A survey of the selenium status of beef cows in Alberta.   总被引：1，自引：1，他引：0  

J R Campbell  G K Jim  C W Booker    P T Guichon 《The Canadian veterinary journal. La revue veterinaire canadienne》1995,36(11):698-702

An epidemiological survey was conducted in Alberta to measure the selenium status in blood of beef cows during the fall and to determine the risk of selenium deficiency among specific geographic regions of Alberta. Three census divisions of Alberta based on the Statistics Canada Census of Agriculture were chosen as the study areas for the project. Soils and plants in area A (Edmonton area) and area B (Calgary area) were known to be deficient in selenium, while soils and plants in area C (southeast corner of Alberta) were known to have adequate levels of selenium. Blood samples were collected from 335 cows on 29 farms from the 3 study areas. These samples were collected from cows that had recently been removed from pasture in October and November 1992. Answers to a short questionnaire pertaining to various herd characteristics and management practices were also obtained for each herd. The average value of selenium for all cows sampled was 2.20 mumol/L. The average value of selenium of cows in areas A and B was 1.93 mumol/L. The average value of selenium of cows in area C was significantly (P < 0.05) higher at 2.70 mumol/L. Nine percent of the cows in the study were considered marginal or deficient in selenium (< 1.27 mumol/L selenium). Herds located in area C, herds that were provided with supplemental feed on pasture, and herds that were pregnancy checked had higher average herd selenium values than did other herds. Cow-calf producers located in areas with selenium-deficient soils should pay particular attention to selenium supplementation for their cows. Some of the negative "geographic" effects on selenium values can be overcome by more progressive management practices.  相似文献   

Eosinophilic papulocrustous dermatitis (miliary dermatitis) and eosinophilic inflammatory bowel disease in two cats     

Bell AG  Chard WG  Grayson JL  James MP 《New Zealand veterinary journal》1995,43(4):153-157

Two cats with chronic eosinophilic skin disease were investigated. The clinical investigation of the skin disease in one cat was limited and inflammatory bowel disease was diagnosed post mortem. A history of weight loss and a palpably thickened bowel in the second cat suggested concurrent gastrointestinal disease. Diagnosis of inflammatory bowel disease was confirmed on biopsy. Treatment with azathioprine and methylprednisolone acetate resolved the signs of gastrointestinal disease, the pruritus and 95% of the skin lesions. The concurrence of eosinophilic papulocrustous dermatitis and eosinophilic bowel disease raises the possibility of their being linked bv a common aetiology or pathophysiology.  相似文献   

Effect of cycling temperature on growth,energy metabolism and nutrient retention of individual male turkeys     

P. E. Waibel  M. G. Macleod 《British poultry science》1995,36(1):39-49

1. Each week, from 12 to 20 weeks of age, male turkeys of a heavy strain were subjected to cool (C; 16°C), hot (H; 29°C), and cycling temperatures, and fed on a standard diet ad libitum for 4 d. Lighting was intermittent, 3 h on, 3 h off. Food was given when lights were on. Those given cycling temperatures (3 h C; 3 h H) were given food and light during the cool (eat‐when‐cool, EC) or hot (EH) periods.

2. Birds in all treatments gained similar amounts of weight from 12–14 weeks of age. Thereafter, birds in C maintained gains, the body weight gains of birds in EC and EH declined moderately and birds in H lost weight.

3. Birds in C produced more metabolic heat. Those in H showed increased heat production as they became older.

4. Protein retention was greater in turkeys in C, EC and EH. It was lower in H, becoming negative between 18–20 weeks of age. Birds in H suffered body fat losses which increased with age.

5. Birds in EH and EC gained similar amounts of body weight. Birds in EH exhibited lower heat production and greater energy retention than those in EC.

6. Body temperatures were higher in H than in the other environments.  相似文献   

Observations on hypoglycaemia associated with a hepatoma in a cat     

Thompson JC  Hickson PC  Johnstone AC  Jones BR 《New Zealand veterinary journal》1995,43(5):186-189

Disorientation, muscle fasciculations and weakness seen in a 12-year-old neutered female domestic shorthaired cat were attributed to hypoglycaemia associated with a large hepatoma. Glucagon tolerance tests on this cat and a healthy cat showed that their plasma glucose concentrations increased and decreased at about the same rate. Plasma insulin concentrations in the healthy cat increased and decreased in parallel with the plasma glucose concentration. In the affected cat, plasma insulin concentrations increased initially but decreased more rapidly. Reflecting these observations, the amended insulin to glucose ratios in the affected cat were much lower than those of the healthy cat, until the 4-hour sample. Serum somatostatin, somatomedin and gastrin concentrations were measured but no conclusions as to pathogenesis of the hypoglycaemia could be made. The alterations in insulin secretion in the affected cat suggested that altered hormonal control of glucose homeostasis may have occurred with this tumour.  相似文献   

Dynamics ofRhizoctonia solani (black scurf) in successive potato crops     

G. Jager  H. Velvis 《European journal of plant pathology / European Foundation for Plant Pathology》1995,101(4):467-478

The position of plants withRhizoctonia solani sclerotia (black scurf) on progeny tubers was mapped for an experimental field at Haren where potatoes were grown continuously and in rotation with other crops for five successive years, and for another field at Borgercompagnie with a 12 frequency of potatoes during three potato crops. Initially, the distribution of plants with black scurf on both fields was rather dense and homogeneous. In the following years the distribution became heterogeneous and patchy. The local decline ofR. solani AG 3 (the common potato pathogen) in Haren was apparently caused by an unknown factor selectively suppressingR. solani AG 3, while simultaneouslyR. solani AG 5 increased in mass. This AG 5 type proved to be an inferior competitor of AG 3 on the potato plant in a laboratory experiment. The specificR. solani antagonistVerticillium biguttatum did not play a role. A similar factor could have reduced the formation of black scurf in the experimental field at Borgercompagnie, whereV. biguttatum was also too infrequent to account for the decline.R. solani AG 5 was not present here and could not indicate the presence of a selective factor against AG 3.  相似文献   

Mechanisms of nitrogen retention in forest ecosystems: a field experiment     

Vitousek PM  Matson PA 《Science (New York, N.Y.)》1984,225(4657):51-52

Intensive forest management led to elevated losses of nitrogen from a recently harvested loblolly pine plantation in North Carolina. Measurements of nitrogen-15 retention in the field demonstrated that microbial uptake of nitrogen during the decomposition of residual organic material was the most important process retaining nitrogen. Management practices that remove this material cause increased losses of nitrogen to aquatic ecosystems and the atmosphere.  相似文献   

Ultrahigh Sensitivity from GC-IR     

Maugh TH 《Science (New York, N.Y.)》1984,224(4644):42

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Large yearly production of phytoplankton in the Western bering strait   总被引：1，自引：0，他引：1  

Sambrotto RN  Goering JJ  McRoy CP 《Science (New York, N.Y.)》1984,225(4667):1147-1150

Production in the western Bering Strait is estimated at 324 grams of carbon per square meter per year over 2.12x 10(4) square kilometers. An ice-reduced growing season makes this large amount of primary production unexpected, but it is consistent with the area's large upper trophic level stocks. The productivity is fueled by a cross-shelf flow of nutrient-rich water from the Bering Sea continental slope. This phytoplankton production system from June through September is analogous to a laboratory continuous culture.  相似文献   

Knowledge is power     

Gardner DP 《Science (New York, N.Y.)》1984,224(4656):1383

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The Agricultural Sector in China: Agriculture in China's Modern Economic Development     

Calkins PH 《Science (New York, N.Y.)》1984,224(4650):713-714

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