Milk Production of Dairy Cows Fed Total Mixed Rations After a Grazing Period

Twenty multiparous Holstein cows were used in a completely randomized design with repeated measures to study milk production of cows supplemented or not supplemented with concentrate when they were switched to a total mixed ration (TMR) after grazing. In one group, cows grazed an or-chardgrass/bromegrass pasture and were assigned to one of two treatments: 1) unsupplemented (U; 1 kg/d mineral mix) or 2) concentrate supplemented (CS; 1 kg corn-based concentrate/4 kg milk). Total DMI was greater (26.5 vs 22.0 kg/d), but pasture DMI was less (16.8 vs 21.2 kg/ d), for CS cows because of the substitution rate of 0.49 kg pasture/kg concentrate. Overall, CS cows had greater 3.5% fat-corrected milk (FCM) (32.9 vs 26.5 kg/d), but less milk urea N (MUN; 9.6 vs 14.7 mg/dL) and milk fat (3.13% vs 3.88%), than U cows. Milk response to supplementation averaged 1.08 kg milk/kg concentrate. Cows assigned to both treatments lost BW (-17 kg/d) and body condition score (BCS) (-0.33). At the end of the 6-wk grazing period, all cows were switched to a TMR fed in confinement for 11 wk. Overall, DMI (24.3 kg/d), 3.5% FCM (30.6 kg/d), milk fat (3.26%), milk true protein (2.87%), and MUN (12.7 mg/dL) did not differ between treatments. Cows gained BW (53 kg) and BCS (0.33). A significant treatment × time interaction was found for milk yield. During the first day of TMR feeding, milk yield was greater (30.9 vs 19.3 kg/d) for CS cows. After 10 d on a TMR, milk yields between cows that had previously been on the U or CS treatments did not differ (35.5 kg/d). When cows were switched from only pasture to a TMR, milk yield was comparable with that of cows fed CS after 10 d. Lack of carry-over effects of previous treatments and increased production suggest improvement in nutrition and the potential for greater animal well-being for cows housed in a tiestall barn and fed a nutritionally complete TMR.     

全混合日粮饲养方式对奶牛生产性能的影响

全混合日粮(total mixed ration,TMR)技术是20世纪60年代在美国、英国、以色列等国家首先采用的一种饲养方式,20世纪80年代引入了中国,现在国内的北京、上海、广州等地都已普遍使用了TMR饲养技术,并取得了良好的效果.TMR饲养方式与传统的饲养方式相比,避免了传统饲养方式挑食、摄入营养不平衡的缺点,改善了饲料的适口性,增加了奶牛对饲料干物质的采食量,提高了产奶性能,增强了瘤胃机能,降低了奶牛消化和代谢疾病的发病率.     

奶牛全混合日粮添加过瘤胃脂肪饲养效果对比试验研究

[目的]为了研究日粮中添加过瘤胃脂肪能够有效降低奶牛产后负平衡效果.[方法]本试验选用围产期(产前3～4周)健康的奶牛48头,按照年龄、体重、胎次、体况评分、预产期相同或相近的原则,参考上胎产奶量或母亲产奶量等指标随机分为试验组和对照组,在试验组日粮中添加过瘤胃脂肪300 g/头·日,试验期145 d.[结果]表明:试验组日产奶量提高1.96 kg,产后初次配种间隔缩短8.86 d,差异极显著(P＜0.01);对奶牛体况的改善也有一定的作用,特别是对头胎牛的体况改善明显.[结论]在奶牛全混合日粮中添加过瘤胃脂肪可提高奶牛产奶量、繁殖性能,改善体况.     

不同粗饲料组合混合日粮对奶牛泌乳性能的影响

本试验通过给奶牛饲喂不同粗饲料组合的TMR日粮,探讨日粮中不同粗饲料组合对奶牛泌乳性能的影响.结果表明,日粮鲜重的精粗比从30∶70提高到40∶60后,奶牛的干物质采食量有显著地增加（P＜0.05）.随着精料比例增加,其能量水平、蛋白含量和乳蛋白率增加.同时,蛋白含量和产奶量都有所提高.在试验二组中用青贮代替了全贮,提高了奶牛的采食量和泌乳性能.说明,奶牛全混合日粮（TMR）可以提高日粮养分表观消化率、产奶量和改善乳蛋白质水平.青贮饲料的蛋白质的降解和利用更容易被瘤胃微生物降解和吸收,从而提高奶牛的泌乳性能,取得较高的经济效益.     

