我国牛羊甲烷产量预测模型构建及其影响因素

本研究旨在利用文献数据整合的方法构建基于我国饲养条件下牛羊甲烷(CH4)产量的预测模型，并探究牛羊CH4产量及其影响因素。通过中国知网(CNKI)、维普、Web of Science等数据库，检索2000年1月—2021年9月关于我国牛羊CH4产量的动物试验性文献，依据纳入标准筛选出符合要求的数据后，采用多元回归方法构建牛羊CH4产量的预测模型并进行模型评估，利用方差分解方法对牛羊CH4产量的影响因素进行解析。共纳入文献40篇，其中关于牛CH4产量的文献25篇，羊CH4产量的文献15篇。结果显示：(1)牛CH4产量预测模型为CH4=12.27×ME+5.30×CP–38.56×EE–4.62×ADF+4.29×NDF+0.98×MBW+13.17×DMI(R2=0.62,P<0.05)，模型预测偏差为-0.002L/d，均方根预测误差为40.09%，牛CH4产量主要受代谢体重(MBW)、干物质采食量(DMI)、中性洗涤纤维(NDF)等因素影响，其中饲粮因素可解释69%CH4产量变化，动物因素可解释31%CH4产量变化。(2)羊CH4产量预测模型为CH4=-0.64×ME–1.26...     

氨化处理对稻草体外瘤胃发酵甲烷、二氧化碳和挥发性脂肪酸产量的影响

本文旨在研究氨化处理对稻草体外瘤胃发酵甲烷(CH4)、二氧化碳(CO2)和挥发性脂肪酸(VFA)产量的影响。用不同水平的尿素对稻草进行氨化处理,尿素水平分别为0(对照)、2%、4%、6%、8%,应用M enke体外产气技术进行48 h的发酵,应用气相色谱仪测定CH4、CO2和挥发性脂肪酸产量。结果表明:氨化处理极显著提高了稻草的粗蛋白质含量(P<0.01),极显著降低了中性洗涤纤维含量(P<0.01);氨化处理极显著提高了总产气量、总挥发性脂肪酸(TVFA)、CH4、CO2和乙酸的产量(P<0.01),但对乙酸/丙酸以及气体的相对产量(CH4/TV-FA、CO2/TVFA和总产气/TVFA)没有显著影响(P>0.05)。结果提示,应用氨化处理提高稻草对反刍动物的饲用价值,将不可避免地提高瘤胃CH4、CO2和总产气量,今后有必要研究在使用氨化稻草饲喂反刍动物条件下,降低瘤胃发酵CH4和CO2产量的技术和产品。     

壳聚糖对奶牛人工瘤胃温室气体排放的影响

研究旨在探讨添加不同水平的壳聚糖对奶牛人工瘤胃温室气体排放的影响。试验利用体外培养技术,采集健康荷斯坦奶牛的瘤胃液,以精粗比为40:60的配合饲料为发酵底物,配制人工瘤胃体外培养液。设置5个处理,每个处理6个重复。对照组不添加壳聚糖,试验组分别添加0.3%、0.6%、1.2%和2.4%的壳聚糖,体外厌氧培养24h,分别于培养时间为12和24h时,测定反应体系中CH4、CO2和N2O的产量。结果表明:1~12h,人工瘤胃中CH4的产量随壳聚糖添加剂量的升高,呈现一次线性降低趋势(P=0.074)。13~24h,随壳聚糖添加剂量的升高,各培养瓶中CH4的产量呈现显著的一次线性(P=0.05)降低。此外,人工瘤胃中CO2和N2O的产量与壳聚糖没有显著的剂量依赖关系(P0.05)。由此可见,添加适宜剂量的壳聚糖可以降低瘤胃CH4的产量,一定程度上可以缓解大气的温室效应。     

