酵母蛋白饲喂泌乳奶牛试验报告

本试验通过在荷斯坦泌乳牛日粮中添加酵母蛋白部分替代豆粕,研究其对泌乳牛干物质采食量、产奶量、乳成分及身体健康情况的影响,选取400头胎次、产奶量相近的中国荷斯坦泌乳牛分为对照组和试验组各200头,试验组每头牛每天饲喂500g酵母蛋白,通过60d的试验,结果表明试验组和对照组奶牛平均日产奶量差异不显著（P〉0.05）,分别为32.54kg/d与32.34kg/d。在产奶量不变的基础上,试验组平均干物质采食量降低1.7kg（DM）/d,产奶效率提高,与对照组相比差异极显著（P〈0.01）。     

酿酒酵母培养物奶酵益-X6对奶牛生产性能和健康状况的影响

为验证奶酵益X6对泌乳奶牛的使用效果；采用单因子配对试验设计方法，试验组奶牛日粮添加奶酵益X6,对照组未添加，每天测定采食量、产奶量，观察消化率及粪便评分；试验结束统计试验组平均采食量提升2.00 kg,平均泌乳单产提升2.05 kg,差异极显著。结果表明奶酵益X6对泌乳牛消化率、采食量、产奶量、抗应激均有明显改善作用。     

饲喂高蛋白质酒糟对荷斯坦奶牛产奶量的影响

本试验旨在评价饲喂高蛋白质干酒糟（HPDDG）对奶牛瘤胃降解率、干物质采食量、产奶量和乳成分的影响。选择16头泌乳荷斯坦奶牛（12头经产牛和4头初产牛）,平均泌乳日龄80±14d,随机分配2种处理日粮,采用2×2交叉试验设计。用HPDDG（20％干物质）替换对照组日粮中的全部大豆蛋白和部分粗饲料。每期试验21d,在第19～21天每天记录产奶量和干物质采食量;每期的第20～21天采集奶样。     

日粮阴阳离子水平对围产期奶水牛泌乳性能的影响

本试验研究了日粮阴阳离子(DCAD)水平对围产期的泌乳水牛采食量、尿液pH值、泌乳初期泌乳性能的影响。选择32头2胎以上、品种、上期泌乳量、健康体况相似的处于围产期的泌乳水牛,随机分成4个组,分别饲喂DCAD水平为+139.89、+54.22、-29.11和-110.21mmoL/kg的4种日粮进行试验,试验期为产前21 d开始至产后30 d。结果表明:随着日粮DCAD水平的降低,各组间试验水牛干物质采食量无显著差异,尿液pH值随之显著降低。各组产奶量无显著差异,但可提高水牛产后泌乳量2.50%～4.86%,极显著降低水牛乳体细胞数(P<0.01);乳蛋白率、乳脂率、乳糖率均有显著提高(P<0.05)。综上所述,泌乳水牛日粮适宜DCAD水平为-110.21 mmoL/kg左右。     

脂肪酸钙对中国荷斯坦牛干物质采食量产奶量及经济效益影响的研究

选择6头经产、胎次相同或相近、产后10～20天的中国荷斯坦牛,采用3×3重复拉丁方设计,研究脂肪酸钙对中国荷斯坦奶牛泌乳早期的干物质采食量、产奶量的影响.试验处理分别为处理A组为基础日粮;处理B组为基础日粮+200克脂肪酸钙处理C组为基础日粮+400克脂肪酸钙.试验结果表明(1)日添加200克的B组对干物质采食量没有影响(P＞0.05);日添加400克的C组使干物质采食量显著下降,日干物质采食量比对照组下降了1.2千克(P＜0.05).(2)B组日产奶量比对照组提高了2.33千克(P＜0.05),C组产奶量未得到显著提高(P＞0.05);(3)日添加200克脂肪酸钙经济效益显著,每头牛每天可增加纯收入2.90元人民币;400克组从经济效益分析每头每天亏损0.92元人民币.     

