尿素和微生物青贮添加剂对青贮饲料营养成分的影响

不同比例添加微生物青贮添加剂及尿素处理全株玉米青贮,对不同处理的青贮料进行常规营养成分测定,分析微生物青贮添加剂及尿素对青贮饲料质量的影响.结果表明:添加微生物青贮添加剂和尿素的青贮样品所含粗蛋白均有所提高,最高含量高于未处理样品1.3％,而粗纤维含量均降低,最大降低0.54％.说明微生物青贮添加剂与尿素混合使用能有效提高青贮饲料的质量.     

不同种植密度与不同肥料施用量及其配比组合对青贮玉米生物产量的影响

为了给吉林省中西部地区青贮玉米高产栽培提供技术支撑,试验研究了种植密度、磷酸二铵、尿素和硫酸钾4因素及其不同水平配比组合对青贮玉米生物产量的影响。结果表明:4因素对青贮玉米生物产量影响的大小顺序依次为密度硫酸钾磷酸二铵尿素;密度和硫酸钾不同水平对青贮玉米生物产量的影响达到极显著水平(P0.01),且随着密度和硫酸钾施用量的增加青贮玉米生物产量明显提高;磷酸二铵不同水平对青贮玉米生物产量的影响达到显著水平(P0.05),较低的施用量即可达到增产效果;尿素不同水平对产量的影响差异不显著(P0.05);密度、磷酸二铵、尿素和硫酸钾不同水平的配比组合对青贮玉米生物产量的影响达到极显著水平(P0.01),应用种植密度7.0万株/hm2、硫酸二铵150kg/hm2、尿素150kg/hm2和硫酸钾150kg/hm2配比组合,可获得高产。     

不同处理方式对蔗梢营养价值的影响

[目的]为弄清不同处理方式对蔗梢营养品质的影响,为科学利用甘蔗梢提供依据。[方法]采用切碎、直接青贮、添加0.6%尿素青贮和添加0.7 mL/kg EM青贮的不同方式处理蔗梢,青贮60 d后测定其pH值、常规营养成分、纤维成分和能量含量。[结果]1）直接青贮与添加尿素或EM青贮,青贮饲料感官评定均属优质青贮料。2）与鲜蔗梢相比,直接青贮可提高蔗梢的EE含量（P〈0.01）,但降低了CP（P〈0.01）、Ca（P〉0.05）和P（P〈0.01）的含量。3）与直接青贮蔗梢相比,添加尿素和EM青贮均显著提高了蔗梢的CP、EE、Ca和P（P〈0.01）含量。4）不同方式处理蔗梢的主要纤维成分之间没有显著差异（P〉0.01）。5）直接青贮、尿素青贮和微贮三种方式均可提高蔗梢的能量含量,且添加尿素和EM青贮的提高幅度更大（P〈0.01）。[结论]直接青贮对提高蔗梢的营养价值意义不大,但在青贮过程中添加尿素或EM均可改善青贮甘蔗梢品质,提高其营养价值。     

添加尿素和糖蜜对甘蔗尾打捆青贮品质的影响

试验采用单因子设计研究不同水平的尿素、糖蜜及糖蜜与尿素混合处理对甘蔗尾打捆青贮品质的影响。试验共分5组,其中1组为对照组,甘蔗尾经揉搓后直接青贮,2~5组为试验组分别添加0.6%尿素、1.0%的尿素、5%糖蜜和0.6%尿素+5%糖蜜,每个处理3个重复,青贮期90 d。试验结果表明,添加0.6%、1%的尿素及0.6%尿素+5%糖蜜均能显著提高青贮饲料的粗蛋白质含量（P<0.05）,但3个组间差异不显著（P>0.05）;单独加尿素的两组青贮料pH较对照组和其它试验组高,外观品质有所下降;添加5%的糖蜜和0.6%尿素+5%糖蜜均能显著降低青贮料的粗纤维含量,增加可溶性糖的含量,青贮料的pH及外观品质较好;综合营养成分和外观品质, 甘蔗尾用尿素与糖蜜混合处理其青贮料的品质最好。     

