几种培育措施对河西走廊盐化草地影响的研究

在连续３年的定位研究中：（１）对以芦苇＋海韭菜为主要的草地进行施肥、划破草皮和刈割等培育措施。结果表明,拖肥可提高草地质量,当施Ｎ量不超过３００ｋｇ／ｈｍ＾２时,草地产量随施Ｎ量的增加而增加;最佳的刈割时间为秋季;采用的划破草皮的方法对草地质量无显著的影响。（２）在芦苇－赖草为主的草地中,研究了３不同的灌溉频率处理对草地植被和土壤水盐含量的影响。草地土壤含盐量随灌溉次数的增加而降低;连续灌溉第３年     

退化人工草地更新效果观测

利用草地建植方法,对１７５．７ｈｍ＾２退化人工草地进行了更新改良,结果,当年平均干草产量达３５７０ｋｇ／ｈｍ＾２比未更新地带提高２０５８ｋｇ／ｈｍ＾２;播种牧草相对重量６５．９％,未更新地带１５．１％,优势度由重建前的２７．０％上升至６１．８％,恶性杂草竞争力下降,基本形成白叶＋黑麦草＋鸭茅＋画眉草＋红三叶＋狗尾草＋白茅＋蒿类的格局。     

江河源头草地生态环境现状及恢复途径

江河源头共有可利用天然草地１８８．６７万ｈｍ＾２,其中“黑土型”退化草地约为２１３．０３万ｈｍ＾２,此类草地鲜草产量４００．５ｈｍ＾２,植被平均盖度为４５．４２％。恢复草地生态环境的途径是：改变认识观念;建立人工草地;利用多年生人工草地进行幼畜放牧育肥;通过退化草地施肥、毒杂草防除等措施恢复天然植被。     

云南人工草地综合复壮技术的研究

用正交试验方法,通过除杂、施肥,补播等综合措施,对因杂草侵入,缺水缺肥,利用过度而导致建植草种过早丧失生产性能的“多年生黑麦草－白三叶”人工草地进行复壮试验,结果表明,施肥是较有效的复壮措施,牧草产量提高６５．４％;１００％除杂,施用尿素１５０ｋｇ／ｈｍ＾２,普钙１０５ｋｇ／ｈｍ,硫酸钾３０ｋｇ／ｈｍ＾２,松土撒播多年生黑麦草种子１３．５ｋｇ,白三叶草籽４．５ｋｇ为最佳技术组合,２年平均其牧草产量     

不同施氮量对高山草甸草地牧草产量及营养成分的影响

对高山草甸草地施氮５０ｋｇ／ｈｍ＾２和８０ｋｇ／ｈｍ＾２的试验结果：产草量提高１１０．２％和１７２．２７％，粗蛋白质产量提高１２６．３９％和１９６．１０％，但施氮对牧草其它营养成份无明显影响。实施本项技术措施后，能提高高山草甸冬春牧地的载畜量，具有显著的经济效益和生态效益。     

科尔沁草甸草原放牧强度对肉牛增重与草地的影响

研究了不同放牧强度下（０．８ｎｍ＾２／牛和１．２ｈｍ＾２／牛）科尔沁肉牛的日增重和单位面积产量的差异,以及其对草地状况的影响,研究结果表明,不同放牧强度下肉牛的日增重无显著差异（分别是０．４４１ｋｇ和０．４４８２ｋｇ）;高放牧强度的处理,单位面积的产量高（分别是０．５５２５ｋｇ／ｈｍ＾２－ｄ和０．３７３５ｋｇ／ｈｍ＾２．ｄ）,但对草地持续生产不利,导致草群中禾草比例下降而杂草比例上升。     

施氮与株丛切割对退化新麦草草地的改良效果

本文研究了施氮肥和株丛切割对退化新麦草人草地生产性能的影响，结果表明，施氮肥和株丛切割提高了新麦草草地生产性能和生产力。此外，施氮肥可改善牧草品质及土壤牮氮能力。株丛切割和施氮肥（１２０ｋｇ／ｈｍ＾２）相结合与单施氮肥相比，成本较低，对退化新麦草草地的改良效果良好，年均产草量２６７９．５ｋｇＤＭ／ｈｍ＾２。     

围栏草地施肥效果试验

１９９８年５月在黄南州河南县进行了天然草地施肥试验。结果表明：施尿素为２２５ｋｇ／ｈｍ２、１５０ｋｇ／ｈｍ２、７５ｋｇ／ｈｍ２时,其产量（ＤＭ）分别为：５４７０ｋｇ／ｈｍ２、５０９３．３ｋｇ／ｈｍ２、５０４６．７ｋｇ／ｈｍ２;比对照高３４．７３％、２５．４５％、２４．３０％;施羊板粪１５０００ｋｇ／ｈｍ２时,其产量为４８２３．３ｋｇ／ｈｍ２,比对照高１８．８０％。     

利用荒漠和盐碱地建立人工草地的效益分析

１９９１～１９９２年，在海西州德令哈市利用荒漠建立半人工草地８６．１ｈｍ＾２，利用盐碱弃耕地建立人工草地７４．６ｈｍ＾２，取得了明显的生态、社会和经济效益，建植第三年的沙打旺人工草地植被盖度由原来的１５％提高至７０％～８０％，耕层（０－３０ｃｍ）总盐平均含量由原来的９．３ｇ．ｋｇ＾－１，下降１．２３ｇ．ｋｇ＾－１，脱盐率达８６．２６％，在受益期内，１６０．７ｈｍ＾２人工、半人工草地可新增牧草３６０     

草地改良对高寒退化草地植被影响的研究

针对近年来高寒草地退化问题,进行了围栏封育、划破草皮和施肥三种改良试验研究。结果表明,三种改良措施都增加草群高度、盖度、密度、频率和产量,施肥改良使可食牧草产量增加４５．９％～１９１．１％;围栏封育使可食牧草产量增加６０．５％～１５８．３％;划破草皮使可食牧草产量增加３２．７％～１１３．９％。由此可知,施肥和围栏封育是草地改良的有效途径。     

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