苎麻青贮替代苜蓿干草对奶牛生产性能、乳成分及血清指标的影响

本试验旨在研究苎麻青贮替代饲粮中苜蓿干草对奶牛生产性能、乳成分及血清指标的影响。选用24头体重、胎次、产奶量接近的健康荷斯坦奶牛,随机分为4组,每组6头,各组以苎麻青贮分别等量替代基础饲粮中0(对照组)、33%(试验1组)、67%(试验2组)和100%的苜蓿干草(试验3组)。预试期14 d,正试期60 d。结果表明:1)苎麻青贮中的粗蛋白质、粗脂肪、粗纤维以及粗灰分的含量均高于苜蓿干草。2)苎麻青贮替代苜蓿干草对奶牛干物质采食量、产奶量及乳成分含量均无显著影响(P0.05)。3)苎麻青贮替代苜蓿干草对血清中总蛋白、白蛋白、葡萄糖、甘油三酯、谷胱甘肽过氧化物酶含量及谷草转氨酶、谷丙转氨酶活性均无显著影响(P0.05)。4)试验3组的血清尿素氮含量显著高于试验1组和试验2组(P0.05),与对照组之间无显著差异(P0.05)。5)对照组和试验1组血清总胆固醇含量显著高于试验2组(P0.05),试验2组与试验3组之间无显著差异(P0.05)。6)随着苎麻青贮添加比例的增加,血清总抗氧化能力和超氧化物歧化酶含量逐渐升高,试验3组显著高于对照组(P0.05)。综合得出,苎麻青贮可以替代奶牛饲粮中苜蓿干草,而不影响生产性能、乳成分及血清指标,适宜的替代比例为33%~67%。

Effects of Replacing Different Partial Alfalfa Hay with Ramie Silage on Performance,Milk Composition and Serum Parameters of Dairy Cows

This experiment was conducted to study the effects of replacing alfalfa hay with ramie silage in diet on performance, milk composition and serum parameters of dairy cows. Twenty?four healthy Holstein cows with similar body weight, parity and milk yield were randomly divided into four groups with 6 cows per group. Different proportions [0 (control group), 33% (trial group 1), 67% (trial group 2) and 100% (trial group 3) ] of alfalfa hay in diet were replaced with equivalent ramie silage. The pretrial lasted for 14 d, and the trial lasted for 60 d. The results showed as follows:1) the contents of crude protein, ether extract, crude fiber and crude ash were higher in ramie silage than alfalfa hay. 2) Dry matter intake, milk yield and milk composition contents were not significantly affected by replacing of alfalfa hay with ramie silage ( P>0.05) . 3) Serum total protein, albumin, glucose, triglyceride and glutathione peroxidase contents, and aspartate aminotransferase and alanine transarninase activities were not significantly affected by replacing of alfalfa hay with ramie silage ( P>0.05) . 4) Serum urinary nitrogen content of trial group 3 was significantly higher than that of trial groups 1 and 2 ( P<0.05) , but no significant difference with control group was found ( P>0.05) . 5) Serum total cho?lesterol content of control group and trial group 1 was significantly higher than that of trial group 2 ( P<0.05) , and there was no significant difference between trial groups 2 and 3 ( P>0.05) . 6) With the increase of ramie silage proportion, serum total antioxidant capacity and superoxide dismutase content were increased, and trial group 3 was significantly higher than control group ( P<0.05) . Therefore, alfalfa hay can be replaced with si?lage ramie in diary diet without effects on performance, milk composition and serum parameters, and the opti?mum proportion was 33% to 67% under this experimental conditions.