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1.
This study aimed to determine whether using inoculants and re-ensiling in sorghum silages affect the intake and feeding behaviour, apparent digestibility, digestible energy, and nitrogen balance of sheep in maintenance. Half the sorghum was inoculated on the day of harvest, and the other half received the same inoculation volume but with water. Sorghum was ensiled in 100 experimental metal drum silos of 200 L covered with plastic: 50 silos with inoculants and 50 without them. After 56 days, 25 drums with inoculants and 25 without were exposed to air for 48 h. The other silos remained closed. The treatments were arranged in a 2 × 2 factorial scheme with inoculation and re-ensiling. The sheep received the silages after 211 days of ensiling and 155 days of re-ensiling to determine the intake, apparent digestibility, and feeding behaviour of animals. The experimental design was a simultaneous double 4 × 4 Latin square. The re-ensiling process increased silage pH, N-NH3.TN−1, butyric acid, and propionic acid. The inoculant increased propionic acid in ensiled and re-ensiled silages. Lactic acid concentration presented a statistical interaction with the inoculated and ensiled silage, 58% higher than the other treatment averages. The ADFap digestibility showed a complex interaction, in which the control ensiled and the inoculated and re-ensiled silages were about 35% lower than the inoculated ensiled silage. The Nbal:Nint ratio (g.g−1) in the inoculated and re-ensiled silage had lower nitrogen retention than intake compared with the other treatments. These results indicate that exposing inoculated silages to air does not compromise their use in sheep feeding.  相似文献   

2.
Electrospinning has been recognized as an efficient technique for the fabrication of neural tissue engineering scaffolds. Many approaches have been developed on material optimization, electrospinning techniques, and physical properties of scaffolds to produce a suitable scaffold for tissue engineering aspects. In this study, structural properties of scaffolds were promoted by controlling the speed of fiber collection without any post-processing. PLGA scaffolds, in two significantly different solution concentrations, were fabricated by the electrospinning process to produce scaffolds with the optimum nerve cell growth in a desired direction. The minimum, intermediate and maximum rate of fiber collection (0.4, 2.4, 4.8 m/s) formed Random, Aligned and Drown-aligned fibers, with various porosities and hydrophilicities. The scaffolds were characterized by fiber diameter, porosity, water contact angle and morphology. Human nerve cells were cultured on fiber substrates for seven days to study the effects of different scaffold structures on cell morphology and proliferation, simultaneously. The results of MTT assay, the morphology of cells and scaffold characterization recommend that the best structure to promote cell direction, morphology and proliferation is accessible in an optimized hydrophilicity and porosity of scaffolds, which was obtained at the collector linear speed of 2.4 m/s.  相似文献   

3.
Models which simulate the development of potato early blight, potato late blight and fungicide dynamics were used to analyze the effects of host resistance, fungicide and weather on individual and combined epidemics of these diseases. Fungicide and host resistance effects were based on (and accurately reflected) products and cultivars available to commercial potato growers in northeastern USA. Moderate resistance to early blight had a 2-3 fold greater effect than did moderate resistance to late blight in suppressing early and late blight, respectively. Analysis of simulation experiments indicated that replacement of an early blight susceptible cultivar with a cultivar moderately resistant to the disease would permit a reduction in the fungicide application frequency from once every week to once every two weeks without loss of disease suppression. Fungicide effect in suppressing late blight was 2-3 fold greater than in suppressing early blight. Variation in seasonal weather (typical of northeastern USA) influenced late blight development more strongly than it affected early blight development, and it affected epidemics of individual diseases more than combined epidemics.  相似文献   

4.

Background  

Variation in carrying capacity and population return rates is generally ignored in traditional studies of population dynamics. Variation is hard to study in the field because of difficulties controlling the environment in order to obtain statistical replicates, and because of the scale and expense of experimenting on populations. There may also be ethical issues. To circumvent these problems we used detailed simulations of the simultaneous behaviours of interacting animals in an accurate facsimile of a real Danish landscape. The models incorporate as much as possible of the behaviour and ecology of skylarks Alauda arvensis, voles Microtus agrestis, a ground beetle Bembidion lampros and a linyphiid spider Erigone atra. This allows us to quantify and evaluate the importance of spatial and temporal heterogeneity on the population dynamics of the four species.  相似文献   

