CHANGES IN THE STRUCTURE OF MARSH SOILS FOLLOWING DRAINAGE AND ARABLE CULTIVATION     

D. L. Dent    E. J. B. Downing  H. Rogaar 《European Journal of Soil Science》1976,27(2):250-265

Measurements of apparent density (dry bulk density) have been used to monitor structural change in gleyed alluvial soils in Norfolk following drainage and cultivation. In Waveney series silty clay loam, drained for 9 years, soil ripening has been the dominant pedological process. Apparent density has increased throughout the drained profile due to loss of water and consequent structural rearrangement. In silty clay loam alluvium, reclaimed from the Wash over a 120-year period, soil ripening appears to be terminated after 40 years but, under continuous arable use, apparent density continues to increase in, and immediately below, the plough layer. This increase in density is accompanied by a decline in the organic-matter content of the plough layer.  相似文献   

Pathology of Brucella ovis infection in red deer stags (Cervus elaphus)     

AL Ridler  DM West  MG Collett 《New Zealand veterinary journal》2013,61(2):146-149

Abstract

AIM: To describe the pathology of the reproductive tract of red deer stags with active Brucella ovis infection and in stags in which B. ovis infection had resolved.

METHODS: Twenty-three red deer stags of varying history were slaughtered and their epididymides and accessory sex glands examined grossly and by histopathology. At the time of slaughter five of the stags had an active B. ovis infection of 24–55 days duration following exposure to infected rams, 10 stags had been experimentally infected with B. ovis by intravenous inoculation 649 days previously and had developed an active infection but the bacterial infection had resolved at least 308 days prior to slaughter, and eight stags had not been exposed to B. ovis at any time.

RESULTS: Of the five stags with an active infection, one had gross enlargement of the epididymides that could be detected by scrotal palpation. Histological lesions in all five stags included mild to severe, predominantly non-suppurative epididymitis, vesiculitis, prostatitis and ampullitis, with neutrophil exudation in associated glandular ducts. Additional lesions in the epididymides were spermatic granulomas and epithelial hyperplasia with intra-epithelial cyst formation. Of the 10 stags in which the bacterial infection had resolved, two had gross enlargement of the epididymides. The histological lesions were similar to those in stags with active infection but were generally milder, with increased periductal scar tissue in the epididymides. The lesions seen in stags resembled those seen in rams with B. ovis infection but they were usually less florid and had fewer plasma cells. No gross abnormalities or histopathological lesions were detected in the non-infected stags.

CONCLUSIONS: Only a small percentage of red deer stags infected with B. ovis develop lesions of epididymitis that can be detected by scrotal palpation. Gross and histological lesions of the genital tract of stags associated with B. ovis infection are similar to the lesions seen in rams. Lesions in stags persist for >300 days after the bacterial infection has resolved.

CLINICAL RELEVANCE: Brucella ovis infection should be considered when there are gross lesions of epididymitis or histological evidence of inflammation in the epididymides or accessory sex glands of red deer stags. Retrospective diagnosis of B. ovis in stags could be achieved by histological examination of the reproductive organs.  相似文献   

Endometrial gene expression in primiparous dairy cows at the end of the voluntary waiting period is affected by nutrition: Total mixed ration vs increasing levels of herbage allowance          下载免费PDF全文

AL Astessiano  M Carriquiry  DA Mattiauda  ML Adrien  P Chilibroste  A Meikle 《Reproduction in domestic animals》2017,52(5):798-805

