浅谈青海省“黑土滩“综合治理措施

青海省天然草地由于粗放经营管理,过度放牧,鼠虫和人类活动的影响,加之严酷自然条件的制约,生态环境日趋恶化,草地退化十分严重.据调查,全省"黑土滩"面积约为703.19×104hm2,此类草地产草量为400.5kg/hm2,植被平均盖度为45.42%.草地退化严重制约着畜牧业的发展.为了使"黑土滩"恢复其生产力,必须进行综合治理,使草地生态系统向良性循环发展,提出了几项综合治理措施.     

青海省泽库县草地现状与畜牧业可持续发展对策

在综述泽库县草地退化现状的基础上,综合分析了草地退化的原因,提出了畜牧业可持续发展的策略.泽库县的草地退化是自然因素和人为因素综合作用的结果.人类活动和气候变化是导致泽库县草地退化、区域生态环境恶化的两大因素,鼠虫害对它们产生的影响起了促进作用.只有合理利用和保护天然草地,优化产业结构,使草地生态系统步入良性循环,才能使泽库县的草地畜牧业协调发展.     

青海省玛多县草地退化原因及畜牧业可持续发展

在玛多县草地退化现状的基础上,综合分析了玛多县草地退化的原因,指出了玛多县畜牧业可持续发展的策略.玛多县的草地退化是自然因素和人为因素共同作用的结果.人类活动和气候变化是导致玛多县草地退化、区域生态环境恶化的两大因素,鼠虫害对它们产生的影响起了促进作用.只有合理利用和保护天然草地,优化产业结构,使草地生态系统步入良性循环,才能使玛多县的草地畜牧业协调发展.     

青藏铁路植被恢复和“黑土型”退化草地治理的实践与启示

由于高、寒和旱的独特特点,青藏高原生态系统具有特殊的环境敏感性和脆弱性。近年来,工程扰动、放牧等人类活动的加剧对青藏高原生态系统稳定性的影响日渐凸显,集中表现为植被退化、土壤贫瘠化和水土流失加剧等。目前,为了尽可能避免人类活动对生态系统造成的负面影响,遏制生态环境的进一步恶化,已采用了多种方式和手段进行环境保护和植被恢复。本研究以青藏铁路工程植被恢复和"黑土型"退化草地治理两个典型案例为例,总结了青藏高原进行植被恢复的经验,提出了青藏高原植被恢复的基本原则和注意事项,对今后青藏高原工程扰动和草地退化后进行植被恢复具有指导意义。     

浅议达日县草地资源与草地改良

达日县的天然草地由于粗放经营管理,达度放牧,鼠虫危害和人类活动的加剧以及严酷自然条件的影响,生态环境恶化,草地退化已十分严重,“黑土型”退化草地的面积１９８６年为１６．７７万ｈｍ＾２,１９９４年增到１７．９６万ｈｍ＾２,平均每年以０．３１万ｈｍ＾２的速度递增,已严重制约畜牧业的发展。为改善草地植物生长条件,提高草地生产力和促进草地生态系统良性循环,提出了对退化草地的几项改良措施。     

青海省果洛州草地退化探析及畜牧业可持续发展策略

分析了果洛州草地退化的原因,指出了果洛州畜牧业可持续发展的策略。果洛州的草地退化是自然因素和人为因素综合作用的结果。人类活动和气候变化是导致果洛州草地退化、区域生态环境恶化的两大因素,鼠虫害起了促进作用。只有合理利用和保护天然草地、优化产业结构、使草地生态系统步入良性循环,才能使果洛州的草地畜牧业协调发展。     

青海省草地资源可持续发展研究

青海独特的自然环境、生态环境以及丰富的草地资源和畜种资源优势,使青海省草地畜牧业具有广阔的发展前景.由于高寒自然条件的限制、超载放牧、鼠虫危害、草地退化、沙化、水土流失、生物多样性减少、生态环境进一步恶化等原因,严重制约着青海省草地资源的可持续发展.只有合理利用和保护天然草地,优化产业结构,使草地生态系统步入良性循环,才能使青海省的草地畜牧业得以协调发展.     

青海省同德县草地现状及畜牧业可持续发展策略

在调查同德县草地退化现状的基础上,综合分析了同德县草地退化的原因,指出了同德县畜牧业可持续发展的策略。同德县的草地退化是自然因素和人为因素共同综合作用的结果。人类活动和气候变化是导致同德县草地退化、区域生态环境恶化的两大因素,鼠虫害对它们产生的影响起了促进作用。只有合理利用和保护天然草地,综合治理退化草地,优化畜牧业产业结构,使草地生态系统步入良性循环,才能使同德县的草地畜牧业协调发展。     