5.
Dalapon (2.8 kg ha×1) was applied in July, either annually or biennially, to a sown sward that contained about 50%Lolium perenne measured on a ground cover basis. The sward was grazed with young beef animals at three stocking rates throughout the 4 years of the experiment. In unsprayed plots, the proportion of L. perenne declined to less than 20% (30, 14 and 16% on high, medium and low stocking rates respectively). Lolium perenne was replaced largely by Holcus lanatus and Poa spp. Annual applications of dalapon checked the decline in L. perenne. After 4 years of annual treatment with dalapon, 44%L. perenne was present on heavily stocked plots, 41% on medium stocked plots and 26% on lightly stocked plots. Biennial applications of dalapon had slightly less effect on the proportion of L. perenne. The proportion of Trifolium repens in the sward was affected by dalapon and stocking rate in much the same way as that of L. perenne. Monthly cattle weights showed that dalapon caused a slight check to individual animal performance in the month after spraying, but total liveweight gain per unit area was not significantly affected. Increasing stocking rates were inversely related to performance per animal and directly related to output per unit area. Dalapon × stocking rate interactions were generally non-significant. There was a slight tendency for higher animal gains to be associated with higher proportions of L. perenne, but this only held for the first half of the growing season. Mean maximum liveweight gain of about 1000 kg ha?1 was achieved in 1974, by which time the proportion of Holcus lanatus had risen to a mean value of nearly 40%. The value of indigenous grasses for summer beef production is discussed.  相似文献   

6.
The effects of allowance of extended (deferred) grazed herbage (AEGH) and herbage allocation management (HAM) were studied in ewe lambs (248) and late‐gestation ewes (152), respectively, on commercial farms in south‐east Ireland in 2005–06. In Experiment 1, which consisted of four treatments, the effects of AEGH (0·75, 1·25 and 1·75 kg DM per head daily) and concentrate supplementation (0·5 kg per head daily with the 0·75 kg DM herbage allowance) on lamb performance during the extended grazing (16 December to 3 March) and subsequent grazing (4 March to 11 August) seasons were evaluated. Increasing AEGH increased herbage intake linearly (P < 0·001) and live weight (P < 0·001) at the end of extended grazing and the subsequent grazing season. In Experiment 2, single‐ and twin‐bearing ewes were allocated to either a conventional (single‐ and twin‐bearing ewes grazed separately) or leader–follower system (twin‐ and single‐bearing ewes, as leaders and followers respectively) of HAM from 30 January to 24 March. The same quantities of herbage were offered daily for each system. System of HAM affected ewe condition score at lambing but did not alter (P > 0·05) subsequent lamb birth or weaning weights. It is concluded that increasing AEGH to ewe lambs increased liveweight gain during extended grazing and resulted in heavier animals in mid August of the subsequent grazing season. For ewe lambs each 1 kg concentrate DM had the same feed value as 2·4 kg DM AEGH. Use of a leader–follower system for ewes in late pregnancy did not alter lamb birth weight or subsequent performance.  相似文献   

7.
To achieve higher titer of rabies virus higher density of host cells will need. In this study, capability of FibraCel disks packed in 500 mL spinner basket versus Cytodex-1 in 500 mL spinner flask was investigated for propagation of Vero cells and PV rabies virus proliferation. Minimal Essential Medium (MEM) + 10% Foetal Calf Serum (FCS) and Virus Production- Serum Free Medium (VP-SFM) +4 mM L-glutamine were used in growth phase and MEM+ 0.2% Bovine Serum Albumin (BSA) and VP-SFM were used in virus production phase. Adapted Vero cells grown in VP-SFM were used in all SFM experiments while batch and stepwise perfusion modes were applied and compared in growth stage. The highest Vero cell density were achieved in the trials with 10 g FibraCel disk in stepwise perfusion mode equal to 6.12 x 10(6) and 5.87 x 10(6) cells mL(-1) in MEM and VP-SFM, respectively while with 2.73 g Cytodex-1 lower density equal to 4.2 x 10(6) and 4.0 x 10(6) cells mL(-1) were achieved. The highest titer of rabies virus and overall virus production rate were resulted in VP-SFM and on 10 g disks equal to 2.9 x 10(7) Fluorescent Focus Unit (FFU) mL(-1) and 0.14 FFU/Cell/h, respectively versus 1.7 x 10(7) FFU mL(-1) and 0.08 FFU/cell/h on cytodex-1 in similar conditions. The second harvest of virus was also satisfactory in experiment with 10 g disks (1.7 x 10(7) FFU mL(-1)) in compare to Cytodex-1 (0.51 x 10(7) FFU mL(-1)). An equal surface area at 6600 and 12000 cm(-2) were provided in all comparable trials with seeding density of 12.5 x 10(3) cells cm(-2). Adapted Vero cells grown in VP-SFM were used in all SFM experiments while batch and stepwise perfusion modes were applied and compared in growth stage.  相似文献   

