土壤理化性质与青稞根腐病发生的关系

调查了甘肃省甘南州成株期青稞根腐病的发生危害,并采集青稞健康植株和根腐病植株根际土壤,测定了土壤理化性质和土壤酶活性,以评价土壤理化性质与青稞根腐病的关系。结果表明,甘肃甘南州青稞发病率在5%~20%,同一样地青稞病健康植株根际土壤黏粒、粉粒、砂粒、有机质、有效磷、速效钾、铵态氮、硝态氮的含量及pH无差异,即与根腐病发病率相关性不显著,但土壤酶活性均存在显著差异,健康植株根际过氧化酶活性大于病株(HD)的占64%,其中,50%差异显著;健株根际土壤碱性磷酸酶活性大于病株(HD)的占93%,其中,有79%差异显著;健康植株根际土壤脲酶活性大于病株(HD)的占71%,且均有显著性差异;健康植株根际土壤纤维素酶活性小于病株(HD)的占93%,其中有79%存在显著差异;健康植株根际土壤蔗糖酶活性大于病株(HD)的占93%,且均有显著性差异。脲酶和蔗糖酶与成株期青稞根腐病发病率呈中度负相关,相关系数分别为0.64和0.62,其他3种酶则与成株期青稞发病率相关性不显著。     

喜旱莲子草对不同生境植物群落多样性的影响

为了测定外来入侵植物——喜旱莲子草对其他物种的影响,采用样方法对喜旱莲子草的不同生境内植物群落进行了调查,测定了其伴生植物的种类、数量和盖度,检测了喜旱莲子草的植株茎长、分枝数、叶长、叶宽、节间距等形态指标,分析了该入侵植物在不同生境中的重要值和群落多样性。结果表明,1)在湿生环境中,喜旱莲子草的生长状态较好,植株的茎长、叶面积和节间距等均与其他生境中的植株呈显著性差异;但是,在人为干扰较强生境中(农田、路边)的植株叶面积和节间距明显较其他生境中的相应指标减小或者缩短。2)当喜旱莲子草的重要值超过一定值(60.96%)时,群落内植物的多样性指数呈下降趋势,表明喜旱莲子草的入侵影响了群落内植物种类的丰富度,即当该入侵植物形成一定的优势时,将导致群落内其他物种的减少甚至消失。     

转DREB1A/Bar双价基因马铃薯的耐旱性及除草剂抗性分析

在前期获得DREB1A/Bar双价转基因马铃薯的基础上,对转基因植株进行了耐旱性和除草剂抗性分析。耐旱性分析显示,在正常浇水条件下,对照和各转基因马铃薯株系生长状态良好且大致相同,各株系的丙二醛含量、相对电导率和SOD酶活性无显著差异(P0.05)。经过控水10d后,非转基因对照植株叶片明显萎蔫卷曲,而转基因植株仍然保持良好的生长状态;转基因株系的丙二醛含量和相对电导率显著低于非转基因株系(P0.05),而SOD酶活性显著高于非转基因对照(P0.05)。控水18d时,大部分对照植株死亡,死亡率为74.33%;转基因植株只有极少数植株死亡,DR2和DR5的死亡率分别为20.43%和5.65%。用0.3%的市售草铵膦喷施各株系,10d后,对照植株全部枯死,转基因株系的个别叶片干枯,绝大多数叶片及所有茎秆生长状态良好。以上分析表明,DREB1A和Bar基因的导入,明显增强了转基因马铃薯对干旱和除草剂的抗性。     

