控释氮肥在模拟运动场草坪中的应用研究

采用PVC管为模拟运动场的基础构造，研究控释氮肥对运动场草坪颜色、均一度、生长速度、地上生物量的影响以及模拟超量降雨条件下收集的淋洗液硝酸盐动态变化情况。研究结果表明：控释氮肥养分释放速率最低、肥效最长，与尿素相比可改善运动场草坪的外观品质；控释氮肥抑制草坪草过分生长，减少运动场草坪的修剪次数，控释氮肥通过控制氮素的释放减少氮肥淋失，降低水体硝酸盐污染和富营养化。     

速效氮肥和缓释肥混施对早熟禾草坪的影响

按氮肥对植物产生效果的快慢可分为速效氮肥和缓释氮肥。速效氮肥能很快改善草坪质量，但用量太高时不但会灼烧草坪，而且还会使营养成分大量淋失。而施用量太低，有可能满足不了草坪生长发育的需要，而且必须经常施用，需要大量的人力、物力。缓效肥料又称长效肥料、迟效肥料，     

春播冷季型草坪草苗期管理措施对草坪建植质量的影响

研究结果表明，北京地区春季播种的匍匐剪股颖、草地早熟禾和高羊茅三种冷季型草坪草，播后施氮肥并防除杂草，较单独施氮肥或单独防除杂草明显地提高了苗期草坪盖度，增加了草坪草种苗的地下和地上生物量，缩短了成坪所用时间；除草地早熟禾单独施氮肥、单独防除杂草和对照处理外，三种草坪草的各处理均在进入炎热的夏季前成坪；防除杂草可明显地提高三种草坪草的分蘖能力，增加草坪密度；草地早熟禾较匍匐剪股颖和高羊茅对杂草更为     

氮肥对草坪作用的研究进展

氮肥在草坪草的生长发育过程中起着主导作用,对草坪的表观质量、利用性状、绿期及抗性等方面有重要影响.本文综述了国内外氮肥对草坪影响的现状,提出了今后草坪肥料的研究方向.     

草坪在生态城市建设中的作用及其应用

论述了草坪在城市生态系统中的生态效应是目前我国在应用草坪提高城市生态质量方面存在的问题，通过对城市生态系统特殊性的分析，提出了草坪系统规划的目的和原则，力求把城市建设成为生态协调、可持续利用和良性循环的人居环境。     

草地早熟禾草坪夏季施肥

氮肥用量是提高草地早熟禾草坪生长速率和修剪量的主要因素。含氮肥的磷酸二胺和尿素处理都能改善草地早熟禾草坪夏季颜色和盖度 ,提高草坪质量 ,但同时不同程度加重了草坪夏季病害 ,而施用磷酸二氢钾的处理提高了草坪的抗病性。     

氮素和磷素在草坪系统中的转化

<正> 硝酸盐在草坪生态系统中的淋溶是变化无常的.影响硝酸盐淋溶的因素包括土壤类型,灌溉、降水、温度、氮肥的种类、用量及使用季节。着重研究了不同的草坪和气候区域中氮、磷化合物的转化。研究内容以氮的活动为主。 试验还没有完成,但目前获得的数据可以进行一些比较,其中包括所有项目中每年硝酸盐淋溶量的大体比较。不同气候区、不同土壤类型中硝酸盐的淋溶量比较、以及氮的     

草坪型黑麦草氮肥品种及氮磷钾配施肥效试验

在含氮量相同前题下，氮肥品种为硫酸铵，硝酸铵，尿素，磷酸氢二铵以及氮磷钾以Ｎ：Ｏ２Ｏ５：Ｋ２Ｏ＝５：３：２配施这５种肥料作为黑麦草的追肥材料，分析记录草坪草的叶绿素，密度，盖度，频度，分蘖数，越冬率，含Ｎ量，生长率，利用草坪质量评定方法及灰色系统理论中的关联分析方法进行分析评估，结果表明：ＮＰＫ配施草坪草达优等，氮肥品种中硝酸铵肥料肥效最好，尿素，磷酸氢二铵次之，硫酸铵最差。     

草坪施肥与硝态氮淋溶问题研究进展

综述了近年来国内外对草坪硝态氮淋溶问题的研究现状与进展,以及国内草坪施肥管理的研究现状,对有效的减少我国草坪硝酸盐淋失的途径和方法进行了探讨。影响草坪硝酸盐淋溶的因子主要包括：氮肥种类、施氮水平、施肥时间、灌溉、土壤状况等。减少硝态氮淋溶的合理途径有：合理确定施肥量;选择合适的氮肥种类和施肥方式,如使用缓释氮肥,碳／氮比高的有机肥;施用硝化抑制剂;合理的灌溉等。目前,国内有关草坪硝酸盐的研究与国外相比,还较为欠缺,研究适合我国草坪的长效氮肥,制定舍理、有效、安全的草坪施肥制度已成为研究发展的趋势。     

施氮后氨的挥发损失及其对草坪草生长的影响

在多年生黑麦草草坪施用速效与缓效氮肥后,对氨的挥发损失进行田间定位测定。结果表明,占施入量0.77%～20.7%的氮以 NH3的形式挥发。氮肥种类不同,挥发动态各异,损失量之间差异显著。在供试的5种氮肥中,氮素损失率的顺序为:普通尿素 >塑膜包衣尿素 >国产草坪专用肥 >IBDU草坪肥 >日本包膜缓释肥。缓效性能越好,氨的挥发损失越少,缓释氮肥不但显著降低氨的挥发,而且能持久高效地保持草坪质量。     

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.     

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