The study postulated that differential nutritional management during the early lactation period would be reflected in endometrial expression of genes related to embryo growth at the end of the voluntary waiting period. Thus, the effect of the combined use of total mixed ration (TMR) and grazing under different herbage allowances during the first 75 days post‐partum (DPP) on endometrial gene expression was evaluated in primiparous dairy cows. Cows were blocked by body weight, age and body condition score and randomly assigned to three grazing treatments: high (HA, 30 kg DM per cow per day), medium (MA, 15 kg DM per cow per day) and low (LA, 7.5 kg DM per cow per day) herbage allowance (mixed pasture, 2,600 kg DM per ha) plus 8 kg DM of supplement or TMR (55% forage, 45% concentrate) fed ad libitum (TMR) from calving to 75 DPP. At 57 DPP, cows were synchronized for oestrus (day 0, 68 DPP) and at day 7, endometrial biopsies were obtained. The nutritional treatment did not affect insulin, IGF‐1 and leptin concentrations on days 0, 4 or 7. Expression of IGF1, IGFBP3, IGFBP4, ADIPOR1 and ADIPOR2 mRNA was significantly affected by the nutritional treatment. Endometrial IGF1 and IGFBP4 mRNA were twofold greater in TMR and HA than MA and LA cows. Expression of IGFBP3 and ADIPOR1 mRNAs was greater in TMR and HA than MA cows, but did not differ from LA cows. All groups had greater expression of ADIPOR2 mRNA than MA cows. This study provided solid evidence of the importance of nutritional management during early lactation on uterine environment at the end of the voluntary waiting period. The greater expression of genes related to embryo growth and uterine function (IGF system, progesterone and adiponectin receptors) in cows fed diets maximizing energy intake suggests a favourable environment for embryonic growth, which may explain the improved reproductive performance of cows in good energy balance.  相似文献   

后备小母牛限饲的可行性     

AL kertz  武书庚 《中国畜牧杂志》2010,46(22)

<正>因为要在佛罗里达反刍动物营养讨论会上做一个题为《小母牛限饲方案》的报告,笔者查阅了大量的相关文献,对此有了较深的认识,本文是该报告的梗概。过去的40年里,生长小母牛的饲养方案经历了多个阶段  相似文献   

Seasonal changes in a deep‐water fish assemblage in response to monsoon‐generated upwelling events     

JENNIFER L. MCILWAIN  EUAN S. HARVEY  SIMON GROVE  GLENN SHIELL  HAMED AL OUFI  NASR AL JARDANI 《Fisheries Oceanography》2011,20(6):497-516

The coastal shelf of the Gulf of Oman experiences periodic upwelling events during the summer months that are driven by the southwest monsoon. It is unclear what role these events play in the spatial and temporal distribution of the region’s fish assemblage. We carried out trials on two different video techniques to characterize the habitat and fish assemblage along the continental shelf margin near Muscat, Oman. Exploratory surveys with a drift stereo‐video revealed three main habitat types: Sand, Reef and Megabenthos. Three areas were chosen for additional sampling using stereo‐BRUVS (‘baited’ remote underwater‐video systems). On two separate occasions (November 2005 and March 2006) replicate stereo‐BRUVS were deployed in each area stratified by the main habitat types. For each teleost and elasmobranch species encountered on the video, an estimate of total body length and the relative abundance (MaxN_i) was made. The stereo‐BRUVS recorded a wide range of demersal and pelagic teleosts including species of conservation interest such as sharks, rays and groupers. The drift stereo‐video recorded significantly fewer species than the stereo‐BRUVS (N = 15 versus N = 43). Species diversity from the stereo‐BRUVS increased by 96% in March 2006 (N = 41) compared to November 2005 (N = 23), a pattern consistent at all three areas. The structure of the overall fish assemblage (using canonical analysis of principal coordinates analysis) was highly variable both in time and space. There was ample evidence of strong habitat associations, particularly with depth and seasonal shifts in abundance and diversity. We argue the upward migration of oxygen‐depleted water into the shallow depths during the late monsoon displaces the demersal fish community along this coast.  相似文献   

Land and water interface zones   总被引：1，自引：0，他引：1  

John P. Downing  Michel Meybeck  James C. Orr  R. R. Twilley  H. W. Scharpenseel 《Water, air, and soil pollution》1993,70(1-4):123-137