不同甜高粱品种（系）农艺性状与产量、品质的相关性研究

为探讨甜高粱农艺性状与产草量和营养品质之间的关系,本研究以15份甜高粱品种（系）为材料,对其农艺性状、产草量、营养成分含量开展研究。结果表明：15个引进品种（系）在甘肃临夏山旱地区均能正常生长,但均达不到完全成熟。农艺性状在各品种（系）间均存在显著性差异（P < 0.05）。株高与鲜草产量呈极显著正相关（P < 0.01）,与干物质产量呈显著正相关（P < 0.05）。主茎叶片数与酸性洗涤纤维呈极显著正相关（P < 0.01）,与中性洗涤纤维呈显著正相关（P < 0.05）,与总可消化养分含量呈极显著负相关（P < 0.01）|全株叶片数和节间数与酸性洗涤纤维、中性洗涤纤维均呈显著正相关（P < 0.05）,节间数与总可消化养分含量呈显著负相关（P < 0.05）|茎粗和单株茎重与可溶性糖含量呈极显著正相关（P < 0.01）,单株鲜重与可溶性糖含量呈显著正相关（P < 0.05）。株高与粗蛋白质产量呈显著正相关（P < 0.05）。通过聚类分析,将供试品种（系）划分为3类,第1类8个品种（系）,典型特点为品质最优,产量较低|第2类5个品种（系）,典型特点为高糖,产量、品质中等|第3类2个品种（系）,典型特点为产量最高,但品质较差。综合分析认为,以品质较优为目的时,应选择植株较低、茎秆粗壮和分蘖数较少品种|以单位面积产草量和营养物质产量较高为目的时,应选择植株较高、茎秆较细和分蘖数较多品种。 [关键词] 甜高粱|农艺性状|产草量|品质性状|相关性|聚类分析     

中华鳖饲料复合植物蛋白替代鱼粉的效果研究

为降低中华鳖饲料生产成本，本试验在中华稚鳖[（6.93±0.28）g]饲料中使用不同量的复合植物蛋白源（大米蛋白粉、发酵豆粕和去皮豆粕），同时不同程度降低进口鱼粉和国产鱼粉的用量，根据饲料配方中复合植物蛋白源（P）与鱼粉（F）使用量的比值从低到高分别设置对照组（生产配方P/F28C），试验组P/F28E、P/F33E和P/F41E 4种粉状饲料，在温棚中饲养中华鳖稚鳖49 d|并于养殖试验结束时（此时视作冬眠初期），于原池铺沙进行为期6个月的抗低温（冬眠）应激试验。结果表明：养殖试验期间，四种饲料对中华鳖的生长和形体指数均无显著影响（P ＞0.05），但P/F28E组增重率稍显弱势，P/F28C和P/F33E组血清中溶菌酶活力显著高于P/F28E、P/F41E两组（P ＜ 0.05）。冬眠期间，所有试验组的增重率均表现为先下降后上升，但P/F28C和P/F33E组能在冬眠复苏后快速适应环境而增加体重，P/F41E组相对增重率均显著低于其他试验组（P ＜ 0.05）|P/F33E组在冬眠初期和中期血清中碱性磷酸酶活力显著高于其他试验组（P ＜ 0.05），且在整个冬眠期血清超氧化物歧化酶（SOD）活力波动最小。综上可知，在本试验条件下，P/F28C和P/F33E组为最适配方，考虑生产成本因素，则P/F33E组为最优配方。 [关键词] 中华鳖|复合植物蛋白|冬眠|生长性能|血清指标|消化酶     