添加尿素和糖密对甘蔗屋打捆青贮品质的影响

试验采用单因子设计研究不同水平的尿素、糖蜜及糖蜜与尿素混合处理对甘蔗尾打捆青贮品质的影响.试验共分5组,其中1组为对照组,甘蔗尾经揉搓后直接青贮,2～5组为试验组分别添加0.6%尿素、1.0%的尿素、5%糖蜜和0.6%尿素+5%糖蜜,每个处理3个重复,青贮期90 d.试验结果表明,添加0.6%、1%的尿素及0.6%尿素+5%糖蜜均能显著提高青贮饲料的粗蛋白质含量(P〈0.05),但3个组间差异不显著(P〉0.05);单独加尿素的两组青贮料pH较对照组和其它试验组高,外观品质有所下降;添加5%的糖蜜和0.6%尿素+5%糖蜜均能显著降低青贮料的粗纤维含量,增加可溶性糖的含量,青贮料的pH及外观品质较好;综合营养成分和外观品质,甘蔗尾用尿素与糖蜜混合处理其青贮料的品质最好.     

青贮金针菇对荷斯坦奶牛瘤胃发酵、甲烷排放及原生动物数量的影响

文章旨在研究不同水平青贮金针菇及尿素对奶牛养分消化率、瘤胃发酵、甲烷排放及原生动物数量的影响。试验选择15头荷斯坦奶牛[(542±68)kg],随机分为5组,每组3个重复,每个重复1头牛。试验一共设计5种日粮,对照组饲喂基础日粮,各处理组分别在基础饲粮中添加青贮金针菇,处理1组(90%青贮金针菇,10%玉米秸秆),处理2组(90%青贮金针菇,9%玉米秸秆,1%尿素),处理3组(80%青贮金针菇,20%玉米秸秆),处理4组(80%青贮金针菇,19%玉米秸秆,1%尿素)。试验期分为2周适应期和1周数据收集期。饲粮中添加青贮金针菇较对照组显著提高了酸性洗涤木质素的摄入量(P<0.05);金针菇添加水平和尿素对干物质和其他营养素的摄入量无显著影响(P>0.05)。与对照组相比,在处理组日粮中添加青贮金针菇显著增加总短链脂肪酸(SCFA)和丙酸含量(P<0.05),但乙酸含量及乙酸与丙酸比值显著降低(P<0.05)。添加青贮金针菇和尿素对短链脂肪酸含量有显著影响(P<0.05)。日粮添加80%青贮金针菇和1%尿素时,乙酸浓度显著高于未添加尿素组(P<0.05);青贮金针菇日粮添加尿素显著降低了瘤胃丁酸含量(P<0.05)。与对照组相比,在日粮中添加青贮金针菇可显著降低瘤胃原生动物总数(P<0.05)。饲粮中添加青贮金针菇可导致荷斯坦奶牛瘤胃原生动物总数逐步减少(P<0.05)。青贮金针菇日粮组中螺旋体数量显著高于对照组(P<0.05)。饲喂青贮金针菇的荷斯坦奶牛较对照组显著降低了甲烷排放量(P<0.05)。综上所述,用金针菇废弃底物与尿素、玉米秸秆混合日粮可以提高奶牛日粮的营养价值,日粮添加青贮金针菇显著降低了奶牛瘤胃原生动物种群和肠道甲烷排放量。     

添加剂对全株玉米青贮饲料品质的影响

研究不同的添加剂对全株玉米青贮品质的影响,分别设甲酸 甲醛、尿素 食盐、乳酸菌制剂和对照组,从感官鉴定和实验室评定两方面得出各添加剂对青贮品质的影响.结果表明:全株玉米青贮较易获得成功,且加入适量甲酸 甲醛、尿素 食盐、乳酸菌制剂均可提高青贮饲料的质量,其中添加尿素 食盐使CP/DM%显著提高,添加乳酸菌制剂和甲酸 甲醛显著提高DM/FM%、CP/DM%和WSC/DM%.     

