王草菠萝皮混合青贮发酵品质研究

研究了王草菠萝皮不同比例混合青贮发酵品质。试验设5个处理,分别为王草单独青贮(CK)、90 %王草+10 %菠萝皮(KP1)、80 %王草+20 %菠萝皮(KP2)、70 %王草+30 %菠萝(KP3)、60 %王草+40 %菠萝皮(KP4)。青贮后第1、3、5、7、14、30天开窖取样,测定青贮饲料发酵品质。结果表明：与对照相比,王草与菠萝皮混合青贮显著提高了乳酸含量,显著降低了pH值和氨态氮/总氮;各混合处理组均未检测到丁酸,pH值、乙酸、丙酸、挥发性脂肪酸和氨态氮/总氮无显著差异。从发酵品质和菠萝皮利用角度出发,40 %菠萝皮和王草混合青贮是可行的。     

热研2号柱花草和热研4号王草混合青贮对其营养成分及发酵品质的影响

为合理开发和利用热带牧草资源，研究热研2号柱花草和热研4号王草混合青贮对其营养成分及发酵品质的影响，以期筛选出适宜的混合青贮比例，为调制高品质的青贮饲料提供理论依据。本研究将热研4号王草和热研2号柱花草混合青贮比例分别设置为100∶0(CK)、85∶15(A1)、70∶30(A2)、55∶45(A3)4组，青贮30 d后开封取样检测。结果表明：A2组混合青贮感官评价最佳，随着热研2号柱花草比例的升高，pH和氨态氮/总氮（NH3-N/TN）值逐渐升高，A1、A2、A3组与CK组差异显著（P<0.05）；乳酸（LA）含量逐渐降低，A3组显著低于CK组（P<0.05）；各试验组乳酸/乙酸（LA/AA）值均大于2.6；且A2组丁酸（BA）显著低于其他各处理组（P<0.05）。随着热研2号柱花草比例升高，各处理组粗蛋白（CP）、干物质（DM）和粗脂肪（EE）含量随之升高，且显著高于CK组（P<0.05）；水溶性碳水化合物（WSC）含量呈上升趋势，且各试验组差异不显著（P>0.05）；中性洗涤纤维（NDF）逐渐降低，且各处理组间差异不显著（P>0.05）；各试验...     

添加酶制剂对饲用苎麻与麦麸混合青贮品质的影响

为了探究酶制剂对苎麻混合青贮品质的影响,本试验在苎麻与麦麸(80%苎麻+18%麦麸+2%蔗糖)混合青贮中分别添加10 mL蒸馏水(对照组)、纤维素酶2 g/kg、纤维素酶2 g/kg+半纤维素酶0.4 g/kg、纤维素酶2 g/kg+半纤维素酶0.4 g/kg+果胶酶0.7 g/kg,30天后开包取样分析各项指标。结果表明,苎麻与麦麸混合青贮发酵品质和营养品质均较好。与对照相比,添加酶制剂显著提高了碳水化合物、干物质和粗蛋白含量(P<0.05),显著降低了中性洗涤纤维、酸性洗涤纤维、粗纤维的含量和氨态氮/总氮比值(P<0.05),但是对pH值、乳酸、乙酸和丙酸含量无显著影响(P<0.05)。本试验条件下,添加酶制剂能够有效提高苎麻混合青贮的品质,单独添加纤维素酶与复合酶制剂无显著性差异,从节约成本角度考虑,单独添加纤维素酶组为最佳选择。     

不同添加剂对柱花草青贮品质的影响

以热研2号柱花草为原料， 通过直接青贮（CK）、 添加山梨酸（0.2％）、 蔗糖（2％）、 青贮宝（0.1％）等处理， 30 d后测定了柱花草青贮饲料pH值、 乳酸、 乙酸、 丙酸、丁酸等含量并分析其主要营养成分含量。结果表明： 柱花草直接青贮品质较差， 添加山梨酸、 蔗糖、 青贮宝等处理能降低pH值和提高乳酸含量， 添加2％蔗糖能极显著降低pH值(p<0.01)、 提高乳酸含量(p<0.05)， 改善青贮品质， 提高营养价值。     