8.
Mesembryanthemum crystallinum L., a halophytic species, displays modified trichomes, epidermal bladder cells (EBC), on the surfaces of its aerial organs. EBCs serve to sequester excessive salt from underlying metabolically active tissues. To elucidate the molecular determinants governing EBC development in the common ice plant, we constructed a cDNA-based suppression subtractive hybridization library and identified genes differentially expressed between the wild-type and the EBC-less mutant. After hybridization, 38 clones were obtained. Among them, 24 clones had homology with plant genes of known functions, whose roles might not be directly related to EBC-morphology, while 14 clones were homologous to genes of unknown functions. After confirmation by northern blot analysis, 12 out of 14 clones of unknown functions were chosen for semi-quantitative RT-PCR analysis, and the results revealed that three clones designated as MW3, MW21, and MW31 preferentially expressed in the EBC-less mutant, whereas the other two designated as WM10 and WM28 preferentially expressed in the wild type. Among these genes, the expression of a putative jasmonate-induced gene, designated as WM28 was completely suppressed in the EBC-mutant. In addition, the deletion of C-box cis-acting element was found in the promoter region of WM28 in the EBC-less mutant. Overexpression of WM28 in Arabidopsis resulted in increased trichome number due to the upregulation of key trichome-related genes GLABRA1 (GL1), and GLABRA3 (GL3). These results demonstrate that WM28 can be an important factor responsible for EBC formation, and also suggest the similarity of developmental mechanism between trichome in Arabidopsis and EBC in common ice plant.  相似文献   

