日粮类型对细毛羊甲烷排放及代谢物碳残留的影响

为探索减少或控制反刍动物向大气中排放污染物的方法,该文就日粮类型对绵羊甲烷排放及代谢物中碳残留的影响进行探讨。试验选择60只4月龄、体重为25 kg左右的新疆细毛羊进行完全随机试验设计分成4组。Ⅰ组和Ⅱ组日粮精粗比为2：8,Ⅲ组和Ⅳ组日粮精粗比为4：6,Ⅰ组和Ⅲ组粗饲料为玉米秸秆,Ⅱ组和Ⅳ组粗饲料为玉米青贮。结果表明,用玉米青贮完全替代玉米秸秆饲喂绵羊时,甲烷产量Ⅱ组比Ⅰ组显著降低（P＜0.01）,Ⅳ组比Ⅲ组降低了12%（P＞0.05）。当粗饲料为玉米秸秆时,产甲烷效率随日粮精粗比的提高显著降低（P＜0.05）。当粗饲料为玉米青贮时,产甲烷效率组间差异不显著（P＞0.05）。代谢物中的碳残留量Ⅳ组比Ⅰ组显著降低（P＜0.05）,Ⅱ组和Ⅳ组分别比Ⅰ组和Ⅲ组降低16.67%和9.09%（P＞0.05）。研究结果表明,日粮类型对新疆细毛羊排放甲烷有显著影响,同时也影响其代谢物中碳的残留量。     

盐渍土地区杂交酸模、豆秸与青贮玉米秸饲喂肉牛对比试验

为提高盐渍土地区秸秆利用率和开辟新的饲料资源,按规模饲养方式对26头杂交公牛进行了耐盐杂交酸模、豆秸和青贮玉米秸的饲喂对比试验.试验1进行了耐盐杂交酸模最大采食量和不同比例的饲喂,结果表明周岁活体肉牛日采食量可达18kg,食欲和消化不受影响;当占粗草比例20%以下时,日增重在1.05kg～1.16kg,与对照无明显差异(P＞0.05).试验2是饲喂豆秸和青贮玉米秸,并分为3个周期观察不同精料喂量对豆秸和青贮玉米秸饲喂效果的影响,结果表明肉牛日增重均无明显变化.从豆秸组与青贮玉米秸组的日增重及秸秆的成本效益分析,饲喂豆秸优于青贮玉米秸.豆秸粉碎后是一种可选择的粗饲料资源.     

花生壳和麦秸用于饲养肉牛的营养价值和化学处理

为了评定花生壳、麦秸和花生壳-麦秸型典型肉牛日粮的营养价值，分析了粗饲料和日粮的营养成分，以3只瘤胃瘘管山羊和尼龙袋技术评价了粗饲料和日粮中干物质和粗蛋白质的瘤胃降解率，以5头肉牛进行了日粮消化率测定；对花生壳和麦秸分别进行氨化处理和综合化学处理，以不同组的肉牛进行60 d的饲养试验，比较氨化处理以及综合化学处理对粗饲料饲养效果的影响。结果表明，花生壳中粗纤维含量高于麦秸，花生壳和麦秸中粗蛋白质含量低、干物质降解率高而粗蛋白质降解率低；以花生壳和麦秸为主要成分的典型肉牛日粮，干物质和粗蛋白质的降解率高且稳定，其干物质、粗蛋白质和粗纤维的消化率分别为44.60%, 61.88% 和30.41%。以3.5%的尿素氨化处理花生壳及麦秸对肉牛具有良好的饲养育肥效果；对花生壳以3.5%的尿素和4%的Ca(OH)₂进行综合化学处理，其效果优于单纯的氨化处理。     

不同类型日粮奶牛体外消化性能与甲烷产生量比较

为控制动物甲烷排放提供参考依据,以奶牛为瘤胃液供体动物,采用体外消化法进行了日粮类型对CH4产生量及其与消化性能关系的研究。结果表明,日粮精粗比均为40∶60的条件下,粗料为玉米秸秆青贮日粮的CH4产生量、消化单位干物质（DM）的CH4产生量、单位消化能量的CH4产生量比粗料为干玉米秸秆日粮分别减少了30%、37%、32%,差异显著（P〈0.05）;粗料均为玉米秸秆青贮的条件下,精粗比60∶40日粮的CH4产生量、消化单位DM的CH4产生量、单位消化能量的CH4产生量比精粗比40∶60日粮分别减少了21%、23%、23%,差异显著（P〈0.05）。玉米秸秆经过青贮处理或适当增加日粮中精料比例可以显著减少甲烷的产生,同时可以提高干物质消化率和消化能比例。     

盐渍土和非盐渍土地区杂交肉犊牛饲养对比试验

在盐渍土和非盐渍土地区各选6月龄断奶公犊30头,以青贮玉米秸为粗饲料,采用高量精料和适量精料饲喂进行144天的饲养试验.结果表明,尽管高量精料饲喂提高肉牛日增重,却大幅度消耗精料,提高单位增重饲养成本;在维持日增重1kg和适量精料饲喂的条件下,精料重比3.551,净肉率51%,公犊的营养需要为每kg增重需要饲料增重净能(NEg)26.16MJ和粗蛋白(CP)0.78kg.     

