天然草地分类的Bayes判别分析法

基于多元统计分析理论,综合考虑天然草地的生态状况、可再生产能力和经济条件等因素,选择植被覆盖度、可食风干牧草产量、牧草利用率、草地可利用面积系数、草群中优良牧草比率和羊单位需草地面积6个参数作为判别因子,建立了天然草地分类的Bayes判别分析法。将天然草地分为温性荒漠类、温性草原类和低山地草甸类3个类别,并作为Bayes判别分析的3个正态总体,以新疆准噶尔盆地西部地区的31个天然草地为样本(其中18个为训练样本),以Bayes线性函数值和后验概率对样本所归属的总体进行识别,将建立的模型对训练样本进行回判,以回代误判率对模型进行检验。研究表明,Bayes判别分析模型可以很好地反映不同类型天然草地间的资源属性,对训练样本的回代误判率为0;对另外13个天然草地样本的分类结果与灰色关联度分析法、投影寻踪法、投影寻踪动态聚类法、集对分析法、SOFM神经网络法以及突变级数法等的分类结果基本一致。     

基于SOFM网络法的天然草地分类

自组织特征映射(SOFM)模型是一种无监督的人工神经网络计算方法,适用于解决多种分类和识别问题。本研究首次将SOFM网络法用于中国新疆准噶尔盆地西部地区的天然草地分类中,基于该法的聚类功能,依据草地生产、生态、经济等方面的6个天然草地分类指标,结合Matlab软件对神经网络进行权值训练,将这31份草地样本数据分为温性荒漠类、温性草原类、草甸类3类。并将分析结果与集对分析法、灰色关联度分析法、投影寻踪法做了对比分析。结果表明,SOFM网络法与上述3种方法分析基本一致,可以很好地反映和提取样本中复杂的信息,分类效果较好。说明了SOFM网络法对不同类型草地之间草地资源的整体性有很好的区分度。由此得出SOFM网络法对草地进行分类具有很好的实用价值,可以在聚类分析中广泛应用。     

基于PCA方法以牧草营养成分评判青海省海南州天然草地类型质量初探

为了科学评价天然草地类型及牧草饲料的质量,应用主成分分析法对青海省海南州天然草地各草地类型牧草饲料,在常规分析的基础上进行了综合质量评定和量化评估,通过对各天然草地类型牧草饲料品质主成分分析的综合得分进行对比,较为全面客观地评价天然草地各草地类型的优劣。结果表明：天然草地各类型中高寒草原类牧草饲料品质最好,其次是低平地草甸类、高寒草甸类、温性荒漠类、温性荒漠草原类、温性草原类。     

基于PCA方法以牧草营养成分评判青海省海南州天然草地类型质量初探

为了科学评价天然草地各草地类型中牧草饲料品质的质量,在常规分析的基础上,采用主成分分析法对青海省海南州天然草地各草地类型中的牧草饲料进行了综合质量评定和量化评估,通过对天然草地各草地类型牧草饲料品质主成分分析的综合得分进行对比,较为全面客观地评价了天然草地各草地类型的优劣。结果表明,天然草地各草地类型中高寒草原类牧草饲料品质最好,其次是低平地草甸类、高寒草甸类、温性荒漠类、温性荒漠草原类、温性草原类。     

阿克苏地区温性荒漠类草地分布、特征

阿克苏地区天然草原有11个草地大类，温性荒漠类草地是其中之一，其面积134.19万hm2，占全地区天然草地总面积的37.92%。温性荒漠类草地生态系统脆弱性，是草原生态补奖机制重要的禁牧区，是天山南坡平原绿洲的保护屏障，在草地生态系统中占有重要位置。查清温性荒漠类草地的分布、特征，为该草地的利用、保护和维护温性荒漠类草地生态系统的良性循环提供基础资料。     

用模糊概率综合比较法对海南州天然草地类型饲草营养成分品质的评定

为了科学评价天然草地类型饲草饲料品质的质量,采用模糊概率综合质量比较法对海南州天然草地各草地类型饲草饲料,在常规分析的基础上进行了综合质量评定,结果表明:天然草地各草地类型中温性草原类饲草饲料品质最好,其次是高寒草原类、高寒草甸类、低平地草甸类、温性荒漠草原类、温性荒漠类饲草饲料,分别居第3、4、5、6位。     

柴达木盆地草地类型及其分布规律

柴达木盆地天然草地面积696．9万公顷，依据中国草地类型分类系统，可分为温性草原类、高寒草原类、温性荒漠类、高寒荒漠类、低地草甸类、山地草甸类、高寒草甸类及沼泽类等8类、38个草地型。主要由于水分、热量条件的变化，导致柴达木盆地草地类型在东半部以温性草原类为主，西半部以温性荒漠类为主。受地形地貌特征及海拔高度的影响，草地类型垂直分布格局明显，从盆地中心至边缘呈现沼泽类、低地草甸类、山地草甸类、温性荒漠类或温性草原类、高寒草原类、高寒草甸类或高寒荒漠类。     

用模糊概率法评定各类型天然草地饲草品质初探

为了科学评价天然草地各类型饲草的质量,采用模糊概率综合质量比较法对海南州天然草地各类型饲草,在常规分析的基础上进行了综合质量评定,结果表明:天然草地各类型中温性草原类饲草品质最好,其次是高寒草原类,高寒草甸类、低平地草甸类、温性荒漠草原类、温性荒漠类饲草分别居第3、4、5、6位。     

用模糊概率法评定各类型天然草地饲草品质初探

为了科学评价天然草地各类型饲草的质量，采用模糊概率综合质量比较法对海南州天然草地各类型饲草，在常规分析的基础上进行了综合质量评定，结果表明：天然草地各类型中温性草原类饲草品质最好，其次是高寒草原类，高寒草句类、低平地草甸类、温性荒漠草原类、温性荒漠类饲草分别居第3、4、5、6位。     

中国天然草地的分类

本文根据８０年代全国草地资源调查研究的实践，在总结以往草地分类原则和方案的基础上，提出了我国天然草地新的分类原则和类、组、型三级分类体系及其相应的分级标准。并将我国天然草地划分为８个类。     

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.     

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.     

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.     

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

Tropical Animal Health and Production -     

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.     

Chemotaxis of macrophage in inflammation

Our particular attention in this article was given to natural mediators for macrophages isolated from the sites of tissue injury. A number of chemotactic factors, which may satisfy many criteria making them acceptable as inflammatory leucocyte chemotactic factors, has been separated. Among them, our laboratory has isolated three macrophage (monocyte) chemotactic factors (MCF-a, -b and -c). Their purification, characterization and functional specificity are discussed.     

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