饲喂苜蓿干草对引入澳大利亚奶牛生产性能的影响

为探讨日粮中添加不同比例苜蓿干草,对引入纯种澳大利亚荷斯坦奶牛的影响,选择48头产奶量、膘情、年龄,泌乳阶段一致的引入纯种奶牛进行完全随机单位组设计,分为试验Ⅰ组(对照组)、试验Ⅱ组和试验Ⅲ组。分别饲喂苜蓿干草2.5kg/d、5kg/d、7.5kg/d,3kg精料基础料加每产4kg奶补1kg产奶料,玉米青贮自由采食。测定产奶量、干物质采食量、乳成分和试验前后奶牛体重。结果对照组、试验Ⅱ组和试验Ⅲ组干物质采食量、产奶量、乳脂率、4%标准乳日产量、乳蛋白率、乳糖率和干物质含量差异不显著(P>0.05);乳脂和乳蛋白的平均日产量均随苜蓿喂量增加而显著增加(P<0.05);试验Ⅱ组体细胞数量比对照组显著减少(P<0.05),试验Ⅲ组比对照组和试验Ⅱ组极显著减少(P<0.01)。增加苜蓿干草喂量,对提高引入澳大利亚高产荷斯坦奶牛的产奶量和奶品质有一定提高作用。     

陈皮和酸甜剂对奶牛采食量和生产性能的影响

本文探讨了日粮中添加陈皮和酸甜剂对奶牛采食量和生产性能的影响。试验选取45头健康无病,体况、采食量、胎次、泌乳天数、产奶量相近的中国荷斯坦牛,随机分为3个处理组(n=15),即对照组、试验1组和试验2组。对照组饲喂基础日粮,试验1组在基础日粮基础上添加陈皮,试验2组在基础日粮基础上添加酸甜剂,预试期14d,正试期90d。试验结果表明,在整个试验期内,试验1组与对照组相比干物质采食量提高3.80%(P0.05),产奶量提高2.34%(P0.05);与试验2组相比,干物质采食量提高2.43%(P0.05),产奶量提高1.95%(P0.05)。试验2组在第1~30天干物质采食量较对照组提高2.51%(P0.05),之后试验阶段两组无明显差异,试验第30、90天测定发现2组乳脂率显著高于1组、对照组;试验第30、60、90天,试验1组乳蛋白率、乳蛋白产量显著或极显著高于2组和对照组,体细胞数也低于后二者,且在第90天达极显著水平。结果表明,在日粮中添加陈皮和酸甜剂能够不同程度提高奶牛干物质采食量和产奶量,提高牛奶乳蛋白率,降低牛奶体细胞数,进而提高奶牛的生产性能,而且添加陈皮的效果比酸甜剂更好。     

产前日粮碳水化合物来源和莫能菌素对经产奶牛围产期代谢和泌乳的影响

选用85头经产荷斯坦奶牛随机设计,评估产前碳水化合物来源及莫能菌素对围产期奶牛干物质采食量、血液参数和泌乳性能的影响。日粮处理按照2×2阶乘排列设计,包括传统的干奶料(CONV)和不含有草料纤维来源的干奶料(NFFS),补充或不补充330 mg/d.头莫能菌素。CONV日粮包括70%的草料,NFFS日粮28%的草料用棉籽壳和大豆壳替代。在整个干奶期(产前60 d)饲喂试验日粮(CONV和NFFS)。在预期产犊日期之前的28 d开始每天追加一次莫能菌素直到分娩。分娩后,所有奶牛饲喂相同的泌乳期奶牛料。结果发现,在妊娠的最后28 d,与饲喂CONV日粮相比,饲喂NFFS产前日粮干物质采食量(15.8 vs 11.9 kg/d)、干物质采食量体重百分比(2.1%vs1.6%体重)、血糖(67.4 vs 64.6 mg/dl)和血清胰岛素浓度(0.59 vs 0.45 ng/ml)更高,非酯化脂肪酸浓度(185 vs 245μEq/L)较低。在泌乳的前56 d,产前CHO、莫能菌素或两者混合效应对平均产奶量或乳成分没有明显的影响。但随着时间的延长,产前碳水化合物来源有影响产奶量的趋势。产前28 d补给莫能菌素对围产期产奶量没有影响。产前日粮对产后干物质采食量、血糖、非酯化脂肪酸、胰岛素浓度或肝脏甘油三酯没有影响。研究结果表明,在干奶期日粮中用NFFS部分替换传统日粮碳水化合物提高或维持了产前干物质采食量,因此增强了分娩前代谢水平。产前更高的干物质采食量可能潜在增加泌乳早期的产奶量。     