微波爆玉米花制备条件的优化研究

探讨物料量、时间和调味料与微波玉米爆开率(Y₁)、膨胀率(Y₂)和感官分数(Y₃)的响应曲面关系，模型Y₁、Y₂、Y₃的失拟性检验不显著（p₁＞0.05、p₂＞0.05和p₃＞0.1），无失拟性因素存在；而模型的显著性检验达显著水平（p₁＜0.05、p₂＜0.01和p₃＜0.01），说明模型较好地拟合玉米爆开率、膨胀率和感官分数与各参试因子之间的关系，R²分别为0.8139、0.8737和0.9160。利用期望函数途径，对响应曲面模型进行模拟预测和验证，得到制备微波玉米的优化条件为物料量1.518水平、微波时间0.518水平、调味料比例1.118水平，玉米爆开率、膨胀率、感官分数同时达到最高，分别为97.5%、11.0和7.2。     

川中丘陵区农村生活污水资源化利用后的土壤养分特征

[目的] 探究川中丘陵地区施用经无害化处理的生活污水后，不同类型土壤在不同深度土层中各养分指标的变化特征，为农村生活污水的无害化处理和资源化利用提供科学支撑。 [方法] 对三格化粪池处理后的农村生活污水进行资源化利用。在耕地中设置G₀(37.5 L/m²)，G₂(75 L/m²)，G₀(空白)3种施用处理；在林地中设置L₁(37.5 L/m²)，L₂(75 L/m²)，L₃(112.5 L/m²)，L₀(空白)4种施用处理。结合层次分析法(AHP)与主成分分析法(PCA)对各养分指标权重进行计算，对各处理在不同深度土层中的施用效果进行综合评分。 [结果] 在生活污水不同的资源化利用处理除L₃土壤养分评价等级为“良”外，其余处理皆为“优”。各处理下，耕地中各深度土层养分评价得分排序一致表现为：G₁＞G₀＞G₂；林地中0-20 cm土层表现为：L₀＞L₂＞L₁＞L₃；20-40 cm土层表现为：L₁＞L₀＞L₂＞L₃。耕地施用对提升土壤有机质、全氮、全磷、速效磷、速效钾有明显的效果；林地少量施用对提升20-40 cm除速效钾外其余土壤养分的效果较好。 [结论] 短期来看，在农村生活污水资源化利用时，适量的施用可改善耕地土壤的养分，对于林地无需施用土壤养分就可较好保持。     

育肥猪舍甲烷排放浓度和排放通量的测试与分析

畜禽养殖是重要的温室气体排放源，畜禽养殖的甲烷排放量受动物生长特性、粪便收集方式和气候条件的影响。为了探讨中国特有的饲养管理方式下育肥猪舍温室气体排放规律，为减少甲烷排放提供依据，该研究在北京选择一典型猪场，对不同季节育肥舍的甲烷排放浓度进行了试验测定，从2004年5月至2005年3月，每2个月一次连续采集72～80 h甲烷浓度和相关数据，并根据二氧化碳平衡原理，对猪场的甲烷排放量进行了估算。结果表明：育肥猪舍内甲烷浓度有明显的季节性和日变化特性，2005年1月舍内甲烷的平均浓度为(22.98±10.52)mg/m³，7月舍内甲烷浓度为(2.68±0.68)mg/m³；每日最低甲烷浓度出现在9:00 am～17：00 pm时段；冬季舍内二氧化碳浓度明显偏高，夜间比允许浓度高1倍；每头育肥猪饲养期间的甲烷排放量为68.10～207.01 mg/h，折合每标准动物单位排放量：436～1185 mg/h·(500 kg)，在IPCC推荐的发展中国家猪呼吸代谢甲烷排放1.0 kg/(a·头)范围内。     

