Effects of Forage Species on Milk Protein Production by Lactating Dairy Cows

Eighteen multiparous early lactation Holstein cows were assigned to a replicated 3 × 3 Latin square with 28-d periods to evaluate milk protein production potential when corn silage (CS) or small grain silage (SGS) was added to diets based on alfalfa silage (AS). Treatments consisted of all AS, a mixture of AS and CS, or a mixture of AS and SGS. Treatment diets were isonitrogenous, isofibrous, and contained maximal amounts of carbohydrates to challenge the milk protein production of cows under intensive milk production systems fed these forages. Lactation performance, milk composition, nutrient intakes, and diet digestibilities were measured. There were no significant differences in milk yield of the cows fed diets containing AS, CS, or SGS. Cows fed diets containing all AS-produced milk with a higher fat percentage than did cows fed CS, and cows fed diets containing all AS produced more milk fat and protein than cows fed CS or SGS. There were no significant differences in the percentage of casein, whey protein, or true protein in milk when cows were fed AS, CS, or SGS. There were also no significant differences in the percentage or production of lactose or solids-not-fat when cows were fed diets containing different silages. Similarly, there were no significant differences in DMI or dietary DM digestibility by cows when fed diets containing different silages. Data suggest that adding CS or SGS to AS-based diets does not improve DMI, lactation performance, or milk protein production of lactating cows.     

日粮瘤胃能氮平衡对奶牛生产性能和牛奶中尿素氮的影响

本研究以12头泌乳中期荷斯坦牛为研究对象,采用随机区组设计分为3组,在干物质进食量相似的条件下,增加瘤胃快速可发酵能量,用玉米粉颗粒替代甜菜渣颗粒,三个处理分别替换0kg、0．4kg和0．8kg,试验期61d。结果表明,日粮处理对奶牛的产奶量和乳成分没有明显影响,玉米粉颗粒替代甜菜渣颗粒饲喂奶牛后可显著降低牛奶中尿素氮（MUN）浓度,评价目粮的瘤胃能氮平衡表明为正平衡,有明显低水平的MUN。试验证明,可以用日粮瘤胃能氮平衡判断饲喂日粮对奶牛MUN的影响。     

不同能量物质对泌乳奶牛产奶性能的影响

本文探讨了不同能量补充物质对泌乳奶牛生产的影响。,以麸皮作对照,用全棉籽、膨化全脂大豆和脂肪酸钙作为能量补充物质,35d试验结果显示,奶牛产奶量分别提高了6．7％、14．4％和18．2％．．乳脂肪分别提高19．（／9％、11．82％和11．21％、经济效益分别比对照组提高4．20、5．36和8．72．＇L／（头·d）!试验表明,全棉籽、膨化全脂大豆和脂肪酸钙作为能量补充物质,可减轻夏季热应激,提高牛奶产量和牛奶品质,尤以脂肪酸钙效果最佳。     

N1型纳豆芽孢杆菌对泌乳期奶牛产奶量及乳品质的影响

试验旨在研究N1型纳豆芽孢杆菌(Bacillus subtilis natto)对泌乳期奶牛生产性能及乳品质的影响。试验选用泌乳期、胎次、产奶量、体重相近的荷斯坦奶牛36头,试验设计采用完全随机区组设计,分成3个处理组,分别是试验1组添加N1型纳豆芽孢杆菌固体制剂30 g,试验2组添加N1型纳豆芽孢杆菌固体制剂60 g,对照组不添加。试验期为60 d,预试期10 d,分别在试验期的0、30、60 d采集奶样,每周测定1次产奶量。试验结果表明,日粮中添加N1型纳豆芽孢杆菌能够提高产奶量、提高乳脂校正乳产量（P<0.05）;提高乳脂含量、乳蛋白含量、干物质含量,提高乳脂产量、乳蛋白产量（P<0.05）、干物质产量（P<0.05）,对乳糖含量没有影响;牛奶中体细胞数有降低趋势。     

菜籽饼(粕)的抗营养因子及其对奶牛生产的影响

菜籽饼(粕)中的抗营养因子限制了其在饲料中的应用.文章主要阐述了菜籽饼(粕)中的抗营养因子及其作用机理,以及这些抗营养因子对奶牛生产的影响.     

