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1.
Regarding the estimation of the energy concentration or digestibility of herb-dominated forage and plant samples from winter pastures, it could be expected that the estimation is only reliable when in vitro methods with rumen fluid as inoculum (= gas production techniques) are used. For the verification of this thesis based on logical reflections, an in vitro-method with rumen fluid added as inoculum, as well as chemical, and enzymatic methods were applied under consideration of existing estimating functions. As a possible reason for the observed divergence of the methods, effects of fungal infections or, respectively, secondary compounds in herbs are discussed. At the present state of knowledge, it is adequate to estimate the energy concentration in vitro by gas tests, as far as fattening types like suckler cows and beef cattle are concerned, maybe in contrast to the forage evaluation for dairy cows. 相似文献
2.
Phosphorus availability and farm structural factors: examining scarcity and oversupply in north‐east Germany 下载免费PDF全文
Assessing factors influencing phosphorus (P) availability in soils is important in preventing its overexploitation and excessive application in agricultural systems. Despite high historical P applications in the federal state of Brandenburg (Germany), county data on soil test P (STP) reveal considerable disparities in soil available P. In addition, negative soil balances as a result of small mineral P and manure inputs have been observed, raising questions about the factors leading to this situation. Our work focused on identifying possible causes operating at the farm management level by conducting a letter survey in two administrative districts of Brandenburg, the counties Barnim and Uckermark, linking farm management factors (ownership type, farm size, land tenure, animal husbandry with or without grassland and its intensity, presence of a biogas plant and organic production) to farmers’ self‐indicated levels of STP. Small‐ to medium‐sized individual farms tended to have (very) high STP, while large partnership farms and companies/cooperatives were sensitive to factors resulting in low STP. Farms with low shares of land ownership, the presence of grassland, extensive cattle farming and stockless organic farming had lower STP. On the other hand, biogas plants, partly in combination with intensive livestock (cattle) farming, were associated with larger STP. It was concluded that more care should be devoted to the design of agricultural policies and that further (inter‐ and transdisciplinary) research on this topic is needed. 相似文献
3.
Tappeiner Ulrike Leitinger Georg Zariņa Anita Bürgi Matthias 《Landscape Ecology》2021,36(8):2317-2328
Landscape Ecology - Landscape ecology early on developed the awareness that central objects of investigation are not stable over time and therefore the historical dimension must be included, or at... 相似文献
4.
The golden shiner, Notemigonus crysoleucas, is a major bait and forage fish species in the USA. Farmers produce millions of golden shiners annually that are distributed live, many across state boundaries. Native over much of the eastern and central USA, this species is often present but rarely abundant in natural systems, as fish density is apparently controlled by predation rather than by food resources. Aquaculture of the golden shiner is a century‐old practice and culture methods have evolved over time, resulting in today's farm‐raised, certified specific pathogen– and aquatic nuisance species–free baitfish. Federal and state agencies and universities have a long history of developing culture methods and promoting baitfish culture to replace the indiscriminate and wasteful harvest of fish from natural waters. Despite advances in culture methods and the advantages of a farm‐raised species produced under controlled and biosecure conditions, golden shiner farming is only marginally profitable and remaining farmers survive on farm equity and increased market share from others exiting the business. Ironically, increasing regulations and restrictions leading to a reduction in the supply of farm‐raised baitfish could drive anglers back to harvesting bait from natural waters, the very concern that initiated government support for baitfish culture a century ago. 相似文献
5.
Anita Sønsteby Arnfinn Nes Finn Måge 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(3):128-134
The effects of bark mulch and NPK fertilizers on yield and leaf and soil nutrient status of ‘Korona’ strawberry plants (Fragaria×ananassa Duch.), were studied over a period of three years. A significant effect of mulching was found in the first harvest year, but additional fertilizer did not affect total yield. Bark mulch slightly decreased the level of leaf nitrogen, but increased the level of leaf phosphorus and potassium in all years. Bark had a significant, negative effect on soil nitrate and ammonium content in the two first seasons. Mulching increased the soil moisture content in all years. 相似文献
6.