9.
D. Gray 《Potato Research》1972,15(4):317-334
Summary Immature tubers of all the varieties gave very little or no breakdown when canned. Breakdown on canning increased with a delay in harvest. However, at maturityMaris Peer, Sutton’s Foremost, Arran Pilot andSieglinde gave much less breakdown thanKing Edward, Red Craig’s Royal, Ulster Viscount orUlster Concord. In 1970, but not in 1969, tubers from crops grown at high plant densities (269 eyes/m2) broke down more than those from low densities (59 eyes/m2). There was no significant relationship between tuber breakdown and tuber dry matter content. Tuber cell surface area decreased with a delay in harvest in all varieties. In general, increases in tuber breakdown with delay in harvest were associated with decreases in cell surface area. A simple cooking test which could be adopted for field use and estimates accurately the amount of breakdown that would be produced on canning is described.
Zusammenfassung Aus unsern Versuchen, durchgeführt in den Jahren 1969 und 1970, wurden Muster von 2–4 cm grossen Knollen entnommen, um die Einflüsse von Sorte, Erntedatum und Pflanzabstand auf die Qualit?t der Dosenkartoffeln zu ermitteln und um den Wert des TS-Gehaltes der Knollen und die Zelloberfl?che für die Vorhersage des Zerfalls der Knollen bei der Verarbeitung zu untersuchen. Ueber das Zerfallen der Knollen wurde von zwei Arten von Kochtests berichtet. In jedem Verfahren wurden 2–4 cm grosse Knollen innerhalb 48 Stunden nach der Ernte nach dem Standard-Konservierungsverfahren der Campden Food Preservation Research Association (CFPRA) in Dosen verpackt. Zudem wurden Muster aus diesen Verfahren im Salzwasser in die Klassen (Spez. Gewicht) 1,060–1,070, 1,070–1,080 und 1,080–1,090 sortiert und einem Kochtest im Autoklav (Material und Methoden) unterworfen. Das Zerfallen der Knollen in diesem Test stand in direktem Zusammenhang zum Ausmass des Zerfallens bei gleichen Mustern, die nach dem CFPRA-Verfahren (r=0,90, P<0,01) verarbeitet wurden. Ferner wurden Zelloberfl?che und TS-Gehalt der Knollen bei den im Salzwasser sortierten Mustern bestimmt. Knollen von allen Sorten, die zu einem frühen Zeitpunkt (kurz nach der Blüte) geerntet wurden, zerfielen im wesentlichen nicht bei der Verarbeitung auf Dosenkartoffeln (Tabelle 1). Im allgemeinen nahm das Ausmass des Zerfallens der Knollen fast bei allen Sorten bei einer sp?teren Ernte zu (Tabellen 1 und 2a). Ausnahmen bildeten die SortenSutton’s Foremost undSieglinde in Versuch 1, bei denen die Muster von beiden Erntedaten nicht zerfielen. Es bestanden jedoch grosse Unterschiede im Zerfallen zwischen den ausgereift geernteten Sorten, z.B.Maris Peer, Sutton’s Foremost, Arran Pilot undSieglinde zerfielen bei der Verarbeitung auf Dosenkartoffeln weniger alsKing Edward, Red Craig’s Royal, Ulster Viscount orUlster Concord. 1969 konnte kein Einfluss der Pflanzdichte auf das Zerfallen festgestellt werden, dagegen zerfielen 1970 Knollen aus Best?nden mit grosser Pflanzdichte st?rker als solche aus weniger dichten Best?nden (Tabelle 2b). Obwohl in beiden Jahren die gleichen Pflanzgutmengen verwendet wurden, bildete sich 1970 eine gr?ssere Stengeldichte (18–94 Stengel/m2), als 1969 (13–59 Stengel/m2), was die festgestellten unterschiede in der Reaktion auf die Pflanzdichte erkl?ren mag. Unterschiede im Zerfallen der Knollen, das durch diese Behandlungen bewirkt wurde, ergaben sich ohne Rücksicht auf die Unterschiede im TS-Gehalt der Knollen (Tabelle 3). Die Oberfl?che der Zellen in den Knollen nahm bei sp?terer Ernte ab, und dies war verbunden mit einem st?rkeren Zerfallen der Knollen (Abb. 1). In allen Versuchen bestand ein gesicherter Zusammenhang zwischen dem Zerfallen und der Zelloberfl?che. Durch die lineare Regression zwischen diesen beiden Merkmalen k?nnen über 65% der Streuung im Knollenzerfall erkl?rt werden. Es gab jedoch Ausnahmen. z.B. in Versuch 2 war trotz einer Zelloberfl?che von 45 bis 56 mm2/mm3 nur ein kleiner Unterschied im Knollenzerfall bei früh geerntetem Material. In Versuch 4 wurde die Zelloberfl?che durch die Pflanzdichte nicht beeinflusst, trotz Unterschied im Knollenzerfall, der durch dieses Verfahren verursacht wurde (Tabelle 5). Es ist nicht anzunehmen, dass die Messung des TS-Gehaltes oder der Zelloberfl?che, allein oder zusammen, genügend genaue Anhaltspunkte ergibt, um das wahrscheinliche Ausmass des Knollenzerfalls bei der Herstellung von Dosenkartoffeln zu bestimmen. Die enge Uebereinstimmung zwischen dem Ausmass des Knollenzerfallens beim Kochtest im Autoklav und dem Ergebnis der Standard-Verarbeitungsmethode von gleichen Knollenmustern aus einer grossen Reihe von Verfahren deutet darauf hin, dass Kochteste zuverl?ssigere Vorhersagen betreffend Knollenzerfall liefern als die Bestimmung des spezifischen Gewichtes.