“连黄”中草药添加剂对东兰乌鸡生长性能及日粮养分代谢的影响

为探讨“连黄”中草药添加剂对东兰乌鸡生长性能及日粮养分代谢率的影响,试验将1日龄东兰乌鸡480羽分为4组,每组设6个重复,每个重复20羽。其中A组喂基础日粮为对照组|B、C、D组为试验组,分别在基础日粮中添加0.25%、0.50%和1.00%的“连黄”中草药添加剂,试期70 d|饲养试验结束时,从每组中抽取24羽体重相似的试验鸡,以饲养试验相同设计,继续饲喂原日粮进行代谢试验,测定养分代谢率。结果显示：除了50 ～ 70 d之外,B组在其他各阶段的平均日增重（ADG）分别比A组提高了5.00% ～ 9.15%（P < 0.05）,70 d平均个体重也提高了4.86%（P < 0.05）|C组在36 ～ 49、1 ～ 49 d和1 ～ 70 d的ADG及70 d时平均个体重也分别高于A组5.90%、2.66%、2.68%和2.57%（P > 0.05）|36 ～ 49 d时A组的平均日采食量（ADFI）高于B组6.04%（P < 0.01）,分别高于C、D组5.12%和4.13%（P < 0.05）,且在1 ～ 49 d时A组高于C组2.86%（P < 0.05）,此外的各阶段4组试鸡之间均无明显差异（P > 0.05）|料重比（F/G）：在22 ～ 35 d和1 ～ 70 d时B组低于A组6.32%和3.41%（P < 0.05）,在36 ～ 49 d和1 ～ 49 d时低于A组11.43%和7.31%（P < 0.01）|36 ～ 49 d时C组的F/G低于A组10.15%（P < 0.05）,且在1 ～ 49 d时低于A组5.29%（P < 0.01）,其他阶段两组间均无明显差异（P > 0.05）|养分代谢：本添加剂的3种不同添加量,对日粮的DM、CP、CF、NFE、CA、Ca、P、TE等养分的代谢率均有不同程度提高,其中尤以0.25%和0.50%添加量的提高程度显著。综上所述,日粮添加0.25%的“连黄”中草药添加剂可显著提高东兰乌鸡的生长性能及主要养分代谢率。 [关键词] “连黄”中草药添加剂|东兰乌鸡|生长性能|养分代谢率     

标记辅助选择在猪育种中应用效果的研究

本研究针对猪育种中重点考虑的窝产活仔猪数（NBA）、达100 kg体重日增重（ADG）、饲料利用率（FCR）、达100 kg体重的背膘厚（BF）、肌内脂肪含量（IMF） 5个性状,利用连锁平衡（linkage equilibrium,LE）、连锁不平衡（linkage disequilibrium,LD）标记和直接标记（direct marker,DR）3种类型的分子遗传标记,设计了3个规模不同的基础群,母猪数分别为100、200、300头,公猪数都为10头,基础群个体间无亲缘关系,育种群实施闭锁繁育。用Monte Carlo方法模拟了MAS的5个世代选择试验。育种值估计采用标准BLUP（Standard BLUP,SBLUP）模型（此育种值作为对照）、QBLUP模型（使用DR标记）、MBLUP模型（使用LD和LE标记）。结果表明,利用DR标记在各种情况下都比利用LD和LE标记获得的选择效率高;5个性状中,MAS对低遗传力、限性性状NBA的选择效率最高;当性状的QTL方差占遗传方差基本相同时,中等遗传力性状FCR的选择效率比高遗传力性状BF的更高;当性状的遗传力差异不大时,QTL方差占遗传方差比例大的性状FCR的选择效率比QTL方差占遗传方差比例小的性状ADG的更高。当利用QBLUP模型时,MAS对NBA的选择效率最高,ADG的选择效率最低。     

丝茅侵入量对结缕草相对产量及竞争力的影响

通过取代试验设计,设置5个丝茅侵入量梯度,模拟入侵草坪细叶结缕草(Zoysia tenuifolia)100d后,测定草坪草单株生物量、相对产量、相对产量和、攻击指数、竞争平衡指数等指标,研究侵入量对结缕草竞争力及生长潜力影响的差异。结果表明:丝茅侵入量对结缕草的地上相对产量无显著影响(P>0.05),但对地下相对产量(RS)有极显著影响(P<0.01);侵入量对群落地上相对产量总和(S)有显著影响(P<0.05),对群落地下相对产量总和(R)无显著影响(P>0.05),两物种的地上茎叶系统有拮抗作用。当丝茅侵入量为20%～30%时,两物种地下部分也有拮抗作用;侵入量对丝茅地上、地下攻击力指数均有极显著影响(P<0.01),10%侵入量时丝茅的攻击力最强,随侵入量增加丝茅的攻击力指数急剧下降,表现为种内竞争;丝茅侵入量对竞争平衡指数无显著影响(P>0.05),结缕草的竞争能力小于丝茅。丝茅入侵主要影响结缕草的分蘖能力和地上茎叶的生物量累积,从而刺激了地下根系的发育。所以,增加草坪密度、加快生物量积累是提高结缕草竞争力的有效途径。     

