Conception rate following artificial insemination with sexed semen in Holstein heifers under artificial cooling during summer compared with winter season     

Correa-Calderón  Abelardo  Angulo-Valenzuela  Ismael  Betancourth  Fernando  Oroz-Rojo  Francisco  Fierros-Castro  Karina  Macías-Cruz  Ulises  Díaz-Molina  Raúl  Avendaño-Reyes  Leonel 《Tropical animal health and production》2020,52(1):203-209

Tropical Animal Health and Production - The objective of this study was to compare the fertility of Holstein heifers under cooling and inseminated with sexed semen during the summer versus winter...  相似文献   

Response to salinity of three grain legumes for potential cultivation in arid areas     

Raúl López-Aguilar  Andrés Orduño-Cruz  Armando Lucero-Arce  Bernardo Murillo-Amador  Enrique Troyo-Diéguez 《Soil Science and Plant Nutrition》2013,59(3):329-336

Abstract

The material balance of all the chemical species associated with the phosphate sorption reaction by two amorphous clays, silica-alumina gel and synthetic goethite was investigated adjusting the initial pH to 4.0, 5.0, 6.0, and 7.0. Phosphate sorption was found to decrease with increasing initial pH. During phosphate sorption, the equilibrium pH rose, adsorption of Cl^- decreased to a state of negative adsorption, adsorption of Na⁺ increased markedly, silicate was released, and Al in the solution was precipitated. With increasing initial pH, the amount of apparent released OH^- increased, the amount of Na⁺ adsorption increased, and the amount of released silicate decreased. The overall relationship of the material balance is explained in terms of the charge balance associated with phosphate sorption.  相似文献   

Simulated nitrogen deposition affects soil fauna from a semiarid Mediterranean ecosystem in central Spain   总被引：1，自引：0，他引：1  

Raúl Ochoa-Hueso  Iluminada Rocha  Carly J. Stevens  Esteban Manrique  María José Luciañez 《Biology and Fertility of Soils》2014,50(1):191-196

Nitrogen (N) deposition is a major threat to the semiarid Mediterranean ecosystems. We simulated a gradient of N deposition (0, 10, 20 and 50 kg N ha^?1 year^?1?+?6.4 kg N ha^?1 year^?1 ambient deposition) in a Mediterranean shrubland from central Spain. In autumn 2011 (after 4 years of experimental duration), soil cores were taken to extract the soil fauna. Acari (45.54%) and Collembola (44.00%) were the most represented taxonomical groups, and their abundance was negatively related to soil pH. Simulated N deposition had an impact on the total number of individuals in soil as well as on Collembola and Pauropoda abundance. Collembola abundance increased with N loads up to 20 kg N ha^-1 year^-1 and then decreased. This response was attributed to soil acidification (between 0 and 20 kg N ha^-1 year^-1) and increased soil ammonium (between 20 and 50 kg N ha^-1 year^-1). Pauropoda were favoured by additions of 50 kg N ha^-1 year^-1, and it was the only taxonomical group whose abundance was exclusively related to N deposition, suggesting their potential as bioindicators. Contrary to predictions, there was a negative relationship between soil faunal abundance and plant diversity. In conclusion, soil faunal communities from semiarid Mediterranean ecosystems in central Spain seem to be primarily influenced by soil chemistry (mainly pH) but are also susceptible to increased N deposition. The main drivers of change under increased N deposition scenarios seem to be soil acidification and increased ammonium in soils where nitrate is the dominant mineral N form.  相似文献   

Comparative analysis of using cereal grains and compound feed in semi-intensive common carp pond production     

Zoran Marković  Marko Stanković  Božidar Rašković  Zorka Dulić  Ivana Živić  Vesna Poleksić 《Aquaculture International》2016,24(6):1699-1723

The semi-intensive system of carp farming is dominant in inland aquaculture. Although it appears to be simple, this system has a whole range of options, from those based on traditional rearing methods with use of plants from the region where the fish are reared to production based on the use of high-quality concentrated feeds. In this paper, we conduct a comparative analysis of the effect of using cereal grains as opposed to compound feed (pelleted and extruded) on the quantity of fish produced, flesh quality, histological changes in the digestive tract, water quality, and structure of the biocoenosis in the pond ecosystem. When the fish are fed cereal grains, production ranges from 500 to 1500 kg/ha, while using compound feed gives production that is twice as great. The proportions of protein and water are higher and that of lipids lower in flesh of common carp reared on compound feed in relation to fish fed cereal grains. Use of extruded feed gives better content of n-3 polyunsaturated fatty acids and a better n-3/n-6 ratio than when pelleted feed and cereal grains are used. Comparison of water quality in carp ponds under conditions of using various types of feed indicates that there are no significant differences. Although it was expected that feed with a higher percentage of proteins would cause disturbances in the aquatic ecosystem, their continual incorporation into the cycling of matter in the water contributes to maintenance of ecological equilibrium and even indirectly promotes growth of the common carp.  相似文献   