Résumé On a prélevé des échantillons de tubercules de 2–4 cm de volume dans quatre expériences effectuées, en 1969 et 1970, dans le but de déterminer les effets de la variété, de la date de récolte et de l’espacement sur l’aptitude des pommes de terre à l’appertisation, pour déterminer aussi la signification de la teneur en matière sèche du tubercule et de la surface cellulaire dans la prévision du délitement. Le délitement du tubercule est déterminé dans deux types de test de cuisson. Les tubercules de 2–4 cm de chaque traitement sont appertisés selon le procédé standard d’appertisation de l’association de recherches pour la conservation des aliments Campden (CFPRA), 48 heures après l’arrachage. En outre. des échantillons de ces mêmes traitements sont classés, par passage dans la saumure, dans les catégories suivantes de poids spécifiques 1,060–1,070, 1,070–1,080 et 1,080–1,090 et soumis à un test de cuisson à l’autoclave (matériels et méthodes). Le délitement des tubercules dans ce test est en relation directe avec l’importance du délitement observé dans le processus d’appertisation CFPRA (r=0,90; P<0,01). On a, de plus, déterminé la surface cellulaire et la teneur en matière sèche sur les échantillons classés par trempage dans la saumure. Les tubercules de toutes les variétés récoltées à un stade précoce de croissance (aussit?t après la floraison) ne montrent pratiquement aucun délitement lors de l’appertisation (tableau 1). En général, le délitement augmente chez presque toutes les variétés avec le retard dans la récolte (tableaux 1 et 2a), à l’exception toutefois deSutton’s Foremost etSieglinde dans l’expérience 1, lesquelles ne montrent aucun délitement dans les deux récoltes. Néanmoins de grandes différences s’observent entre les variétés arrachées à maturité, par exempleMaris Peer, Sutton’s Foremost, Arran Pilot etSieglinde, se délitent moins queKing Edward, Red Craig’s Royal, Ulster Viscount ouUlster Concord. En 1969 on n’a observé aucun effet de la densité de plantation mais, en 1970, les tubercules provenant de cultures à haute densité se délitaient davantage que les tubercules provenant de cultures de faible densité (tableau 2b). Mais, en dépit de quantités de plants semblables utilisées au cours des deux années pour réaliser les haute et basse densités, on observe une densité de tiges plus élevée en 1970 qu’en 1969, (18–94 tiges/m2 en 1970; 13–59 tiges/m2 en 1969), fait qui peut avoir causé les différences observées dans la réaction à la densité de plantation. Les différences dans le délitement observées dans les deux traitements paraissent indépendantes des différences de teneur en matière sèche des tubercules (tableau 3). La surface cellulaire par unité de volume diminue avec le retard de la récolte, et le phénomène’s’accompagne d’un accroissement du délitement à l’appertisation (fig. 1). Dans toutes les expériences, les régressions linéaires entre l’exemption, le délitement et la surface cellulaire sont significatives, celle-ci intervenant pour plus de 65% dans la narration du délitement. Cependant il y a des exceptions, par exemple, dans l’expérience 2, il y a peu de différence entre le délitement des tubercules récoltés à un stade précoce de croissance en dépit d’une classe de surface cellulaire de 45–56 mm2/mm3. Dans l’expérience 4, la surface cellulaire n’est pas affectée par la densité de plantation en dépit de la différence dans le délitement causé par ce traitement (tableau 5). Il est improbable que les mensurations de la teneur en matière sèche ou de la surface cellulaire, seules ou en combinaison, puissent constituer un guide suffisamment précis pour prévoir le délitement possible à l’appertisation. Le rapport étroit entre l’importance du délitement obtenu dans le test de cuisson à l’autoclave et dans le processus standard d’appertisation dans des échantillons identiques provenant d’une grande série de traitements suggère que les tests de cuisson au champ pourraient être plus dignes de confiance pour prévoir le délitement que les tests de poids spécifique.
  相似文献   

10.
A perennial ryegrass (Lolium perenne L.)‐dominated sward on a well‐drained soil (Experiment 1) and a creeping bent (Agrostis stolonifera L.)‐dominated sward on a poorly drained soil (Experiment 2) were subjected to four treading treatments: control (C, no damage), light damage (L), moderate damage (M) or severe damage (S) to quantify the effects on herbage dry‐matter (DM) production and tiller density. In Experiment 1, treading damage was imposed in spring. In Experiment 2, one‐third of the site was damaged in autumn, one‐third in spring and one‐third in both spring and autumn. Both sites were rotationally grazed after treading treatments. Pre‐grazing herbage mass was measured eight times in Experiment 1 and seven times in Experiment 2 on each plot, and tiller density was assessed four times in each experiment. In Experiment 1, pre‐grazing herbage mass was reduced by 30% in S plots at the first harvest after damage, but cumulative pre‐grazing herbage DM production was not different between treatments (12·7 t DM ha?1). In Experiment 2, annual cumulative pre‐grazing herbage mass was reduced by between 14 and 49%, depending on intensity of treading damage event and season when damage occurred. Tiller density was not affected by treatment in either experiment. A perennial ryegrass‐dominated sward on a well‐drained soil was resilient to heavy treading damage. A creeping bent‐dominated sward on poorly drained soil requires a more careful grazing management approach to avoid major losses in cumulative pre‐grazing herbage mass production during wet weather grazing events.  相似文献   