不同碳水化合物源对饲料油菜青贮品质的影响

为油菜多功能开发利用、促进种养结合，以饲料油菜华油杂62为材料，添加不同来源碳水化合物进行青 贮比较试验，研究高水分饲料油菜青贮技术。试验分为5组，分别将20%的各碳水化合物原料（麸皮、玉米粉、米糠、 玉米淀粉）与高水分饲料油菜混合青贮，青贮45 d后进行感官评定并测定营养成分、pH、有机酸含量等。结果表明， 添加各碳水化合物原料均可以显著降低油菜的含水量至70%以下。油菜添加上述碳水化合物青贮后，可改善青贮 感官品质，显著提高乳酸含量，降低pH；其中，玉米粉与油菜混合青贮后因感官评分高、乳酸含量最高且氨态氮含量 最低，被认为效果最佳。     

添加蔗糖和甲酸对红麻青贮饲料品质的影响

探讨甲酸和蔗糖两种添加剂对红麻青贮的影响。以刈割后的红麻为青贮原料,添加不同计量的蔗糖(10 g/kg,15 g/kg和20 g/kg)和甲酸(3 m L/kg,6 m L/kg和9 m L/kg),并分别设空白对照,密封青贮60 d后分析。结果显示,添加蔗糖或者甲酸能够显著提高粗蛋白含量(P0.05)和可溶性碳水化合物含量(P0.05)降低红麻青贮饲料的PH值,实验组p H均小于4.0,乳酸含量显著增加(P0.05),氨态氮含量显著降低(P0.05),实验组均没有检测到丁酸含量,青贮发酵品质良好;且在本实验研究范围内认为,添加20 g/kg的蔗糖得到的红麻青贮饲料的品质优于其他实验组,添加9 m L/kg的甲酸得到的红麻青贮饲料的品质优于其他实验组。     

不同青贮方式对菠萝茎叶饲用品质的影响

分析添加尿素和废糖蜜对青贮菠萝茎叶营养成分的影响,并测定青贮后菠萝茎叶养分的瘤胃降解率。为提高菠萝茎叶的饲料化利用提供理论依据。试验以直接青贮菠萝茎叶为对照组,分别添加10 g/kg尿素、20 g/kg废糖蜜、10 g/kg尿素+20 g/kg废糖蜜为试验组,青贮45 d后进行营养成分、养分的瘤胃降解分析。结果表明:与对照组相比,添加10 g/kg尿素青贮菠萝茎叶可以显著降低单宁含量,提高粗蛋白(CP)、氨态氮(NH3-N)含量(p0.05);添加20 g/kg废糖蜜,CP、单宁含量显著提高(p0.05);添加10 g/kg尿素+20 g/kg废糖蜜,CP、NH3含量提高,乙酸含量降低,差异显著(p0.05);3个试验组中,DM、CP、中性洗涤纤维(NDF)在瘤胃内经72 h后的降解率均显著高于对照组(p0.05)。本试验中,添加10 g/kg尿素+20 g/kg废糖蜜可以显著提高青贮菠萝茎叶的品质,并提高青贮菠萝茎叶养分的瘤胃降解率。     

播期对青贮大麦产量和青贮品质的影响

为探究新疆北部地区播期对青贮大麦产量、青贮原料品质和青贮品质的影响,以3个大麦品种(系)(垦啤麦13、P13-3和甘啤4号)为材料,分别于3月18日、4月2日、4月17日播种,对其青贮农艺性状、干草产量、青贮原料营养成分和青贮品质进行分析。结果表明,随着播期的推迟,青贮大麦生育期大幅度缩短,4月17日播种时生育期较3月18日缩短22~23 d。晚播会显著降低大麦干草产量,晚播(4月17日)时3个品种(系)干草产量比早播(3月18日)降低15.2%~24.2%,其中垦啤麦13降幅最大。推迟播种使垦啤麦13和甘啤4号茎、穗的干物质分配比例下降,叶的干物质分配比例上升。晚播使P13-3和甘啤4号洗涤纤维含量(中性和酸性)和粗脂肪含量分别显著上升和下降,显著降低P13-3的粗蛋白含量,提高甘啤4号可溶性碳水化合物含量。播期对青贮品质影响因品种(系)而异,晚播降低了甘啤4号青贮的pH值、氨态氮含量,提高乳酸含量,对其他品种(系)无显著性影响。总体来看,新疆青贮大麦在外界条件允许的条件下,应适当早播。     