奶牛乳房炎发展的过程

1细菌侵入乳头乳头是乳房防止细菌入侵的第1道防线。正常情况下,不挤奶时,乳头括约肌会紧紧关闭着乳头管。细菌的入侵最常发生在挤奶期间。当有多余的空气进入挤奶器时,在奶中或乳头末端的细菌会被吸入乳头管和乳腺池中。正常的乳头管只有在挤奶1～2小时内处于扩张状态,但是损伤乳头的乳头管长期处于部分开放状态。环境中的微生物或存在于乳头末端损伤皮肤内的微生物很容易侵入开放或半开     

Pb胁迫下内生真菌侵染对德兰臭草生长及生理的影响

采用盆栽试验,对带菌(E+)和不带菌(E-)的德兰臭草进行不同浓度的铅(Pb)胁迫处理,探究Pb胁迫下内生真菌侵染对德兰臭草生长及生理的影响。结果表明,随着Pb浓度的升高,德兰臭草的株高呈现先增加后减少的趋势,当胁迫浓度达到1500 mg·L^-1时,德兰臭草的株高受到了显著的抑制,且根鲜重的下降幅度最大,显著低于对照82.5%(P<0.05);德兰臭草叶片中MDA含量显著增加(P<0.05),在胁迫浓度为2000 mg·L^-1时,E+植株MDA含量显著高于对照87.3%(P<0.05);德兰臭草体内的脯氨酸含量也呈现先增加后减少的趋势,当胁迫浓度达到500 mg·L^-1时,E+植株脯氨酸含量显著高于对照35.2%(P<0.05)。与不带菌植株相比,E+植株地上和地下的生物量均高于E-植株;E+德兰臭草的MDA显著低于E-(P<0.05),在Pb浓度为2000 mg·L^-1时,E+植株的MDA含量显著低于E-25.0%(P<0.05);E+植株的脯氨酸含量在Pb浓度为1500 mg·L^-1时显著高于E-植株84.1%(P<0.05)。总的来说,感染内生真菌的德兰臭草减轻了Pb对宿主的毒害,增强其对重金属Pb胁迫的生理生化适应能力。     

氟甲砜霉素（Florfenicol）在猪体内的药物动力学

健康猪6头,体重(24.7±1.0)kg,单剂量静注、肌注、内服氟甲砜霉素(Florfenicol)20mg/kg,用高效液相色谱法测定其血药浓度,实验所得的血药浓度-时间数据采用非房室模型统计矩原理分析处理.静注给药的主要药物动力学参数为AUC90.13mg/(L     

A preliminary investigation of the relationship between the “moment of resistance” of the canine spine, and the frequency of traumatic vertebral lesions at different spinal levels

The aims of this work were to re-evaluate the moments of resistance (MoRs) of the vertebral column proposed by Slijper (1946) in the dog and to study the relationship between the MoRs and the frequency distribution of vertebral traumas in the same species. The spine (C2-L7) of four dogs was measured to obtain MoRs and subsequently scanned with a dual-energy X-ray absorptiometer (DXA). These findings were then analysed retrospectively the frequency distribution of canine vertebral fractures and luxations, diagnosed radiographically at a referral practice. The highest percentage of vertebral injuries affected the T9-L7 tract. This study confirmed that this segment was characterized by a rising trend of the MoR curves and presumably bore the major bending forces. The significant correlation between T9-L1 MoRs and DXA values supports the Slijper’s hypothesis suggesting the posterior thoracic region as the weakest segment of the body-axis.     

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.