青藏高原草地退化原因述评

导致青藏高原草地退化的因子很多,主要有气候、野生动物和人类活动等。在气候因素中以气温和降水的影响为主,短期内气候的变化不会成为草地退化的主导因素,从长期来看,气候变化与草地退化之间的相互作用可引起草地生态系统的退化;野生动物因素中主要以植食性小哺乳动物的影响为主,其危害程度取决于其种群数量的高低,同时大型野生草食动物对草地退化的影响也不容忽视;人类活动因素中主要以家畜过度放牧为主,在一定程度上,家畜放牧强度的高低直接决定草地的退化程度;草地退化是多种因素综合作用的结果。不同地区导致草地退化的主要因素不尽相同,导致青藏高原草地退化最主要的因子是过度放牧和植食性小哺乳动物种群爆发。针对退化的原因,提出了青藏高原退化草地恢复与管理过程中应注意的事项。     

放牧强度对川西北高寒草甸土壤理化性质的影响

土壤是草地生态系统的基础环境,土壤的稳定性(土壤养分的持续供给水平和根土比例)是支撑草地生态系统结构和功能稳定性、生态系统恢复的重要因素。适当的放牧,使植物群落丰富度增加,维持了植物群落的稳定,有利于提高群落的生产力。随着放牧程度的增加,植被盖度、地上生物量、土壤水分含量、有机质、全氮、全磷、全钾、土壤微生物及多数酶的活性呈现下降的趋势,而土壤容重、p H值呈现升高的趋势。长期不合理的放牧将会导致草地退化、盐碱化和生态环境恶化。因此,探讨放牧对草地土壤的理化性质的变化规律,揭示草地退化机理具有重要意义。     

Anaesthesia and analgesia of the donkey and the mule

The number of donkeys and mules throughout the world is stable, and awareness of their use and concern for welfare, pain recognition and treatment are receiving increasing veterinary interest. Therefore, accurate information about anaesthesia and analgesia in donkeys and mules is important to ever more equine practitioners. Since donkeys are physiologically and pharmacologically different from horses, knowledge on species specific aspects of anaesthesia and analgesia are very important. Mules combine elements from both donkey and horse backgrounds, leading to great diversity in size, temperament and body type. Physiologically, they seem to resemble horses more than donkeys. This review highlights the current knowledge on various anaesthetic and analgesic approaches in donkeys and mules. There is still much information that is not available about donkeys; in many circumstances, the clinician must use available equine information to treat the patient, while monitoring carefully to observe for differences in response to therapy compared to the horse.     

Ultrasonographic examination of the caecum and the proximal and spiral ansa of the colon of cattle

The large intestine of 10 cows was examined from the right abdominal wall with a 3.5 MHz linear transducer. The cows were then slaughtered, and the organs were re-examined in a water bath. The caecum was visualised from the middle region of the abdominal wall. It ran caudo-cranially, varied in diameter from 5.2 to 18.0 cm and was situated immediately adjacent to the abdominal wall. The lateral wall of the caecum appeared as a thick, echogenic, crescent-shaped line. It could be visualised as far cranially as the 12th intercostal space. Although its junction could not be identified, the proximal ansa of the colon was recognised on the basis of its anatomical position and its diameter, which was smaller than that of the caecum. The spiral ansa of the colon and the descending colon were situated dorsal to the caecum and could be identified by moving the transducer horizontally along the abdominal wall to the last rib. The spiral ansa of the colon was situated ventral to the descending colon, and its walls appeared as thick echogenic lines. In a contracted state, the spiral colon had the appearance of a garland.     

Effects of age and diet on the development of the pancreas and the synthesis and secretion of pancreatic enzymes in the young pig

Effects of age and diet composition on amylase, trypsin and chymotrypsin activities in the pancreas and intestinal contents, pancreas weights and body weights were determined from birth to 56 d. A total of 120 pigs, five to seven pigs/litter from 18 litters, were slaughtered at birth, 14, 27, 29, 31, 42 and 56 d. Litters were allotted to dietary treatments (corn-soy, A; corn-soy + 20% dried whey, B; corn-soy + 5% lard, C) and offered these diets as creep feed at 14 d. All pigs were weaned at 28 d, placed in elevated nursery pens and fed their respective diets. Total activities of amylase, trypsin and chymotrypsin in the pancreas and small intestine increased (P less than .05) with age. Both trypsin and amylase activities, measured per kilogram body weight or gram pancreas weight, were low at 29 d in the intestine and increased to 56 d. Pigs on diet B had the highest level of trypsin and chymotrypsin in the intestinal contents (P less than .05). Trypsin activity in the pancreas (units/kg body weight) was lowest (P less than .05) for pigs on diet B and highest (P less than .05) for those on diet C (units/g pancreas and units/kg body weight). Amylase activity (units/kg body weight) was lower (P less than .05) in the pancreas for pigs on diet B than for those on diets A and C. Pigs on diet A had lower (P less than .01) intestinal amylase activities than those on diets B and C. Enzyme activities in the intestinal contents and pancreas were low following weaning. In the pancreas, activities decreased at 31 d.(ABSTRACT TRUNCATED AT 250 WORDS)     

The behavior and the husbandry conditions of small laboratory animals--possibilities and limits of the evaluation of the appropriateness and fairness of the treatment of animals

