泛酸可改善猪的躯体成分     

T.R.Lutz  单伟林 《国外畜牧学(猪与禽)》2002,(6):21-22

猪对维生素的需要量主要取决于性能测定时某种能导致最大生长的维生素在日粮中的浓度。然而，某些维生素还可引起一些代谢效应，从而除了可改变生长率之外还可能改变生长的组分。  相似文献   

Effects of Stocking Sac-Fry and Hatchery-Fed Fry on Production of Fingerling Channel Catfish Ictalurus punctatus     

Charles R.  Weirich  Clifford C.  O'Neal  Brendan C.  Delbos  C. Greg  Lutz 《Journal of the World Aquaculture Society》2001,32(1):112-116

Abstract.— Channel catfish Ictalurus punctatus fry are typically held under hatchery conditions for 7 to 14 d after hatching to allow feeding and growth before they are stocked into nursery ponds to produce fingerling catfish. In an attempt to reduce hatchery operating costs, several catfish fingerling producers in Louisiana presently stock fry within 2 d after hatching before yolk absorption is complete. Fry at this stage of development are commonly referred to as "sac-fry." Although research has shown that fry can be stocked at the onset of yolk absorption with no detrimental effects on subsequent fingerling production, stocking sac-fry has been reported to result in reduced fingerling survival. To further investigate this topic, production trials were conducted in experimental outdoor pools over the course of two growing seasons to evaluate the effect of stocking fry of three different ages (2-, 7-, and 14-d post-hatch, DPH) on survival, growth (weight and length), condition factor (K), yield, feed consumption, and feed conversion ratio (FCR) of fingerling catfish. Results from both trials indicated that the age at which fry were stocked had no effect on production characteristics with the exception of growth. Specifically, fingerlings reared from fry stocked at 2 and 7 DPH were significantly larger than fingerlings reared from fry stocked at an age of 14 DPH. These findings suggest that the practice of stocking sac-fry may be a suitable alternative to the traditional procedure of holding and feeding fry under hatchery conditions prior to stocking. However, in order to fully evaluate the effects of early-age stocking of catfish fry on fingerling production, additional studies must be conducted under pond conditions. Furthermore, these studies must be coupled with a rigorous economic analysis before the practice of stocking sac-fry can be recommended to the catfish industry.  相似文献   

Prevalence of feline leukemia virus and antibodies to feline immunodeficiency virus in cats in Norway.     

K Ueland  H Lutz 《Zentralblatt für Veterin?rmedizin. Reihe B. Journal of veterinary medicine. Series B》1992,39(1):53-58

Serum samples from 224 Norwegian cats were analyzed for the presence of feline leukemia virus (FeLV) p27 common core antigen, and for antibodies to feline immunodeficiency virus (FIV). Ninety specimens originated from the serum bank at the central referral clinic at the Norwegian College of Veterinary Medicine, which had been collected during the years 1983-1989; 67 sera were submitted from veterinarian practitioners; while 67 sera originated from cats presented for euthanasia. The cats were classified into one "healthy" and one "sick" group. Only 2.2% of sick cats and 1.2% of healthy cats showed FeLV antigenemia, a finding which is lower than which has been reported from many other countries. The prevalence of FIV antibodies was 10.1% in sick cats and 5.9% in healthy cats. Antibodies to FIV was most prevalent in male cats (14.7%) than in female cats (2.1%), and more prevalent among domestic cats (12.0%) compared to pedigree cats (2.4%). Antibodies to FIV in the cats demonstrated increasing prevalence with increasing age. It may be concluded that FeLV causes minor problems in Norwegian cats, while FIV is present in a similar prevalence to what is reported from other countries.  相似文献   

Wie repräsentativ sind die Stichprobenverfahren von landwirtschaftlichen Expertensystemen?     

Dipl.-Geogr. Gregor Spickermann  Prof. Dr. Lutz Plümer 《Gesunde Pflanzen》2003,55(8):222-227

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Effect of the Glucagon‐like Peptide‐1 Analogue Exenatide Extended Release in Cats with Newly Diagnosed Diabetes Mellitus          下载免费PDF全文

A. Riederer  E. Zini  E. Salesov  F. Fracassi  I. Padrutt  K. Macha  T.M. Stöckle  T.A. Lutz  C.E. Reusch 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2016,30(1):92-100

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Einfluss selektiver mechanischer Fruchtbehangsregulierung auf Ethylensynthese als Stressindikator sowie Ertrag und Fruchtqualität bei Kernobst     

