运输应激对动物组织器官的影响研究进展

运输是当代畜牧业生产过程中的一个重要环节,动物在运输过程中易受到多种因素影响,从而产生运输应激反应。运输应激会对动物健康造成不利影响,给畜牧业带来巨大的经济损失。本文就运输应激对动物组织器官的影响进行综述,以期为减轻运输应激对动物的损害和抗运输应激新药物的开发提供参考。     

家禽应激模型的研究与应用

应激是近年来家禽研究的一个热点,应激模型是研究应激问题的重要手段,本文从应激源、应激后动物应激反应、应激反应模型的建立和敏感指标的确定,以及应激时家禽的生产和代谢等方面进行了综述,并提出了应该进一步研究的方向。     

家禽应激模型的研究与应用

应激是近年来家禽研究的一个热点,应激模型是研究应激问题的重要手段,本文从应激源、应激后动物应激反应、应激反应模型的建立和敏感指标的确定,以及应激时家禽的生产和代谢等方面进行了综述,并提出了应该进一步研究的方向.     

运输应激对动物机体功能影响的研究进展

运输应激作为一种强烈的刺激源,能够显著影响动物机体的生理功能,甚至引起动物的疾病、死亡,给畜牧业造成巨大经济损失。文章综述了运输应激对动物机体内分泌激素、血液生化指标、动物行为和机体免疫功能等方面的影响,为研究运输应激相关机理和指导畜牧业生产实践提供了理论依据。     

猪应激综合症的防治

（一）病因 动物的应激综合症是与遗传因素和应激源共同作用有关。生产中引起应激的因素很多,主要是指环境中导致动物不适或危难状态的因子。引起动物应激反应的应激源包括饲养管理因素：断奶、过度拥挤,环境过冷过热、长途运输、驱赶、换群、打架、混群、去势、免疫接种、抓捕、声音、灯光、电击等。一般认为,动物最适宜环境温度是18℃～24℃,超过32℃,即可引起应激反应。     

猪应激综合症的防治

（一）病因 动物的应激综合症是与遗传因素和应激源共同作用有关。生产中引起应激的因素很多,主要是指环境中导致动物不适或危难状态的因子。引起动物应激反应的应激源包括饲养管理因素：断奶、过度拥挤,环境过冷过热、长途运输、驱赶、换群、打架、混群、去势、免疫接种、抓捕、声音、灯光、电击等。一般认为,动物最适宜环境温度是18℃～24℃,超过32℃,即可引起应激反应。     

矿物质营养与动物抗应激

在畜牧生产中常发生热应激、免疫应激、氧化应激等许多应激反应。研究证实在动物产生应激反应时会有营养因子再分配现象(Beise,1977)。即使日粮营养水平能够满足生长需要,也可能无法满足达到应激反应时抗体最佳水平和疾病抵抗水平的需要量(Nockels,1988),     

运输应激对动物机体影响的研究现状

运输应激是指动物机体在运输途中禁食、环境变化、颠簸、心理压力等应激源的综合作用后所产生的适应性和防御性反应。本文从行为变化、神经内分泌的变化、物质和能量代谢的变化、免疫功能的变化及生产性能的变化等方面综述了运输应激对动物机体的影响,旨在为运输应激的相关研究和畜牧生产实践提供理论参考。     

运输应激对动物机体影响的研究现状

运输应激是指动物机体在运输途中禁食、环境变化、颠簸、心理压力等应激源的综合作用后所产生的适应性和防御性反应。本文从行为变化、神经内分泌的变化、物质和能量代谢的变化、免疫功能的变化及生产性能的变化等方面综述了运输应激对动物机体的影响,旨在为运输应激的相关研究和畜牧生产实践提供理论参考。     

抗应激与AB01富安宝

应激是机体对各种非常刺激产生的全身非特异性应答反应的总和，能引起动物应激反应的各种环境因素统称为应激源。动物机体受到环境因素刺激后，可引起动物对待定刺激产生相应的特异性反应，而有些刺激(即应激源)不仅使动物产生特异性反应，还会使机体产生相同的非特异性反应，其表现为：肾上腺皮质变粗，分泌活性提高；胸腺、脾脏和其他淋巴组织萎缩，血液嗜酸性白细胞和淋巴细胞减少，嗜中性白细胞增多；胃和十二指肠溃疡出血。这种变化称为“全身适应综合征(GAS)”。机体出现这种生理反应的目的是动员机体的防御系统去克服应激源造成的不良影响，以使机体在不利的环境中仍能保持体内平衡。机体通过应激反应扩大了其适应范围，增强了其适应环境的能力。如果机体缺乏应激反应或应激反应失调，就会在任何超出一般生理调节范围(特异反应)的刺激下，导致机体内平衡破坏，产生疾病或导致死亡。     

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