添加有机酸改善木薯叶青贮品质和营养成分

为了改善木薯叶青贮品质,研究有机酸对木薯叶青贮品质及营养成分的影响,以确定青贮木薯叶最适合的有机酸种类及添加量。本研究以华南7号木薯幼嫩茎叶为原料进行青贮试验,设对照组、甲酸（0.2%）、乙酸（0.2%）和丙酸（0.2%）处理组,30 d后测定木薯叶青贮饲料pH、乳酸（LA）、乙酸（AA）、丙酸（PA）和丁酸（BA）含量以及主要营养成分含量。结果表明,木薯叶直接青贮品质较差,添加有机酸处理与对照相比显著降低青贮饲料的pH和丁酸含量（P<0.05）,降低中性洗涤纤维（NDF）和酸性洗涤纤维（ADF）含量（P<0.05）,提高了饲料相对值（RFV）。添加有机酸可以改善木薯叶青贮品质并提高营养价值,添加乙酸（0.2%）和丙酸（0.2%）青贮品质较好,可作为木薯叶青贮添加剂。     

椰糠在不同氮源发酵过程中养分变化规律的研究

以烘干鸡粪、尿素、磷酸氢二铵等作为氮源,调整椰糠发酵堆(椰糠基质)的碳氮比为30:1,并添加酵素菌进行短期发酵,研究椰糠基质在添加不同氮源发酵后的养分含量变化规律。结果表明:(1)发酵后椰糠基质的有机质含量均呈动态下降的趋势,其中以纯鸡粪为氮源的A、H处理的有机质含量下降最多。(2)发酵后椰糠基质的全氮、速效氮、速效磷的含量,以C、F、E、B、D等含化肥氮源的处理较高;速效钾的含量,以A、H两个以纯鸡粪为氮源处理的含量较高,以E、D两个以部分鸡粪为氮源处理的次之。(3)从发酵后椰糠基质的养分含量分析来看,以C(100%磷酸二氢氨-氮)、E(33.3%鸡粪-氮+33.3%尿素-氮+33.3%磷酸氢二铵-氮)、F(50%尿素-氮+50%磷酸二氢氨-氮)处理发酵后的养分含量较高,为椰糠基质发酵的优良配方。     

RESEARCH NOTE

Data from twenty-two experiments conducted at tour ADAS Research Centres during 1980–92 were used to compare untreated silages with silages treated with formic acid, with or without added formalin, commercial inoculants or molasses. The sillages were made from herbage whose dry-matter (DM) and water-soluble carbohydrate (WSC) contents were 277 (s.e. 0.46) g DM kg⁻¹ and 36 (s.e. 8.1) g kg⁻¹ respectively. Inoculant use significantly decreased silage pH and ammonia-N, significantly increased lactic acid and total acid content, and decreased butyric acid and total short-chain fatty acids. Formic acid use significantly increased silage lactic acid and total acid content, and decreased butyric acid content, whereas formic acid+formalin significantly decreased silage ammonia-N level. Molasses had little effect upon silage fermentation. Improvements in silage fermentation, however, produced little benefit in terms of either silage DM intake or liveweight gain when the silages were offered to growing lambs.
It is suggested from the results that inoculant- and formic acid-based additives can be used to improve the fermentation of big-bale silages.     

Inclusion of alfalfa improves nutritive value and in vitro digestibility of various straw–grass mixed silages in Tibet

To enlarge the feed resources and enhance the utilization efficiency of straws as ruminant feed in Tibet, four kinds of local crop straws with tall fescue (Festuca arundinacea Schreb.) based on the ratio of 40/60 (fresh weight) were ensiled with four levels (0, 10%, 20% and 30% of fresh weight) of alfalfa (Medicago sativa L.), respectively. The laboratory silos (1L) were opened after 45 days of ensiling, and the fermentation characteristics, nutritive value and in vitro digestibility of the mixed silages were analysed. The silages including alfalfa had significantly (p < 0.05) or numerically (p > 0.05) higher lactic acid and crude protein contents, lactic acid bacteria counts, in vitro digestibility of dry matter, neutral detergent fibre (NDF) and acid detergent fibre (ADF), and lower NDF and ADF contents than controls. The results suggest that inclusion of alfalfa to mixtures of straws and tall fescue had favourable effects on fermentation quality and obviously improved the nutritive value and in vitro digestibility of mixed silages. This effect was most evident when the inclusion proportion of alfalfa was 30% in oat straw mixed silage.     