板栗总苞多酚对奶水牛抗氧化指标及生产性能的影响

[目的]本试验选用意大利皮尔蒙特大区某规模化养殖场60头奶水牛,研究不同浓度的板栗总苞多酚对奶水牛抗氧化能力及生产性能的影响。[方法]将试验奶水牛随机分为5组(日粮中植物多酚添加剂量为0.1%、0.2%、0.3%,0.4%),每组12头奶水牛,在饲养的第15天和第30天分别取血样,测定抗氧化性能;每周采集一次乳样、连续4周,记录试验牛日产奶量并测定奶水牛乳汁中乳蛋白率、乳脂率、非脂固形物(SNF)及乳糖(L)的含量和体细胞数量。[结果]结果表明,日粮中添加植物多酚水平为0.3%时,可以显著提高奶水牛机体总抗氧化能力(T-AOC)、总超氧化物歧化酶(T-SOD)、谷胱甘肽过氧化物酶(GSH-Px)的活力(P0.05),并可以显著降低血液中过氧化产物丙二醛(MDA)的含量(P0.05)。同时0.3%组奶水牛产奶量显著高于对照组(P0.05),体细胞数量显著低于对照组(P0.05)。[结论]说明在奶水牛饲粮中添加水平为3%的植物多酚可以显著改善奶水牛的抗氧化指标,提高产奶量和乳品质。     

小肠代谢蛋白中赖氨酸、蛋氨酸水平对荷斯坦牛产奶性能的影响

本试验采用对比试验设计,选取头胎荷斯坦牛140头为试验组,试验阶段Ⅰ(8月19日~9月6日)饲喂MPlys和MPmet含量为7.2%、2.4%的试验日粮,试验阶段Ⅱ(9月7日~9月30日)饲喂MPlys和MPmet含量分别为6.6%、2.2%的试验日粮,试验期内监测生产性能指标,并与2012年同期的135头头胎荷斯坦牛相关生产性能指标进行比较。结果显示,当试验阶段Ⅰ结束时,期末比期初产奶量提高了3.34kg/(头·d),提高了10.48%,该阶段平均产奶量提高1.45kg/(头·d),增幅比对照组提高1.48kg/(头·d),提高了4.44%,差异极显著(P<0.01);试验阶段Ⅱ,当MPlys和MPmet水平降为6.6%、2.2%时,产奶量出现下降趋势,但平均产奶量仍较试验前提高了1.84kg/(头·d),增幅比对照组提高1.62kg/(头·d),提高了4.86%,差异极显著(P<0.01);试验组全期单产增加量比对照组多出1.55kg,提高了4.65%,差异极显著(P<0.01)。试验组干物质采食量在试验阶段Ⅰ持续增加,进入试验阶段Ⅱ则出现下降。整个试验期,试验组与对照组干物质采食量差异不显著(P>0.05),但饲料转化率由1.55提高到1.62,提高了4.52%;乳脂率、乳蛋白等理化指标也有明显改善。说明在本试验条件下,提高日粮小肠代谢蛋白中氨基酸水平可增加产奶量,改善牛奶品质,提高饲料转化率。     