木薯叶粉饲喂肉鸭效果及影响其利用因素的研究

本试验的目的是探讨木薯叶饲喂肉鸭的效果和影响木薯叶利用的因素。将３３０只１０日龄樱桃谷鸭随机分为１０组，每组３３只。１组（对照组）日粮按商业部饲料局提供的内用鸭饲养标准配制，２，３，４组日粮分别使用５％～１０％（前期５％，后期１０％），１０％～２０％和２０％～３０％木薯叶粉，饲料中粗蛋白质水平与１组相同；５，６，７组分别在１组日粮基础上添加氰化钾、单宁及氰化钾加单宁；８，９，１０组分别在４组日粮基础上补加猪油、蛋氨酸及猪油加蛋氨酸。结果表明：随日粮中木薯叶粉含量的增加，饲料中氰化物和单宁含量也增加，鸭增重、饲料能量和粗蛋白质的利用率逐渐降低，但５％～１０％木薯叶粉组与对照组无显著差异；补加猪油和蛋氨酸能显著改善增重、饲料报酬及能量利用率，粗蛋白质利用率也提高。综合试验结果表明，限制木薯叶利用的因素是其能量低，蛋氨酸缺乏及抗营养因子的存在。５％～１０％木薯叶粉组与对照组无论增重、饲料报酬及能量、粗蛋白质利用率均无显著差异。建议肉鸭饲料中前期添加５％，后期添加１０％的木薯叶粉。     

家畜肠道和粪便甲烷排放研究进展

家畜采食饲料在胃肠道发酵及其排泄粪便在处理贮存过程中会产生甲烷，目前每年的排放量超过全球甲烷排放总量的1／4。甲烷是主要的温室气体，会破坏大气臭氧层。减少家畜肠道和粪便的甲烷产量对提高饲料能量利用率和改善环境具有重要意义。该文在对目前反刍动物甲烷排放影响因素、肠道甲烷排放量和粪便甲烷排放量测定方法等方面的研究现状进行分析的基础上，就如何减少家畜肠道和粪便的甲烷产量提出了自己的看法。     

Livestock methane emission: From the individual grazing animal through national inventories to the global methane cycle

Methane is a potent greenhouse gas whose atmospheric abundance has grown 2.5-fold over three centuries, due in large part to agricultural expansion. The farming of ruminant livestock, which generate and emit methane during digestion (‘enteric fermentation’), is a leading contributor to this growth. This paper overviews the measurement or estimation of enteric methane emissions at a range of spatial scales. Measurement of individual animal emissions focuses particularly on grazing livestock for which the SF₆ tracer technique is uniquely appropriate. Gaining insight into factors that influence methane production requires that feed intake and feed properties be determined, enabling the methane emitted to be expressed per unit of intake. The latter expression is commonly encapsulated in the ‘methane conversion factor’, Y_m, an entity that enables small-scale methane emission estimates to be extrapolated to national and global enteric methane inventories. The principles of this extrapolation and sources of uncertainty are discussed, along with the significance of this global source within the global methane cycle. Micrometeorological and similar measurement techniques over intermediate spatial scales are also surveyed.     

Selenium accumulation in beef: effect of dietary selenium and geographical area of animal origin

Selenium (Se) is an essential nutrient with multiple human health benefits; the single most important dietary source of Se is beef. The Se content of beef varies, and cattle fed a high selenium diet may have Se concentrations in beef that are well above average. Such beef is potentially a unique supplemental source of dietary Se. To examine factors affecting Se accumulation in beef, 16 steers (initial wt 374.4 +/- 33.7 kg) were taken from seleniferous or nonseleniferous areas and fed in a 2 x 2 factorial design with diets high or moderate in Se (11.9 or 0.62 mg Se/kg diet). Diets contained 50% alfalfa, 25% wheat, and 25% corn on a dry matter basis. All dietary Se was from agricultural products, and Se in the high Se diet was primarily from high Se wheat and alfalfa hay. A loin muscle biopsy was taken at the start of the trial to determine initial Se content of beef. Steers were slaughtered after 14 weeks of the trial, and edible carcass (round, sirloin, shoulder clod, and ribeye) and organ samples were collected. Diets did not affect growth or feed intake (P > 0.05), and Se toxicity signs were not observed. Different cuts of meat had similar Se concentrations, and the Se content of all cuts was increased by both high dietary Se and high Se background. Except for liver and kidney, Se in tissues was increased by seleniferous background (P < 0.02) and high dietary Se (P < 0.001). Kidney Se concentrations of animals fed the high Se diet were lowest in animals from seleniferous areas (P = 0.04), suggesting a possible adaptation to the high Se diet. These results demonstrate that cattle fed diets high in Se from agricultural products will accumulate substantial amounts of Se in the beef without developing signs of Se toxicity and that prior Se status regulates Se accumulation in some organs. They further demonstrate that management practices may be altered so as to make beef a significant source of dietary Se.     