不同添加剂对皇竹草青贮营养价值的影响

试验旨在研究不同青贮添加剂对皇竹草青贮的影响。试验分为8个处理组,分别为对照组、乙酸组、蔗糖组、尿素组、蔗糖+乙酸组、蔗糖+尿素组、乙酸+尿素组、乙酸+蔗糖+尿素组。各组样品青贮60 d后开罐取样,测定青贮饲料的营养成分。结果表明:与对照组相比,所有试验组的青贮品质都有提高;乙酸组的粗脂肪和粗蛋白含量显著高于对照组(P0.05);蔗糖+乙酸组、蔗糖+尿素组和乙酸+尿素组的粗蛋白及干物质含量均显著高于对照组(P0.05),其中蔗糖+乙酸组的有机物含量显著高于对照组(P0.05);乙酸+蔗糖+尿素组的粗蛋白含量最高,并且pH值最低,青贮效果最佳。     

甘蔗副产物的饲料化利用研究

为评估不同处理方式对甘蔗副产物营养品质的影响,科学利用甘蔗副产物提供依据。试验以甘蔗梢为原料,分别添加EM菌剂＋糖蜜、尿素、稻草、香蕉茎叶进行青贮30d后,测定其常规营养成分。结果表明,四组处理（EM菌剂蔗梢青贮组、尿素蔗梢青贮组、稻草蔗梢青贮组、香蕉茎叶蔗梢青贮组）均显著改善了蔗梢青贮品质。其中,EM菌液能有效提高粗蛋白、粗脂肪及磷含量,降低中性洗涤纤维含量;尿素能有效改善蔗梢青贮过程中氮素的不足,增加一定量的无机态氮素,平衡青贮过程中的碳氮比,有利于微生物发酵,从而提高了甘蔗青贮的粗蛋白,提高草食动物的消化利用率;利用甘蔗梢和稻草、香蕉茎叶分别青贮,可以有效提高青贮饲料的粗蛋白和钙、磷含量,有效降低酸性洗涤纤维和中性洗涤纤维含量。     

Effects of propionic acid and urea on the quality of whole-crop corn silage

以全株玉米（Zea mays）为研究材料,通过对其发酵品质和化学成分的分析,探讨添加丙酸（0．3％）、尿素（0．5％）、丙酸（0．3％）＋尿素（0．5％）对袋装全株玉米青贮品质的影响,60d后取样分析。结果表明,全株玉米可以单独调制出良好的青贮料,添加丙酸可以降低青贮饲料的pH值、乙酸和氨态氮含量,并能显著提高全株玉米青贮乳酸含量（P〈0．05）;添加尿素能显著提高全株玉米青贮的粗蛋白含量（P〈0．05）;添加丙酸＋尿素可以进一步改善全株玉米青贮品质。     

Intake, performance and carcass characteristics of beef cattle offered diets based on whole-crop wheat or forage maize relative to grass silage or ad libitum concentrates

