藏系绵羊对高寒环境适应性研究

藏系绵羊(Tibetan sheep)是分布于青藏高原上的特有家畜品种之一.采用RA(C)Ⅲ型密闭回流式呼吸测热装置,将温度控制在5℃、10℃、15℃、20℃、25℃、30℃、35℃梯度内,测量不同温度下藏系绵羊呼吸频率及直肠温度.当环境温度为 12.45℃时,产热量最小值为267.60 KJ*d-1*w-0.75.藏系绵羊的热中性区是8～15℃ ,与其它地区绵羊相比(10～20℃),热中性区更为狭窄,且临界温度下限更低,从而表现出适应寒冷气候条件的生存特征.     

河北省舍饲绵羊的热应激评价及温湿参数与羊生理指标的相关性研究

本研究旨在评价河北省三大区域(冀北燕山、太行山区和冀中南平原)羊场夏季绵羊的热应激程度,并分析温热环境参数与绵羊个体生理指标的相关性,为改善羊舍环境提供理论依据。选择3个区域12个规模化羊场,自动检测并记录夏季羊舍的环境温度和相对湿度2个月,同时检测各场绵羊的直肠温度和呼吸频率。结果表明,冀北燕山、太行山区和冀中南平原的羊舍日均温度分别达24.3、28.5和28.7℃,温湿指数(THI)分别达72.40、79.91和79.47,冀北燕山区域绵羊正遭受轻度热应激,而太行山区和冀中南平原地区的绵羊遭受中度甚至重度热应激,可见,夏季河北省舍饲绵羊的热应激防控需要引起关注,加强夏季的防暑降温措施刻不容缓。从绵羊个体生理指标看,3个区域绵羊的直肠温度范围为39.1～39.8℃,呼吸频率为42～114次·min~(-1),直肠温度与环境温度、THI之间均未表现出显著相关关系(P0.05),但与相对湿度间表现出显著的线性负相关关系(P0.05,r=0.60);呼吸频率与环境温度、THI之间表现出极显著正相关关系(P0.01,r=0.84;P0.01,r=0.87),与相对湿度间未表现出显著相关关系(P0.05)。因此,通过羊舍温湿参数和THI的测定可以推断绵羊的个体生理状况,对实际生产中舍饲羊热应激的预防及相关疾病的诊断提供依据。     

草地藏系绵羊mtDNA D-Loop区多态性分析

文章研究了草地藏系绵羊mtDNA D-Loop区多态性,获得了草地藏系绵羊mtDNA D-Loop区全长序列信息,这一区段的DNA长度为1 179～1 183 bp(A型)和1106 bp(B型),其长度存在明显差异,这主要是由于该区内串联重复序列数目的不同造成的,因此草地藏系绵羊可分为A型(3个重复)和B型(4个重复)两种类型.     

环境温度对肉羊有害气体排放、环境微生物和血清生化指标的影响

本试验研究了环境温度对杂交肉羊呼吸代谢室内氧气(O2)、二氧化碳(CO2)、甲烷(CH4)、氨气(NH3)和硫化氢(H2S)的浓度以及微生物数量和肉羊血清生化指标的影响。试验采用单因子试验设计,设3个环境温度范围:10～15℃、20～25℃、30～35℃。选择1岁左右、体况良好、体重(35.34±1.07) kg的杂交公羊(杜泊羊×小尾寒羊♀) 24只,随机分为3组,每组8只羊。预试期7 d,正试期10 d。正试期内利用呼吸代谢室进行气体和微生物检测试验。正试期第10天早晨采血,测定肉羊血清中肾上腺皮质酮(CORT)、免疫球蛋白(IgG)浓度和肌酸激酶(CK)和乳酸脱氢酶(LDH)活性。结果表明:1)温度对呼吸代谢室内CH4、NH3浓度有极显著影响(P0.01),其中10～15℃呼吸代谢室内CH4浓度极显著高于20～25℃和30～35℃呼吸代谢室内CH4浓度(P0.01),30～35℃呼吸代谢室内NH3浓度极显著高于10～15℃和20～25℃呼吸代谢室内NH3浓度(P0.01);但对CO2和H2S浓度无显著影响(P 0. 05)。2) 30～35℃呼吸代谢室内大肠杆菌数量极显著高于10～15℃和20～25℃吸代谢室内大肠杆菌数量(P0.01)。在30～35℃和20～25℃呼吸代谢室内沙门氏菌和总菌数量极显著高于10～15℃呼吸代谢室内的沙门氏菌和总菌数量(P0.01)。3)温度对肉羊血清中CORT、IgG浓度和CK、LDH活性未产生显著影响(P 0.05)。综上所述,不同环境温度可影响肉羊有害气体的排放及微生物的数量,但对肉羊血清生化指标没有显著影响。     

