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261.
Zimbabwe’s smallholder dairying faces many challenges that affect the welfare of dairy cows; however, the status of this welfare has not yet been determined. A cross-sectional study was conducted in Midlands Province on 41 active smallholder dairy farms with 86 cows in winter and summer to determine the risk factors and indicators to impaired cow welfare. These objectives were achieved using farmer questionnaires and direct observations. Eleven percent of the observed cows were severely lame in summer while only 5% were severely lame in winter. Lameness was significantly associated with season, absence of shade, breed, and low dipping frequency; 58% of the cows had low body condition scores (BC?<?3) and this low BC was associated with low frequency of protein (p?=?0.002) and vitamin (p?=?0.012) supplementation recorded in more than 52% of the farms visited. In winter, only 11% of the observed cows were heavily soiled (score 3), while in summer 64% of the cows were heavily soiled and this was associated with slurry accumulation in more than 80% of the observed cattle pens as well as the study season (p?<?0.001). A quarter (26%) of the studied animals had visible teat lesions on the teat skin and this was associated with the type of lubricant used (p?=?0.011). Only 34% of the cows allowed an approaching stockman to touch them and this was associated with shouting (p?=?0.012) and whipping of cows (p?=?0.002). The study concluded that welfare of dairy cows was poor in most of the smallholder dairy farms studied. 相似文献
262.
通过对4个安装了简易T型瘘管的断奶仔猪研究表明,添加植酸酶并没有提高玉米-豆粕型日粮(试验组1)、小麦-豆粕型日粮(试验组2)和大麦-豌豆-菜籽粕型日粮(试验组4)粗蛋白和氨基酸的回肠表观消化率(AID),而使小麦-豆粕-菜粕型日粮的粗蛋白和氨基酸回肠表观消化率或粗蛋白和消化能的总消化道表观消化率(ATTD)得到了显著的提高(P<0.05)或呈提高的势态(P<0.10)。这些结果表明,氨基酸对细菌性植酸酶的反应因子取决于日粮的组成。 相似文献
263.
Muneera S. M. Al-Saleem Wafaa H. B. Hassan Zeinab I. El Sayed Mahmoud M. Abdel-Aal Wael M. Abdel-Mageed Eman Abdelsalam Sahar Abdelaziz 《Marine drugs》2022,20(5)
Marine sponge-derived endozoic fungi have been gaining increasing importance as promising sources of numerous and unique bioactive compounds. This study investigates the phytochemical profile and biological activities of the ethyl acetate extract of Penicillium chrysogenum derived from Cliona sp. sponge. Thirty-six compounds were tentatively identified from P. chrysogenum ethyl acetate extract along with the kojic acid (KA) isolation. The UPLC-ESI-MS/MS positive ionization mode was used to analyze and identify the extract constituents while 1D and 2D NMR spectroscopy were used for kojic acid (KA) structure confirmation. The antimicrobial, antioxidant, and cytotoxic activities were assessed in vitro. Both the extract and kojic acid showed potent antibacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa with MIC 250 ± 0.82 µg/mL. Interestingly, the extract showed strong antifungal activity against Candida albicans and Cryptococcus neoformans with MIC 93.75 ± 0.55 and 19.53 ± 0.48 µg/mL, respectively. Furthermore, KA showed the same potency against Fusarium oxysporum and Cryptococcus neoformans with MIC 39.06 ± 0.85 and 39.06 ± 0.98 µg/mL, respectively. Ultimately, KA showed strong antioxidant activity with IC50 33.7 ± 0.8 µg/mL. Moreover, the extract and KA showed strong cytotoxic activity against colon carcinoma (with IC50 22.6 ± 0.8 and 23.4 ± 1.4 µg/mL, respectively) and human larynx carcinoma (with equal IC50 30.8 ± 1.3 and ± 2.1 µg/mL, respectively), respectively. The current study represents the first insights into the phytochemical profile and biological properties of P. chrysoenum ethyl acetate extract, which could be a promising source of valuable secondary metabolites with potent biological potentials. 相似文献
264.