Beef authentication and retrospective dietary verification using stable isotope ratio analysis of bovine muscle and tail hair

Stable isotope ratio analysis (SIRA) was used as an analytical tool to verify the preslaughter diet of beef cattle. Muscle and tail hair samples were collected from animals fed either pasture (P), a barley-based concentrate (C), silage followed by pasture (SiP), or silage followed by pasture with concentrate (SiPC) for 1 year (n = 25 animals per treatment). The (13)C/(12)C, (15)N/(14)N, (2)H/(1)H, and (34)S/(32)S isotope ratios in muscle clearly reflected those of the diets consumed by the animals. By applying a stepwise canonical discriminant analysis, a good discrimination of bovine meat according to dietary regimen was obtained. On the basis of the classification success rate, the (13)C/(12)C and (34)S/(32)S ratios in muscle were the best indicators for authentication of beef from animals consuming the different diets. Analysis of (13)C/(12)C and (15)N/(14)N in tail hair sections provided an archival record of changes to the diet of the cattle for periods of over 1 year preslaughter.     

Effect of wheat-based dried distillers' grains with solubles inclusion on barley-based feed chemical profile, energy values, rumen degradation kinetics, and protein supply

The objectives of this study were to determine the effect of replacing the barley grain portion of the diet by wheat-based dried distillers' grains with solubles (wDDGS) at graded levels on feeding value for beef cattle. Two cultivars of barley were mixed with two sources of wDDGS in ratios of 100:0, 75:25, 50:50, and 25:75% (weight DM basis; denoted B0, B25, B50, and B75, respectively). This study revealed that increasing wDDGS inclusion level increased most of the nutritional composition linearly except for starch, which linearly decreased (from 609 to 320 g/kg of DM). Soluble, slowly degradable, and undegradable Cornel Net Carbohydrate and Protein System (CNCPS) protein and carbohydrate fractions linearly increased with increasing wDDGS inclusion level, whereas their rapidly and intermediately degradable fractions decreased. With increasing wDDGS inclusion, the rumen degradation rate of all measured parameters decreased linearly, the extent of degradability of organic matter was not affected, and the extent of CP degradability (g/kg DM) as well as the predicted protein supply in the small intestine and degraded protein balance in the rumen was increased. The inclusion of wDDGS in barley-based diets up to 50% did not alter energy values of the diet. Furthermore, optimum N to energy balance of the feed mixture for microbial growth in the rumen was reached by replacing 25% of barley by wDDGS. Thus, the nutritive value of the barley-based diets is manipulated by including wDDGS, which can be used to overcome the shortcomings of barley-dominated diets for beef cattle.     

Interpreting the variations in atmospheric methane fluxes observed above a restored wetland

The eddy flux of methane (CH₄) was measured over 14 months above a restored wetland in western Denmark. The average annual daily CH₄ flux was 30.2 mg m⁻² d⁻¹, but the daily emission rates varied considerably over time. Several factors were identified that explained some of this variation. (1) Grazing cattle moving through the source area of the eddy flux mast increased the measured emission rates by one order of magnitude during short time periods. (2) Friction velocity exerted a strong control on the CH₄ flux whenever there were water pools on the surface. (3) An exponential response of the daily CH₄ flux to soil temperature at 20 cm depth was found for most of the study period, but not for parts of the summer season that coincided with a low water level in the river flowing through the wetland. (4) Additional variations in the CH₄ emission rates were related to the spatial heterogeneity of the source area. This area covered not only different plant communities but also a gravel road and a river surface, and it had a microtopography that visibly induced a large spatial variability in the wetness of the top soil. It is shown that the control mechanisms for the methane emission from restored wetlands are more complex than those reported for natural wetlands, since they include both management activities and slow adaptive processes related to changes in vegetation and hydrology. On the basis of eddy fluxes of carbon dioxide measured at the same site it is finally demonstrated that the variability in the CH₄ fluxes strongly affects the greenhouse gas sink strength of the restored wetland.     

