产前和产后香味剂印迹训练对仔猪断奶后采食偏好的影响及其机理     

张鑫  李方方  朱宇旌  郑丽莉  张勇 《动物营养学报》2015,(6)

仔猪断奶后受到心理、营养、环境等多方面的刺激,导致应激反应,影响仔猪的采食量。固体饲粮代替母乳是最大的应激源,通过在母猪饲粮中添加香味剂对仔猪产前和产后进行香味剂印迹训练,使仔猪逐渐喜欢这种气味,降低其对添加相同香味剂饲粮的应激反应,并对有相同气味的饲粮有采食偏好,从而提高仔猪的采食量。本文对产前和产后香味剂印迹训练对仔猪断奶后采食偏好的影响及其机理进行综述,为养猪业相关试验研究提供理论依据。  相似文献   

Changes in Physical Properties of Soils with Land Use Time in the Brazilian Savanna Environment     

Kleber Trabaquini  Antnio Roberto Formaggio  Lênio Soares Galvo 《Land Degradation \u0026amp; Development》2015,26(4):397-408

Soils from central Brazil have been intensively used over the last decades because of the rapid conversion of savannas ( Cerrado ) into corn/soybean fields. The objective of this work is to study modifications in the physical properties of soils in the Rio Verde watershed, as a function of the land use time for agriculture, determined from classification of Landsat satellite images between 1980 and 2010. Soil samples were collected at surface (0–20 cm) and subsurface (20–40 cm) horizons for the different classes of land use time (<10, 10–20, 20–30, and >30 years). The following physical properties were measured: bulk density (BD), air permeability (K_a), penetration resistance (PR), microporosity (MI), macroporosity (MA), and total porosity (TP). Results showed a strong expansion with time of agriculture that occupied 35·3% (1980), 37·4% (1990), 51·3% (2000), and 60·9% (2010) of the watershed area. When properties were compared with those from the reference areas (preserved soils under native vegetation), significant differences were observed for all the physical attributes of soils for a land use time higher than 20 years. Overall, BD and PR increased with land use time, and the opposite was verified for K_a, MA, and TP. Some physical properties presented values (e.g., 1·54 g cm⁻³ for BD and 0.06 cm³ cm⁻³ for MA) close to the critical ones reported to affect crop development, but they were not still impacting on local soybean yield. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

Continuous infusion of propofol in calves: bispectral index and hemodynamic effects          下载免费PDF全文

Mauricio Deschk  Juliana T Wagatsuma  Marcelo A Araújo  Guilherme GF Santos  Sergio SR Júnior  Caio JX Abimussi  Carlos E Siqueira  Jéssica CL Motta  Silvia HV Perri  Paulo SP Santos 《Veterinary anaesthesia and analgesia》2016,43(3):309-315

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Effects of gossypol from cottonseed cake on the blood profile in sheep     

Antônio Carlos Lopes Câmara  André Menezes do Vale  Cláudio Roberto Scabelo Mattoso  Marília Martins Melo  Benito Soto-Blanco 《Tropical animal health and production》2016,48(5):1037-1042

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Phenotypic and genotypic characterization of Paenibacillus larvae isolates     

Antúnez K  Piccini C  Castro-Sowinski S  Rosado AS  Seldin L  Zunino P 《Veterinary microbiology》2007,124(1-2):178-183

Paenibacillus larvae is the causative agent of American Foulbrood (AFB), a severe disease of honeybees (Apis melifera). The aim of this work was to develop a strategy for the subtyping and the epidemiological analysis of P. larvae. Phenotypic characterisation, susceptibility to several antibiotics, electrophoresis of whole bacterial proteins, rep-PCR, ribotyping and DGGE were assessed using a collection of P. larvae isolates from different Uruguayan and Argentinean locations. Results indicated that there are two P. larvae genotypes circulating in Uruguay ERIC I-BOX A (worldwide distributed) and ERIC I-BOX C (exclusively detected in Argentina until this study). These results suggest that P. larvae isolates had moved between Argentina and Uruguay, probably through the Uruguay River. Patterns of whole bacterial proteins, DGGE and ribotyping did not improve the P. larvae intraspecific discrimination. Antibiotic susceptibility assays showed that 100% isolates were OTC-sensitive and 22% (belonging to ERIC I-BOX A group) were sulfisoxazole-resistant. This work may contribute to the elucidation of basic aspects related to the epidemiology of AFB in Uruguay and in the region.  相似文献   

Feeding preference and intraguild interactions between the parasitoid Trichogramma achaeae and the predator Macrolophus pygmaeus,two biological agents of Tuta absoluta     

Isabel Borges  Luisa Oliveira  Ana Durão  Patricia Arruda  António O. Soares 《Pest management science》2023,79(11):4376-4382

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Comparison of water status indicators for young peach trees   总被引：12，自引：1，他引：12  

Damiano?RemoriniEmail author  Rossano?Massai 《Irrigation Science》2003,22(1):39-46