体外产气法研究不同尿素水平对瘤胃发酵和甲烷产量的影响

本试验采用体外产气法研究不同尿素水平对瘤胃发酵和气体成分的影响。尿素占日粮干物质比例为0%、0.4%、0.8%、1.2%、1.6%和2.0%。结果表明:各处理组瘤胃液p H值、氨态氮浓度和总挥发酸产量无显著差异(P0.1),添加尿素未改变瘤胃发酵模式,仍倾向于乙酸发酵;各处理组间乙酸和丁酸差异显著,均呈二次曲线变化(Q,P=0.01)且变化趋势相反;随着尿素水平提高,体外发酵72 h总产气量和干物质消化率差异显著,并呈现线性升高趋势;添加尿素对12 h CH4产量无影响,但线型提高了24 h CH4产量。结论,当尿素添加量不超过2%时,未对瘤胃发酵造成负面影响,然而添加尿素会提高瘤胃CH4的产量。     

泌乳奶牛乳脂中奇数链和支链脂肪酸含量与肠道甲烷产量的相关性研究

试验旨在运用多元线性回归(MLR)、偏最小二乘回归(PLS)及遗传算法(GA)探讨泌乳奶牛乳脂中奇数链和支链脂肪酸(OBCFA)含量与肠道CH4产量的相关性。数据库选自13个试验,包含有224个瘤胃液乙酸、丙酸和丁酸的配对数据,以及7个OBCFA的数据。甲烷的产量(mmol/molVFA)根据乙酸、丙酸和丁酸计算得来,以占总VFA含量的相对值来表示。CH4产量与乳脂中OBCFA含量的相关分析采用MLR和PLS,结果显示该模型为线性预测模型。GA模型根据乳脂中OBCFA含量预测瘤胃液中各VFA占总VFA的相对比例;该模型的CH4产量根据乙酸、丙酸和丁酸占总VFA的比例预算得来,预测误差低(均方根预测误差<5%),数据方差高达66%,相关系数接近0.8。预测误差的方差小于由CH4含量计算得来方差的40%。7个OBCFA数据显示,支链脂肪酸iso C14∶0,iso C15∶0和iso C16∶0与CH4产量呈正相关,而奇数链脂肪酸C15∶0和C17∶0与C17∶1cis-9之和与CH4产量呈负相关。因此,该模型分析显示,乳脂中OBCFA含量与瘤胃CH4产量密切相关,可以用来预测CH4的产量。     

反刍动物瘤胃甲烷产生的营养调控

甲烷是仅次于CO2的全球第二大温室气体,其中,反刍动物年产CH4约7.7×107 t,占大气中的CH4总量的25%,而且每年还以1%的速度递增。因此研究反刍动物瘤胃甲烷的营养调控对甲烷的生成影响有重要意义。本文综述了瘤胃甲烷的产生机制、瘤胃产甲烷菌与瘤胃微生物的关系和反刍动物瘤胃甲烷的营养调控措施。     

瘤胃甲烷生成过程中微生物之间的相互关系

反刍动物瘤胃含有甲烷菌,是主要的甲烷(methane,CH4)排放源,甲烷菌利用饲料发酵过程中生成的氢和CO2作为主要的电子受体和供体通过还原反应生成甲烷,在瘤胃功能性生态生境(niche)中发挥重要作用.除甲烷菌以外,其他瘤胃微生物也影响甲烷产量.瘤胃微生物总体来说可分为产氢微生物(hydrogenogens)和耗氢...     

反刍动物瘤胃甲烷产生的营养调控

甲烷是仅次于CO2的全球第二大温室气体,其中,反刍动物年产CH4约7.7×107吨,占大气中的CH4总量的25%,而且每年还以1%的速度递增。因此研究反刍动物瘤胃甲烷的营养调控对甲烷的生成影响有重要意义。本文综述了瘤胃甲烷的产生机制、瘤胃产甲烷菌与瘤胃微生物的关系和反刍动物瘤胃甲烷的营养调控措施。     

脂肪酸添加剂对奶牛瘤胃挥发性脂肪酸和甲烷的影响

21头安装瘤胃瘘管的荷斯坦产奶牛随机分为对照组和试验Ⅰ~Ⅵ组,每组3头,对照组饲喂全混日粮(TMR),试验Ⅰ~Ⅵ组每天饲喂TMR加50.0 g、100.0 g、150.0 g、200.0 g、250.0 g、300.0 g/头复合脂肪酸日粮,主要探讨复合脂肪酸对奶牛瘤胃甲烷(CH4)产量、挥发性脂肪酸(VFA)、氨氮(NH3-N)浓度和pH值及产奶性能的影响。结果,TMR中每天添加150.0~200.0 g/头复合脂肪酸,明显(P<0.05)提高奶牛乳脂率和瘤胃乙酸浓度,显著(P<0.05)降低奶牛的CH4释放量、CH4能/GE值和瘤胃NH3-N浓度,对奶牛的标准乳(FCM)、乳干物质、乳蛋白和乳糖均有提高趋势,能有效地提高奶牛的经济效益和生态效益。     

