补饲全脂膨化大豆对奶牛生产性能和消化代谢的影响

Effects of Supplemental Full-Fat Extruded Soybean on Performance and Digestion Metabolism in Early Lactation Dairy Cows

本研究旨在探究泌乳早期奶牛补饲不同水平的全脂膨化大豆(ESB)对瘤胃发酵、消化代谢、血液指标以及生产性能的影响,并以此判断ESB对缓解泌乳早期奶牛能量负平衡的应用效果。本试验选择4头体重、体况评分和泌乳日龄相近,并装有永久性瘤胃瘘管的泌乳早期健康荷斯坦奶牛,采用4×4拉丁方设计,分别补饲不同水平的ESB[0(对照)、1.0、2.0、3.0 kg/d]。结果表明:随着ESB补饲水平的增加,泌乳早期奶牛产奶量(P=0.070)和能量校正乳产量(P=0.068)有增加的趋势,乳脂率有降低的趋势(P=0.081),而非脂固形物(SNF)和乳尿素氮含量及乳蛋白、乳糖和SNF产量以及脂蛋比显著增加(P<0.05);瘤胃pH有下降的趋势(P=0.062),且当ESB补饲水平为2.0和3.0 kg/d时,pH低于6.2,氨态氮(NH 3-N)、丙酸、戊酸和异戊酸含量显著升高(P<0.05);当ESB补饲水平为2.0 kg/d时,乙酸/丙酸显著低于对照组(P<0.05);粗蛋白质和粗脂肪表观消化率显著提高(P<0.05),干物质表观消化率有增加的趋势(P=0.061);粪尿氮总排泄量、尿氮占总摄入氮的比例以及氮沉积显著增加(P<0.05),而粪氮占总摄入氮的比例显著下降(P<0.05),尿素氮占总尿氮的比例有下降的趋势(P=0.063);血浆尿素氮含量显著增加(P<0.05);当ESB补饲水平为2.0 kg/d时,血浆总胆红素含量有下降的趋势(P=0.072)。综合考虑,本试验条件下,泌乳早期奶牛补饲ESB的最佳推荐水平为1.0~2.0 kg/d,有利于缓解能量负平衡并提高生产性能。

The aim of this study was to investigate the effects of supplemental different levels of extruded full-fat soybean(ESB)on the rumen fermentation,digestion and metabolism and blood parameters of early lactation dairy cows,and to judge the application effect of ESB on alleviating the negative energy balance of dairy cows.Four ruminally cannulated early lactating Holstein cows with the similar body weight,body condition score and age of lactation were assigned to 4 dietary treatments in a 4×4 Latin square design.Dietary treatments consisted of supplementing ESB at different levels[0(control),1.0,2.0,and 3.0 kg/d].The results showed as follows:with the increase of ESB supplementation level,milk yield(P=0.070)and energy correcting milk yield(P=0.068)had a tendency to increase,and milk fat rate had a tendency to decrease(P=0.081),but non-fat solid matter(SNF)and milk urea nitrogen contents,milk protein,lactose and SNF production and fat/protein were significantly increased(P<0.05).Rumen pH tended to decrease(P=0.062),and pH was lower 6.2 when ESB supplemental levels were 2.0 and 3.0 kg/d,but ruminal ammoniacal nitrogen(NH 3-N),propionate,valerate and isovalerate contents increased significantly(P<0.05);when the addition ESB was 2.0 kg/d,acetate/propionate was significantly lower compared with control group(P<0.05);apparent digestibility of crude protein(CP)and ether extract(EE)increased significantly(P<0.05),and that of dry matter(DM)tended to increase(P=0.061);total nitrogen excretion,ratio of urinary nitrogen to total nitrogen intake and nitrogen retention increased significantly(P<0.05),but the ratio of fecal nitrogen to total nitrogen intake decreased significantly(P<0.05),while the ratio of urea nitrogen to total urinary nitrogen tended to decrease(P=0.063);plasma urea nitrogen content increased significantly(P<0.05),and when the addition ESB level was 2.0 kg/d,plasma total bilirubin content tended to decrease(P=0.072).Therefore,it’s concluded that under this experimental condition,supplementation of ESB at 1.0 to 2.0 kg/d to dairy cows in early lactation is beneficial to alleviate the negative energy balance and improve performance.