Grobler DG Michel AL De Klerk LM Bengis RG 《The Onderstepoort journal of veterinary research》2002,69(3):221-227
A survey to determine the bovine tuberculosis status of buffalo herds north of the Olifants River in the Kruger National Park was conducted, using a new diagnostic approach. Diagnosis of Mycobacterium bovis infection was accomplished using the gamma-interferon assay technique in 608 adult buffaloes out of a total of 29 discreet herds. The animals were immobilized in groups of 10-15, bled, individually marked and then revived and released on site. As soon as test results were available (after 26-36 h), the same buffalo herd was relocated by tracking the frequency of a radio-collar previously fitted to one adult cow per group during the initial operation. Bovine reactors were identified, darted and euthanased from the helicopter. Necropsy and culture findings of all culled buffaloes showed excellent correlation with the results of the ante-mortem gamma-interferon test. The survey revealed that over and above the two positive herds that had been identified during a previous survey carried out in 1996, there were three additional, but previously unidentified, infected herds in the region north of the Olifants River. 相似文献
7.
Michael J Mauel Debra L Miller Anita L Merrill 《Journal of zoo and wildlife medicine》2007,38(3):420-424
Tilapia are cultured worldwide and are increasing in popularity among aquaculturalists in the United States; however, data regarding normal health parameters are limited. Few hematologic and plasma biochemical values of clinically normal tilapia have been reported, but these data may be key for identifying and managing disease issues in recirculating systems. Therefore, blood was collected from clinically normal hybrid tilapia (Oreochromis aureus x Oreochromis nilotica) housed in recirculating systems for the purpose of establishing normal hematologic and plasma biochemical reference ranges. Using standard clinical techniques the following hematologic values were determined: packed cell volume, plasma protein, leukocyte counts, leukocyte differentials, and thrombocyte counts. Additionally, the following plasma biochemical values were determined: albumin, total protein, globulins, albumin/globulin ratio, aspartate aminotransferase, alkaline phosphatase, glucose, uric acid, calcium, phosphorus, magnesium, sodium, potassium, chloride, urea nitrogen, and creatinine. The condition of the sample was also noted (lipemic, hemolysis, and icterus). The reference ranges reported in this study can be used in the management of cultured tilapia in recirculating systems. 相似文献
8.
AbstractThis study examined the performance of mechanically graded timber in bending when exposed to fire at various load
ratios. The test specimens were 150 pieces, each with the dimensions of 60 × 120 × 3500mm. The modulus of elasticity (MOE)
of 150 specimens was measured, and 60 among them were selected to formulate the prediction equation for MOE and modulus of
rupture (MOR), which was used to predict the remaining 90 specimens. These were tested under fire exposure in bending using
three-point loading at 11.1%, 16.7%, 33.3%, 66.7%, and 83.3% of the ultimate load. Using mechanically graded timber, which
means acknowledging the actual strength of the bending member, permits fairly precise application to the targeted design load.
This research confirmed that mechanically graded timber under fire exposure has the following tendencies: under the same load
ratio, time to failure is independent of strength class, and, at any load ratio, the critical strength is dependent on the
timber strength class. The obtained design bending strength under fire exposure using the reduced cross section method and
the reduced strength method conformed to those calculated based on Eurocode 5. Following those findings, mechanically graded
timber can be applied to obtain the design bending strength when taking into account the fire attack. 相似文献
9.
Anita?Firmanti Bambang?Subiyanto Shinjiro?Takino Shuichi?KawaiEmail author 《Journal of Wood Science》2004,50(5):385-390
This study focused on the relationship between stress level and the fire resistance of structural lumber. The 210 samples were prepared from 15-year-old trees of Acacia mangium from the Forest Estate Plantation, Indonesia. Specimens were 20 ® × 20 (T) × 500mm (L) and were air-dried. Sixty samples were tested under four-point bending stress to obtain the modulus of elasticity (MOE) and the modulus of rupture (MOR) for classifying the stress grades of the remaining 150 samples. The tests were performed using a four-point load bending position at various stress level while the specimens were exposed to fire along the shear-free region. Time to failure was affected by the stress levels in an exponential trend. Despite changes in stress level, charring rate, and time to failure, the critical stress of a member from the same species was similar. The fire performance under applied load could be predicted by using simplified fire-testing methods. The developed testing apparatus is valid for evaluating the small-scale fire resistant behavior of structural lumber in bending. 相似文献
10.
Leena Pohjola Laila Rossow Anita Huovilainen Timo Soveri Marja-Liisa H?nninen Maria Fredriksson-Ahomaa 《Acta veterinaria Scandinavica》2015,57(1)