微生态制剂对奶牛产奶量和乳品质与肠道菌群的影响

通过在奶牛饲粮中添加微生态制剂,研究其对奶牛产奶量、乳品质和肠道菌群的影响。试验从200头成年产奶牛中,选取20头年龄、胎次、泌乳月份、妊娠期、产奶量、体重基本相似且身体健康的荷斯坦奶牛,分为试验组和对照组,试验期为35 d。其中对照组按照常规方式饲养,试验组在精料中按1‰的比例加入复合微生态制剂。结果表明:对照组奶牛平均产奶量降低,每头日均产奶量减少0.36 kg(P>0.05),而试验组每头日均产奶量比对照组增加1.81 kg,增产16.97%,差异极显著(P<0.01);与对照组相比,试验组蛋白质、乳糖和非脂乳固体增加,但差异不显著(P>0.05),脂肪降低(P<0.05);最后采用PCR-DGGE技术分析奶牛肠道菌群,结果试验组肠道菌群多样性明显高于对照组,且相似性达到97%,证实微生态制剂具有调节奶牛肠道菌群平衡的作用。     

饲用甜菜块根混贮饲喂荷斯坦牛的试验研究

采用75%切碎的饲用甜菜根茎与15%芦苇草粉、8%棉籽壳及2%玉米粉进行混合青贮,并替代荷斯坦奶牛常规日粮中的部分玉米青贮,进行饲喂对比试验。结果表明,饲用甜菜混贮饲料干物质含量为27.8%、粗蛋白含量为2.76%、粗脂肪含量为0.92%、粗纤维含量为11.28%、粗灰分含量为3.23%、钙含量为0.10%和磷含量为0.04%。饲用甜菜混贮饲料等量替代10kg奶牛日粮中的玉米青贮饲喂奶牛,试验组比对照组每头奶牛日平均产奶量降低0.09kg,试验末期对照组和试验组的乳蛋白率分别为3.17%和3.18%,乳脂率分别为3.66%和3.73%,分析结果表明,产奶量及乳品质差异均不显著。可见饲用甜菜块根混贮是一种较好的饲料,可以替代玉米青贮饲喂奶牛,混贮是饲用甜菜块根一种理想的贮藏方法。     

不同饲草料组合配方养殖奶水牛的效益分析

[目的]针对奶水牛饲草料不足及营养缺乏的现状,开展了不同饲草料组合配方对奶水牛产奶量及养殖效益的研究。[方法]试验设3个不同的饲草料配方处理组,每处理组供试摩杂奶水牛10头,试验正试期100 d,对正试期内的投入及产出进行了养殖效益分析。[结果]紫花苜蓿配方组（紫花苜蓿鲜草15 kg/头＋混合精料2 kg/头＋稻草2 ...     

Effect of fat type and forage level on performance of finishing cattle.

Four trials were conducted to determine the effects of adding various levels and types of fat to dry-rolled corn (DRC) finishing diets containing 0 or 7.5% forage. In Trial 1, 88 yearling steers (mean BW = 352 +/- 38 kg) and 176 heifers (mean BW 316 +/- 15 kg) were blocked by sex and weight into four replications. Treatments were 0, 2, 4, or 6% (DM basis) bleachable fancy tallow (BT) fed with 0 or 7.5% (DM basis) forage. Addition of BT to the 7.5% forage diet had no effect on ADG or gain/feed (G/F). However, adding BT to the all-concentrate diet decreased ADG (linear, P < .01) and G/F (linear, P = .08). In Trial 2, 184 yearling steers (mean BW = 347 +/- 21 kg) and 144 heifers (mean BW 322 +/- 8 kg) were blocked by sex and weight into six replications. Fat treatments were 0% fat, 4% BT, or 4% animal-vegetable oil blend (A-V); each fat treatment was fed with 0 or 7.5% forage. Across forage levels, the addition of fat increased (P < .01) ADG and G/F for cattle fed DRC. In Trial 3, 18 crossbred wether lambs (mean BW = 44.4 +/- 2.5 kg) were fed DRC and 7.5% forage and allotted randomly to the same fat treatments fed in Trial 2. Apparent total tract fat digestibility increased (P < .01) with the addition of BT or A-V. In Trial 4, 40 crossbred wethers (mean BW = 25 +/- 4.1 kg) and 16 ewes (mean BW = 23 +/- 2.7 kg) were individually fed 7.5% forage diets containing 0, 1, 2, or 4% BT. Addition of BT increased (linear, P = .10) G/F. In summary, fat addition to DRC finishing diets fed to yearling cattle did not consistently affect gain/feed, feed intake, and ADG.     

