"黑麦草-水稻”草田轮作系统的研究V.稻田冬种黑麦草的优质高产栽培技术

黑麦草（ＩＲＧ）的栽培方式、播种量、施肥种类和施肥量是影响ＩＲＧ优质高产的主要因素。研究结果表明,高播量（２２．５ｋｇ／ｈｍ＾２）稻底撒播方式可以获得优质高产的ＩＲＧ,干物质产量９１８３．４５ｋｇ／ｈｍ＾２,粗蛋白质产量达１６６８．００ｋｇ／ｈｍ＾２,因其节省劳力,且可以有效利用稻田水分,因此可作为稻田冬种ＩＲＧ的主要方式。中等播量（１５．０ｋｍ／ｈｍ＾２）育苗移栽方式也获得了较高的产量（９７６５     

西红柿黄顶病的初步研究

黄頂病在广州地区发生已有30—40年,过去只是零星发生,为害不大。但自1959年开始則发生普遍,1959年发病率为5—7％,1960年为9—17％,1961年为30—50％,1962年减少至2—3％,1963年又較严重发生,大面积的番茄也几乎全部感染,而且发病早,損失很大。本病在各种品种上的病状特点是:感病后植株顶叶叶色褪綠乃至黄化,叶片变小,叶面皺縮,中部稍凸起,边緣多向下或向上卷曲;严重时,整个叶片呈“棒状”,病株矮化,不定枝丛生。但在薯叶型的品种如“Karlik”上的病状特点則是:顶部     

Early luteal development in Santa Inês ewes superovulated with reduced doses of porcine follicle‐stimulating hormone

The aim was to compare the early luteal development in ewes superovulated with different doses of pFSH. Twenty‐nine Santa Inês ewes received a progesterone device (CIDR®) for 8 days. Gonadotrophic treatment started on Day 6: G200 (control, n = 9, 200 mg); G133 (n = 10, 133 mg); and G100 (n = 10, 100 mg of pFSH). On Day 6, all females received eCG (300 IU). B‐mode and spectral Doppler ultrasonography were performed daily during the early luteal phase (Days 11–15) to monitor the development of corpora lutea (CLs; dimensions) and ovarian arteries indices. CLs were also classified as normal or prematurely regressed (PRCL) on Day 15 by videolaparoscopy. Ewes from G100 and G133 showed gradual increase in luteal diameter during the early luteal phase (p < 0.001), whereas G200 animals presented increase from Day 11 to Day 13, and then decrease on Days 14 and 15 (p < 0.001). The G200 females showed greater percentage of PRCL (45.20%) than those of the other groups (p < 0.001). The normal CLs number was greater in G100 than in G133 (p = 0.04), while the PRCL number was greater in G200 than in the other groups (p = 0.03). Resistive index (RI) was greater in G200 than in G100 (p = 0.02). RI was lower in Day 12 than Day 15 (p = 0.02). Pulsatility index (PI) was greater on Days 14 and 15 (p < 0.01). In conclusion, the lowest dose of pFSH (100 mg) can be considered sufficient for an efficient superovulatory response in sheep, producing better CLs development dynamic in early luteal phase and ovarian blood perfusion and smaller number of PRCL than the traditional (200 mg) pFSH dose.     

Repurposing Ionophores as novel antimicrobial agents for the treatment of bovine mastitis caused by Gram‐positive pathogens

Increasing reports of multidrug‐resistant bacterial infections in animals has created a need for novel antimicrobial agents that do not promote cross‐resistance to critically important antimicrobial classes used in human medicine. In response to the recent emergence of antimicrobial resistance in several bovine mastitis pathogens, in vitro antimicrobial susceptibility was determined for four polyether ionophores (lasalocid, monensin, narasin and salinomycin) against Staphylococcus spp. and Streptococcus spp. isolated from clinical cases. In addition, erythrocyte haemolysis and WST ‐1 cell proliferation assays were used to assess in vitro mammalian cell cytotoxicity and biofilm susceptibility testing was performed using the minimum biofilm eradication concentration (MBEC ?) biofilm assay. Lasalocid, monensin, narasin and salinomycin exhibited bacteriostatic antimicrobial activity against all pathogens tested, including methicillin‐resistant staphylococci, with MIC ₉₀ values <16 μg/ml. Narasin and monensin displayed the least toxicity against mammalian cell lines and all compounds significantly reduced viable cell numbers in a Staphylococcus aureus biofilm. Based on in vitro characterization, all four ionophores offer potentially novel treatments against bovine mastitis but in vivo studies will be essential to determine whether acceptable safety and efficacy is present following intramammary administration.     

