新疆野生沙芦草萌发期抗寒机制研究

以扁穗冰草和沙芦草为研究对象,采用5℃、10℃、15℃、20℃和25℃的低温胁迫处理,测定发芽率、发芽势、胚根长、胚芽长、电导率和丙二醛（MDA）含量,探讨2种牧草种子萌发期抗寒性。结果表明：扁穗冰草在5℃低温胁迫不能发芽、沙芦草能够发芽,10℃和15℃低温胁迫处理下沙芦草的发芽率、发芽势、胚芽长和胚根长都高于扁穗冰草,电导率和丙二醛含量低于扁穗冰草,20℃低温胁迫处理下沙芦草发芽率、发芽势、胚芽长和胚根长与扁穗冰草比,不形成显著差异,电导率和丙二醛含量也与扁穗冰草不形成显著差异;25℃低温胁迫处理下扁穗冰草的发芽率、发芽势、胚芽长和胚根长高于沙芦草。综合表明,沙芦草种子萌发期抗寒性强于扁穗冰草种子。     

贮藏温度和种子含水量对扁穗冰草种子质量的影响

以扁穗冰草(Agropyron cristatum)种子为试验材料,研究不同温度和含水量贮藏10个月后对种子发芽率和萌发过程中生理生化变化的影响。结果表明,贮藏温度和种子含水量对发芽率、根长和芽长均具有极显著影响(P0.01),而对丙二醛含量影响均不显著(P0.05)。扁穗冰草种子在-15℃且含水量为6%的条件下发芽率最高,为79.8%,在室温(20℃)且种子含水量为12%时,发芽率为0。扁穗冰草种子在4℃且含水量为6%的条件下胚根最长;在-15℃且含水量为12%的条件下胚芽最长。贮藏温度在20℃条件下,含水量为6%和12%的种子胚根、胚芽分别表现为最短和没有发芽。扁穗冰草种子在20℃且含水量为12%的条件下电导率最大;在4℃且含水量为4%的条件下电导率最小。相关分析表明,胚根与胚芽极显著正相关(P0.01),与电导率显著正相关(P0.05),其它各指标间均不显著相关(P0.05)。综合各项活力指标,扁穗冰草种子的适宜贮藏含水量为4%~6%,最佳贮藏温度为-15~4℃。     

干旱环境下4种高原禾本科牧草产量及营养品质比较

为筛选适宜干旱、半干旱环青海湖地区生长的优良牧草,测定了高原地区生长的4种禾本科本土牧草的生产性能和营养价值指标,并结合灰色关联度分析法进行了综合评价。结果表明,大颖草(Roegneria grandiglumis)和扁穗冰草(Agropyron cristatum)的叶茎比和鲜干比较高,适口性更好;同德短芒披碱草(Elymus breviaristatus cv.Tongde)的干草产量为最高,大颖草、同德短芒披碱草、同德贫花鹅观草(Roegeria pauciflora cv.Tongde)的草产量之间差异不显著;扁穗冰草的营养价值相对最好;4种供试牧草综合评价表现由高到低为：扁穗冰草>大颖草>同德贫花鹅观草>同德短芒披碱草。     

草原2号杂花苜蓿浸提液对4种牧草种子萌发的影响

通过研究草原2号杂花苜蓿(Medicago varia cv. caoyuan No.2)浸提液对4种牧草种子萌发的影响,探索利用生物检测法初步确定其与自身及其他3种牧草间化感作用。用草原2号杂花苜蓿根、茎、叶水浸提液处理草原2号杂花苜蓿、蒙古冰草(Agropyron mongolicum Keng)、扁穗冰草(Agropyron cristatum (L.) Gaertn.)和红豆草(Onobrychis viciaefolia Scop.)的种子,测定其发芽率、苗高、根长,利用生物检测法确定草原2号杂花苜蓿对受体植物的化感效应。结果表明:草原2号杂花苜蓿的自毒性及化感作用存在浓度效应,即不同浓度的根、茎、叶浸提液对不同受体植物种子萌发、幼苗高度、根长影响效果不同,其叶浸提液对扁穗冰草和蒙古冰草种子发芽的抑制效应小于草原2号杂花苜蓿和红豆草;其叶、茎、根浸提液对蒙古冰草、扁穗冰草的苗高、根长的促进作用大于红豆草和草原2号杂花苜蓿;根据试验结果,初步认为草原2号杂花苜蓿与蒙古冰草、扁穗冰草混、间播效果要比与红豆草混、间播和单一连播杂花苜蓿效果好。     