An aggregation index (AI) to quantify spatial patterns of landscapes 总被引:43,自引:0,他引:43
There is often need to measure aggregation levels of spatial patterns within a single map class in landscape ecological studies. The contagion index (CI), shape index (SI), and probability of adjacency of the same class (Qi), all have certain limits when measuring aggregation of spatial patterns. We have developed an aggregation index (AI) that is class specific and independent of landscape composition. AI assumes that a class with the highest level of aggregation (AI =1) is comprised of pixels sharing the most possible edges. A class whose pixels share no edges (completely disaggregated) has the lowest level of aggregation (AI =0). AI is similar to SI and Qi, but it calculates aggregation more precisely than the latter two. We have evaluated the performance of AI under varied levels of (1) aggregation, (2) number of patches, (3) spatial resolutions, and (4) real species distribution maps at various spatial scales. AI was able to produce reasonable results under all these circumstances. Since it is class specific, it is more precise than CI, which measures overall landscape aggregation. Thus, AI provides a quantitative basis to correlate the spatial pattern of a class with a specific process. Since AI is a ratio variable, map units do not affect the calculation. It can be compared between classes from the same or different landscapes, or even the same classes from the same landscape under different resolutions. 相似文献
265.
Abstract. The histological features of the disease caused by infection of turbot by Herpesvirus scophthalmi are described. Infection of epidermal cells of skin and gill resulted in the formation of giant cells showing a variety of nuclear and cytoplasmic changes associated with the replication of the virus. The effects of the condition together with possible control measures are discussed. 相似文献
266.
S Bell 《Journal of the Association of Official Analytical Chemists》1975,58(4):717-718
A thin layer chromatographic method is presented by which higher and lower sulfonated subsidiary dyes are simultaneously separated from FD&C Yellow No. 6. After separation, the colors are quantitated directly, using a spectrodensitometer. Recoveries of 1, 2, and 5% of added 1-(4-sulfophenylazo)-2-naphthol-3,6-disulfonic acid ranged from 92 to 111%. Recoveries of 1, 2, and 5% of added 1-(4-sulfophenylazo)-2-naphthol ranged from 90 to 110%. 相似文献
267.
An experiment was carried out on a grass/white-clover sward at North Wyke to evaluate the use of mixtures of inorganic and organic nutrient sources to simulate the nutrient effect of animal excreta, both with and without overall PK fertilizer. Grazing with sheep and the return of excreta from caged sheep both increased herbage yields, as did artificial return treatments. Artificial return treatments giving 75% of the nutrient level returned by excreta gave yields comparable with grazing. The effect of the simulated return treatments was not influenced by PK application. Grazing gave a very different botanical composition to that from the treatments in wbich natural or simulated excreta were returned to cut swards. Mixtures simulating excreta may replace the nutrient effect of the grazing animal, but not its physical effect, in some forms of grassland experimentation. They are not recommended for fertilizer trials. 相似文献
268.
269.
Summary A workable level of male and female fertility is present among many haploids (2n–24) obtained from the common potato,S. tuberosum (2n–48). However, the incidence of male fertility and the seed set obtained following numerous interhaploid matings have
been consistently low. Hybrids between the cultivated diploid (2n–24) species (S. ajanhuiri, S. goniocalyx, S. phureja, S. stenotomum) and the pollen-fertileS. tuberosum haploids provide one means of overcoming this low fertility.
Crosses were made among 60 F1-hybrids, resulting fromS. phureja (♀) — haploidS. tuberosum (♂) matings, to determine their pollen and ovule fertility. These hybrids, which represent 16 combinations of 15S. phureja selections (from Plant Introductions 195198, 195214, 225678, 225683, 225685, 225701, 225708, 225710, 243461, 243462, 243466)
with 2 malefertile haploids (US-W 1 fromKatahdin and US-W 42 from,Chippewa), were selected for desirable tuber characteristics and yield. All 60 hybrid selections were fertile both as males and as
females. The seed set obtained was exceptionally high. No self-fertility was found.
The high incidence and level of male and female fertility suggests that lack of fertility is not likely to present an obstacle
to future study of the potato at the 24-chromosome level.