THE ENSILAGE OF AUTUMN-SOWN RYE

Autumn-sown rye was cut on five dates in spring and ensiled in laboratory silos. On two of the dates forage-harvested material was ensiled in PVC silos (containing about 1 t of fresh crop) as well as in laboratory silos. Ensiling was carried out with and without the addition of formic acid or glucose solution. After 96 days in laboratory silos, rye cut before ear-emergence and ensiled without additives gave silages of high pH value and high ammonia content. After ear-emergence satisfactory silage was produced without an additive, but the addition of formic acid always resulted in silages having lower pH values and lower ammonia contents. The addition of glucose resulted in silages with only slightly lower pH values and ammonia contents which were closely similar to those made without addition. Silages made in PVC silos were all well preserved, as indicated by low contents of acetic and butyric acids, but the addition of formic acid resulted in pH values and ammonia contents lower than those found in other treatments.     

Effect of formic acid and a bacterial inoculant on the amino acid composition of grass silage and on animal performance

An Italian ryegrass and hybrid ryegrass sward was harvested on 11 May 1994. The mean dry‐matter (DM) content of the herbage was 197 g kg^–1 fresh matter (FM), and mean nitrogen and water‐soluble carbohydrate contents were 20 and 272 g kg^–1 DM respectively. Approximately 72% of total nitrogen (TN) was in the form of protein‐nitrogen. The herbage was treated with either no additive, formic acid (3·3 l t^–1) (Add‐F, BP) or inoculant (2·3 l t^–1) (Live‐system, Genus) and ensiled in 100 t silos. Changes in effluent composition with time showed that silage fermentation and protein breakdown were delayed by treatment with formic acid. Formic acid and inoculant treatments also inhibited amino acid catabolism during ensilage. All silages were well fermented at opening with pH values < 4·0 and ammonia‐N concentrations of ≤ 50 g kg^–1 TN after 120 d ensilage. Treatment had an effect on protein breakdown as measured by free amino acid concentration, with values of 21·5, 18·2 and 13·2 mol kg^–1 N at opening (191 d) for untreated, formic acid‐treated and inoculated silages respectively. Amino acid catabolism occurred to the greatest extent in untreated silages with significant decreases in glutamic acid, lysine and arginine, and increases in gamma amino butyric acid and ornithine. The silages were offered ad libitum without concentrate supplementation to thirty‐six Charolais beef steers for a period of 69 d (mean live weight 401 kg). Silage dry‐matter intakes and liveweight gains were significantly (P < 0·05) higher on the treated silages. Silage dry‐matter intakes were 7·42, 8·41 and 8·23 kg d^–1 (s.e.d. 0·27) with liveweight gains of 0·66, 0·94 and 0·89 kg d^–1 (s.e.d. 0·058) for untreated, formic acid‐treated and inoculated silage‐fed cattle respectively. In conclusion, additives increased the intake of silage and liveweight gain by the beef steers, and it is suggested that this may be caused in part by the amino acid balance in these silages.     

Effect of two additives on the fermentation,in vitro digestibility and aerobic security of Sorghum–sudangrass hybrid silages

Two additives (Silo Guard (SG) and propionic acid (PA)) were tested for their effects on the quality and aerobic security of sorghum–sudangrass hybrid silages (JC‐1 and WC‐2). Two sorghum–sudangrass hybrid varieties were harvested for ensiling without additives (CK) or after the following treatments: SG at 0·5% of fresh forage or PA at 0·5% of fresh forage, with three replicates per treatment. The addition of SG and PA both affected the fermentation quality and chemical composition of the silages by lowering pH and NH₃‐N/TN and increasing lactic acid, the LA/TA ratio, WSC and CP concentrations compared with the untreated silages. In vitro DM digestibility (IVDMD), in vitro NDF digestibility (IVNDFD) and in vitro CP digestibility (IVCPD) were increased by SG in the JC‐1 silages and WC‐2 silages. Both additives improved the aerobic stability of sorghum–sudangrass hybrid silages. Furthermore, the additives reduced the mould counts and the aflatoxin and zearalenone levels compared with the untreated silages following aerobic exposure. Therefore, ensiling two sorghum–sudangrass hybrid varieties resulted in high‐quality silages. The addition of SG and PA improved silage quality, in vitro digestibility and aerobic security.     