Effect of reduced energy density of close-up diets on dry matter intake,lactation performance and energy balance in multiparous Holstein cows

Energy intake prepartum is critically important to health,milk performance,and profitability of dairy cows.The objective of this study was to determine the effect of reduced energy density of close-up diets on dry matter intake(DMI),lactation performance and energy balance(EB) in multiparous Holstein cows which were housed in a free-stall bam and fed for ad libitum intake.Thirty-nine dry cows were blocked and assigned randomly to three groups fed a high energy density diet[HD,n = 13;6.8 MJ of net energy for lactation(NE_L)/kg;14.0%crude protein(CP)],or a middle energy density diet(MD,n = 13;6.2 MJ NE_L/kg;14.0%CP),or a low energy density diet(LD,n = 13;5.4 MJ NE_L/kg;14.0%CP) from d 21 before expected day of calving.After parturition,all cows were fed the same lactation diet to d 70 in milk(DIM).The DMI and NE_L intake prepartum were decreased by the reduced energy density diets(P 0.05).The LD group consumed 1.3 kg/d(DM) more diet compared with HD group in the last 24 h before calving.The milk yield and the postpartum DMI were increased by the reduced energy density diet prepartum(P 0.05).The changes in BCS and BW prepartum and postpartum were not affected by prepartum diets.HD group had higher milk fat content and lower lactose content compared with LD group during the first 3 wk of lactation(P 0.05).The energy consumption for HD,MD and LD groups were 149.8%,126.2%and 101.1%of their calculated energy requirements prepartum(P 0.05),and 72.7%,73.1%and 75.2%during the first 4 wk postpartum,respectively.In conclusion,the low energy density prepartum diet was effective in controlling NE_L intake prepartum,and was beneficial in increasing DMI and milk yield,and alleviating negative EB postpartum.     

Effect of varying carbohydrate and fat content of milk replacer on body composition of Holstein bull calves

The objective of this study was to determine the effect of varying concentrations of dietary fat and carbohydrate on changes in body composition of Holstein bull calves fed under isocaloric and isonitrogenous intake conditions. Thirty-two calves were assigned to a randomized block design with three dietary treatments, eight calves per treatment, and one baseline group of eight calves. Animals were reared from birth to 85 kg live BW (SEM = 0.57). All calves began treatments between 2 and 6 d of age. Three different milk replacer treatment diets were designed to deliver 14.8 (low fat, LF), 21.6 (medium fat, MF), or 30.6% of DM (high fat, HF) fat; 55.3, 46.7, or 35.4% of DM lactose; and 23.5, 24.8, or 27.0% of DM CP, respectively. Gross energy values were 4.62, 5.09, and 5.77 Mcal/kg for the LF, MF, and HF milk replacers, respectively. From d 1 to 14, calves were offered 0.24 Mcal intake energy/kg BW(0.75), adjusted weekly based on increases in BW, and 0.28 Mcal intake energy/kg BW(0.75) from d 15 to slaughter. Dry feed was not offered. Dry matter, energy, CP, and fat intakes were 55.2 kg, 257.6 Mcal, 13.0 kg, and 8.2 kg; 52.8 kg, 268.8 Mcal, 13.1 kg, and 11.4 kg; and 46.8 kg, 270.3 Mcal, 12.6 kg, and 14.3 kg for the LF, MF and HF treatments, respectively. Energy and CP intakes did not differ among treatments (P = 0.63 and 0.79, respectively). Fat and DMI were different among treatments (P = 0.001 and 0.02, respectively). Empty BW gains were 0.61, 0.61, and 0.65 kg/d for LF, MF, and HF, respectively, and were not different among treatments (P = 0.27). Empty body CP, water, and ash gain were not different among treatments (P = 0.65, 0.99, and 0.57, respectively). Empty body retained energy and fat gain were 27.2 and 57.7% greater for calves fed the HF than for those fed the LF diet (P = 0.06 and 0.006, respectively). Fat as a percentage of the whole empty body on a water-free basis was lower for calves consuming the LF diet (28.6%) than for those fed the HF diet (34.6%), whereas percentage of CP on an empty body, water-free basis was greater for calves consuming the LF diet (59.2%) than for those fed the HF diet (54.9%) (P = 0.006). The results of this study demonstrated that, under isocaloric and isonitrogenous intake conditions, equivalent dietary energy from fat compared to carbohydrate, above 15% fat, has no beneficial purpose unless additional fat deposition is required in the animal. Further, the data demonstrate significant changes in body composition independent of growth rate.     