Cooperation of the Inter-Regional Potato Introduction Project in providingSolanum materials is hereby acknowledged. This research was supported in part by a grant from the National Science Foundation. 相似文献
Zusammenfassung Ein brauchbarer Grad von m?nnlicher und weiblicher Fertilit?t ist bei vielen, von der gew?hnlichen KartoffelS. tuberosum (2n–48) erhaltenen Haploiden (2n=24) vorhanden. Dennoch sind das Ausmass von m?nnlicher Fertilit?t und der nach zahlreichen interhaploiden Paarungen erhaltene Samenansatz st?ndig schwach gewesen. Bastarde zwischen den kultivierten diploiden (2n–24) Arten (S. ajanhuiri, S. goniocalyx, S. phureja, S. stenotomum) und den pollenfertilenS. tuberosum-Haploiden stellen eine M?glichkeit dar, um diese schwache Fertilit?t zu überwinden. Fertile, kr?ftige Bastarde, einige davon mit überraschend guter Knollengr?sse und gutem Ertrag wurden erzeug', wenn die Haploiden als Pollenspender gebraucht wurden. Die Bastarde, welche von den reziproken Kreuzungen stammten, waren ebenso kl?ftig, aber m?nnlich-steril. Um ihre Pollen- und Eizellen-Fertilit?t zu bestimmen, wurden Kreuzungen zwischen 60 F1-Bastarden vorgenommen, die aus Paarungen vonS. phureja (♀) mit, haploidenS. tuberosum (♂) hervorgingen. Diese Bastarde, die 16 Kombinationen von 15S. phureja-Auslesen (aus “Plant Introductions” 195198, 195214, 225678, 225683, 225685, 225701, 225708, 225710, 243461, 243462, 243466) mit zwei m?nnlich-fertilen Haploiden (US-W 1 vonKatahdin und US-W 42 vonChippewa) darstellen, wurden auf wünschenswerte Knolleneigenschaften und Ertrag ausgelesen. 99% der m?glichen 1.770 Kombinationen zwischen den 60 Eltern (1.755 Best?ubungen) und 84% der reziproken Kreuzungen (1.483 Best?ubungen) wurden vorgenommen, indem eine Best?ubung in jeder Richtung angewendet wurde. Der Erfolg nach reziproken Paarungen war mit dem aus Kombinationen, die nur in einer Richtung versucht wurden, vergleichbar (68% und 67% Beeren je Best?ubung). Alle Beeren zusammen brachten einen Durchschnittsertrag von 242 Samen je Beere und 92% ergaben mehr als 100 Samen je Beere (Tabelle 1). Alle 60 Eltern erwiesen sich als m?nnlich- und weiblich-fertil. Keine waren selbstfertil, obwohl alle funktionsf?hige Eizellen und Pollen produzierten. Die Leistungen dieser Selektionen als m?nnliche und weibliche Eltern sind nach Familien zusammengestellt (Tabelle 2). Die Mittelwerte für Einzelauslesen innerhalb einer Familie waren, von weinigen Ausnahmen abgesehen, den Familien-Mittelwerten vergleichbar. Die Zahl der erfolgreichen Best?ubungen zwischen enger verwandten F1-Auslesen war mit jener zwischen “nicht verwandten” Auslesen vergleichbar (Tabelle 3). Der durchschnittliche Samenansatz war hoch, ob die Paarung zwischen Geschwister-, Halbgeschwister- oder “nicht verwandten” Auslesen erfolgte. Ein Vergleich zwischen den rohen (“raw”) Haploiden vonS. tuberosum und den 60 Bastarden ausS. phureja und haploidenS. tuberosum in bezug auf Triebkraft, Abblühen und Fettilit?t ist auffallend. Im Verlauf einer Vegetationsporiode blühten ungef?hr 50% der Haploiden, zirka 30% wurden erfolgreich als weibliche Eltern verwendet, und 3% waren m?nnlich-fertil (Tabelle 4). Demgegenüber blühten alle Bastard-Auslesen reichlich, und alle waren als m?nnliche und weibliche Eltern funktionsf?hig. Das h?ufige Vorkommen und der hohe Grad von m?nnlicher und weiblicher Fertilit?t weist darauf hin, dass der Mangel an Fertilit?t für zukünftige Studien über die Kartoffel mit 24 Chromosomen kaum ein Hindernis bildet.