巨菌草青贮替代全株玉米青贮对奶牛生产性能、乳成分和经济效益的影响

试验旨在研究巨菌草青贮部分或全部替代全株玉米青贮对奶牛生产性能、乳成分和经济效益的影响,采用完全随机试验设计,将90头健康的处于泌乳中后期荷斯坦奶牛,根据体重、年龄、胎次、产奶量相近原则随机分为3组,即对照组、Ⅰ组和Ⅱ组,对照组饲喂以全株玉米青贮为基础的奶牛日粮,试验组分别以巨菌草青贮替代50%和100%玉米青贮,试验期8周,其中预试期2周,正试期6周。结果显示,巨菌草青贮粗脂肪、中性洗涤纤维、酸性洗涤纤维、粗灰分、无氮浸出物分别较玉米青贮高192.3%、45.9%、34.1%、128.6%和194.3%,且均差异显著（P<0.05）,粗蛋白质含量较玉米青贮低15.3%（P>0.05）。与对照组相比,Ⅰ组奶牛日产奶量显著提高了2.38 kg/d（P<0.05）,而Ⅱ组奶牛日产奶量降低了0.87 kg/d,但差异不显著（P>0.05）。乳脂率、乳蛋白和乳糖含量随替代比例的增加而提高,但差异均不显著（P>0.05）。Ⅰ组每头奶牛每天可多盈利7.64元。综上所述,巨菌草青贮具有较高的饲用价值,通过合理的调配其在日粮中所占比例,可提高奶牛经济效益,满足奶牛全年对优质青贮的需要。在本试验条件下,以50%比例替代日粮中全株玉米青贮,效果最佳。     

Effects of Replacing the Corn Silage with Puelia sinese Roxb Silage on Production Performance,Composition of Milk and Economic Benefits in Dairy Cows

This experiment was conducted to study the effects of replacing the corn silage with Puelia sinese Roxb silage on the production performance, composition of milk and economic benefic in dairy cows.90 healthy Holstein cows in middle or late lactation were chosen and randomly divided into 3 groups (control group,groups Ⅰ and Ⅱ). The control group was fed with diet based on corn silage,groups Ⅰ and Ⅱ were fed diets with Puelia sinese Roxb silage instead of 50% and 100% corn silage, respectively. The experiment lasted for 8 weeks,including 2 weeks pre-trail period and 6 weeks formal period.The results showed that:The ether extract,neutral detergent fiber,acid detergent fiber,Ash and nitrogen-free extract of Puelia sinese Roxb silage were 192.3%,45.9%,34.1%,128.6% and 194.3% higher than corn silage respectively (P<0.05),and the crude protein of Puelia sinese Roxb silage was 15.3% lower than that of corn silage (P>0.05).The milk yield of group Ⅰ was significantly increased (2.38 kg/d higher) compared with control group (P<0.05),while that in group Ⅱ was decreased (0.87 kg/d lower)(P>0.05).With the increase of Puelia sinese Roxb silage,the butter-fat percentage, lactoprotein and lactose contents were increased (P>0.05).More profits (7.64 yuan/d) could get in group Ⅰcompared with control group. It was concluded that Puelia sinese Roxb silage had a high feeding value,which could be used to fulfill the requirement of dairy cows in high feeding value silage,and the effect of 50% substitution group was the best.     