Ethological studies are important means to evaluate the behaviour of small laboratory animals (mouse, rat, guinea-pig and rabbit) and their housing conditions. At any rate, the only sparse range of body expressions, the smallness and preference of night activity of these animals and the erratic occurrence of essential behaviour patterns make the investigations more difficult. On the other hand, the standardization of laboratory housing and the genetic definition of these animals turn out to be favourable. By this way, behaviour-environment-relationships are suitable for evaluation. Taking into consideration methodical and biological restrictions, the specific activities such as fight, relaxed resting behaviour and play as well as unbalanced behaviour patterns and stereotypes can be taken as means of evaluation. Particularly in mice and rabbits, upright position and space consuming activities will be possibly restricted by cage sizes.     

Relation between the concentration of sodium and potassium in the erythrocytes of dairy cows and the concentration of these elements in the plasma and urine and the level of blood glucose

Blood and urine samples of 180 dairy cows from 12 herds were examined. Sodium and potassium concentrations were determined in erythrocytes, whole blood, plasma, urine, and glucose concentration in blood: the interrelations were compared. Sodium and potassium concentrations in erythrocytes were 85.15 +/- 11.45 mmol/l, and 25.93 +/- 7.81 mmol/l, respectively. A statistically significant relation was found between sodium and potassium concentrations in erythrocytes (r = 0.3467+++) and the content of electrolyte in blood cells and in whole blood (Na: r = 0.5336+++; K: r = 0.3561+++). No statistically significant relation of intraerythrocyte concentration of both electrolytes was confirmed with respect to the other characteristics (sodium and potassium concentrations in plasma and urine, and glucose concentration in blood). In the conditions of routine laboratory diagnostics in clinically healthy cows, determinations of intraerythrocyte sodium and potassium do not broaden possibilities of evaluating the metabolic state of these electrolytes and cannot be used as the characteristics of energy insufficiency. The cannot replace the analyses performed in serum and urine.     

貉,蓝狐,银狐的胃及十二指肠内嗜银细胞形态分布的研究

本文应用Ｆｏｒｔａｎａ—Ｍａｓｓｏｎ嗜银颗粒染色法研究了貉、蓝狐、银狐的胃及十二指肠内嗜银细胞的形态分布。结果表明：三种动物胃幽门腺中，嗜根细胞数量最多，呈锥状，嗜银颗粒较粗，密度大、染成深黑色。在胃底及胃贲门腺区、嗜银细胞数量少。在十二指肠部嗜银细胞呈蝌蚪形，嗜银颗粒细，呈黑褐色，密度较小。嗜银细胞的分布密度在三种动物中具有一定的差别。     

Liquid flow and capacity of the caecum and colon of the horse

The rate of flow of fluid from the caecum and from the large colon was measured in four Shetland-type ponies fed a hay diet. In two ponies with cannulas in the caecum and at the origin of the right ventral colon, a continuous intracaecal infusion of a solution of chromium EDTA was used and samples were obtained from the cannula at the origin of the right ventral colon. Based on four determinations, the liquid flow from the caecum was 54.2 +/- 1.89 litres d-1. In the other two ponies with cannulas in the origin of the right ventral colon and near the end of the right dorsal colon, a continuous infusion of chromium EDTA was made into the right ventral colon and samples were obtained from the right dorsal colon. The flow rate towards the end of the dorsal colon was 49.4 +/- 1.25 litres d-1, based on four determinations. The capacities of the caecum and large colon after death were 7.0 +/- 0.8 and 17.7 +/- 3.7 litres, respectively.     

Conduction velocities and reflexes of the proximal and distal parts of the saphenous nerve of the dog

The maximal conduction velocities of compound-action potentials in the proximal and distal parts of the saphenous nerve were determined by averaging potentials evoked and recorded through needle electrodes. Antidromic, triphasic compound-action potentials unipolarly recorded from the distal part of the saphenous nerve were of the same minimal latency as potentials having 4 phases which were recorded bipolarly from the same site. However, the unipolarly recorded potentials were of greater amplitude. Monophasic compound-action potentials were recorded through bipolar chlorided silver electrodes from the surface of fascicles of the distal part of the saphenous nerve. The maximal conduction velocity of these potentials was in agreement with the conduction velocity of compound-action potentials of the distal part of the saphenous nerve which were evoked and recorded through subcutaneous needle electrodes. The specificities of the stimulating and recording sites were verified by recording before and after the saphenous nerve was cut between the stimulating and recording sites. Mean conduction velocities were 62.3 +/- 2.0 m/s for the distal part of the saphenous nerve and 66.3 +/- 2.2 m/s for the proximal part of the saphenous nerve. Reflex-evoked muscle activity was elicited in the ipsilateral tensor muscle of the fascia lata and semimembranous muscle after electrical stimulation of the saphenous nerve through subcutaneous needle electrodes. The effects of various stimulus intensities on the latency and duration of these reflex-evoked muscle potentials were determined.