We measured a series of physiological and physical indicators and compared them to xylem sap flow, to identify the most sensitive and reliable plant water status indicator. In the growing season of 1998, 4-year-old peach trees (Prunus persica Batsch cv. 'Suncrest', grafted on 'GF 677' rootstock) were studied under two irrigation treatments, 25 l day^у and no irrigation, and during recovery. Trials were conducted near Pisa (Italy) in a peach orchard situated on a medium clay loam soil and equipped with a drip-irrigation system (four 4 l h^у drippers per tree). Measurements of leaf water potential (ƒ_W), stem water potential (ƒ_S), and leaf temperature (T_l) were taken over 5 days (from dawn to sunset) and analyzed in conjunction with climatic data, sap flow (SF), trunk diameter fluctuation (TDF) and soil water content (SWC). Physiological indicators showed substantial differences in sensitivity. The first indication of changes in water status was the decrease of stem radial growth. TDF and SF revealed significant differences between the two irrigation treatments even in the absence of differences in pre-dawn leaf water potential (pdƒ_W), up until now widely accepted as the benchmark of water status indicators. Irrigated trees showed a typical trend in SF rate during the day, while in non-irrigated plants the maximum peak of transpiration was anticipated. Measurements of water potential showed ƒ_S to be a better indicator of tree water status than ƒ_W. T_l was found to have poor sensitivity. In conclusion, we found the sensitivity of the indicators from the most to the least was: TDF >SF rate >SF cumulated = pdƒ_W=ƒ_S>mdƒ_W>T_l.  相似文献   

Controlled water table management as a strategy for reducing salt loads from subsurface drainage under perennial agriculture in semi-arid Australia   总被引：2，自引：0，他引：2  

John?W.?HornbuckleEmail author  Evan?W.?Christen  James?E.?Ayars  Richard?D.?Faulkner 《Irrigation and Drainage Systems》2005,19(2):145-159

Recent community based actions to ensure the sustainability of irrigation and protection of associated ecosystems in the Murrumbidgee Irrigation Area (MIA) of Australia has seen the implementation of a regional Land and Water Management Plan. This aims to improve land and water management within the irrigation area and minimise downstream impacts associated with irrigation. One of the plan objectives is to decrease current salt loads generated from subsurface drainage in perennial horticulture within the area from 20 000 tonnes/year to 17 000 tonnes/year. In order to meet such objectives Controlled Water table Management (CWM) is being investigated as a possible ‘Best Management Practice’, to reduce drainage volumes and salt loads.During 2000–2002 a trial was conducted on a 15 ha subsurface drained vineyard. This compared a traditional unmanaged subsurface drainage system with a controlled drainage system utilizing weirs to maintain water tables and changes in irrigation scheduling to maximize the potential crop use of a shallow water table. Drainage volumes, salt loads and water table elevations throughout the field were monitored to investigate the effects of controlled drainage on drain flows and salt loads.Results from the experiment showed that controlled drainage significantly reduced drainage volumes and salt loads compared to unmanaged systems. However, there were marked increases in soil salinity which will need to be carefully monitored and managed.  相似文献   

Potato evapotranspiration and yield under different drip irrigation regimes   总被引：1，自引：0，他引：1  

Yaohu?KangEmail author  Feng-Xin?Wang  Hai-Jun?Liu  Bao-Zhong?Yuan 《Irrigation Science》2004,23(3):133-143

A field experiment comparing different irrigation frequencies and soil matric potential thresholds on potato evapotranspiration (ET), yield (Y) and water-use efficiency (WUE) was carried out in a loam soil. The experiment included five treatments for soil matric potential: F1 (-15 kPa), F2 (-25 kPa), F3 (-35 kPa), F4 (-45 kPa) and F5 (-55 kPa) and six treatments for irrigation frequency: N1 (once every day), N2 (once every 2 days), N3 (once every 3 days), N4 (once every 4 days), N6 (once every 6 days) and N8 (once every 8 days). Results indicate that both soil matric potential and drip irrigation frequency influenced potato ET, Y and WUE. Potato ET increased as irrigation frequency and soil matric potential increased. Comparing soil water potential, the highest ET was 63.4 mm (32.1%) more than the lowest value. Based on irrigation frequency treatments, the highest ET was 36.7 mm (19.2%) more than the lowest value. Potato Y and WUE were also found to increase as irrigation frequency increased. Potato Y increased with an increase in soil water potential then started to decrease. The highest Y and WUE values were achieved with a soil matric potential threshold of -25 kPa and an irrigation frequency of once a day.Communicated by J. Ayars  相似文献   

Contrasting edge and pasture matrix effects on ant diversity from fragmented landscapes across multiple spatial scales     

Lasmar  Chaim J.  Queiroz  Antônio C. M.  Rosa  Clarissa  Carvalho  Nathália S.  Schmidt  Fernando A.  Solar  Ricardo R. C.  Paolucci  Lucas N.  Cuissi  Rafael G.  Ribas  Carla R. 《Landscape Ecology》2021,36(9):2583-2597

Landscape Ecology - Harmful effects of habitat loss and fragmentation can be detected across multiple spatial scales, yet most studies that aim to characterize these effects take place at a single...  相似文献