摘要
36头 2～ 4胎的荷斯坦奶牛随机分为 3组 ,各组产奶量、体重、胎次、泌乳天数 (DIM)差异不显著。 3组奶牛日粮中苜蓿干草的添加量分别为 3kg(对照 )、6kg和 9kg,相应的日粮干物质 (DM)中粗蛋白含量分别为 16 .4 %、17.9%和 19.4 % ,组间中性洗涤纤维 (NDF)和产奶净能 (NEL)含量相同 ,分别为 37.8%和 6 .7MJ·kg-1DM。结果表明 ,在以苜蓿干草为主的奶牛日粮中提高粗蛋白含量能极显著提高产奶量 (P <0 .0 1) ,干物质采食量 (DMI)显著增加 (P <0 .0 5 ) ,乳脂率、乳蛋白率、乳糖以及干物质含量没有变化 ,乳脂量显著增加 (P <0 .0 5 ) ,乳蛋白量极显著增加(P <0 .0 1) ,体细胞数 (SCC)显著下降 (P <0 .0 5 )。在日粮NDF相同的条件下用苜蓿干草替代玉米青贮 ,不会降低乳脂率。在奶牛日粮中大量使用苜蓿干草并不增加日粮成本 ,可以大幅度提高经济效益 ,9kg组与对照相比纯增效益最高。苜蓿干草在高产奶牛日粮中的适宜添加量为 9kg。
36 multiparous, lactating Holstein cows were assigned to 3 groups according to milk yield(35.5± 5.2 kg), body weight(550±30 kg), parity(2.9±0.8) and days in milk(DIM)(70±18 d) with a randomized design. No difference was existed among groups. Three diets were formulated to contain the same neutral detergent fiber(NDF)( 37.8 %DM) and net energy for lactation(NE_L) concentration(6.7 MJ·kg -1 DM). The amount of alfalfa hay addition in these diets was 3(control),6, 9 kg respectively, corresponding crude protein(CP) concentration was 16.4%, 17.9%, 19.4%. The results were as follows: As the increment of CP in alfalfa based diet, milk yield and milk protein yield were linearly increased( P <0.01); the average milk yield during test period was 29.06, 31.35 and 33.55 kg respectively; Dry matter intake(DMI) and milk fat yield were also significantly increased( P <0.05); Somatic cell count(SCC) was linearly decreased( P <0.05); No change was found in milk fat percentage, milk protein percentage, lactose and milk solid. Under the same NDF concentration in all three diets, milk fat percentage did not decrease when corn silage was replaced by alfalfa hay. Diet cost did not increase when high proportion alfalfa hay was used. Compared with control using 9 kg alfalfa hay in diet could achieve the greatest profit. So, the optimal amount of alfalfa hay addition in the diet of high producing dairy cow was 9 kg.
出处
《中国农业科学》
CAS
CSCD
北大核心
2003年第8期950-954,共5页
Scientia Agricultura Sinica
基金
农业部"948"重大资助项目 (2 0 2 0 99)