全混合日粮对奶牛生产性能和养分表观消化率的影响

实验研究了不同精粗比全混合日粮对奶牛生产性能和养分表观消化率的影响。实验选用了30头奶牛,根据产奶量、泌乳天数和胎次相近的原则分为5组。试验结果表明,随着全混合日粮中精料比例的增加,奶牛产奶量、4%标准乳产奶量、乳蛋白率、乳糖量、乳固形物产量和乳非脂固形物产量可显著提高(P<0.05),日粮养分中除粗脂肪外,其余各养分的表观消化率均随着日粮精料比例的增加而增加(P<0.05)。     

Effects of Supplemental Carbohydrate Sources on Lactation Performance, Nitrogen Balance, and Ruminal Fermentation in Dairy Cows Fed Energy-Deficient Total Mixed Rations

The effects of supplemental carbohydrate (CHO) sources on milk yield and composition,nitrogen (N) balance,and ruminal fermentation were evaluated in lactating dairy cows fed energy-deficient total mixed rations (TMR).Fifty-six lactating Holstein cows (36.8 ±3.4 kg/d of milk yield; 152 ±26days in milk [ DIM ] ) were randomly assigned to one of four diets:( 1 ) basal TMR ( control ) ; ( 2 ) basal TMR + 1.25 kg/d sucrose (SUC) ; ( 3 ) basal TMR + 2.12 kg/d steam-flaked corn ( SFC ) ; ( 4 ) basal TMR + 2.23 kg/d wheat (WHE).The trial lasted 70 days,including the first 10 days of adaptation.Simultaneously,a 4 × 4 Latin square trial was conducted with four ruminally cannulated cows of similar DMI (Dry Matter Intake) fed on the above four diets.Each testing period lasted 18 days:15 days for adaptation and 3 days for sampling.Cows fed SUC-,SFC-,and WHE-supplemented diets produced 1.6,2.9,and 0.8 kg/d,respectively,more milk than those on the basal TMR control diet,but the difference was not significant (P =0.160).However,the production of energy-corrected milk of cows fed CHO-supplemented diets improved significantly (P =0.020),and the yield of 4％ fat-corrected milk tended to be higher (P =0.063 ) than in control animals.Percentages of milk protein,lactose and solidsnot-fat (SNF) increased significantly in cows fed CHO-supplemented diets ( P ＜ 0.05 ),and yields of milk protein and SNF were significantly higher (P＜0.05); yields of milk fat and lactose were somewhat higher ( P ＜ 0.10 ).Cows receiving supplementary CHO diets consumed more DM (Dry Matter) ( P =0.023 ) ; however,there was no significant difference in N retention,digestibility,or utilization efficiency among the treatments (P ＞ 0.10 ).The average ruminal pH was lowest in cows supplemented with SUC,while that in cows supplemented with SFC and WHE was only slightly reduced (P =0.025 ).Ruminal NH3-N concentration was highest with no supplementary CHO ( P =0.017 ),and changes in postfeeding time were similar across the diets.Total volatile fatty acid concentration was significantly lower in control animals than in those on SUC- and WHE-supplemented diets ( P =0.001 ) ; significant dietary responses were observed in the concentrations of acetate,butyrate,and branched-chain fatty acids and in the acetate-to-propionate ratio ( P ＜ 0.001 ).These results indicate that supplementation with different CHO sources in energy-deficient diets substantially improved the balance of energy and N in the rumen,altered ruminal fermentation,and improved lactation performance in dairy cows.     

