This study was conducted to investigate effects of replacing corn silage with wheat hay and wheat silage on dry matter intake(DMI),milk performance and digestibility of lactating Holstein dairy cows in the middle and late lactation period. 36 healthy Holstein dairy cows in the middle and late lactation period with similar body weight,parity,days in milk and milk production were selected and randomly assigned to three treatments:(1)Control group(n=12);(2)wheat hay group(n=12);(3)wheat silage group(n=12). Each cow was kept in a single barn. The control group,wheat hay group and wheat silage group was fed with total mixed ratio with corn silage,12% wheat hay and 20% wheat silage,respectively. The experiment lasted for 70 day. The first 14 days were pre-fed period and the remaining 56 days were experimental days. The results showed that DMI in wheat hay group was significantly higher than those in control group and wheat silage group(P<0.05). DMI of the control group and wheat silage group had no significant difference(P>0.05). Digestible DMI among three groups was not significantly different(P > 0.05). The wheat hay group had significantly lower digestibility of DM, CP and CF than those in control group and wheat silage group(P<0.05). Nutrients digestibility between control group and wheat silage group was not significantly different(P>0.05). Daily mean milk yield in three groups decreased gradually with the milking days increasing. Daily mean milk yield of the control group was the highest [(16.84±4.92)kg/d],wheat silage group was median [(16.60±4.68)kg/d],wheat hay group the lowest [(16.37±3.66)kg/d)](P > 0.05). The protein content and lactose content in control group was higher than those in wheat hay group and wheat silage group with the milking days increasing(P>0.05). The wheat hay group had significantly higher milk fat content than the control group and wheat silage group(P<0.05). Milk fat content between wheat hay group and control group was not significantly different(P>0.05). In conclusion,replacing corn silage with wheat hay and wheat silage in TMR had no significant influence on intake, milk production and digestibility. Therefore,wheat hay and wheat silage could be used as the feed source for dairy cows.%本试验旨在研究小麦秸秆和小麦青贮替代部分全株玉米青贮对泌乳中后期荷斯坦奶牛采食量、产奶性能和消化率的影响.选取体重、胎次、泌乳期和产奶量相近的36头健康荷斯坦泌乳中后期奶牛,将其随机分为3组(对照组、小麦秸秆组和小麦青贮组),每组12个重复,每个重复1头牛,隔栏单独饲养.对照组饲喂全株玉米青贮的TMR饲粮,小麦秸秆组饲喂含有12%小麦秸秆的TMR饲粮,小麦青贮组饲喂含有20%小麦青贮的TMR饲粮,试验期共70 d,其中预饲期14 d,正式期56 d.结果表明,小麦秸秆组奶牛的干物质采食量(Dry matter intake,DMI)显著高于对照组和小麦青贮组(P<0.05),对照组和小麦青贮组奶牛的DMI无显著差异(P>0.05).3组奶牛的可消化干物质采食量之间无显著差异(P>0.05).小麦秸秆组奶牛的干物质(DM)、粗蛋白质(CP)、粗脂肪(CF)的消化率显著低于对照组和小麦青贮组奶牛(P<0.05),对照组和小麦青贮组奶牛之间的营养物质消化率差异不显著(P>0.05).随着泌乳时间的延长,3组奶牛的日均产奶量逐渐降低.对照组奶牛的日均产奶量最高,为(16.84±4.92)kg/d;小麦青贮组奶牛的日均产奶量为(16.60±4.68)kg/d;小麦秸秆组奶牛的日均产奶量最低,为(16.37±3.66)kg/d,但3组奶牛的日均产奶量差异不显著(P>0.05).随着泌乳天数的增加,对照组奶牛乳蛋白率、乳糖率高于小麦秸秆组奶牛和小麦青贮组奶牛,但差异不显著(P>0.05).小麦秸秆组奶牛的乳脂率显著高于对照组和小麦青贮组(P<0.05),小麦青贮组奶牛的乳脂率与对照组奶牛无显著差异(P>0.05).因此,在本试验条件下,使用小麦秸秆和小麦青贮替代部分全株玉米青贮对泌乳中后期荷斯坦奶牛无显著影响,生产中可以利用小麦秸秆和小麦青贮替代部分全株玉米青贮作为奶牛饲料来源.
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