河北省舍饲绵羊的热应激评价及温湿参数与羊生理指标的相关性研究

本研究旨在评价河北省三大区域（冀北燕山、太行山区和冀中南平原）羊场夏季绵羊的热应激程度,并分析温热环境参数与绵羊个体生理指标的相关性,为改善羊舍环境提供理论依据。选择3个区域12个规模化羊场,自动检测并记录夏季羊舍的环境温度和相对湿度2个月,同时检测各场绵羊的直肠温度和呼吸频率。结果表明,冀北燕山、太行山区和冀中南平原的羊舍日均温度分别达24.3、28.5和28.7℃,温湿指数（THI）分别达72.40、79.91和79.47,冀北燕山区域绵羊正遭受轻度热应激,而太行山区和冀中南平原地区的绵羊遭受中度甚至重度热应激,可见,夏季河北省舍饲绵羊的热应激防控需要引起关注,加强夏季的防暑降温措施刻不容缓。从绵羊个体生理指标看,3个区域绵羊的直肠温度范围为39.1～39.8℃,呼吸频率为42～114次·min^-1,直肠温度与环境温度、THI之间均未表现出显著相关关系（P>0.05）,但与相对湿度间表现出显著的线性负相关关系（P<0.05,r=0.60）;呼吸频率与环境温度、THI之间表现出极显著正相关关系（P<0.01,r=0.84;P<0.01,r=0.87）,与相对湿度间未表现出显著相关关系（P>0.05）。因此,通过羊舍温湿参数和THI的测定可以推断绵羊的个体生理状况,对实际生产中舍饲羊热应激的预防及相关疾病的诊断提供依据。     

营养调控缓解奶牛热应激研究概况

普通奶牛产乳的最适温度为10～15℃,黑白花奶牛产乳的最适温度为0～20℃。超过适宜温度范围时奶牛通过加强呼吸增加散热,降低采食量以减少产热,从而维持体温恒定。通过调整日粮组成,提供全面而充足的营养,以补偿高温应激引起的养分摄入量的不足,可缓解奶牛热应激反应。     

藏系绵羊遗传多样性及其品种(系)分化的研究

以青海和甘肃两省分布的8个藏系绵羊群体为对象,对其基因组DNA进行了RAPD分析,结果表明群体内遗传多样性指数Ho值平均为0.37,总群体平均遗传多样性指数Hsp为1.51;藏系绵羊的遗传多样性75.5%分布在品种群间,24.5%分布在品种群内;品种内个体间的平均D值为0.0177(0.0152～0.0197);品种群间的平均D值为0.0492(0.0419～0.0569).现有藏系绵羊可划分为高原草地型(AltiplanoMeadowType,AMT)和山谷草地型(ValleyGrassplotType,VGT)两大类群.     

环境温度对生长育肥猪绝食代谢的影响

本研究应用密闭式呼吸测热器对生长肥育猪分两个体重阶段(前期30—40公斤;后期70—80公斤)进行了10℃、20℃和30℃环境条件下的饥饿代谢试验。得出绝食产热量(FHP)与环境温度(T)的回归方程:前期为FHP(千卡/公斤~(0.75)·天)=165.38-2.41T(r=-0.81,n=15),后期为FHP(千卡公斤~(0.75)天)=142.63-2.14T(r=-0.76,n=15)。在10℃、20℃、和30℃环境中,体蛋白分解量(克/公斤~(0.75)天),前期分别为2.77±0.35、3.45±1.46、3.06±1.14;后期分别为3.02±1.0、2.88±1.04、3.06±1.15。在10℃和20℃环境中,呼吸商为0.76—0.81;但30℃时,呼吸商偏高,其值为0.80—0.98。     

