TMR日粮不同苜蓿干草长度对奶牛生产性能的影响

探讨TMR日粮中不同长度的苜蓿干草对奶牛产奶量及其乳成分的影响。本试验选用产奶量、泌乳天数、膘情和胎次相近的健康荷斯坦泌乳奶牛40头,随机分为两组,即试验1组20头,饲喂苜蓿干草长度为2.52cm的TMR日粮,试验2组20头,饲喂苜蓿干草长度为6.46cm的TMR日粮。试验分两期完成,Ⅰ期日粮鲜重的精粗比例为20：80,Ⅱ期日粮鲜重的精粗比例为30：70。采用双因子重复方差试验设计。结果表明：在Ⅰ期和Ⅱ期两期试验中,不同长度苜蓿干草TMR日粮对奶牛的产奶量均无显著影响（P〉0.05）,但对奶牛的干物质采食量有显著影响（P〈0.05）,试验1组比试验2组奶牛的干物质采食量在Ⅰ期和Ⅱ期试验中分别显著地提高了18.36%、7.40%。在Ⅰ期试验中,试验2组乳蛋白极显著高于试验1组（P〈0.01）,较试验1组提高了11.82%;在Ⅱ期试验中,试验1组乳脂率显著高于试验2组（P〈0.05）,较试验2组提高了8.89%。

Effect of Different Length of Alfalfa Hay in TMR on Performance of Dairy Cows

The objective of the study was to analysis the effect of different length of alfalfa hay in TMR on milk yield and milk composition of dairy cows.40 healthy Holstein cows which have the similar milk yield,days in milk,fatness and parity,were selected and divided into two groups randomly,20 cows in each group.The cows in Group 1 were fed with the length of 2.52cm alfalfa hay in TMR,Goup 2 was 6.46cm.This experiment included two periods（P1,P2）,P1 concentrate to forage ratio of diets 20：80,P2 of 30：70 concentrate to forage diet.Two-ways repeated ANOVA test design was used for statistics.There was no significant difference on milk yield between G1 and G2 in two periods（P0.05）,but dry matter intake of cows was different significantly（P0.05）.G1 increased 18.36%and 7.40%respectively compared with G2 on dry matter intake of cows in two experiment periods（P0.05）.As for milk protein,G2 was higher than G1（P0.01）,increasing 11.82%compared with G1 in the first period.As for milk fat,G1 was higher than G2（P0.05）,increasing 8.89%compared with G2 in the second period.