Résumé Il existe chez divers haplo?des (2n=24) obtenus de la Pomme de terre commune,S. tuberosum (2n=48), un niveau exploitable de fertilité male et femelle. Cependant les cas de fertilité male et les quantités de semences obtenues à la suite de nombreux croisements inter-haplo?des sont régulièrement bas. L'hybridation entre les espèces diplo?des cultivées (2n=24) (S. ajanhuiri, S. goniocalyx, S. phureja, S. stenotomum) et les haplo?desS. tuberosum à pollen fertile constitue un moyen de surmonter cette basse fertilité. En utilisant les haplo?des comme parents pollinisateurs, on a obtenu des hybrides fertiles, vigoureux, parmi lesquels plusieurs possèdent des qualités surprenantes de grande grosseur de tubercule et de productivité. Les croisements réciproques donnent des hybrides également vigoureux mais affectés de stérilité male. On a effectué des croisements parmi 60 hybrides F1, provenant deS. phureja (♀) S. tuberosum haplo?des (♂), pour déterminer leur fertilité pollinique et ovulaire. Ces hybrides, représentant 16 combinaisons de 15 sélections deS. phureja (provenant des “Plant Introductions” 195198, 195214, 225678, 225683, 225685, 225701, 225708, 225710, 243461, 243462, 243466) avec deux haplo?des avec fertilité male (US-W 1 dekatahdin et US-W 42 deChippewa), avaient été choisis pour leurs bonnes propriétés de tubercule et de productivité. 99% des 1770 combinaisons possibles parmi les 60 parents (1775 pollinisations) et 84% des combinaisons réciproques (1483 pollinisations) ont été réalisées en pollinisant dans les deux sens. Les réussites des croisements réciproques et des croisements dans un sens seulement sont comparables (68 et 67% de fructification respectivement). Sur l'ensemble des baies, la production moyenne de semences par baie était de 242; 92% des baies donnaient plus de 100 semences par baie (Tableau 1). Tous les 60 parents étaient fertiles à la fois comme male et comme femelle. Aucun n'était autofertile alors que tous produisaient des oeufs et du pollen fonctionnels. Les performances de ces sélections comme parents males et femelles sont résumées par familles dans leTableau 2. Les moyennes des sélections individuelles au sein d'une famille étaient, à part quelques exceptions, comparables aux moyennes de la famille. Les nombres de pollinisations fécondes parmi les sélections F1 les plus apparentées étaient comparables à ceux de sélections “non apparentées” (Tableau 3). La production moyenne de semences était élevée, que le croisement implique des sélections soeurs, demi-soeurs, ou “non apparentées”. Les comparaisons de vigueur, de floraison et de fertilité entre les hybrides purs (“raw”) deS. tuberosum haplo?de et les 60 hybridesS. phureja S. tuberosum haplo?de sont frappantes. Au cours d'une saison de croissance, 50% approximativement des haplo?des fleurissent, 30% approximativement sont utilisés avec succès comme parents femelles, et 3% ont la fertilité male (Tableau 4). Au contraire, toutes les sélections d'hybrides fleurissent abondamment et toutes sont des parents males et femelles fonctionnels. Le niveau élevé de fertilité male et femelle suggère qu'un manque de fertilité ne présente vraisemblablement pas un obstacle à l'étude ultérieure de la Pomme de terre au niveau de 24 chromosomes.
Cooperation of the Inter-Regional Potato Introduction Project in providingSolanum materials is hereby acknowledged. This research was supported in part by a grant from the National Science Foundation. 相似文献
270.
A. S. Thomas 《Grass and Forage Science》1962,17(2):103-108
The distinctive vegetation of some anthills in chalk grasslands is shown diagrammatically, and some differences between the soils of anthills and those of the surrounding grasslands are discussed. The termite mounds of the tropics also have soils differing from those of the grasslands in which they are built; some harvester termites destroy areas of pasture: and the large mounds of fungus-eating termites hinder mechanical cultivation. Temperate and tropical pastures benefit from control of ants and termites. 相似文献