Generalized and Specific State-and-Transition Models to Guide Management and Restoration of Caldenal Forests     

H. Raúl Peinetti  Brandon T. Bestelmeyer  Claudia C. Chirino  Alicia G. Kin  María E. Frank Buss 《Strength and Conditioning Journal》2019,72(2):230-236

Management impacts and natural events can produce ecosystem state changes that are difficult to reverse. In such cases, a detailed understanding of drivers, thresholds, and feedback mechanisms are needed to design restoration interventions. The Caldenal ecoregion in central Argentina has undergone widespread state change, and restoration is urgently needed, but as yet there has been no knowledge synthesis to support restoration actions. In this paper, we provide evidence-based guidelines for ecological restoration of the Caldenal forest derived from a general to local conceptual understanding of ecosystem dynamics. We develop a Caldenal forest state transition model based on a generalized fire-mediated savanna-woodland transition model. The generalized model depicts global similarities in fire-grass feedback loops as a primary factor controlling savanna to woodland transition (thicketization) in semiarid savannas around the world. An open forest is considered to be the reference state of the Caldenal that developed under a historical regime of frequent low-intensity fire. The introduction of large livestock herds in the region disrupted the positive fire-grass feedback loop and increased dispersal and recruitment of Prosopis caldenia, creating conditions for thicketization of the forest. Controlled, low-intensity fire can be used to build the resilience of an open forest state. Restoring open forest states from woodland states requires a large-scale selective thinning and pruning operation. Long-term restoration requires breaking the positive livestock-thicketization ? high-intensity fire feedback and reestablishing the positive grass-low intensity fire feedback to ensure the persistence of a restored open forest state.  相似文献   

Nursery fertilisation affects the frost-tolerance and plant quality of Eucalyptus globulus Labill. cuttings     

Manuel Fernández  Celia Marcos  Raúl Tapias  Federico Ruiz  Gustavo López 《Annals of Forest Science》2007,64(8):865-873

Eucalyptus globulus is widely used in productive exotic plantations but the expansion of these plantations is limited by low temperatures, as its cold hardening capacity is limited (0.5 to 3.0 °C). It is not well understood how nursery fertilisation affects the field performance of plants. This led us to study the effect of three mineral nutrients (N, P and K) on both plant quality and frost tolerance. The experiment comprised eight growth treatments in which a high dose (H-) or a low dose (L-) of each nutrient was applied. Nitrogen was the nutrient that determined shoot growth, new root growth after transplanting (root egress), frost tolerance and field performance. Performance was better with treatment H-N than with treatment L-N, leaf nitrogen contents being 1.53 and 0.89% respectively. The effects of phosphorus and potassium were not significant between treatments for any parameter. The exception was P which, when interacting with N, favoured root egress for the H-N treatment. It was concluded that nursery fertilisation offers a management tool for eucalyptus growers concerned with plant stock quality.  相似文献   

Bovine monocytes and a macrophage cell line differ in their ability to phagocytose and support the intracellular survival of Mycobacterium avium subsp. paratuberculosis     

Woo SR  Sotos J  Hart AP  Barletta RG  Czuprynski CJ 《Veterinary immunology and immunopathology》2006,110(1-2):109-120

Bovine monocytes exhibited a greater ability to phagocytose Mycobacterium avium subsp. paratuberculosis (i.e. greater percentage of infected cells, and more bacilli per infected cell), than did a bovine macrophage cell line (BoMac). Phagocytosis of M. paratuberculosis by monocytes, but not the cell line, was significantly enhanced by the addition of autologous serum. Following ingestion, the numbers of viable M. paratuberculosis cells in monocytes increased during the first 4 days and then declined between day 4 and day 8 after infection, as determined by a radiometric method. In contrast, BoMac cells were not permissive for bacillary multiplication; the numbers of M. paratuberculosis remained largely unchanged in the cell line during the 8 day incubation period. The numbers of microscopically visible acid-fast bacilli increased with time in monocytes but not in the macrophage cell line. These observations suggest that replication and inactivation of bacilli may both occur in monocytes. The differing abilities of bovine monocytes and the macrophage cell line to ingest and restrain the intracellular growth of M. paratuberculosis provide contrasting model systems for investigating how M. paratuberculosis enters and persists within its preferred niche, the mononuclear phagocyte.  相似文献   