11.
Background: Diabetes is a major public health problem. The development of new therapies that are able to improve glycemia management and even to cure diabetes is of great interest. In this study, protective effects of sodium tungstate against STZ-induced beta-cell damages were investigated. Methods: Sixty rats were divided into six groups: control, diabetic, sodium tungstate treated diabetic rats from one week before STZ injection (TDB), food-restricted diabetic (FRD), tungstate treated control, sodium tungstate treated diabetic rats from one week after STZ administration (TDA). We evaluated serum insulin, glucose and glucose tolerance; liver glycogen content, glucokinase (GK) activity; blood and pancreas antioxidant power, lipid peroxidation; and fuchsin-aldehyde histochemical staining of beta-cells. Results: Blood glucose levels of TDB group were lower than other diabetic groups (P<0.01). Blood insulin levels of all diabetic groups were lower than controls (P<0.01). Glucose intolerance improved in TDB animals. Blood and pancreas antioxidant power, liver glycogen contents and GK activities and granulated beta cells increased in TDB rats in comparison with other diabetic groups (P<0.01). Likewise, lipid peroxidation decreased significantly in TDB rats (P<0.01). Conclusions: Results suggested that sodium tungstate if administrated before STZ injection improves glycemic state by a direct effect on pancreatic beta-cells and preserves them by reducing the activity of these cells at the time of STZ injection, reducing STZ-induced oxidative stress, reducing insulin secretion, or all of the above mentioned.  相似文献   

12.
This study investigated the long‐term effects on sward composition and animal performance of applying different fertilizer regimes to upland permanent pasture. The experiment, which was carried out in 2008, was based on a set of replicated (n = 3) plots that had been established in 1990. The effects of applying (i) N, P, K and lime, (ii) P and K plus lime and (iii) lime only were compared with a treatment that received no nutrient applications. Using a put‐and‐take stocking system, the plots were grazed to a target sward surface height of 4 cm by ewes and lambs from April to early August and by ewes only from August to mid‐October. The long‐term reduction in nutrient inputs had led to decreases in the percentages of both sown and unsown grass species within the sward (P < 0·05), and an increase in the percentage of mosses and litter (P < 0·05), with a corresponding reduction in nutritional value. Although there were no statistically significant treatment‐related differences in lamb growth rates, lower fertilizer inputs were associated with a marked decline in stock carrying capacity and associated overall productivity during both the pre‐ and post‐weaning periods (P < 0·001). The findings highlight the challenges faced when attempting to reconcile production and environmental objectives in upland systems.  相似文献   

13.
Two systems of grazing management involving preferential treatment of high- yielding dairy cows were compared with a grazing system in which both high- and low-yielders received uniform treatment. Cows were rotationally grazed across I-day paddocks without concentrate supplementation from 23 April to 8 October 1985, with a mean stocking rate over the season of 5-4 cows ha?1. Preferential treatment of high-yielding cows was achieved either by using a leader/follower approach (LF) with high-yielding cows in the leader group, or by preferential forage feeding (PFF) where high-yielding cows were allowed access to grass silage for 1 -5 h daily and grazed alongside low-yielders. Control (C) cows grazed together as a single group. The high grazing stocking rates used on all three treatments resulted in good grass utilization with residual sward heights, assessed by a rising-plate sward stick, of 45, 50 and 48 mm for the LF, PFF and C treatments respectively. Animal performance data for the LF, PFF and C treatments respectively were: milk yield (kg d?1) 15middot;1, 15middot;6 and 14middot;7 (s.e. 0middot;78); milk fat yield (g d?1) 598, 606 and 567 (s.e. 34); milk protein yield (g d?1) 500, 519 and 480 (s.e. 31); and live weight gain (kg d?1) 0middot;12, 0middot;23 and 0middot;25 (s.e. 0·05). These results indicate that leader/follower grazing had little overall effect on animal performance when high grazing severity was imposed, with the improvement in animal performance of high-yielding cows in the leader group being offset by the reduced performance of the follower group. Buffer-feeding of high-yielding, rotationally-grazed cows with high-quality grass silage had little effect on animal performance and resulted in a decrease in the efficiency of grassland utilization. Silage appeared to substitute for herbage, with a reduction in herbage DM intake of 0middot;55 kg per kg silage DM consumed.  相似文献   

14.
Summary This paper examines trends and prospects for potatoes in developed and developing countries with an eye to incorporating a policy, historical, and quantitative perspective into that analysis. The available evidence indicates production surged ahead in many developing countries since 1960, while it stagnated or sharply declined in many, albeit not all, developed countries. Potato tubers are often sold as a high-priced vegetable in developing countries and marketed as a cheap, staple food in much of Europe and North America. Besides changes in incomes and consumers’ quest for more diverse diets, government policy — in both developed and developing countries — has often been an important consideration in influencing production and use of potatoes. Expanding output of potatoes can contribute to efforts to alleviate food shortages, improve rural incomes, and reduce poverty in developing countries — particularly in South Asia where poverty is highly concentrated.  相似文献   

