339 research outputs found

    Evaluation of the performance of a commercial dairy herd using a computerized system of records

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    The aim of this study was to assess performance indexes relative to fertility and milk production in a herd of 750 cows of the Girolando breed enrolled in a dairy herd monitoring program (PMRL) developed by the Estação Experimental de Zootecnia de Ribeirão Preto, SP, Brazil from 1990 to 1999. Results showed that the indexes studied improved over the years. In the regression model some variables, such as total number of cows in the herd, interval from calving to first service, pregnancy rate at first service and pregnancy rate at all services, showed high coefficient of determination (R2 >51%), indicating that these traits responded strongly to the action recommended by the PMRL. Other traits, such as age at first calving, interval from calving to conception, number of services per conception, total milk yield per lactation and at 305 days of lactation, depend more on other factors inherent to the animal itself than on the PMRL. For this group of traits, other sources of variation were included in the analysis model, namely age of cow or number of calving, sex of the calf, genetic group, and month/season and year of calving, in an attempt to improve the R2. In both cases, the variable year of calving indirectly measured the efficiency of the system. The period studied (10 years) was not long enough to perceive the effects of certain other sources of variation such as genetic progress, which could also be involved

    Characteristics of nodule bacteria from Mimosa spp grown in soils of the Brazilian semiarid region.

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    The Brazilian Northeastern dry forest (Caatinga) is one of the diversification centers of Mimosa species. We determined the characteristics of native rhizobia isolates from nodules of Mimosa tenuiflora and Mimosa paraibana grown in pots with soils collected under Caatinga vegetation and compared the restriction ribosomal DNA profiles of the isolates with those of 16 reference strains. All plants formed abundant indeterminate nodules and all nodule isolates formed fast growing colonies. No colony altered the medium to an alkaline reaction and most of them produced low or medium amounts of extracellular polysaccharides. White and creamy colonies predominated among the isolates but orange and green colonies were present. Differences among the isolates from the Mimosa species tested are indicated by the greater phenotypic diversity of those obtained from M. tenuiflora. The analysis of the 16S rDNA gene suggests that the isolates from M. tenuiflora and M. paraibana are closely related and closer to B-rhizobia than to α-rhizobia. However, the similarity with all the tested B-rhizobia reference strains was relatively low suggesting that the isolates may belong to different bacteria species

    Feições de exploração florestal de impacto reduzido na Flona do Tapajós utilizando imagens Landsat e filtros texturais.

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    In the Amazon, the suitable of natural forests is recurring theme in the last years on the world, considering if the same has a huge potential of contribution in products and services. In this context, the reduced impact logging is fundamental in the biodiversity conservation and their forest feedstock sustainable use. Thus, to evaluate a mapping the reduced impact logging in the National forest of Tapajós, Para State, a quantity of information?s and Landsat8 - OLI series merged to orbit-points 227/062 was used to apply in the DETEX methodology (Selective logging Detection), to detect forest exploitation. The results showed significant relationships at use of coherence matrixes of gray levels based on texture characteristics related with remained basal area in fields regarded as reduced impact logging, notably to contrast, entropy, homogeneity and angular second moment texture variables, for the majority of them after the forest exploitation in the area. In addition, the longest filters windows size obtained significant statistical results, aligned with specialized literature about the theme. In this way, is recommended the use of methodology in areas with higher exploitation intensity than used in this study, in order to stablish comparisons and identify levels of intensity in forest exploitation distinc

    Soil biochemistry and microbial activity in vineyards under conventional and organic management at Northeast Brazil.

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    The São Francisco Submedium Valley is located at the Brazilian semiarid region and is an important center for irrigated fruit growing. This region is responsible for 97% of the national exportation of table grapes, including seedless grapes. Based on the fact that orgThe São Francisco Submedium Valley is located at the Brazilian semiarid region and is an important center for irrigated fruit growing. This region is responsible for 97% of the national exportation of table grapes, including seedless grapes. Based on the fact that organic fertilization can improve soil quality, we compared the effects of conventional and organic soil management on microbial activity and mycorrhization of seedless grape crops. We measured glomerospores number, most probable number (MPN) of propagules, richness of arbuscular mycorrhizal fungi (AMF) species, AMF root colonization, EE-BRSP production, carbon microbial biomass (C-MB), microbial respiration, fluorescein diacetate hydrolytic activity (FDA) and metabolic coefficient (qCO2). The organic management led to an increase in all variables with the exception of EE-BRSP and qCO2. Mycorrhizal colonization increased from 4.7% in conventional crops to 15.9% in organic crops. Spore number ranged from 4.1 to 12.4 per 50 g-1 soil in both management systems. The most probable number of AMF propagules increased from 79 cm-3 soil in the conventional system to 110 cm-3 soil in the organic system. Microbial carbon, CO2 emission, and FDA activity were increased by 100 to 200% in the organic crop. Thirteen species of AMF were identified, the majority in the organic cultivation system. Acaulospora excavata, Entrophospora infrequens, Glomus sp.3 and Scutellospora sp. were found only in the organically managed crop. S. gregaria was found only in the conventional crop. Organically managed vineyards increased mycorrhization and general soil microbial activity

    The Brazilian Program for Biodiversity Research (PPBio) Information System.

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    The database of the Brazilian Program for Biodiversity Research (PPBio; GIVD ID SA-BR-001) includes data on the environment and biological groups such as plants. It is organized by site, which is usually a grid with 10 to 72 uniformly-distributed plots, and has already surveyed 1,638 relevés across different Brazilian ecosystems. The sampling design is based on the RAPELD system to allow integration of data from diverse taxa and ecosystem processes. RAPELD is a spatially-explicit sampling scheme to monitor biodiversity in long-term ecological research sites and during rapid appraisals of biodiversity that has attracted support from many management agencies, which are using it as their long-term monitoring system. Vegetation surveys include measurements of cover, biomass and number of individuals from woody and herbaceous vascular plants, along with environmental data. We have recently migrated to a metadata catalog and data repository which allows searching for specific groups across all sites. All RAPELD data have been collected since 2001, though the site also allows data from other long-term plots to be archived as associated projects
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