全混合日粮粒度对奶牛采食、咀嚼活动和生产性能的影响

本试验研究了全混合日粮(TMR)粒度对奶牛采食、咀嚼活动和生产性能的影响,以探讨TMR适宜的粒度及制作过程中苜蓿、羊草的适宜搅拌时间。选用4头经产泌乳中期[泌乳时间(85±7)d]荷斯坦奶牛[体重(616.8±44.3)kg]进行4×4拉丁方设计。通过改变苜蓿、羊草搅拌时间改变TMR粒度,分为4组,分别为细颗粒牧草(FH)组(苜蓿搅拌12 min,羊草搅拌20 min)、中细颗粒牧草(M FH)组(苜蓿搅拌9 min,羊草搅拌15 min)、中长颗粒牧草(M LH)组(苜蓿搅拌6 min,羊草搅拌10 min)和长颗粒牧草(LH)组(苜蓿搅拌3 min,羊草搅拌5 min)。共进行4期试验,每期持续19 d,其中预试期14 d,采样期5 d。记录采样期前3 d的产奶量并采集奶样测定乳成分,采样期的第2和3天视频监控记录奶牛咀嚼活动,采样期最后2 d采集粪样测定养分表观消化率。结果表明:TMR粒度对干物质、有机物、中性洗涤纤维、氮的表观消化率有显著影响(P0.05),与MLH组和LH组相比,FH组和MFH组的表观消化率较高。TMR粒度对奶牛干物质、物理有效中性洗涤纤维、中性洗涤纤维、氮的摄入量,产奶量和乳成分无显著影响(P0.05)。没有观察到TMR粒度对奶牛咀嚼时间有显著影响(P0.05),也没有观察到TM R粒度对血浆生化指标有显著影响(P0.05)。结果提示,TM R适宜的粒度分布如下:≥19.00 mm、8.00~(19.00)mm、1.18~(8.00)mm和1.18 mm的干物质比例分别为45.20%、25.50%、16.55%和12.75%;TM R中苜蓿和羊草适宜搅拌时间分别为9和15 min。     

围产期和泌乳早期奶牛的若干营养策略探讨

通过对围产期与泌乳早期奶牛营养代谢特征及其与生产性能,繁殖率和健康关系的分析,作者提出改善能量负平衡,调整日粮营养组分,补充维生素和矿物质等营养调控手段,是降低奶牛代谢病发生率,改善繁殖性能,提高生产性能的有效策略.     

啤酒糟对产奶中后期荷斯坦奶牛生产性能的影响

试验选用体重、胎次、泌乳月、产奶量及生理状况相近的中国荷斯坦奶牛18头，随机分为3组，每组6头。对照组不喂啤酒糟，试验Ⅰ组用6kg啤酒糟代替0.5kg精料，试验Ⅱ组用9kg啤酒糟代替1kg精料。试验结果表明：试验Ⅱ组乳脂率、产奶量比对照组分别提高13.8%、23.70%，差异极显著（P〈0.01），经济效益也有较大提高，每头每天多增加收入3.54元。因此，产奶中后期奶牛添加9kg啤酒糟比较适宜。     

玉米秸秆青贮饲料与全株玉米青贮饲料饲喂奶牛的差异研究

玉米秸秆和全株玉米均是制作奶牛青贮饲料的重要原料。为比较玉米秸秆青贮饲料与全株玉米青贮饲料对奶牛生产性能的影响,本研究将胎次、年龄、体重及产奶量相同的20 头奶牛分为两组——试验组1和试验组2,分别饲喂玉米秸秆青贮饲料与全株玉米青贮饲料,通过统计各组奶牛产奶量、乳脂率及乳蛋白率,分析玉米秸秆青贮饲料与全株玉米青贮饲料对奶牛生产性能的影响。试验结果表明,试验组2的日平均产奶量高于试验组1,且差异极显著（P<0.01）;试验组1和试验组2乳脂率差异不显著（P>0.05）;试验组2的平均乳蛋白率高于试验组1,且差异显著（P<0.05）,且全株玉米青贮比玉米秸秆青贮经济效益更高,一个泌乳周期可增加736.8 元/头。     