Fermentation dynamics and bacterial diversity of mixed lucerne and sweet corn stalk silage ensiled at six ratios

The fermentation dynamics and bacterial diversity of mixed lucerne (LU) and sweet corn stalk (SS) silage ensiled at six ratios were evaluated. LU and SS, harvested at 187 and 222 g/kg dry matter, respectively, were chopped to a length of about 1 cm and mixed in the fresh weight proportions of 10:0, 8:2 (Mix 1), 6:4 (Mix 2), 4:6 (Mix 3), 2:8 (Mix 4) and 0:10. Silos of each ratio were prepared in triplicate and stored at ambient conditions for 5, 10, 15, 30 and 65 days. The fermentation profile of silage during storage was determined at each point, and the bacterial diversity of silage stored for 65 days was analysed by high‐throughput sequencing. The silages with more SS inclusion in the forage mixtures were higher in lactic acid and lower in butyric acid and ammonia N, regardless of storage time. After 65 days of storage, Lactobacillus (relative abundance, 91.36%–95.86%) dominated the bacterial community in Mix 3, Mix 4 and SS silages, whereas the community composition in LU, Mix 1 and Mix 2 silages was complex, mainly consisting of Lactobacillus (45.48%–61.01%), Enterobacter (11.09%–19.57%) and Weissella (10.44%–14.13%). Inclusion of SS significantly enhanced the fermentation characteristics, and remarkably improved the bacterial community structure, reflected by increasing the relative abundance of Lactobacillus and reducing the relative abundance of Enterobacter and Pantoea. The fermentation quality was better when LU was ensiled in a mixture with ≥ 40% SS.     

Fermentation and chemical composition of high‐moisture lucerne leaf and stem silages harvested at different stages of development using a leaf stripper

Lucerne (Medicago sativa L.) requires four or more cuttings at early bud stage per growing season to optimize the amount of crude protein and digestible fibre for feeding high‐producing dairy cows. However, there is potential to generate a nutrient‐dense feed from lucerne regardless of developmental stage by harvesting its protein‐rich leaves separate from its fibrous stems. In order to determine whether fractionated lucerne can be effectively ensiled under high‐moisture conditions and be nutritionally competitive with wilted whole‐plant silage, leaf and stem fractions, harvested at three developmental stages (early bud, 10%–20% bloom and >50% bloom), were directly ensiled in mini‐silos. At day 0, 1, 3, 21 and 140 of ensiling, silages were analysed for protein and non‐protein nitrogen fractions as well as their fermentation products and carbohydrate composition. Silages from unwilted leaves and stems were more heterofermentative than wilted whole‐plant silages; their fermentation shifted from primarily lactic acid to acetic acid production after 21 days. In leaf silages, the high degree of protein degradation into non‐protein nitrogen (~55%) was most likely due to fermentation quality. Nevertheless, at 140 days of ensiling, leaf silages had 21%–25% higher (p < 0.01) available protein (peptide amino acids, soluble and insoluble protein) content than wilted whole‐plant silages, regardless of developmental stage. Achievement of a more rapid pH decline and improved fractionation may further increase the nutritional value of leaf silages.     

Fermentation patterns of small-bale silage and haylage produced as a feed for horses

The fermentation quality of small‐bale silage and haylage for feeding to horses in Sweden, and using a conventional high‐density hay baler, was investigated in two experiments. Treatments studied were use of additives (inoculants containing lactic acid bacteria and a chemical additive consisting of hexamethylenetetramine, sodium nitrate, sodium benzoate and sodium propionate), the influence of dry‐matter (DM) content of wilted herbage and the effect of number of stretch film layers on fermentation pattern and aerobic stability. All silages and haylages were made from predominantly Timothy swards and were well fermented as indicated by low levels of ammonia and butyric acid. Values of pH were higher and concentrations of organic acids were lower in haylages than in the silages. This was not considered to be indicative of a poor fermentation in the haylage but of a restricted fermentation due to the high DM content of the herbage. The additives enhanced aerobic storage stability because of inhibition of mould growth. The only statistically significant effect of varying the number of stretch film layers was a higher content of CO₂ inside the bales when ten layers of stretch film were applied compared with six layers.