红三叶N、P、K、Ca、Mg元素含量与动态研究

本文研究了红三叶（Trifoliumpratense）各器官在不同生育期N、P、K、Ca、Mg等元素的含量，目的在于揭示其各器官对N、P、K、Ca、Mg的积累能力、对不同元素的选择性吸收以及N、P、K、Ca、Mg在各器官的季节动态。结果表明：红三叶不同器官对各元素的积累能力不同，N：叶＞花＞根＞茎；P：花＞叶＞根＞茎；K和Ca：叶＞花＞茎＞根；Mg：根＞叶＞茎＞花。不同器官对元素选择性吸收系列不同，根为N＞K＞Ca＞Mg＞P；茎：N＞Ca＞K＞Mg＞P；叶：N＞Ca＞K＞P＞Mg；花：N＞Ca＞K＞P＞Mg；红三叶是一种典型的N－Ca型植物。此外，K、P、K、Ca、Mg在根、茎、叶、花中的动态变化有6种基本类型，Ⅰ－渐增型（／）、Ⅱ－递减型（＼）、Ⅲ－U型、Ⅳ－∩型、Ⅴ－增波型（～）、Ⅳ－降波型（～）。     

广西“桂热芒82号”叶片营养规律研究

通过对广西田东地区“桂热芒82”号叶片中N、P、K、Ca、Mg、S6种营养元素含量进行全年跟踪分析,结果表明：“桂热芒82号”生长周期分为4个阶段：营养生长期(8—12月)、生殖生长期(12—2月)、果实膨大期(2-5月)、果实成熟期(5-7月)。叶片养分年平均含量大小为：第一蓬Ca＞N＞K＞Mg＞S＞P、第二蓬Ca＞N＞K＞S＞Mg＞P。各阶段叶片养分含量变化规律有所差异,第一、二蓬叶片变化基本规律一致。第一、二蓬叶片Ca、N、K、Mg、S、P含量（g/kg）为：19.84、15.36、8.34、1.90、1.58、1.32和23.45、14.46、7.22、1.56、1.77、1.18,该品种对钙肥的需求量较大。     

海南台农和金煌芒叶片养分周年动态变化分析

对海南主栽芒果品种台农和金煌芒的叶片养分的变化动态进行了分析。结果表明,相同栽培模式下,芒果叶片养分含量在不同品种、不同生长发育阶段和不同物候期之间存在显著的差异,但总体规律为：Ca＞N＞K＞Mg＞P＞Mn＞Fe＞Cu＞Zn。营养生长期间,不同月份芒果叶片中N、P、K、Mg含量基本保持在同一水平上;生殖生长期间,养分从叶片转移至花芽中,叶片养分明显下降。对于大量元素N、P、K、Mg而言,8月份至12月份叶片养分波动较小,因此10月份芒果的叶片可以作为叶片营养诊断的采样时间。     

紫穗槐植株的养分含量及分布特征

为了探明紫穗槐植株的营养结构特征,测定了生长季(6,7,8,9月)紫穗槐叶和不同径级根、茎的10种养分(有机碳、N、P、K、Ca、Mg、Fe、Mn、Cu、Zn)含量。结果表明,1)根和茎的N、P、K含量与径级呈典型逆相关关系,即随着径级的增大养分含量减少,含量最高的部位集中于叶及小径级的根、茎。2) 各级根、茎的Ca、Mg、Fe、Mn、Cu、Zn含量没有固定的分布特征。3)微量元素间的相关性比其与大量元素的相关性差,茎中所含相关元素对最多,其次是叶,根最少;从元素方面看,N、P、K与较多的元素间存在相关性,与C、Zn、Ca相关的元素较少。4)生长季紫穗槐叶的C、N、Ca、Mn、Cu含量高于根和茎,叶中大量元素的含量顺序为C＞N＞K＞Ca＞Mg＞P,微量元素为Fe＞Mn＞Zn＞Cu。     

云南“帕拉英达”芒果叶片营养规律研究

通过对云南保山地区“帕拉英达”芒果成熟功能叶片中N、P、K、Ca、Mg、S等 6种营养元素含量进行跟踪分析,结果表明：叶片养分年平均含量大小为： Ca＞N＞K＞P＞Mg＞S,其全年平均含量（g/kg）分别为：25.16、15.20、4.56、1.39、1.35、1.34;不同生育期叶片养分含量变化规律有所差异,根据叶片养分含量的变化规律,可把“帕拉英达”芒果生长周期分为4个阶段：营养生长期(8－次年1月)、生殖生长期(1－3月)、果实膨大期(4－5月)、果实成熟期(6－7月)。     

玛曲高寒草地土壤养分对不同利用方式的响应

选取玛曲高寒围封草地(封育草地、修复草地)、开垦地(燕麦地)以及不同退化程度草地(中度退化草地、黑土滩草地、沙化草地),对土壤养分进行分析研究.结果表明:草地的开垦与退化,使土壤有机碳(SOC)、全N、有效N、全P、有效P含量显著下降,而pH值却显著升高.随着草地的开垦与退化,全K、有效K变化不明显,沙化草地土壤中全Ca含量显著增高,约是其它利用方式的3倍以上.中度退化草地的全Mg含量最高,燕麦地、封育草地也出现了较高的Mg含量,但无显著差异.各项养分指标之间存在一定相关性, 尤其是SOC与全N、有效N呈极显著正相关,与全P、有效P、全K、有效K、全Mg含量呈显著正相关,与全Ca含量呈显著负相关关系.土壤pH值与土壤全Ca含量呈显著正相关关系,而与土壤其他养分呈显著负相关关系.土壤全Ca与全Mg之间呈显著正相关.     