15.
Dermatitis caused by stimulation of beetle paederus, is a common health problem in Northern and some southern parts of Iran. Since by now, traditional medicine and some corticosteroid agents have been used for treatment of dermatitis caused by beetle paederus. Because, there are few researches about classical treatment of the disease at academic level, this study planned to compare the effectiveness of triamcinolone ointment and atorvastatin tablet with placebo in treatment ofpaederus dermatitis in Northern Iran. A randomized double-blind clinical trial was carried out on 30 patients referred to the hospital and clinics at Sari and Neka countries in Northern Iran during 6 months. Patients were randomly divided into two therapeutic equal groups. The first group was triamcinolone ointment twice a day and a placebo atorvastatin tablet daily. The second group was oral atorvastatin one tablet (20 mg) daily and a placebo triamcinolone ointment twice a day. In Seventh day of visits, therapeutic response of the patients in triamcinolone and atorvastatin group were 93.33 and 80%, respectively. No significant differences were found in therapeutic outcome between the two groups (p > 0.05). The results showed both oftriamcinolone ointment and oral atorvastatin had similar effect on paederus dermatitis. Because the paederus dermatitis is a self-limited disease use of topical therapy for treatment of the disease is recommend.  相似文献   

16.
大豆皮成分检验及饲料应用效果   总被引:4,自引:0,他引:4  
在查阅了大量的相关资料和总结实验情况基础上,对豆皮的质量指标进行了分析检验,提出了大豆皮做为肉牛和奶牛添加饲料的可能性,同时也指出了对猪、禽做为添加饲料的不可能性,旨在充分开发利用大豆皮这一丰富资源,促进畜牧业发展。  相似文献   

17.
Huang NP  Yu H  Wang YY  Shi JC  Mao X 《Biointerphases》2011,6(4):143-152
Cellular micropatterning with bio-adhesive and nonadhesive areas has attracted increasing interest for the precise design of cell-to-surface attachment in cell biology studies, tissue engineering, cell-based biosensors, biological assays, and drug development and screening. In this paper we describe a simple and efficient method to create a two-dimensional stable cellular microenvironment, which is based on (1) forming a protein-resistant oligo(ethylene glycol) methyl ether methacrylate polymer layer on the substrates via surface-initiated atom transfer radical polymerization; (2) placing a defined photomask on the substrate and exposing the substrate to ultraviolet light; and (3) immersing the patterned surface in a fibronectin solution to form cell-adhesive protein patterns in a cell-resistant background. The resulting surfaces are tailored into cell-adhesive and cell-resistant regions. Three different types of cells (NIH-3T3, PC12, bone marrow-derived mesenchymal stem cells) are seeded on such patterned surfaces to form cellular patterns. The geometric effects on cell behavior are investigated. The long-term stability is tested by NIH-3T3 fibroblasts and mesenchymal stem cells and excellent retention of cellular patterns is observed. The strategy illustrated here offers an efficient way to create a stable, patterned cellular microenvironment, and could be employed in tissue engineering to study the effect of micropatterns on the proliferation and differentiation of cells, and in particular mesenchymal stem cells.  相似文献   

