Examination of metabolism of viscera drained by the portal vein in neonatal calves, using short-term intravenous infusions of glutamine and other nutrients

OBJECTIVE: To quantify glutamine use in viscera drained by the portal vein in neonatal calves and to assess the relative nutritional importance of glutamine, glucose, and acetate for enterocytes. ANIMALS: 5 healthy neonatal calves. PROCEDURE: A femoral artery, jugular vein, and the portal vein were surgically cannulated in each calf. Blood flow in the portal vein was measured by use of an ultrasonographic transit-time flow probe. A series of solutions was infused on 4 days for each calf. On the infusion days, acetate, glucose, glutamine, and saline (0.9% NaCl; control) solutions were administered IV during 1-hour periods via the jugular vein. Venous and arterial blood samples were collected during the last 15 minutes of each 1-hour infusion. RESULTS: Uptake of glutamine and glucose by viscera drained by the portal vein was 0.3+/-1.1 and 1.9+/-3.1 micromol/kg0.75/min, respectively, during saline infusion. During acetate, glucose, and saline infusions, glucose was a greater source of energy for the intestines than was glutamine. However, during glutamine infusion, uptake of glutamine by viscera drained by the portal vein increased significantly (29.9+/-11.2 micromol/kg0.75/min), which was associated with an increase in ammonia production (7.0+/-0.5 micromol/kg0.75/min). Toxicosis was not associated with IV administration of glutamine. CONCLUSION: Glutamine infusion resulted in an increase in glutamine uptake by viscera drained by the portal vein, which was associated with an increase in ammonia production and a slight increase in oxygen consumption. CLINICAL RELEVANCE: These solutions may be used to develop treatments that enhance healing of intestines of diarrheic calves.     

Reproductive efficiency of Thoroughbred and Standardbred horses in north-east Victoria

Objective To evaluate the reproductive efficiency of horse farms in north-east Victoria and identify aspects of management to be targeted for improving reproductive efficiency. Design Retrospective study. Procedure Records from seven Thoroughbred (TB) and four Standardbred (STB) studs in north-east Victoria from 1990 to 2001 were reviewed; 8813 cycles in 4455 mares were analysed. TB mares were inseminated by natural mating, whereas STB mares (89%) were artificially inseminated. Results The overall early pregnancy rate per cycle was 68.8% for TB mares and for STB mares, 68.3%. Multiple pregnancy per cycle was more frequent in TB (8.3%) than in STB (4.6%) mares (P < 0.001). Early embryonic death occurred in 7.1% of TB and 7.5% of STB pregnancies. TB mares had fewer inseminations per cycle (1.03) than STB mares (1.43) (P < 0.001). There was a significantly lower proportion of barren reproductive status within the TB than the STB mares. Pregnancy rate per cycle among stallions ranged from 48% to 79%. Conclusions On-farm pregnancy rates in both breeds were higher than previously reported and likely reflect improvements in reproductive management. The disparity between breeds in the inseminations per cycle and proportion of barren mares exposed the differing structures of the two industries, and presents a target for improving the reproductive efficiency in STBs. The difference between breeds in the multiple pregnancy rate per cycle likely reflects the higher ovulation rate of TB mares. The variability in pregnancy rate per cycle between the 22 stallions was associated with differences in individual inherent fertility and the quality of stallion management.     

生物结皮对高寒退化草地植物群落的影响

生物结皮在各类生态系统中扮演着重要的角色,具有调控土壤水分,养分含量与侵蚀敏感性等作用,并可直接或间接地影响地上植物群落,但对植物群落发展存在促进还是抑制作用尚不清楚。本研究于2017年在青海贵南县森多镇高寒草原,设置大样方,对生物结皮种类和分布格局进行调查。结果表明：在青藏高原高寒退化草地生态系统中,生物结皮的存在显著影响了植物的群落结构,降低了杂草的比例;苔藓生物结皮的盖度与草本植物盖度在初级发育阶段的生物结皮（地衣和苔藓共存）的样方中呈显著正相关关系（P<0.05）,在高级发育阶段的生物结皮（仅有苔藓结皮存在）的样方中正相关关系极显著（P<0.01）。由此可见,生物结皮是高寒草地生态系统的重要组成部分,有调节高寒退化植物群落的结构和功能的作用。     

Determination of the Trace Element Contents in Plants Using Atomic Absorption Spectrophotometer

The aim of the study is to investigate the contents of trace dement Se, Cd, Pb in three plants including burdock, ginkgol and garlic via graphite fumace atomic absorption and standard addition method. The results show that Se in burdock stem, skin and leaf are 32.40, 48.63, 38.10 μg/g, respec-tively; Cd in burdock stem, skin and leaf are 0. 160 0, 0.300 0, O. 140 0 isg/g, respectively; Cd in burdock stem, skin and leaf are 2.020, 3.960,2. 410 μg/g, respectively. In the ginkgo and ginko leaf, Se contents are 17.63 and 16.91 la.g/g, respectively; for Cd are 0.181 0 and 0.202 0 μg/g, respec-tively ; for Pb are 3.572 and 4.021 μg/g, respectively. In garlic, $e, Cd and Pb are 73. 900 O, 6.900 0 and 0.390 0, respectively. All the standard devi-ations of measured results are below 2.3%, recovery rate are from 99% to 101%.     

GIS支持下1985-2000年北京林地数量、质量演变与驱动分析

在收集、研究1985年、1995年、2000年北京土地覆盖类型的图像和矢量数据的基础上,提取不同时间段北京林地相关的数据信息,并从多个角度分析研究区内各类林地与其它土地覆盖类型之问相互转化和各类林地之间的演替情况,得出2000年北京各类林地面积总量与1985年相比有少量增加,但林地总体质量水平却有下降趋势;并从经济社会发展以及国家及北京的生态环保政策等方面,对林地演变的驱动因子进行分析.     