日粮中氨化稻草水平对体外培养发酵甲烷和挥发性脂肪酸产量的影响

本试验旨在研究日粮中不同氨化稻草水平对瘤胃甲烷(CH4)和挥发性脂肪酸(VFA)产量的影响。以2头安装有永久性瘤胃瘘管的成年西门塔尔牛作为瘤胃液供体,以未处理稻草、4%尿素氨化稻草和6%尿素氨化稻草为粗料,分别与精料混合料以6种比例配合日粮,其中精料与粗料的混合比例分别为0∶100、20∶80、40∶60、60∶40、80∶20、100∶0。应用Menke等(1979)的体外培养发酵技术进行培养发酵并测定日粮48 h的总产气量、CH4和VFA产量。结果表明:日粮精料/粗料为0∶100时,4%尿素氨化稻草组和6%尿素氨化稻草组总VFA(TVFA)产量显著高于未氨化稻草组(P<0.05);随着日粮精料比例增加,乙酸、丙酸和TVFA产量显著增加(P<0.05),乙酸/TVFA和乙酸/丙酸显著下降(P<0.05);当日粮精料/粗料为40∶60时,4%尿素氨化稻草组和6%尿素氨化稻草组48 h CH4产量显著高于未氨化稻草组(P<0.05),并且4%尿素氨化稻草组48 h总产气量显著高于未氨化稻草组(P<0.05),在一定程度上高于6%尿素氨化稻草组(P>0.05);随着日粮精料比例增加,CH4产量和总产气量显著增加(P<0.05);48 h总产气量和CH4产量的组合效应值最高的组为日粮精料/粗料40∶60的4%尿素氨化稻草组;各组48 h总产气量均产生正组合效应,4%尿素氨化稻草组中CH4/TVFA均产生负组合效应。由此可知,CH4产量与日粮精料/粗料和日粮中粗料的品质有关。当日粮精料/粗料为40∶60时,4%尿素氨化稻草组48 h总产气量和CH4产量最高,但CH4/TVFA最低。     

Phase I evaluation of CCNU (lomustine) in tumor-bearing cats

1-(2-Chloroethyl)3-cyclohexyl-1-nitrosourea (CCNU) is an alkylating agent in the nitrosourea subclass. A prospective evaluation of CCNU was done to determine the maximally tolerated dosage of CCNU in tumor-bearing cats. Response data were obtained when available. Twenty-five cats were treated with CCNU at a dosage of 50-60 mg/m3 body surface area. Complete hematologic data were available for 13 cats. Neutropenia was the acute dose-limiting toxicity. The median neutrophil count at the nadir was 1,000 cells/microL (mean, 2,433 cells/microL; range, 0-9,694 cells/microL). The time of neutrophil nadir was variable, occurring 7-28 days after treatment, and counts sometimes did not return to normal for up to 14 days after the nadir. Based on these findings, a 6-week dosing interval and weekly hematologic monitoring after the 1st treatment with CCNU are recommended. The nadir of the platelet count may occur 14-21 days after treatment. The median platelet count at the nadir was 43,500 cells/microL. No gastrointestinal, renal, or hepatic toxicities were observed after a single CCNU treatment, and additional studies to evaluate the potential for cumulative toxicity should be performed. Five cats with lymphoma and 1 cat with mast cell tumor had measurable responses to CCNU. Phase II studies to evaluate antitumor activity should be completed with a dosing regimen of 50-60 mg/m3 every 6 weeks.     