苏丹草干物质积累及养分吸收规律的研究

在田间试验的条件下研究了苏丹草Sorghum sudanense干物质积累及养分吸收规律.结果表明,苏丹草干物质积累量随着生长进程不断增加,出苗后39～62 d,干物质量增加最快,占干物质总量的35.4%,日积累量也最大,为335.59 kg/(hm2·d).试验条件下,苏丹草鲜草产量为190.00 t/hm2,需吸收N 489.9、P2O5 122.4、K2O 585.3、Ca 106.6、Mg 38.3 kg,N:P2O5:K2O:Ca:Mg为1:0.25:1.19:0.22:0.08;需吸收Fe 6 364.6、Mn 1 383.9、Cu 236.2、Zn 1 498.0 g,N:Fe:Mn:Cu:Zn为1 000:13.0:2.8:0.5:3.1.养分吸收量和比例可作为苏丹草合理施肥依据.     

铁尾矿区沙棘-桑树人工混交林的养分分配状况

为了评估铁尾矿区废弃地的植被恢复中,利用沙棘-桑树人工混交林提高林地养分总体水平的可行性,测定混交林中沙棘、桑树和草本植物的地上部分、根系及枯枝落叶中的N、P、K、Ca、Mg含量与贮量,测定沙棘、桑树根系周围土壤中的养分含量。结果表明:沙棘的根、干、枝、叶、皮中的N含量明显高于桑树,尤其是不同土层根系中的N含量可达到桑树根系的3.03～4.33倍,沙棘根系中的Ca、Mg含量高于桑树,P含量与桑树相近,而桑树地上部分的P、K、Ca、Mg含量以及各土层根系中的K含量大多高于沙棘;沙棘根系周围土壤中的全N含量高于桑树根系周围土壤,其平均含量为桑树的1.88倍,根系周围表层0～20 cm土壤的全N含量为桑树的3.18倍;混交林中乔木、草本、枯落物的总养分贮量大小为:沙棘>枯枝落叶>桑树>草本植物,其中沙棘的养分贮量占混交林系统养分总贮量的56.10%。研究结果提示:沙棘在整个混交林系统的养分分配中起到支配性作用,可为桑树的正常生长发育提供良好的养分空间,沙棘-桑树混交林是生态效益与经济效益双赢的混交模式。     

"黑麦草-水稻"草田轮作系统研究Ⅶ黑麦草残留物的田间分解及营养元素的释放动态

采用尼龙网袋分解法,将一定量的黑麦草根系和地上留茬(统称黑麦草残留物)置于田间耕作层令其自然分解,分别于埋设后11,39,70,109,161和244 d收集尼龙网袋内的样品,洗净,烘干,称重后用于分析全量N、P、K、Ca、Mg、Mn和Fe的含量.结果表明,黑麦草残留物在大田中通过生物降解,将养分释放到土壤中,在后作水稻的生长发育过程中,分解初期的释放量较高,埋设10 d后黑麦草残留物样品中近90%的Ca和37%～50%的C、N、P、K和Fe被释放,Mn和Mg则只有0.4%～13.4%被释放.在早稻生长过程中黑麦草残留物有74.9%被分解,C、N、Mn和Mg的矿化率均在80%以下,表现出一定的缓释效应.晚稻收获时各养分的释放率达到92%～99%.理论上黑麦草根系可以为0～20 cm土层贡献有机质、N、P、K、Fe、Mn、Mg和Ca分别达到865.42 g/kg,26.92 g/kg,1.75 g/kg,23.83 g/kg,2 741 mg/kg,75 mg/kg,162 mg/kg和46 mg/kg.     

纽荷尔和清家脐橙果实大量元素含量与累积变化

以30年生枳砧清家脐橙和纽荷尔脐橙为材料,分析果实生长发育过程中N、P、K、Ca、Mg、和S 6种大量营养元素含量和累积量变化。结果表明,果实生长发育过程中,纽荷尔和清家果实中N、P、Mg和S含量4月最高,Ca在10月最高,纽荷尔和清家K含量分别在9月和7月最高;纽荷尔果实的N、P、K、Mg和S主要累积时期为7～9月,Ca主要累积时期为9～10月;清家果实的N、P、K、Mg和S主要累积时期为6～8月,Ca主要累积时期为8～10月。清家脐橙果实中大量营养元素的主要累积时期比纽荷尔脐橙早1个月左右。     

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