Seventy beef steers, mean initial live-weight 424 (S.D. 33.0) kg, were blocked by live-weight and breed and allocated to one of 5 dietary treatments in a randomised complete block design. Treatments, including supplementation with 3 kg concentrates/head/day, were grass silage (GS), maize silage (MS), fermented whole-crop wheat (FWCW), urea-treated, processed whole-crop wheat (UPWCW), and ad libitum concentrates supplemented with 5 kg grass silage/head/day (ALC). The grain in urea-treated, processed whole-crop wheat (WCW) was cracked and the crop ensiled with a urea plus urease-based additive. The mean dry matter (DM) of the grass silage, maize silage, fermented WCW and urea-treated, processed WCW was 174, 315, 404 and 716 g/kg, respectively. Total DM intake and carcass growth were lowest for GS (P < 0.001). Relative to ALC, feed conversion efficiency (FCE) (P < 0.05), live-weight gain (P < 0.05), carcass-weight gain (P < 0.01) and kill-out rate (P < 0.05) were lower for GS, FWCW and UPWCW. The MS had a better FCE than the UPWCW (P < 0.001) or the FWCW (P < 0.05). Plasma urea concentration was lowest for MS and highest for UPWCW (P < 0.001). Animals offered the GS treatment had the most yellow fat (higher (P < 0.05) ‘b’ value) and those offered UPWCW had the whitest fat (lower (P < 0.01) ‘b’ value). It is concluded that MS, FWCW and UPWCW supported superior levels of growth by cattle compared to GS (in vitro DM digestibility 674 g/kg). There was no animal productivity advantage with UPWCW compared to FWCW.     

Effects of urea addition on the fermentation of sorghum (Sorghum bicolor) silage

This study was conducted to evaluate the effects of urea addition on fermentation characteristics, losses and chemical composition of silage of sorghum (Sorghum bicolor) ‘BRS Ponta Negra’. The sorghum plant was chopped and treated with different levels of urea (0.1756, 0.3512, 0.7024 and 1.4048 g per 10 kg fresh forage for the respective proportions of 0.5%, 1.0%, 2.0% and 4.0% of forage (dry matter [DM] basis), and packed into quintuplicate experimen- tal silos to determine its effects on fermentation, losses and chemical composition of sorghum silages. Addition of urea increased lactic acid bacteria up to the level of 60 g kg^?1 (DM basis). Compared with control silage, the addition of urea (p < 0.05) reduced DM losses. Urea-treated silages linearly increased (p < 0.05) the ammoniacal nitrogen and crude protein contents, and linearly reduced (p < 0.05) the ethanol content. The pH in urea-treated silages indicated better preservation of substrates obtained from fermentation. The intermediate level of 2.0% urea additive can be used to improve fermentation, reducing losses in sorghum silage without compromising lactic acid production. However, the addition of 0.5% and 1.0% urea to sorghum silage is sufficient to improve aerobic stability.     

Production and economic performance of F1-crossbred dairy cattle fed non-conventional protein supplements in Zimbabwe

The effects of supplementing crossbred cows with non-conventional protein sources on dry matter intake, milk yield parameters and economic returns were investigated. Twenty-five lactating F₁ Holstein-Mashona crossbreds averaging 115?±?24 days in milk were used. Five treatments, total mixed ration (TMR), urea-treated maize stover, untreated maize stover, Macroptilium atropurpureum (Siratro) hay and veld hay, were randomly assigned to cows and replicated five times in a completely randomised design. Nutrient composition, intake, milk yield and economic returns were determined. M. atropurpureum hay, urea-treated maize stover and TMR had equal crude protein content. Daily dry matter intake and yield differed significantly among the treatment diets (P?<?0.05). Cows on TMR, urea-treated maize stover and M. atropurpureum consumed more (P?<?0.05) than cows on untreated maize stover and veld hay. Supplementing with TMR, urea-treated maize stover and M. atropurpureum hay increased (P?<?0.05) milk yields. Mean daily milk yield was highest for cows supplemented with urea-treated maize stover. Percent fat, protein and total solids in milk from cows fed urea-treated stover compared favourably to that of milk for cows supplemented with TMR. Income over supplement cost was highest for cows supplemented with M. atropurpureum hay and urea-treated maize stover. Urea-treated maize stover and M. atropurpureum can therefore be used as a replacer protein supplements for dairy cattle in Zimbabwe.     