Furosemide continuous rate infusion in the horse: evaluation of enhanced efficacy and reduced side effects

Continuous rate infusion (CRI) of furosemide in humans is considered superior to intermittent administration (IA). This study examined whether furosemide CRI, compared with IA, would increase diuretic efficacy with decreased fluid and electrolyte fluctuations and activation of the renin-angiotensin-aldosterone system (RAAS) in the horse. Five mares were used in a crossover-design study. During a 24-hour period, each horse received a total of 3 mg/kg furosemide by either CRI (0.12 mg/kg/h preceded by a loading dose of 0.12 mg/kg IV) or IA (1 mg/kg IV q8h). There was not a statistically significant difference in urine volume over 24 hours between methods; however, urine volume was significantly greater after CRI compared with IA during the first 8 hours ([median 25th percentile, 75th percentile]: 9.6 L [8.9, 14.4] for CRI versus 5.9 L [5.3, 6.0] for IA). CRI produced a more uniform urine flow, decreased fluctuations in plasma volume, and suppressed renal concentrating ability throughout the infusion period. Potassium, Ca, and Cl excretion was greater during CRI than IA (1,133 mmol [1.110, 1,229] versus 764 mmol [709, 904], 102.7 mmol [96.0, 117.2] versus 73.3 mmol [65.0, 73.5], and 1,776 mmol [1,657, 2.378] versus 1,596 mmol [1,457, 1,767], respectively). Elimination half-lives of furosemide were 1.35 and 0.47 hours for CRI and IA, respectively. The area under the excretion rate curve was 1,285.7 and 184.2 mL x mg/mL for CRI and IA, respectively. Furosemide CRI (0.12 mg/kg/h) for 8 hours, preceded by a loading dose (0.12 mg/kg), is recommended when profound diuresis is needed acutely in horses.     

Prevalence of gastric lesions in racing Alaskan sled dogs

Human and equine athletes are reported to have a high prevalence of gastric disease, and anecdotal evidence suggests a similar phenomenon applies to racing sled dogs. To investigate the prevalence of gastric disease in racing sled dogs, we conducted 2 gastroscopy studies on dogs competing in the annual Iditarod Sled Dog Race. A pilot study of dogs that were either dropped from the 2000 Iditarod Sled Dog Race because of illness or that finished the race indicated that, approximately 5 days after competing, 10 of 28 dogs (35%) had endoscopic evidence of gastric ulceration, erosion, or hemorrhage. The next year, an endoscopic study of 73 dogs participating in the 2001 Iditarod race was performed in order to evaluate a larger population of dogs. Data from 70 of these dogs could be used; 34 (48.5%) had ulceration, erosion, gastric hemorrhage, or some combination of these findings. When this group of 70 dogs was compared retrospectively to a control group of 87 dogs presented to the Texas A&M University (TAMU) Veterinary Medical Teaching Hospital, the Iditarod sled dogs had a significantly higher prevalence (P = .049) of gastric lesions. These findings suggest that, similar to athletes of other species, elite canine athletes have an increased prevalence of gastric disease compared to the canine population at large.     

The Epidemiology of Gastrointestinal Nematodes of Dairy Cattle in Central Kenya

The epidemiology of H. placei and of other gastrointestinal nematodes in yearling dairy cattle was examined on two farms in Kiambu District, central Kenya during each of 13 one-month periods from April 1993 to April 1994. On each farm, 32 newly weaned dairy calves were given a single dose of albendazole and then placed on experimental pastures. Twelve of the animals were designated for bi-monthly slaughter (n = 2) and analysis of worm population characteristics and 20 were designated for blood and faecal collection and for weighing. Two parasite-free tracer calves were grazed alongside the weaner calves each month throughout the study period and were also slaughtered for analysis of worm populations. Faecal egg counts, haematological and serum pepsinogen determinations, herbage larval counts, and animal live weight changes were recorded monthly. The study revealed that Haemonchus placei, Trichostrongylus axei, Cooperia spp. and Oesophagostomum radiatum were responsible for parasitic gastroenteritis and that H. placei was the predominant nematode present in the young cattle on both farms. Faecal egg counts from resident cattle and necropsy worm counts revealed that pasture larval levels were directly related to the amount of rainfall. The total worm burdens in the animals were highest during the rainy season (March–June and October–December) and lowest during the dry seasons (July–September and January–February). The very low recovery of immature larvae of H. placei from the tracer calves indicated that arrested development is not a feature of the life cycle of this parasite in central Kenya. The maintenance of the parasite population depended on continuous cycling of infection between the host and the pasture. The agroclimatic conditions of the study area were such that, in general, favourable weather conditions for the development and survival of the free-living stages of gastrointestinal nematodes existed all year round.     