亚临床酮病对泌乳早期奶牛繁殖性能和血液生化指标的影响

试验旨在探究围产期亚临床酮病与泌乳早期奶牛繁殖性能、卵泡发育之间的关系,并检测试验牛血液生化指标的变化。试验在黑龙江某大型集约化牛场开展,根据产后血酮水平确定亚临床酮病组（SCK）和健康组（C）奶牛共60头,根据试验牛产后50 d内发情状况,将SCK组再分为发情组（SCKE,16头）和乏情组（SCKA,14头）,C组也同样分为发情组（CE,25头）和乏情组（CA,5头）。所有试验牛在产后50 d通过直肠检查和B超检查了解子宫复旧及卵泡发育状况,记录繁殖性能数据,并进行血液生化指标分析。结果表明：与健康组发情奶牛相比,亚临床酮病发情奶牛产后首次发情日期推迟约10 d（P<0.05）;产后50 d卵泡直径差异极显著（差值约4 mm）（P<0.01）。亚临床酮病乏情奶牛子宫复旧延迟发生率显著高于健康组发情奶牛（P<0.05）;亚临床酮病奶牛血浆中胰岛素样生长因子-1（IGF-1）含量显著低于健康奶牛（P<0.05）,而泌乳量极显著提高（P<0.01）。与发情奶牛相比,乏情奶牛血浆中甘油三酯（TG）含量显著升高（P<0.05）;葡萄糖（Glu）、胰岛素（Ins）、雌二醇（E₂）、孕酮（P₄）含量显著或极显著降低（P<0.05;P<0.01）。综合以上试验结果,奶牛患亚临床酮病而导致能量代谢指标异常是引起奶牛乏情、产后卵泡发育受阻和繁殖障碍的主要因素,进而导致奶牛繁殖力下降。     

Effects of Supplemental Undegradable Protein During Early Lactation on the Performance of Beef Cows Grazing Native Range

Two experiments were conducted (Exp. 1, n = 63; Exp. 2, n = 72) using Angus x Hereford cows grazing Oklahoma dormant tallgrass prairie to determine the effects of increasing supplemental undegradable intake protein (UIP) on performance. In each experiment following parturition (February and March), cows were blocked by body weight, body condition score (BCS), and calving date and randomly assigned to one of four dietary treatments. For Exp. 1, supplements provided 396 g/d of degradable intake protein (DIP) with increasing amounts of UIP (211, 274, 337, and 400 g/d, respectively). For Exp. 2, supplements provided 281 g/d of DIP with 142, 196, 248, and 301 g/d UIP, respectively. Cows were individually fed 1.59 kg supplement 6 d/wk. Body weight and BCS were determined biweekly until the end of supplementation (Exp. 1, 37 + 1.5 d; Exp. 2, 45 + 1.2 d). Milk production was estimated 30 and 45 d postpartum. Plasma progesterone concentrations were quantified weekly to determine interval to first normal luteal function (PPI). Weight loss, BCS, and PPI were not influenced by treatment. In Exp. 2, there was a linear (P<0.08) decrease in weight gain of calves post-treatment to weaning as supplemental UIP increased, and a quadratic effect (P<0.06) of additional UIP on milk production at 30 d postpartum. In these experiments, metabolizable protein requirements were met by microbial protein, forage UIP, and a minimum of 142 g of supplemental UIP.     

冬牧70黑麦草、紫花苜蓿等牧草对奶牛的饲喂效果

选择身体健康的二胎荷斯坦奶牛32头，分为四组，对照组、试验：Ⅰ组、试验Ⅲ组和试验Ⅲ组分别饲喂传统青饲料（野草、速冻菜厂下脚料等）、金华当地的多花黑麦草、2003--2004年间经牧草引种试验证明在生物学特性、鲜草产量及营养成分等方面表现较好的品种——冬牧70黑麦草和紫花苜蓿进行了为期20d的饲养试验。结果对照组、试验Ⅰ组、试验Ⅱ组和试验Ⅲ组的平均日产奶量分别为9．89kg、10．23kg、11．56kg、和12．86kg。在其它饲养条件不变的情况下，饲喂紫花苜蓿的试验Ⅲ组奶牛产奶量极显著高于饲喂多花黑麦草的试验Ⅰ组及传统青饲料的对照组（P〈0．01），与饲喂冬牧70黑麦草的试验Ⅱ组差异显著（P〈0．05）；试验Ⅱ组奶牛产奶量与对照组差异极显著（P〈0．01），与试验Ⅰ组差异显著（P〈0．05）；试验Ⅰ组和对照组差异不显著（P〉0．05）。乳中总固体物质含量、乳脂率及乳蛋白率各组间差异不显著（P〉0．05）。表明紫花苜蓿、冬牧70黑麦草对奶牛饲喂效果好，可显著提高产奶量，改进乳成分。     