Ting Kong  Lutz Damerow  Michael Blanke 《Erwerbs-Obstbau》2009,51(2):39-53

The overall objective of this work was to improve fruit quality, break alternate bearing and reduce hand thinning using fewer chemicals in fruit crops. A device was constructed for mechanical thinning, which consisted of three independent horizontal rotors with ropes and freely adjustable angles on a frame, mounted on a front three point hitch and powered by the tractor hydraulics. This can be adapted to any fruit tree trained as spindle, Solaxe, (tall) vertical axis or fruit wall (le mur fruitier) irrespective of rootstock employed. Rotor speed varied from 300 to 460?rpm at either 5 or 7.5?km/h tractor speed. Eight-year-old or twelve-old apple trees cvs. ‘Gala’ and ‘Golden Delicious’ were mechanically thinned in 2007 between pink bud and full bloom (flower bud stages 6–8 or F1–F2) near Bonn, Germany; non-thinned and hand-thinned apple trees of the same block and variety served as control. Mechanically thinned flowering branches showed a similar amount of ethylene efflux (0.4–0.6?ppm C₂H₄/branch) as non-thinned flower branches, preventing potentially unexpected subsequent fruit drop, except for those removed by the rotors. The impact of the horizontal rotors on the branches was from the upper side and removed excessive flowers right to the tree trunk viz. the centre of the tree canopy, where fruits of lesser quality are expected leaving 2–3 flowers per cluster. Leaf damage was less than??10%, even at the fast rotor speed of 420?rpm, which was associated with negligible wood injury. Mechanical thinning induced firmer and sweeter fruit, i.e. tastier apples with longer shelf life, relative to control fruit from non-thinned apple trees. The greatest efficacy in terms of final fruit quality in the grading/sorting was achieved by a rotor speed of 360?rpm at a tractor speed of 5?km/h: Fruit mass increased by up to 20?g and the proportion of fruit larger than 70–75?mm by 10–30% compared with the fruit from non-thinned trees. Mechanical thinning with this newly constructed device led to a 10–20% reduction in yield, but increased returns due to better fruit size and colouration in apple with the potential to overcome alternate bearing.  相似文献   

Combining agent-based and stock-flow modelling approaches in a participative analysis of the integrated land system in Reichraming, Austria   总被引：1，自引：0，他引：1  

Veronika Gaube  Christina Kaiser  Martin Wildenberg  Heidi Adensam  Peter Fleissner  Johannes Kobler  Juliana Lutz  Andreas Schaumberger  Jakob Schaumberger  Barbara Smetschka  Angelika Wolf  Andreas Richter  Helmut Haberl 《Landscape Ecology》2009,24(9):1149-1165

The integrated modelling of coupled socio-ecological systems in land-change science requires innovative model concepts capable of grasping the interrelations between socioeconomic and natural components. Here, we discuss the integrated socio-ecological model SERD (Simulation of Ecological Compatibility of Regional Development) that was developed for the municipality of Reichraming in Upper Austria in a participative 2-year process involving local stakeholders. SERD includes three main components: (1) an agent-based actors module that simulates decisions of farmsteads, the municipal administration and other important actors; (2) a spatially explicit (GIS based) land-use module that simulates land-use change at the level of individual parcels of land and (3) an integrated socio-ecological stock-flow module that simulates carbon and nitrogen flows through both socioeconomic and ecological system compartments. We report on outcomes of a scenario analysis that outlines possible future trajectories depending on both external (e.g. agricultural subsidies and prices) and internal (e.g. innovation, willingness to co-operate) factors. We find that both external and internal factors can affect the behaviour of the integrated system considerably. Local and regional policies are found to be able to counteract adverse global socioeconomic conditions to some extent, but not to reverse the trend altogether. We also find strong interdependencies between socioeconomic and ecological components of the system. Fully evaluating these interdependencies is, however, not possible at the local scale alone and will require explicit consideration of higher-level effects in future research.  相似文献   

Die Mitzweisung der Magnetnadel     

Prof. Dr. C. W. Lutz 《European Journal of Forest Research》1923,45(6):219-226

Ohne Zusammenfassung  相似文献   

Pesticide contamination of the upper Elbe River and an adjacent floodplain area     

Karlsson  Anneli S.  Lesch  Michael  Weihermüller  Lutz  Thiele  Björn  Disko  Ulrich  Hofmann  Diana  Vereecken  Harry  Spielvogel  Sandra 《Journal of Soils and Sediments》2020,20(4):2067-2081

Journal of Soils and Sediments - Pesticide contamination of river waters is a global problem, and therefore, authorities regularly monitor the water quality status. Especially, flood events might...  相似文献   

III. Buchbesprechungen     

von Pechmann  Huber  H. Waldbauer  J. L. Lutz  Ernst  Speer  E. Weiger 《European Journal of Forest Research》1951,70(12):760-768

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