18.
First-harvest direct-cut, double-chopped grass (190 and 164g DMkg?1 in Experiments 1 and 2 resptectively) was ensiled without an additive or, in Experiment 1, with 30 kg t?1 grass of an absorbent additive based on sugar beet pulp (Sweet ‘n’ Dry) or with 3·441 t?1 grass of formic acid and, in Experiment 2, with 30, 50 and 70 kg t?1 grass of Sweet ‘n’ Dry or with 50kg t?1 grass of unmolassed sugar beet pulp. The preservation and nutritive value of the silage, in-silo losses (including silage effluent production), silage intake and animal performance of adult and growing cattle were examined. In Experiment 1 all three silages were well preserved, although the formic acid-treated silage displayed significantly lower pH, ammonia nitrogen (NH3N) [g kg?1 total nitrogen (TN)] and volatile fatty acids (VFAs) than the other two silages. In Experiment 2 absorbent-treated silages displayed significantly lower pH, buffer capacity (Bc), NH3N (gkg?1 TN), CP, modified acid detergent fibre (MADF) and VFAs than untreated silage. Treatment of grass with the absorbent additives at ensiling resulted in reduced effluent production. In Experiment 1 each kilogram of Sweet ‘n’ Dry retained approximately 11 effluent, and in Experiment 2 silages made with Sweet ‘n’ Dry applied at 70kgt?1 and sugar beet pulp applied at 50 kg t?1 produced similar volumes of effluent and each kilogram of absorbent retained 1·0 and 1·31 of effluent respectively. In Experiment 1 sixty beef cattle [mean initial live weight (LW) 460 kg] were grouped according to LW and allocated to treatment at random. For untreated silage (unsupplemented or with 1 or 2 kg supplement head?1 day?1), absorbent-treated silage (unsupplemented or with 1 or 2 kg supplement head?1 day?1) and formic acid-treated silage (1 kg supplement head?1 day?1) the daily silage DM intakes were 6·12, 6·21, 6·40, 7·65, 7·45, 7·11 and 7·85 (s.e. 0·280) kg respectively, the daily liveweight gains were 0·22, 0·56, 0·81, 0·59, 0·74, 0·81 and 0·75 (s.e. 0·071) kg respectively and daily carcass gains were 0·31, 0·47, 0·67, 0·47, 0·61, 0·70 and 0·57 (s.e. 0·043) kg respectively throughout a 75-day feeding period. In Experiment 2, fifty-six growing cattle (mean initial weight 312 kg) were grouped according to LW and allocated to treatment at random. For untreated silage (unsupplemented or with 1·5 kg Sweet ‘n’ Dry or 1·5 kg commercial concentrates head?1 day?1), silage treated with Sweet ‘n’ Dry at 30, 50 and 70 kg t?1 grass and silage treated with 50kg sugar beet pulp t?1 grass the daily silage DM intakes were 5·46, 5·28, 5·33, 6·21, 6·27, 6·60 and 6·62 (s.e. 0·154) kg respectively and daily liveweight gains were 0·39, 0·75, 0·81, 0·63, 0·76, 0·94 and 1·75 (s.e. 0·052) kg respectively throughout a 122-day feeding period. In this experiment 360g kg?1 more absorbent was required when it was included at ensiling rather than offered as a supplement to untreated silage to achieve the same individual animal performance.  相似文献   

19.
Utilization of long‐chain fatty acids (LCFA) as diet composition markers, combined or not with alkanes, was evaluated in a study performed with sheep, goats and cattle fed on two different diets composed of herbaceous species and heather. Proportions of plant species were estimated from LCFA concentrations in plant species and faeces, using least‐square procedures, and were compared with those obtained using alkanes or LCFA + alkane. The impact of grouping plant species with similar LCFA + alkane profiles and the application of different levels of feeding selectivity within the dietary group on the accuracy of estimates were also assessed. Results showed that LCFA faecal recoveries were incomplete and tended to increase with carbon‐chain length in a curvilinear fashion in both diets and all animal species. Furthermore, differences between ruminant species and diets in the LCFA faecal recovery were observed. Combination of alkanes and LCFA provided the most accurate estimates of diet composition, while estimates based on LCFA alone were better than those using alkanes alone. Accuracy of these estimates differed among animal species but was not influenced by diet composition. Grouping plant species with similar LCFA + alkane profiles reduced the accuracy of estimates with a clear underestimation of the dietary group.  相似文献   

20.
Crop rotation can be an effective mechanism for reducing disease incidence and contributing nitrogen (N) to succeeding crops. Interactions of plant pathogen suppression and soil nutrient availability may also exist, adding to the cropping system complexity. This study examined the impact of crop rotation, N fertilization, and their interaction on growth, yield, andRhizoctonia solani incidence in potato (Solanum tuberosum L. Norwis). Potato was grown continuously and in two-year rotations with annual alfalfa (Medicago sativa L. Nitro), hairy vetch (Vicia villosa Roth), white lupin (Lupinus albus L. Ultra), and oat (Avena sativa Astro). Fertilizer was banded at potato planting with 0, 45, 90, 135, 180, or 225 kg N ha?1 as (NH4)2SO4. Approximately 58% of continuous potato possessed stem lesions caused byR. solani, but only 12 to 22% of potato stems from other rotations possessed lesions. Tuber dry weight was affected by crop rotation in 1989, a dry year, but not in 1990. Apparent N fertilizer replacement values for hairy vetch, Nitro alfalfa, white lupin, and oat were 65, 43, 26, and 11 kg N ha?1, respectively. All crop rotations studied appeared to enhance potato production by reducing stem infection byR. solani. Vetch and alfalfa provide additional benefits through their N contributions.  相似文献   

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