不同类型日粮对奶牛十二指肠食糜中氨基酸含量的影响

本研究利用2种粗饲料(玉米秸秆青贮和玉米秸秆)3种精粗比(3:7、4.5:5.5和7:3)设计了6种试验日粮饲喂奶牛,选择3头安装永久性十二指肠近端瘘管的体重550-600 kg的健康荷斯坦奶牛,采用3×3拉丁方设计,试验分2个阶段进行,每个阶段3期,探讨了不同类型日粮对奶牛十二指肠食糜中氨基酸含量及组成的影响.结果显示,本试验条件下,粗饲料种类及精粗比均可影响奶牛十二指肠食糜中的氨基酸含量.粗饲料种类对奶牛十二指肠食糜中氨基酸含量及组成的影响较小,而精粗比的影响较大;日粮组成对奶牛十二指肠食糜中氨基酸含量的影响因氨基酸种类而异,各种氨基酸中,影响最大的是Met、Thr、Leu,其次是Val、Lys、Phe、His,而Arg、Ile基本不受日粮组成的影响.以上结果说明粗饲料种类及精粗比均可影响奶牛十二指肠食糜中的氨基酸含量.     

The Effects of a Short-term Increase in Supplementation on the Reproduction Performance in Lactating Crossbred Dairy Cows

The hypothesis that dairy cows partially suckling their calves would ovulate following removal of calves when restored to positive energy balance by a short-term increase in supplementation was investigated in 65 crossbred cows. Five treatments (T1, T2, T3, T4, and T5) that differed in the amount of total concentrate fed from calving to week 24 were involved. Calves were allowed to suck residual milk to 12 weeks of age. Energy balance was estimated by measuring intake, milk yield and organic matter digestibility. The occurrence of ovulation was determined by the analysis of milk progesterone (P4) concentration. Four groups that were receiving additional supplementation were restored to positive energy balance, while the control group (T1) remained in negative energy balance. The percentage of cows ovulating was 36%, 58%, 92%, 90% and 60% for T1, T2, T3, T4 and T5, respectively (p = 0.026). Comparison of the timing of ovulation for combined results from T1+T2 and T3+T4+T5 estimated mean time to fail to ovulate as 110+/-9.0 and 87+/-7.6 days, respectively (p = 0.023). The percentage of the cows showing oestrus was 9%, 8%, 33%, 40% and 40% for T1, T2, T3, T4 and T5, respectively (p = 0.197). Short-term increases in supplementation are unlikely to be an attractive means of reducing calving intervals.     

全混合日粮中添加高活性干酵母对奶牛生产性能的影响

试验将96头荷斯坦牛,按年龄、胎次、泌乳天数、日产奶量相近的原则随机配对分成2组。试验组奶牛每头添加1g/d高活性干酵母,饲喂30d。结果表明：高活性干酵母对奶牛产奶量有所提高,但差异不显著（P〉0.05）;对乳脂肪率和乳蛋白率无显著影响（P〉0.05）;对尿素氮存在显著影响（P〈0.05）;乳中体细胞数有降低的趋势,但差异不显著（P〉0.05）。     

聚氨酯包被尿素对奶牛泌乳性能和血浆生化指标的影响

本试验旨在研究饲喂包被尿素对奶牛泌乳性能及血浆生化指标的影响.选用24头荷斯坦泌乳牛,随机分为3组,分别饲喂含有豆粕(豆粕组)、聚氨酯包被尿素(包被尿素组)、饲料级尿素(尿素组)的等氮饲粮,粗蛋白质水平为17%.结果表明,与尿素组相比,包被尿素组和豆粕组奶牛干物质采食量提高了12.8%和12.6%,差异显著(P=0.02);产乳量由32.48 kg/d提高到34.48和34.53 kg/d,差异不显著(P>0.05),乳蛋白质产量有增加的趋势(P=0.06).尿素组奶牛乳蛋白质率显著低于其他2组(P=0.04),而乳尿素氮浓度显著高于其他2组(P=0.03).与尿素组相比,包被尿素组和豆粕组奶牛血浆中尿素氮含量由18.7 mg/dL降低到16.7和16.4 mg/dL(P=0.05).乳尿素氮含量和血浆尿素氮含量存在正相关(R2=0.85).由此得出,聚氨酯包被尿素可以部分替代饲粮中的豆粕,而不会对奶牛的泌乳性能产生不利影响.     