Effects of treating rice straw with urea or urea and calcium hydroxide upon intake, digestibility, rumen fermentation and milk yield of dairy cows

Three, multiparous Holstein crossbred dairy cows with initial body weight of 385 ± 19 kg were randomly allocated to 3 treatments of rice straw (T1 = untreated rice straw; T2 = 5.5% urea-treated rice straw (5 g urea in 100 ml water to 100 g air-dry (91% DM) straw); T3 = 2.2% urea + 2.2% calcium hydroxide treated rice straw (2.0 g urea and 2.0 g Ca(OH)₂ in 100 ml to 100 g air-dry (91% DM) straw) according to a 3 × 3 Latin square design. Each period lasted for 21 days in which feed, feces and rumen fluid were collected during the last 7 days for chemical analyses. The findings revealed significant improvements in dry matter intake and digestibility by using 5.5% urea-treated rice straw and 2.2% urea + 2.2% calcium hydroxide treated rice straw. Ruminal pH and NH₃-N were found higher (P < 0.05) as compared with urea-treated rice straw fed group, while blood urea nitrogen and milk urea nitrogen were in normal ranges. Volatile fatty acid concentrations especially those of acetic acid were decreased (P < 0.05) and those of propionic acid were increased (P < 0.05), thus acetic acid:propionic acid was subsequently lowered (P < 0.05) in cows fed with 5.5% urea-treated rice straw and 2.2% urea + 2.2% calcium hydroxide treated rice straw, respectively. Moreover, ruminal viable and cellulolytic bacterial counts were enhanced by urea and calcium hydroxide treatments. Milk protein and fat concentrations were additionally increased by respective treatments while 3.5% fat-corrected milk was highest; ranking from 2.2% urea + 2.2% calcium hydroxide treated rice straw, 5.5% urea-treated rice straw and urea-treated rice straw fed groups. Based on this study, implications could be made that using 2.2% urea + 2.2% calcium hydroxide treated rice straw for straw treatment could be an alternative treatment to 5.5% urea treatment with regards to its effectiveness and treatment cost for lactating dairy cows.     

Effects of contrasting forage diets on phosphorus utilisation in lactating dairy cows

The effects of different forage mixtures on duodenal flow and faecal output of phosphorus (P) were measured in lactating dairy cows in two experiments. The forages comprised grass silage (GS) alone or mixtures of GS and urea-treated whole crop wheat (WCW). Replacement of GS by high levels of WCW resulted in a significant decrease in total P (TP), water-soluble P (WSP) and acid-soluble P (ASP) intakes, but increased phytate P (PP) and acid-insoluble P (AIP) intakes. Duodenal flows of all P fractions were unaffected by dietary treatments. However, the amounts of all fractions flowing to the intestine were much higher than the amounts consumed—with the exception of AIP, which was unchanged, and PP, which was considerably reduced. Diets did not significantly affect faecal outputs of TP, ASP, PP and AIP; however, faecal outputs of WSP were significantly higher on WCW than GS diets. Inclusion of WCW significantly decreased TP and WSP availabilities in the total tract but did not affect PP and AIP availabilities. A new fraction of P, which was not present in the feeds, was found in significant amounts in the intestines and proved to be soluble in dilute acid but insoluble in water. Estimated annual excretions for a herd of 100 cows ranged from 1550 to 1721 kg for total P of which 337-786 kg was WSP. The results suggest that GS based diets deposit more P in the environment. However, the potential to cause P pollution depends not only on the quantity but also on the nature of faecal P and on soil parameters.     

Effects of urea-treated fibrous diets on nutrient intake, digestibility, performance and haematological parameters of Yankasa rams