Short-term effects of single or combined application of mineral N fertilizer and cattle slurry on the fluxes of radiatively active trace gases from grassland soil

After implementation of legislative measures for the reduction of environmental hazards from nitrate leaching and ammonia volatilisation when using organic manures and fertilizers in Europe, much attention is now paid to the specific effects of these fertilizers on the dynamics of global warming-relevant trace gases in soil. Particularly nitrogen fertilizers and slurry from animal husbandry are known to play a key role for the CH₄ and N₂O fluxes from soils. Here we report on a short-term evaluation of trace gas fluxes in grassland as affected by single or combined application of mineral fertilizer and organic manure in early spring. Methane fluxes were characterised by a short methane emission event immediately after application of cattle slurry. Within the same day methane fluxes returned to negative, and on average over the 4-day period after slurry application, only a small but insignificant trend to reduced methane oxidation was found. Nitrous oxide emissions showed a pronounced effect of combined slurry and mineral fertilizer application. In particular fresh cattle slurry combined with calcium ammonium nitrate (CAN) mineral fertilizer induced an increase in mean N₂O flux during the first 4 days after application from 10 to 300 μg N₂O-N m⁻² h⁻¹. ¹⁵N analysis of emitted N₂O from ¹⁵N-labelled fertilizer or manure indicated that easily decomposable slurry C compounds induced a pronounced promotion of N₂O-N emission derived from mineral CAN fertilizer. Fluxes after application of either mineral fertilizer or slurry alone showed an increase of less than 5-fold. The NO_x sink strength of the soil was in the range of −6 to −10 μg NO_x-N m⁻² h⁻¹ and after fertilization it showed a tendency to be reduced by no more than 2 μg NO_x-N m⁻² h⁻¹, which was a result of both, increased NO emission and slightly increased NO₂ deposition. Associated determination of the N₂O:N₂ emission ratio revealed that after mineral N application (CAN) a large proportion (c. 50%) was emitted as N₂O, while after application of slurry with easily decomposable C and predominantly -N serving as N-source, the N₂O:N₂ emission ratio was 1:14, i.e. was changed in favour of N₂. Our work provides evidence that particularly the combination of slurry and nitrate-containing N fertilizers gives rise to considerable N₂O emissions from mineral fertilizer N pool.     

Nutritive and antioxidative potential of fresh and stored pomegranate industrial byproduct as a novel beef cattle feed

Pomegranate peel is a nutritive-rich byproduct whose amounts are extensively growing due to the exponential increase in the production of pomegranate juice and "ready to eat" arils. Pomegranate peel is a rich source for antioxidants and thus may serve in the prevention of cattle diseases and in the improvement of beef products, making it an attractive component in beef cattle diets. The present study aims to evaluate the effect of commonly used storage practices on the nutritive and antioxidative properties of pomegranate peel. In general, storage conditions preserved most antioxidant capacity. Ensiling ambivalently affected the nutritive values of the peel and promoted increased levels of antioxidative components. In addition to polyphenols, nonphenolic components, such as alpha- and gamma-tocopherols, contributed to the total antioxidative capacity, and several minerals found in the peel added to its nutritional value. Dietary supplementation with fresh peels promoted significant increases in feed intake and alpha-tocopherol concentration in the plasma, with positive tendency toward increased weight gain of bull calves. All in all, the nutritive value and the antioxidant capacity of pomegranate peel turn it into a favorable health-promoting constituent of feedlot beef cattle diet.     

Gridded ammonia emission fluxes in Japan

In order to fully understand the acidification of precipitation, it is essential to determine ammonia emissions. Detailed gridded emission fluxes of NH₃ have been compiled in Europe. In East Asia they have been determined on a national basis(Zhao and Wang, 1994). In Japan we have calculated NH₃ emission fluxes on a 1° latitude × 1° longitude basis for livestock and the application of fertilizer. Livestock emission factors developed by W.A.H. Asman(Asman, 1992) for Europe were used 23.04 and 5.36 kg NH₃/animal/yr. for cattle (dairy cows and beef), and pigs, respectively. Domestic animal population data was collected by prefecture and apportioned to grid cells based on the prefectural area in each grid cell. For fertilizer emissions, NH₃ emission were calculated assuming a 10% ammonium nitrogen evaporation rate for ammonium sulfate, urea, and other nitrogen-containing fertilizers. Since prefectural fertilizer data were not available, total fertilizer usage for Japan was distributed to prefectures based on cultivated area. The maximum calculated NH₃ emission fluxes for each of the three animal categories were as follows: Dairy cows, 4730 (Hokkaido), beef cattle, 4540 (Kyushu) and pigs, 3480 (Kanto) tonnes NH₃/grid/yr. The total NH₃ emissions due to livestock in Japan were 4.6, 6.0 and 4.4 × 10⁴ tonnes NH₃/yr. from dairy cows, beef cattle and pigs, respectively. The overall total NH₃ emission from livestock and the application of fertilizer was 2.0 × 10⁵ tonnes NH₃/yr. The NH₃ emission by Japan is small compared to those of most European countries.