrogen concentrations in 0.3/0 and 0.3/30 groups were significantly lower than those in the other groups (P<0.05 or P<0.01); the serum insulin and glucagon concentrations in 0.3/30 and 0.3/60 groups were extremely significantly higher than those in 0/0 group (P<0.01); the thyroxin concentration in 0.3/0, 0/30, 0.3/30, 0/60, 0.1/60, 0.2/60, 0.3/60 and 0/90 groups was extremely significantly lower than that in 0/0 group (P<0.01), and significantly lower than that in the other groups (P<0.05); the triidiothyronin concentration in 0.3/30 and 0.3/60 groups was extremely significantly higher than that in the other groups (P<0.01). 3) The serum glutamic oxalacetic transaminase activity in the groups supplemented with 0 to 0.3 mg Se and 0 to 30 IU kg vitamin E and 0/60 group was significantly lower than that in the other groups (P<0.05); the serum activities of glutamic-pyruvic transaminase in 0.3/60 group and glutathione peroxidase in 0.3/30 and 0.3/60 groups were extremely significantly lower than those in 0/0, 0.1/0, 0/30, 0/60, 0/90 and 0.3/90 groups (P<0.01). In conclusion, the optimal levels of Se and vitamin E are 0.3 mg and 30 to 60 IU/kg, respectively.