温度变化对麻花艽（Gentiana Straminea Maxim）叶片光合作用及相关生理参数光响应的影响

气候变化对植物光合作用及相关生理参数影响是气候变化对陆地生态系统影响的关键,目前关于温度变化对高寒草甸植物光合作用及相关生理参数光响应影响并不十分清楚。本文利用开顶式小室（OTC）方法和LI-6400便携式光合测定系统叶室控温方法,分析了温度变化对高寒草甸典型植物-麻花艽叶片光合作用及相关生理参数光响应的影响。结果显示：麻花艽叶片净光合速率在光合有效辐射强度为0～800umol&#183;m^-2&#183;s^-1时随光合有效辐射强度增加而增加,1000～1200μmol&#183;m^-2&#183;s^-1时达最高,1200～3000μmol&#183;m^-2&#183;s^-1时变化不大,并且在10℃、15℃及30℃下较低、20℃和25℃下较高;叶片气孔导度也随光合有效辐射强度增加而增加,在10℃和30℃下较低、15℃、20℃及25℃下较高;胞间CO2浓度在光合有效辐射强度为0～800μmol&#183;s^-1时随光合有效辐射强度增加而呈现下降趋势,800～3000μmol&#183;s^-1时变化不大,并且在10℃和15℃下较高、20℃、25℃到30℃时较低;蒸腾速率随光合有效辐射强度增加而增加,在15℃、20℃和25℃较高、10℃和30℃时较低;水分利用效率在光合有效辐射为0—1200μmol&#183;s^-1随光合有效辐射强度增加而增加,1200～3000μmol&#183;m^-2&#183;s^-1变化不大,在15℃、20℃和25℃下较高、10℃和30℃下较低。相同光合有效辐射强度和温度下,麻花艽叶片净光合速率、气孔导度、胞间CO2浓度、蒸腾速率和水分利用效率在OTC样方中比自然环境样方内要高。结果说明,温度变化对高寒草甸植物的光合作用、气孔导度、胞间CO2和蒸腾速率及水分利用效率光响应有一定的影响。     

彭波半细毛藏系母绵羊AMH激素含量与年龄的相关性分析

通过测定彭波半细毛藏系母绵羊AMH激素含量,判定不同年龄阶段母羊的卵巢储备功能,确定无繁殖能力母羊的年龄上限,提高藏系绵羊的养殖效率。试验通过采集0.5～9.5岁不同年龄彭波半细毛藏系母绵羊颈静血每组各5只,1 500 r/min离心15 min后取血清,采用酶联免疫吸附(ELISA)法测定0.5～9.5岁彭波半细毛藏系母绵羊50个样本中的AMH血清含量。结果表明,彭波半细毛藏系母羊在0.5～1.5岁阶段AMH含量相对最高,分别为7.6774±3.1806 pg/mL和8.0673±2.8938 pg/mL;2.5～5.5岁AMH含量从5.5628±2.2902 pg/mL下降到5.4551±0.9973 pg/mL,呈逐渐下降趋势;6.5岁开始下降急剧直至9.5岁1.0402±0.5817 pg/mL。此外,4.5岁、6.5岁、8.5岁和9.5岁分别与0.5～1.5岁差异极显著(P0.01);6.5岁与2.5岁、5.5岁,7.5岁与0.5～1.5岁,8.5岁与2.5岁,9.5岁与5.5岁都差异显著(P0.05);6.5岁之后各年龄段均不显著,且从6.5岁开始AMH浓度含量低于3.0000 pg/mL以下。结果表明,彭波半细毛藏系母绵羊AMH含量随年龄的增高而降低,呈负相关,说明卵巢储备功能随之减弱,从6.5岁开始卵巢储备功能降低至无繁殖能力,可界定为淘汰年龄上限。     

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.     

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.     

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     

Avian brood parasitism — a growing research area in behavioral ecology (part Ⅱ)

正We are pleased to publish the second special issue on avian brood parasitism and to be responsible guest editors for the two special issues of Chinese Birds (Vol. 3, No. 4, 2012 and Vol. 4, No. 1, 2013), entitled "Avian Brood Parasitism - A Growing Research Area in Behavioral Ecology". The first issue was published in December 2012. The goal of the two special issues is to publish accumulated knowledge and some of the recent developments in     

Internal Parasites and Haematological Values in Cattle Slaughtered in Buea Subdivision of Cameroon

Tropical Animal Health and Production -