调控饲料对奶牛产奶量和乳成分的影响

为研究调控饲料对奶牛产奶量和乳成分的影响,试验选择10头年龄、胎次、泌乳天数、产奶量相近的泌乳牛,按照配对试验设计分为2组,一组为对照组(饲喂基础日粮),另一组为试验组(饲喂添加调控饲料的基础日粮)。结果表明,试验组每头奶牛日均增奶量比对照组多1.366kg(P<0.05),乳蛋白、乳脂率、乳糖、乳中干物质含量相比差异不显著。通过试验前后对比可知,调控饲料显著提高了奶牛的产奶量。     

日粮添加赛乐硒对奶牛产奶量和乳品质的影响

选用35头处于干奶期40d、泌乳期相近和上胎平均日产奶量20kg的中国荷斯坦奶牛，采用完全随机区组设计分为7组，即：对照组、亚硒酸钠组（7．5mgSe／d、15mgSe／d和22．5mgSe／d）和赛乐硒组（7．5mgSe／d、15mgSe／d和22．5mgSe／d），研究赛乐硒和无机硒对奶牛泌乳性能和乳硒含量的影响。结果表明：在泌乳期30d、60d、90d赛乐硒组较对照组显著提高奶牛产奶量、乳蛋白率和乳干物质含量，有提高乳脂率和乳糖含量的趋势。试验前各组乳硒差异不显著，试验期赛乐硒组较无机硒组、对照组显著提高乳硒含量。     

日粮中添加油料籽实对奶牛生产性能及乳脂脂肪酸组成的影响

本文旨在研究在日粮中添加油料籽实对中国荷斯坦奶牛乳脂肪酸组成及生产性能的影响,为提高奶牛乳脂中共轭哑油酸(CLA)含量,改善乳品质寻找合适的途径.试验选取16头泌乳前期(62±11)d、胎次一致(3胎)、泌乳量相近的中国荷斯坦奶牛,随机分为4组(对照组、菜籽组、亚麻籽组、葵花籽组),每组4头.试验共进行40 d(预试期10 d,正试期30 d),分别在正试期第1天、第15天和第30天测定乳产量、分析乳成分,用气相色谱仪分析乳脂肪酸组成.结果表明,与对照组相比,日粮中添加油料籽实,显著提高了奶牛的泌乳性能(P<0.05),降低了乳脂率(P<0.05),对乳中其他常规成分影响差异不显著(P>0.05);日粮中添加葵花籽后乳脂中CLA含量提高98.28%(P<0.05).菜籽组、亚麻籽组、葵花籽组的乳脂中C14:0和C16:0的含量分别比对照组降低了17.86%和26.75%、15.99%和27.18%、21.99%和21.74%.乳脂中多不饱和脂肪酸(PUFA)含量分别比对照组提高40.83%、47.06%和41.52%(P<0.05).乳脂中的t11-C18:1(x)与CLA(y)的比例(%)存在正相关性,y=0.34x 0.20,R<'=0.696 2(P<0.01).日粮中添加植物油籽显著提高了乳脂中CLA、PUFA的比例,降低了C14:0和C16:0的比例,改善了乳脂的构成,提高了乳品质.     

苜蓿鲜草和青饲玉米对奶牛生产性能和乳品质的影响

探讨日粮中添加苜蓿鲜草和青饲玉米对奶牛生产性能及其乳成分的影响,本试验选用荷斯坦泌乳奶牛20头,随机分为2组,对照组饲喂秸秆和精料补充料;试验组饲喂苜蓿鲜草、青饲玉米和精料补充料日粮。试验结果表明,日粮中添加苜蓿鲜草和青饲玉米,可极显著提高奶牛的生产性能和乳脂率(P<0.01),显著提高干物质采食量和乳蛋白含量(P<0.05)。     