Growth Performance by Stocker Steers Fed Magnesium-Mica During a Grazing and Feedlot Period

Two experiments were conducted to determine the effects of Mg-mica supplementation on grazing and feedlot performance of stocker steers. In Exp. 1, eight groups of six steers were fed a basal diet of 80% ground grain sorghum, 15% corn silage, and 5% control protein supplement (DM basis) or a supplement containing Mg-mica (9% of supplement; 4.5 mg/kg diet DM) for 141 d. Marbling scores tended (P<0.10) to be greater, and the percentage of carcasses grading USDA Choice or higher was greater (P<0.05), from steers fed Mg-mica than from those fed the control supplement. In Exp. 2, eight groups of nine head each were offered either a control grain sorghum-based supplement or one containing 34 g/d of Mg-mica (2.7 g Mg) while grazing smooth bromegrass pastures for 112 d. Pasture groups were then placed in feedlot pens for 120 d and fed a basal diet similar to that described above. Two groups fed each pasture supplement received a control supplement, and two received a supplement containing Mg-mica (10% of supplement; 5 mg/kg diet DM). Steers fed Mg-mica during the pasture phase tended to have heavier (P=0.11) hot carcass weights, higher (P<0.05) dressing percentages, numerically (P>0.10) higher marbling scores, and a higher percentage of carcasses grading USDA Choice than steers fed the control supplement during the pasture phase. Therefore, adding Mg-mica to pasture supplements or feedlot diets appears to have no impact on grazing or feedlot performance, but may improve carcass quality.     

奶牛TMR质量监控体系的构建

近年来TMR饲喂技术在我国得到迅速推广,这极大地提升了奶牛饲养管理水平.为了更好地总结TMR应用效果及其质量监控的经验,本文从天津嘉立荷牧业有限公司的实际出发,介绍了奶牛饲草饲料供应策略及TMR分级监控措施,构建了一套行之有效的TMR质量监控体系.     

丙三醇对泌乳早期奶牛采食量、泌乳性能和代谢产物的影响

选用36头经产奶牛,根据泌乳期、上一泌乳期305天产奶量和预产期,采用随机区组设计分为4组,研究丙三醇（0、100、200和300 g.d-1）对泌乳早期奶牛采食量、泌乳性能、体质量变化、能量平衡、血液代谢产物和尿酮浓度的影响。结果表明：日粮添加丙三醇对奶牛的采食量、产奶量、乳蛋白率、乳糖率和乳干物质率无显著影响,200和300 g.d-1组饲料转化效率显著高于对照组（P〈0.05）,300 g.d-1组乳脂率显著低于对照组和100 g.d-1组（P〈0.05）。添加丙三醇后,和300 g.d-1组血浆葡萄糖浓度显著高于对照组（P〈0.05）,而血浆游离脂肪酸（NEFA）浓度显著低于对照组（P〈0.05）,300 g.d-1组β-羟丁酸浓度显著低于对照组（P〈0.05）;和300 g.d-1组尿酮浓度显著低于对照组（P〈0.05）。添加丙三醇200和300 g.d-1均显著改善了泌乳早期奶牛能量负平衡,减少了体质量下降。     