Aphid Antixenosis Mediated by Volatiles in Cereals

Abstract

Experimental results indicate the existence of an inducible system that can temporarily help cereal plants to defend themselves against cereal aphids. The induction is released by volatiles emitted when aphids attack a neighbour plant individual. Similar effects are obtained with mildew attacked plants. The system shows moderate specificity and affects the allocation of biomass in the plant.     

Evolution of Bacterial Community in Experimental Sand Filters: Physiological and Molecular Fingerprints

Stability and transport of As species in soils were investigated in three contaminated Central European regions in the Czech Republic; one of them represents naturally contaminated area, the others are results of a former mining activity. Total As content varied from 60 to <18,000 ppm depending on locality and sampling layer. Sequential extraction procedure (SEP) enabled to distinguish five main fractions of As in soils based on different chemical and binding properties. Non-specifically and weakly sorbed As, as well as As remained in solid rests of samples did not exceed 10% of total As; specifically bounded As varied from 5 to 15%. The substantial portion of As was bound to hydrated Fe oxides (HFO) in amorphous and poorly-crystalline forms (10–30% of the total As) and/or to a well-crystallized forms of the same phases (50–80%). As sorption on HFO surface, particularly on well-crystallized phases represented the most significant and stable As bond in soils. Model leaching experiments illustrated the increased mobility of As species at pH ≈ 7.0 in the soil–groundwater–surface water systems.     

冬种黑麦草最终割草时间对早稻生长发育和产量的影响

通过田间试验研究了对冬种黑麦草最终刈割时间对早稻生长发育及产量的影响。结果表明，在所设计的４种时间间隔中，间隔１５ｄ的处理最为理想，对早稻的分蘖，生长高度，有效分蘖，穗长，千粒重和产量等性状在该处理条件下表现最佳，因此，建议ＩＲＲ系统中黑麦草和早稻前后作采用１５ｄ的间隔时间。     

甘肃省森林鼠类区系调查初报

通过甘肃省陇南山地、定西地区、小陇山林区、子午岭林区和祁连山林区等5个区初步调查，表明甘肃省有森林害鼠51种，隶属于3目10科。区系成分以古北界为主，占总种数的84.4%，东洋界占9.8%，广布种占5.8%。种群数量上中华鼢鼠为优势种，甘肃鼢鼠、达乌尔鼠兔为次优势种。     

A nationwide survey on seroprevalence of Neospora caninum infection in beef cattle in Uruguay

Bovine abortions due to Neospora caninum infection have been reported worldwide and its economic impact on the beef industry has been acknowledged as a problem. Uruguay has the largest export value of beef per acre in South America. However, no data on the prevalence of N. caninum infection have been available in this country. The objective of this study was to estimate the prevalence and distribution of N. caninum infection in beef cattle in Uruguay through a nationwide survey. A two stage sampling design was used with farms being selected in stage one and animals being selected in stage two. A brief questionnaire was administered on each farm. Seroprevalence of N. caninum in 4444 beef cattle from 229 farms in all the counties, except Montevideo, of Uruguay was determined by an ELISA. The data were then analyzed to identify associations between infection and variables such as type of animal (cow or heifer), herd size, use of veterinary advice, productivity of the soil in relation to the national average, use of improved grass, use of mineral salts, use of supplemental feed, and presence of a dog(s) on the farm. The estimated proportion of positive farms for all the beef cattle operations was 69.2% (95% confidence interval [CI], 53.7-84.7). The overall cattle seroprevalence was estimated as 13.9% (95% CI, 11.6-16.3). The prevalence estimation by animal category was 14.3% (95% CI, 11.4-17.2) for beef cows and 12.9% (95% CI, 10.0-15.8) for beef heifers. There was no significant difference in the estimated prevalence between the two animal types. There was no significant difference in the animal level prevalence of N. caninum infection among different herd sizes. None of the herd demographic or management variables was significantly associated with the seropositivity to N. caninum infection. In conclusion, these results show that N. caninum infection is common among beef herds across Uruguay. Since the beef industry is one of the key industries in Uruguay, the economic effect and risk factors of N. caninum infection among beef cattle in this country should be further evaluated in the near future.