Diversity of Ectoparasites in Sheep Flocks in Sa~o Paulo,Brazil

The occurrence of ectoparasites in sheep flocks is frequently reported but seldom quantified. Sheep production used to be a predominantly family activity in the state of Sa~o Paulo (Brazil), but it began to become a commercial activity in the past decade. Thus, information about the ectoparasites existing in sheep flocks has become necessary. The present data were obtained by means of questionnaires sent to all sheep breeders belonging to the `Associaça~o Paulista de Criadores de Ovinos' (ASPACO; Sa~o Paulo State Association of Sheep Breeders). Response reliability was tested by means of random visits paid to 10.6% of the respondents. Most of the properties (89.5%) reported the presence of one or more ectoparasites. Screw-worm (Cochliomyia hominivorax) was the most frequent ectoparasite (72.5%), followed by bot fly larvae (Dermatobia hominis, 45.0%), ticks (Amblyomma cajennense) and Boophilus microplus, 31.3%) and finally lice (Damalinia ovis, 13.8%). Combined infestations also occurred, the most common one being screw-worm with bot fly larvae (36.0%) followed by bot fly larvae with ticks (13.9%), screw-worm with ticks (9.3%), bot fly larvae with lice (6.9%), and ticks with lice (5.0%). The most common triple combination was screw-worm, bot fly larvae and ticks (12.8%). Breeds raised for meat or wool were attacked by bot fly larvae and ticks more often than other breeds. Lice were only absent from animals of indigenous breeds. The relationships among these ectoparasites are discussed in terms of sheep breeds, flock size, seasonality and the ectoparasitic combinations on the host.     

Evaluation of biohydrogenation rate of canola vs. soya bean seeds as unsaturated fatty acids sources for ruminants in situ

An experiment was conducted to study disappearance of C14 to C18 fatty acids, lag times and biohydrogenation (BH) rates of C18 fatty acids of ground soya bean and canola seeds in situ. Three ruminally fistulated Dallagh sheep were used to determine ruminal BH of unsaturated fatty acids (UFAs). Differences in the disappearance of fatty acids through the bags and lag times were observed between the oilseeds. We saw that the longer the incubation time of the oilseeds in the rumen, the lower the content of C18:2 and C18:3. Significantly higher lag times for both C18:2 and C18:3 were observed in ground canola compared to ground soya bean. BH rates of C18:2 and C18:3 fatty acids in soya bean were three times higher than those of canola. These results suggest that the fatty acid profile of fat source can affect the BH of UFAs by rumen micro‐organisms. So that UFAs of canola had higher ability to escape from ruminal BH. It seems that fatty acid profile of ruminant products is more affected by canola seed compared to soya bean seed.     

Serum biochemical values and mineral element contents of tissues in yaks

Serum biochemical values and the wet weight to dry weight ratios of tissues were determined in yaks in Shandan county of Gansu province. The liver, kidney, heart and muscle contents of seven elements in yaks were also analysed. Most serum biochemical values were similar to those of cattle, camels and sheep, but the calcium concentration was considerably above the normal range for other ruminants. The liver contained the highest concentrations of copper, manganese and cobalt and the kidney of selenium, iron and calcium.Abbreviations Alb albumin - ALT alanine aminotransferase - AST aspartate aminotransferase - BUN blood urea nitrogen - Chol cholesterol - Glob globulin - -GT -glutamyl transpeptidase - IP inorganic phosphorus - TP total protein     

Avian brood parasitism — a growing research area in behavioral ecology (part Ⅱ)

正We are pleased to publish the second special issue on avian brood parasitism and to be responsible guest editors for the two special issues of Chinese Birds (Vol. 3, No. 4, 2012 and Vol. 4, No. 1, 2013), entitled "Avian Brood Parasitism - A Growing Research Area in Behavioral Ecology". The first issue was published in December 2012. The goal of the two special issues is to publish accumulated knowledge and some of the recent developments in     

Internal Parasites and Haematological Values in Cattle Slaughtered in Buea Subdivision of Cameroon

Tropical Animal Health and Production -