奶牛专用霉菌毒素吸附剂对泌乳奶牛生产性能的影响

奶牛饲料原料中霉菌毒素广泛存在,并严重地威胁着奶牛健康,影响着奶牛生产性能的发挥。本试验选择年龄、胎次、产奶量、泌乳天数接近的荷斯坦奶牛90头,随机分成两组考察奶牛专用霉菌毒素吸附剂对乳牛生产性能的影响。在饲喂等量的基础日粮上,对照组额外添加20g/(d·头)精料补充料,试验组添加霉菌毒素吸附剂——普乐菲特20g/(d·头),其他饲养管理方式不变。该试验预饲期7d,试验期77d。结果表明,霉菌毒素吸附剂的添加不影响乳脂、乳蛋白,但对提高产奶量以及降低原料奶中体细胞数(P0.05)有明显的效果。本研究表明,日粮添加霉菌毒素吸附剂可有效提高原料奶质量,提高牧场整体经济效益。     

复合酵母培养物对奶牛生产性能的影响

通过在日粮中添加复合酵母培养物,研究其对荷斯坦牛生产性能的影响。结果表明,添加复合酵母培养物的试验组奶牛产奶量显著高于对照组(P<0.05),乳脂率也略有提高,但乳蛋白率和乳糖率与对照组相比差异不显著。     

不同青贮饲料日粮对奶牛产奶量和乳成分的影响

根据胎次相同、产奶量、泌乳时间相近的原则选择泌乳中前期奶牛30头,随机分为2组,每组15头,分别饲喂全株玉米青贮和小麦青贮饲料,研究其对奶牛产奶量和乳成分的影响.结果发现,与全株玉米青贮相比,小麦青贮组奶牛产奶量提高0.26kg/d,乳脂率、乳糖、非脂固形物和总固体均有提高,但差异不显著(P＞0.05);小麦青贮替代全株玉米青贮可实现每头奶牛每天多盈利0.31元.结果表明,小麦青贮替代全株玉米青贮能够提高奶牛产奶量和改善乳成分.     

过瘤胃赖氨酸对奶牛产乳量及乳成分的影响

试验采用随机分组试验设计,选择健康的中国荷斯坦奶牛48头,按照胎次、产奶量、泌乳日期一致原则,均匀分成4组,试验各组基础日粮相同,就饲粮中添加过瘤胃赖氨酸对乳牛产乳量及乳成分的影响进行研究。4个处理组分别为：对照组（0添加组）不添加过瘤胃赖氨酸（RPLys）、试验Ⅰ组添加10g/（头·d）、试验Ⅱ组添加20g/（头·d）和试验Ⅲ组添加30g/（头·d）。试验结果显示：经过饲喂后,试验各组与对照组相比,产奶量显著提高;试验Ⅲ组和试验Ⅱ组都与对照组差异显著（P〈0.05）,其中试验Ⅲ组与对照组差异极显著（P〈0.01）;乳蛋白含量有所提高,其中试验Ⅲ组与对照组有显著差异（P〈0.05）;其他乳成分指标略有提高,但差异不显著（P〉0.05）。     

奶牛专用霉菌毒素吸附剂对泌乳奶牛生产性能的影响

奶牛饲料原料中霉菌毒素广泛存在,并严重威胁着奶牛健康,影响奶牛生产性能的发挥.选择年龄、胎次、产奶量、泌乳天数接近的荷斯坦奶牛90头,随机分成两组,考察奶牛专用霉菌毒素吸附剂对乳牛生产性能的影响.在饲喂等量的基础日粮上,对照组额外添加20 g/d·头精料补充料,试验组添加霉菌毒素吸附剂--普乐菲特20g/d头·其他饲养管理方式不变.该试验预饲期7 d,试验期77 d.结果表明,霉菌毒素吸附剂的添加不影响乳脂、乳蛋白,但对提高产奶量及降低原料奶中体细胞数(P<0.05)有明显效果.研究表明,日粮添加霉菌毒素吸附剂可有效提高原料奶质量,提高牧场整体经济效益.