Comparison on left ventricular contractility between Tibetan antelope and Tibetan sheep

AIM: To investigate the characteristics of adaptation of the heart to high altitude in Tibetan antelope.METHODS: Both Tibetan antelope and Tibetan sheep were captured at altitude of 4 300 m and then transported to Gurmud (2,800 m), where the study was conducted immediately after arrival. The heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP) and the maximum rate of change in left ventricular pressure (±dp/dt) were measured directly by cardiac catheterization. After the baselines of the parameters were obtained, the animals were inhaled hypoxic gas of 14.6% O₂ or 12.5% O₂, which was simulated to the altitudes of 5,300 m and 6,300 m, and then those measurements were repeated within 15 min. The ratios of heart weight to body weight (HW/BW) and right to left ventricular plus septum weights were determined.The Ultra-structural changes of the cardiac muscle were also observed under electron microscope.RESULTS: The HW/BW of Tibetan antelope was significantly greater than that of Tibetan sheep (P<0.01), and no difference of RV/(LV+IVS) was observed between both animals. At baselines, HR and SBP of Tibetan antelope were significantly lower than those of Tibetan sheep . The value of +dp/dt in Tibetan antelope was similar to that of Tibetan sheep . However, after inhaled 14.6% or 12.5% hypoxic-gas for simulating the altitudes of 5,300 m and 6,300 m, the +dp/dt of Tibetan antelope was significantly increased to 145.1% and 148.1% respectively, while the Tibetan sheep was decreased to 68.4% and 70.5% of those in normoxia condition, respectively. Ultra-structural changes of the cardiac muscle indicated that there were more abundant mitochondria in the myocardium of the Tibetan antelope than those in the Tibetan sheep.CONCLUSION: The heart functions of Tibetan antelope are well adapted to hypoxic environment in the high altitude by increasing myocardial weight and mitochondria. On the other hand, the cardiac contractility of Tibetan antelope is normal in the rest, but obviously increases under stress conditions.     

Anion gap correlates with serum D- and DL-lactate concentration in diarrheic neonatal calves

The objective of this study was to investigate the relationship between serum D- and L-lactate concentrations, and anion gap (AG) in neonatal calves. The association of AG with lactic acidosis in diarrheic calves has only been investigated by measurement of L-lactate in calves with experimentally induced diarrhea. D-lactate has recently been reported to be present in high concentrations in the serum of some diarrheic neonatal calves. The contribution of this acid to AG is not reported. The relationship between AG and L- and D-lactate concentrations was examined in 24 healthy calves and 52 calves with naturally occurring infectious diarrhea with metabolic acidosis. AG was calculated as [Na+ + K+] - [Cl- + HCO3-]. D- and L-lactate were quantified using high-performance liquid chromatography. There was no correlation between L-lactate and AG, contrary to previous reports in the literature. Moderate correlations between D-lactate concentration and AG (r = .74, P < .0001), and between DL-lactate and AG (r = .77), P < .0001) were detected. No differences existed due to the age or sex of the calf. This study indicates that AG provides information on the nature of acidosis in the diarrheic, neonatal calf and reinforces the importance of investigating clinical, in addition to experimental, populations.     

Failure of an intramuscular injection of an analogue of gonadotrophin-releasing hormone 11 to 13 days after insemination to increase pregnancy rates in dairy cattle

At 11 to 13 d after insemination, 1028 dairy cows on 19 farms were given an intramuscular injection of 10 micrograms of the GnRH analogue buserelin. Their reproductive performance was compared to 1022 control cows receiving a placebo. The GnRH analogue-treated cows had fewer short interoestrous intervals compared to the control cows, but there were no significant differences in pregnancy rates to either the insemination preceding or following treatment, in calving to conception interval, or to percent pregnant by the end of mating. There were no differences between treatments in herds of high, average or low pregnancy rate, in 2-year-old cows or cows greater than 2-years-old and in cows calved 40 d or less, or greater than 40 d. The use of 10 micrograms of the GnRH analogue, buserelin, 11 to 13 d after insemination, cannot be recommended as a method of improving reproductive performance in dairy herds.     

Reproductive performance of Thoroughbred mares on six commercial stud farms

The records of 1630 mare years from 6 Thoroughbred stud farms in south eastern Australia were analysed for the years 1981 to 1986. Overall pregnancy and foaling rates were 83.9% and 69.3%, respectively. When calculated per served oestrous cycle, pregnancy and foaling rates were 54.7% and 43.1%, respectively. Pregnancy and foaling rates were higher (P < 0.001) for mares 3 to 10 years of age than for older mares. There was no difference in the pregnancy rates of maiden, barren and foaling mares. The foaling rate was significantly higher (P < 0.001) in mares that became pregnant during the first served oestrous cycle (77.8%) than in mares that needed two served oestrous cycles to become pregnant (65.4%). Of all diagnosed pregnancies, 19.5% were not completed. Pregnancy loss was lower (P < 0.05) in maiden (12.4%) than in barren (19.7%) or foaling (20.9%) mares. Twins were diagnosed in 7.8% of all pregnancies. If one conceptus was lost without external interference, 84.1% of pregnancies went to term. If one conceptus was manually crushed, 55.9% of pregnancies were maintained. If prostaglandin was used to terminate twin pregnancies, 60% of mares so treated produced foals the following year.