不同泌乳量奶牛行为学差异及其与泌乳性能的相关性

本试验旨在研究不同泌乳量奶牛的行为学差异,并分析奶牛行为学与泌乳性能的相关性。选择24头泌乳中期[(114.6±7.5)d]中国荷斯坦奶牛,平均体重为(670±24)kg,胎次为(2.6±0.4)胎,分为高产组[泌乳量(31.90±1.76)kg/d]和低产组[泌乳量(19.30±1.76)kg/d],每组12头。通过24 h视频监控系统、精准饲喂系统及计步器等,观察和统计奶牛48 h内采食(采食量、采食时间、采食次数、反刍时间、反刍次数)、饮水(饮水时间、饮水次数)、运动(躺卧时间、躺卧次数、站立/游走时间、游走步数)等参数,研究奶牛行为学与泌乳量的相关性。结果表明:1)低产组奶牛的乳蛋白率极显著高于高产组奶牛(P<0.01),低产组奶牛的乳脂产量、乳蛋白产量和乳糖率显著或极显著低于高产组奶牛(P<0.01)。2)高产组奶牛的干物质采食量、饮水时间和饮水次数显著或极显著高于低产组奶牛(P<0.05或P<0.01),高产组奶牛的游走步数极显著低于低产组奶牛(P<0.01)。3)总泌乳量与干物质采食量(r=0.829,P<0.01)、饮水时间(r=0.473,P<0.05)、饮水次数(r=0.429,P<0.05)呈正相关,而与游走步数(r=-0.574,P<0.01)呈负相关。综上所述,奶牛行为学与泌乳量之间存在相关性,这些行为的差异,可为寻找通过改变行为学提高奶牛产奶性能的方法提供理论依据。     

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。     

精粗比不同的全混合日粮对育成前期梅花鹿营养物质消化率和生产性能的影响

为了探究不同精粗饲料比例的全混合日粮(TMD)对育成前期梅花鹿营养物质消化率和生产性能的影响。试验选择健康、年龄、体重一致的9头育成前期梅花鹿,随机分成A、B、C 3组,每组3只。分别饲喂精粗比例为45∶55,58∶42,36∶64的全混合日粮。结果表明:随着日粮精饲料比例的降低,育成前期梅花鹿干物质采食量、粗纤维采食量、可消化粗纤维提高显著(P0.05)。随着精饲料比例的提高,育成前期梅花鹿粗蛋白采食量、可消化粗蛋白提高显著(P0.05)。结果显示,采用精粗比例为36∶64的全混合日粮饲喂育成前期梅花鹿效果较好,而且降低了饲养成本。     

饲喂高淀粉饲粮时不同瘤胃降解淀粉水平对奶牛泌乳性能、营养物质表观消化率和氮平衡的影响

本试验旨在研究饲喂高淀粉饲粮时不同瘤胃降解淀粉水平对奶牛泌乳性能、营养物质表观消化率和氮平衡的影响。选用10头荷斯坦经产奶牛[平均泌乳天数为(214±38)d,平均乳产量为(26.2±2.4)kg/d,平均体重为(727±65)kg]作为试验动物,随机分成2组,每组5头。试验设计2种不同瘤胃降解淀粉水平的试验饲粮,分别为瘤胃降解淀粉水平为62.3%(占总淀粉的百分比)的低瘤胃降解淀粉水平饲粮(L-RDS)和瘤胃降解淀粉水平为72.1%(占总淀粉的百分比)的高瘤胃降解淀粉水平饲粮(H-RDS)。采用交叉试验设计,试验分为2期,过渡期7 d,每期试验21 d,其中适应期14 d,采样期7 d。结果显示:1)相比L-RDS组,H-RDS组有机物和淀粉的表观消化率显著升高(P0.05),中性洗涤纤维和酸性洗涤纤维的表观消化率显著降低(P0.05),干物质表观消化率有升高趋势(P=0.07),蛋白质表观消化率无显著差异(P0.05)。2)相比L-RDS组,H-RDS组尿素氮及它们占摄入氮比例有降低趋势(P=0.09),摄入氮、乳氮、粪氮、尿氮和沉积氮及它们占摄入氮比例无显著变化(P0.05),尿中总嘌呤衍生物排出量和微生物蛋白产量亦无显著变化(P0.05)。3)饲粮瘤胃降解淀粉水平对奶牛干物质采食量、乳产量和乳成分均无显著影响(P0.05)。综合以上结果可知,饲喂高淀粉饲粮时不同瘤胃降解淀粉水平影响饲粮营养物质的表观消化率,对泌乳性能和氮平衡无显著影响。