An experiment was conducted to investigate the effects of urea-treated fibrous diets on the intake, nutrient digestibility, performance and haematological parameters of Yankasa rams. A total of 48 Yankasa rams (BW 10.00?±?1.50 kg; 6–8 months old) were allocated into four treatment groups in a completely randomised design (12 rams per treatment). Animals were placed on complete rations of yam peels, maize bran and rice husk treated with 0, 1.0, 1.5 or 2.0 % urea. The experiment lasted for 18 weeks. Yankasa rams fed with urea-treated diets had higher feed intake (949.88 and 938.04 g/day for U₁₅ and U₂₀, respectively), daily weight gain (227.67 and 181.00 g/day for U₁₅ and U₂₀, respectively) and better feed conversion ratio (4.17 and 5.18 for U₁₅ and U₂₀, respectively). Rams on urea-treated diets had higher haemoglobin and red blood cell contents and higher weight gains, indicating that urea treatment enhanced nutrient supply and utilisation at the tissue level. It was concluded that urea treatment of fibrous farm by-products is a promising feeding strategy especially during the dry season when there is scarcity of high-quality forages. Addition of 1.5 % urea to roughage diets and farm by-products to form a total mixed ration may preclude the search for supplements.     

青贮饲料的加工调制技术

青贮饲料是在厌氧环境下,使用青贮设施长期保存的青绿多汁饲料。加工调制好的青贮饲料,不但能有效保存青贮原料中的营养成分,还能保证奶牛全年青绿饲料的均衡供应,提高奶牛产奶量。本文从分析青贮原料与发酵过程入手,在强调满足青贮条件的同时,分别介绍了青贮窖青贮、袋装青贮、裹包青贮、青贮塔青贮等不同种类青贮饲料的加工调制方法,以期为奶牛养殖场（户）提供帮助。     

内蒙古青贮饲料质量研究

为探讨内蒙古青贮饲料品质现状,采用抽样方法对内蒙古青贮饲料质量进行研究。结果表明,内蒙古青贮设备主要以窖贮和壕贮为主,青贮时间一般为9和10月,青贮种类主要有全株玉米青贮、玉米秸青贮、甜菜类青贮等;青贮饲料发酵品质总体表现较好,通过对青贮饲料有机酸进行费氏评分,达到优良等级的占总样品的83%,全株玉米青贮和甜菜类青贮经费氏评分均达到优等,但是,全株玉米青贮饲料中的乳酸含量显著高于甜菜类青贮饲料(P＜0.05),乙酸和丁酸含量均显著低于甜菜类青贮饲料(P＜0.05),玉米秸青贮饲料费氏评分为良,内蒙古青贮饲料有机酸费氏评定结果与感官评定结果基本相符;3种青贮饲料中,甜菜类青贮饲料的营养品质最好,全株玉米青贮饲料次之,玉米秸青贮饲料最劣。综合分析结果表明,内蒙古全株玉米青贮饲料和甜菜类青贮饲料营养保存率高,发酵效果好,玉米秸青贮饲料质量较差。     

紫花苜蓿青贮技术及其应用探讨

对国内外紫花苜蓿青贮技术的研究进展做了系统总结，并讨论了不同青贮技术的优缺点。在此基础上指出半干青贮、添加剂青贮、混合青贮、拉伸膜裹包青贮均是适合的紫花苜蓿青贮方法。在生产实践中，可考虑将半干青贮、添加剂青贮或混合青贮与拉伸膜青贮相结合，改进青贮方法，进一步提高紫花苜蓿青贮饲料的品质，发展高效畜牧业。     

黄蒿的可青贮性研究

以黄蒿为原料,通过添加采禾添加剂青贮和和直接青贮,探讨黄蒿的可青贮性。试验结果表明,直接青贮和添加剂青贮后感官性状的评分分别为16和17分,达到了优良等级。添加剂青贮后的pH值为4.26,直接青贮后的pH值为5.09,直接青贮乳酸和乙酸占总酸的百分比高于添加剂青贮,丁酸占总酸的百分比为添加剂青贮高于直接青贮,氨态氮占总氮的百分比表现为直接青贮高于添加剂青贮。通过费氏评分法的评价结果来看,直接青贮为87分,为优良青贮;而添加剂青贮为56分,为合格。综合感官性状、发酵品质,黄蒿可以采用青贮方式进行保存,对黄蒿青贮时采用直接青贮的方法更好。