This paper reports analyses of C pools and fluxes in land-water interface zones completed at the International Workshop: Terrestrial Biospheric Carbon Fluxes; Quantification of Sinks and Sources of CO₂ (Bad Harzburg, Germany, March 1–5, 1993). The objective was to determine the role of these zones as global sinks of atmospheric CO₂ as part of a larger effort to quantify global C sinks and sources in the past (ca. 1850), the present, and the foreseeable future (ca. 2050). Assuming the world population doubles by the year 2050, storage of atmospheric C in reservoirs will also double, as will river loads of atmospheric C and nutrients. It is estimated that C sinks in temperate and boreal wetlands have decreased by about 50%, from 0.2 to 0.1 Gt C yr^?1 since 1850. The total decrease for wetlands may be considerably larger when tropical wetlands are taken into account, however, the area and C density of tropical wetlands are not well known at this time. Changes in cultivation practices and improved sampling of methaneogenesis have caused estimates of CH₄ emissions from ricelands to drop substantially from 150 to 60 Tg yr^?1. Even with doubled N and P loads, rivers are unlikely to fertilize more than about 20% of the new primary production in the coastal ocean. The source of C for this new production may not be the atmosphere, however, because the coastal ocean exchanges large quantities of DIC with the open ocean. Until the C fluxes from air-sea exchange of CO₂ and DIC are better quantified, the C-sink potential of the coastal ocean will remain a major uncertainty in the global C cycle. Analysis of model simulations of oceanic C uptake reconfirmed that the open ocean appears to take up about 2.0 Gt C yr^?1 from the atmosphere and that model estimates are in better accord now, ±0.5 Gt C yr^?1, than ever before. Land use management must consider the unique C sinks in coastal and alluvial wetlands in order to minimize the future negative impacts of agriculture and urban development. Long-term monitoring will be essential to prove the success, or failure, of management practices to sustain wetlands in the future. Relative to the other systems examined at the workshop, the C-sink capacity of the ocean (excluding estuaries) is not likely to be measurably affected in the foreseeable future by the management scenarios considered at the workshop.  相似文献   

鹿蹄草等中草药对油桃采后褐腐病抑制效果研究   总被引：5，自引：2，他引：5  

于庆华  吴小虎  艾启俊  肖艺  张伟 《北京农学院学报》2007,22(1):8-11

在离体和活体条件下,测定鹿蹄草、厚朴等中草药单剂及鹿蹄草为主的各中草药复配组合对油桃采后褐腐病菌的抑制效果。结果表明:11号(鹿蹄草+厚朴+大黄),14号(鹿蹄草+高良姜+虎杖)复配组合在离体试验中抑菌效果最好,10 mg/mL浓度的抑制率分别达到89.77%,85.50%;两种组合的最小抑菌浓度(MIC)分别是1.25,2.5 mg/mL;最小杀菌浓度(MBC)分别是2.5,5.0 mg/mL。活体抑菌测定结果表明,11号和14号复配组合对油桃褐腐病菌有不同程度延缓侵染和抑制作用,但不能完全防治;0.05 mg/mL扑海因与11号组合20 mg/mL,0.10 mg/mL扑海因与11号组合10 mg/mL均能完全抑制褐腐病菌在油桃果实上的发生和蔓延。  相似文献   

EFFECT OF BOAR PRESENCE IN THE PREWEANING PERIOD ON THE REPRODUCTIVE PARAMETERS OF SOWS     

G. Borchardt Neto  I. Wentz  AL. Guidoni  F.P. Bortolozzo 《Reproduction in domestic animals》1996,31(2):311-312

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Reply     

JWA LARSEN  AL VIZARD  N. ANDERSON  GA ANDERSON 《Australian veterinary journal》1995,72(2):75-76

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Book reviews     

Frederick H. Buttel  Mary T. Dailey  Theodore E. Downing  Maynard Kaufman 《Agriculture and Human Values》1984,1(2):29-35

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