ATP release by infected bovine monocytes increases the intracellular survival of Mycobacterium avium subsp. paratuberculosis     

Woo SR  Barletta RG  Czuprynski CJ 《Comparative immunology, microbiology and infectious diseases》2009,32(5):365-377

Mycobacterium avium subsp. paratuberculosis is the etiologic agent of Johne's disease, a chronic intestinal infection in ruminants. Adenosine 5'-Triphosphate (ATP) has been reported to induce killing of several Mycobacterium species in human and murine macrophages. We investigated whether ATP secreted from M. avium subsp. paratuberculosis-infected bovine monocytes affects intracellular survival of the bacilli. Bovine monocytes constitutively secreted ATP during an 8-day incubation period in vitro; however, M. avium subsp. paratuberculosis infection did not enhance ATP release. Removal of extracellular ATP by the addition of apyrase increased the viability of infected monocytes, but surprisingly decreased the number of viable intracellular bacilli. In contrast to previous reports, addition of extracellular ATP (1mM) increased intracellular survival of M. avium subsp. paratuberculosis in bovine monocytes. Neither apyrase nor ATP altered production of reactive oxygen intermediates (ROI) or reactive nitrogen intermediates (RNI) by bovine monocytes. These results suggest that ATP release from infected bovine monocytes improves, rather than decreases, the intracellular survival of M. avium subsp. paratuberculosis.  相似文献   

The prevalence of Toxocara cati in domestic cats in Mexico City   总被引：2，自引：0，他引：2  

Martínez-Barbabosa I  Vázquez Tsuji O  Cabello RR  Cárdenas EM  Chasin OA 《Veterinary parasitology》2003,114(1):43-49

The faeces of 520 domestic cats, resident in the 16 municipal authorities of Mexico City, were analysed using the method of centrifuging with zinc sulphate (at 33%). Three hundred and ninety-nine animals lived in houses, 121 in apartments. For the purpose of this study they were divided into seven age groups, of 6 months each. Toxocara cati eggs were found in the faeces of 42.5% of the animals. 20.7% of apartment cats and 49.1% of house cats were infected. This difference in the rate of infection is statistically significant (P<0.002.) for the house cats. T. cati was found in all the age groups although most infection was found in animals less than 1 year old.The fact that infection occurred in the whole age range of the cats and in all the municipal authorities means that the risk of being contaminated with this helminth in Mexico City is high. As a consequence, the possibility of developing illness as a result of becoming a host to larva migrans is also high.  相似文献   

Peanut and Amaranthus leucocarpus lectins discriminate between memory and naive/quiescent porcine lymphocytes     

Hernández J  Garfias Y  Reyes-Leyva J  Chávez R  Lascurain R  Vargas J  Zenteno E 《Veterinary immunology and immunopathology》2002,84(1-2):71-82

Lectins are relevant tools to isolate and characterize different cellular sub-populations. In this work, we used the lectins Arachis hypogaea (Peanut agglutinin, PNA) and Amaranthus leucocarpus (ALL), specific for Galss1, 3GalNAc, to characterize naive and memory lymphocytes from pigs, experimentally infected with the porcine rubulavirus (RvP). Our results showed that both lectins recognized preferentially lymphocytes with the CD4(+)CD8(+) phenotype (P<0.05). The phenotypic analysis of the cells recognized by these lectins indicated that PNA(+) lymphocytes showed higher rate of the CD29 antigen (PNA(+)CD29(high)) than ALL(+) (ALL(+)CD29(low)). The number of PNA(+)CD29(high) lymphocytes increased after 8 weeks of experimental infection with RvP, and most of the ALL(+)CD29(low) cells became CD29(middle). PNA(+) lymphocytes isolated from infected pigs proliferated after stimulation with the RvP, whereas ALL(+) cells did not. In vitro assays indicated that the ALL(+) cells from previously infected pigs diminished from 7.5 +/- 2 to 0.5 +/- 0.3% after RvP stimulation; whereas PNA(+) cells increased from 4 +/- 1 to 42 +/- 2%, whereas no modification in ALL(+) or PNA(+) cellular population was identified in lymphocytes from naive animals after RvP stimulation. Our results suggest that the cellular distribution/organization of the O-glycosydically linked glycans on lymphocytes may correlate with biological functions, and that PNA could be a tool to isolate specifically porcine memory T cell subsets, whereas ALL could be useful to isolate naive/quiescent T lymphocytes.  相似文献