饲粮粗蛋白质水平对泌乳水牛产奶量及氮代谢的影响

本试验旨在研究饲粮粗蛋白质水平对泌乳水牛产奶量及氮代谢的影响。试验采用４×４拉丁方试验设计,选用 １６头体况良好、上期泌乳量相近、产犊胎次 ２～３胎、健康的泌乳前期水牛,随机分为４组,进行动物饲养试验和消化代谢试验。将４组泌乳水牛随机分配到４个梯度的饲粮粗蛋白质水平组,即 １６．０％、１５．２％、１４．４％、１３．６％ ４个组,每组 ４头,进行 ４期饲养试验,每期 ２１ｄ,共 ８４ｄ。按照 ４×４拉丁方设计给各期各组泌乳水牛饲喂不同粗蛋白质水平的饲粮,每期试验预试期 ７ｄ。在第 ２期和第 ４期饲养试验的最后 ４ｄ开展 ２期氮消化代谢试验。结果表明,总采食氮、可消化氮、乳氮／进食氮以及氮表观消化率在部分组间差异显著（Ｐ＜０．０５）;乳氮、粪氮、尿氮在各组间差异不显著（Ｐ＞０．０５）。饲喂不同粗蛋白质水平饲粮对水牛产奶量、乳蛋白率、乳脂率、乳非脂固形物率和乳糖率均无显著影响（Ｐ＞０．０５）。血清总蛋白和尿素氮含量各组间差异不显著（Ｐ＞０．０５）。以试验期间进食氮水平（ｇ／ｄ）为横坐标（ｘ）,标准乳产量（ｋｇ／ｄ）为纵坐标（ｙ）,获得进食氮水平与标准乳产量的二次曲线关系,即 ｙ＝－０．００１６ｘ２＋０．９５５６ｘ－１２９．９１。由此可见,饲粮粗蛋白质水平对泌乳水牛生产性能及血液生化指标影响不显著,根据进食氮水平与标准乳产量的二次曲线关系可得,当进食氮水平为 ２９８．６２５ｇ／ｄ时,得到水牛标准乳产量最大值为 １２．７７３ｋｇ／ｄ。     

不同乳脂率德宏奶水牛乳腺组织脂滴形成相关基因的表达研究

本研究旨在探索脂滴形成相关基因嗜乳脂蛋白(BTN1A1)、黄嘌呤脱氢酶(XDH)、围脂滴蛋白1(PLIN1)和PLIN2在不同乳脂率德宏奶水牛乳腺组织中的表达差异。试验选取同一养殖小区的健康德宏奶水牛216头,采集乳样,用乳品分析仪测定乳脂率。根据乳脂率测定结果,分为低乳脂率组(L组,<7.0%)、中乳脂率组(M组,7.5%±0.5%)和高乳脂率组(H组,>8.0%),每组选取第2胎、年龄相近、处于泌乳中期的德宏奶水牛各3头,采集乳样,进行乳脂率测定;屠宰后采集乳腺组织,提取总RNA,利用实时荧光定量PCR技术检测脂滴形成相关基因的mRNA表达水平,并与乳脂率及脂肪酸含量进行相关性分析。试验结果显示,BTN1A1、XDH、PLIN1和PLIN2基因具有相同的表达趋势:H组>M组>L组;其中H组德宏奶水牛乳腺组织BTN1A1、XDH、PLIN1和PLIN2基因mRNA表达水平均极显著高于M组和L组(P<0.01);M组BTN1A1基因表达水平与L组差异不显著(P>0.05),但XDH、PLIN1和PLIN2基因mRNA表达水平均极显著高于L组(P<0.01)。相关性分析表明,BTN1A1、XDH、PLIN1和PLIN2基因表达水平均与乳脂率、总脂肪酸、长链脂肪酸及不饱和脂肪酸含量呈极显著正相关(P<0.01)。本研究结果表明,BTN1A1、XDH、PLIN1和PLIN2基因在乳腺组织的表达可能对德宏奶水牛的乳脂合成及分泌有显著促进作用,可为深入解析脂滴形成相关基因在泌乳过程中的调控机制提供参考。     