龙牧11扁穗冰草生物学特性及生产性能研究

龙牧11扁穗冰草(Agropyron cristatum(Linn.)Gaerta.cv.No.11)是黑龙江省畜牧研究所1994~2011年引种驯化的野生栽培品种。通过多年多点对其物候期、生长速度、越冬率等生物学特性和生产性能的研究,试验结果表明:该品种返青早,青绿期持续长,抗寒,耐旱,适应性强,生长发育快,分蘖多,饲草品质好,草产量和种子产量高,干草产量达4 181.71kg/hm2,比对照品种野生扁穗冰草(3 271.92kg/hm2)增产27.8%。种子平均产量为576.29kg/hm2,较野生扁穗冰草(428.95kg/hm2)增产34.3%,是东北寒冷干旱区建植人工草地、改良天然草场的优良饲草品种。     

龙牧扁穗冰草的生态生物学特性和生产性能的研究

对选育的龙牧扁穗冰草（Agropyron cristatum（Linn．）Gaertn．Longmu）连续3年进行植物学特征、生态生物学特性、生产性能等方面研究，结果表明：龙牧扁穗冰草须根发达，具有根茎，叶表皮被毛。不同生长年限的龙牧扁穗冰草物候期、分蘖能力、形成的枝条数量、草产量和种子产量存在差异。3年平均干草产量为4022．41kg／km^2，种子产量为512．39kg／km^2.     

6种高寒牧区禾本科牧草抗旱性研究与评价

本研究选择在高寒地区种植多年的6种禾本科牧草,对其进行种子萌发期和苗期抗旱性试验。用PEG模拟水分胁迫及连续干旱法来研究干旱胁迫对种子发芽率及种子幼苗期生理指标的影响,以此来综合评价六种禾本科牧草的抗旱性强弱。种子萌发期研究结果表明,5%的PEG浓度有效促进种子萌发,高PEG浓度显著抑制种子发芽率。经连续干旱胁迫法处理的苗期牧草,测定其相对含水量、丙二醛含量、可溶性糖含量和叶绿素含量四项生理指标。对两个时期隶属值综合分析可知,六种牧草的抗旱性强弱为：草原看麦娘（Alopecurus pratensis） > 无芒雀麦（Bromus inermis） > 同德短芒披碱草（Elymus breviaristatus） > 同德贫花鹅观草（Roegneria pauciflora） > 大颖草（Roegneria grandiglumis） > 扁穗冰草（Agropyron cristatum）。     

扁穗雀麦种子萌发吸水特性与萌发温度的研究

对扁穗雀麦种子萌发吸水特性与不同温度处理下的萌发进行研究,结果表明:扁穗雀麦种子萌发吸水过程大致可分为三个阶段,吸水速度呈先快后慢的趋势,在2h时达最大值0.1363g/h,种子萌发最低吸水量为种子原重量的83.66%.在不同温度处理下,扁穗雀麦种子在25～30℃恒温条件下萌发相对较好,发芽率达97%,发芽指数较高.25℃萌发条件下活力指数最大,为679.41,其次为30℃.胚根的适宜生长温度为20～30℃,胚芽为25℃.综合发芽率、发芽指数和活力指数,最后确定扁穗雀麦的最适发芽温度为25～30℃.当温度降低到10℃或升高到40℃时,种子发芽受阻,发芽率均为0.     

碱胁迫下硅促进冰草种子萌发

以塔乌库姆冰草(Agropyron cristatum cv.Tawukumu)种子为材料,采用人工模拟碱(NaHCO3)胁迫,设10、30、60、90、120mmol·L-1 5个浓度作为碱处理,各浓度添加1.0mmol·L-1 Na2SiO3溶液作为碱+硅处理,研究碱胁迫下硅对冰草种子萌发的影响。结果显示,在不同浓度的碱胁迫下添加外源硅显著增加了冰草种子发芽势、发芽率、发芽指数、活力指数、胚根和胚芽生物量(P0.05),明显缩短了萌发时间,提高了发芽整齐度。这一结果初步说明在碱胁迫下硅参与种子的萌发过程,在一定程度上降低渗透胁迫和离子毒害,增强了冰草种子在碱胁迫下的抵抗力。     

旱作条件下冰草属5种牧草农艺性状的评价

摘要：为了筛选出优良的牧草材料用于寒冷的干旱与半干旱地区草地改良与建设,研究对不同来源冰草属Agropyron的5种牧草进行农艺性状评价比较。试验结果表明：所有供试材料均能完成全生育期,年均生育时间119124 d,越冬率高达93%以上;同时供试材料间各项测试性状也有显著差异。综合考虑鲜草、干草及种子产量等指标,供试的5种牧草中,采自河北的冰草A.cristatum表现第一,来自美国的细茎冰草A.trachycaulum表现第二,而来自山西的光穗冰草A.cristatum 、美国的沙生冰草A.desertorum、甘肃的蒙古冰草A.mongolicum表现一般。     

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