Performance of tropical dairy cows fed whole crop rice silage with varying levels of concentrate

The objective of this experiment was to evaluate the effect of concentrate/milk yield ratios on feed intake, nutrient digestibility, rumen fermentation efficiency, and milk production in dairy cows fed with a basal diet of whole crop rice silage (WCRS). Sixteen crossbred cows (75 % Holstein-Friesian (HF) and 25 % Thai cows) in mid-lactation were assigned to four dietary treatments in a completely randomized design. Treatments corresponding to four concentrate/milk yield ratios (0, 1:1, 1:2, and 1:3 (kg/kg)) were used. All cows were offered WCRS (with 1.5 % urea and 3 % molasses) ad libitum. Silage and concentrate were fed individually twice a day. Results revealed that dry matter intake (12.8–14.5 kg/day), nutrient digestibility (62.5–68.7 %), and rumen fermentation efficiency were not significantly affected by concentrate supplementation. Milk yield (10.2–11.5 kg/day) and milk composition were similar between cows fed with sole WCRS and those supplemented with concentrate mixture, although milk fat tended to increase in cows fed with sole WCRS. In conclusion, sole WCRS fed to dairy cows without concentrate supplementation resulted in similar feed intake, nutrient digestibility, rumen fermentation, and milk production as compared to those supplemented with concentrate in lactating dairy cows. These results suggest that in tropical areas where rice crop is surplus, WCRS could sustain reasonable levels of milk production among dairy cows with little or no concentrate supplementation provided that urea and molasses are included in the silage.     

补饲高蛋白质、高脂肪精饲料对驴产乳量和乳成分的影响

本试验旨在研究补饲高蛋白质、高脂肪精饲料对驴产乳量和乳成分的影响。选择 ３～７岁的健康泌乳母驴 ３４头,设 Ａ（１２头）、Ｂ（１０头）和 Ｃ（１２头）３个区,共 ５个处理。所有驴饲喂基础饲粮。每个区均设对照组,各试验组驴分别补饲粗蛋白质水平为 ３１．４４％（试验 １组,Ａ区,４头）、粗脂肪水平为 ２５．７７％［２０％棉籽油（试验 ２组,Ａ区,４头）、２０％葵花籽油（试验 ３组,Ｂ区,５头）、２０％菜籽油（试验 ４组,Ｃ区,６头）］的试验精饲料 １．５ｋｇ／ｄ。预试期 １４ｄ,正试期１４ｄ。结果表明：１）除含 ２０％葵花籽油的试验精饲料外,其余试验精饲料采食量（＞１３００ｇ／ｄ）均达到预期的采食量,且未出现消化异常,表明所用精饲料适口性较好,驴对它们有较好的适应性;２）补饲含 ２０％棉籽油和含 ２０％菜籽油的试验精饲料均显著提高了驴日均产乳量（Ｐ＜０．０５）,驴日均产乳量可达 １．５ｋｇ／ｄ,而日均总泌乳量可达 ４ｋｇ／ｄ;３）补饲不同试验精饲料对乳成分无显著影响（Ｐ＞０．０５）,驴乳中乳蛋白、乳糖、粗灰分含量较稳定,而乳脂含量变化非常大。总之,补饲高蛋白质、高脂肪的精饲料可提高驴产乳量,但对乳成分的影响不明显。