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Ojeda A.,Central University of Venezuela | Canelones C.,Central University of Venezuela | Munoz D.,Central University of Venezuela | Gil J.L.,Instituto Nacional Of Investigaciones Agricolas
Tropical and Subtropical Agroecosystems | Year: 2013

To determine the chemical composition and nutritive value of selected browse species by buffaloes (Bubalus bubalis L.) in a silvopastoral system at a semi-deciduous tropical forest (SDTF), epidermal fragments in fecal samples from 14 males of Murrah breed were evaluated. The animals grazed for 91 days in 85 ha located in Portuguesa State, Venezuela, of which 35 ha corresponded to natural grass pastures (969.3 ± 28.6 kg DM ha-1), and the rest to SDTF with 463 plant ha-1. Eleven botanical families and 22 species were identified, 40.9% belonged to the Fabaceae family. The specie Guazuma ulmifolia (Sterculiaceae) had the highest relative dominancy (60.4%) and an Importance Value Index of 162.6. 60.4% of epidermal fragments corresponded to herbaceous Poaceae, and the rest was distributed among five different species, with the highest occurrence (94.6%) for Samanea saman and Sida acuta. There were differences (P<0.05) among selected species in the proximal composition (40.9 ± 7.1% dry matter, 16.0 ± 4.1% crude protein and 2.9 ± 1.2% ether extract), neutral detergent fiber (41.6 ± 2.2%), acid detergent fiber (25.9 ± 3.8%), minerals (1.6 ± 0.59% Ca and 0.1 ± 0.02% P), condensed tannins (0.9 ± 0.7%), potential gas production (67.8 ± 37.3 ml g-1 DM), and in vitro organic matter digestibility (54.2 ± 8.0%). In general, the edible fraction of selected browse species evaluated here was similar to other tropical browse forages and confirms the strategic value of this biomass in buffalo nutrition at silvopastoral system. Furthermore, these browse species could be employed in agroforestry systems to achieve a better integration of livestock production in tropical areas.

Uzcategui J.,University of Los Andes, Venezuela | Araujo Y.,Instituto Nacional Of Investigaciones Agricolas | Mendoza L.,University of Los Andes, Venezuela
Bioagro | Year: 2011

The horticultural farms in Pueblo Llano, Mérida State, have been using uncontrolled quantities of different kinds of pesticides, so the aim of this work was to determine the residual levels of organochlorine pesticides (OCPs) in those soils. Samples were taken in 20 farms, and Soxhlet extraction procedure (EPA 3540C) and sulfur elimination (EPA 3660B) were performed. According to the EPA 8081A method, the OCPs were determinined by gas chromatography with electronic capture detector. Nine OCPs were quantified in most samples in the following concentration ranges (mg·kg -1): DDT (0,04-0,99); DDE (0,01-0,56); DDD (0,04- 0,83); α-endosulfan (0,01-0,47); β-endosulfan (0,02-0,45); endosulfan sulfato (0,04-0,62); aldrin (0,005-0,009); dieldrin (0,01- 0,03), and endrin (0,01-0,04). The soils presented high levels of organic matter, which may favor OCPs retention. It was found that the total OCPs concentration, DDT and isomers (DDE and DDD) decrease as the soil pH increases, and enlarge as the clay percentage increases. The soils were classified as potentially contaminated, according to their levels of DDT, dieldrin and endrin.

Rice cultivars are affected directly and indirectly by the insect sogata. The mechanical damage or direct loss, is produced after feeding and ovoposition on the young leaves tissues, while the indirect damage is produced after the transmission of the Rice hoja blanca virus. We studied the morpho-anatomic structures associated with the resistance of the mechanical damage produced by the insect, in six rice cultivars, including controls for resistance and susceptibility (Makalioka and Bluebonnet 50), during August 2011, in Fundacion Danac, Venezuela. Samples were taken from leaf 3, where cuticle thickness, presence of macrohair, microhair and silica bodies in the second third of the leaf was evaluated. A significant difference to thickness of the cuticle, the presence of microhair in the leaves, and presence of silica bodies was observed among cultivars, determining a significant correlation among the number of macrohair and microhair in the adaxial leaf blade with the presence of silica bodies, and thickness of the cuticle and number of posed insects. Thickness of the cuticle and presence of silica bodies in the intercostals space of microhair and macrohair showed to be the variables most related to mechanical damage and resistance mechanism.

With the aim of identifying the social and economical characteristics of producers that integrate the socialist red of productive innovation (SRPI) of ovine and goat, a descriptive research was done with a transactional design in the field, at Goajira parish, Zulia state, Venezuela, which is a limited area by its arid weather to semi arid and high temperatures. The population considered for this research was formed by 215 producers of ovine and goat of the Wayuu ethnic that form the SRPI. 140 producers were selected at random, out of which were applied a structured survey that asked about social and economic variables. The obtained results show that a high percentage of producers are women that combine the production of ovine and goat along to craftwork (59%), also, producers live in production units, have a low educative level and an elevate illiterate rate. A high percentage does not have legal documentation of the property of their lands (60%), that is why it is so difficult to have access to financing processes to improve their production systems and elevate their improvements and reduce the elevate number of extreme poverty (90%).

Bonfante-Cabarcas R.,University Centroccidental Lisandro Alvarado | Rodriguez-Bonfante C.,University Centroccidental Lisandro Alvarado | Vielma B.O.,University Centroccidental Lisandro Alvarado | Vielma B.O.,Instituto Nacional Of Investigaciones Agricolas | And 4 more authors.
Cadernos de Saude Publica | Year: 2011

This study investigated risk factors associated with positive serological status for Trypanosoma cruzi antibodies in 26 rural communities including 905 households, 2,156 humans, and 333 dogs in Lara State, Venezuela. Serology was performed with ELISA and MABA. Data were obtained from entomological, demographic, and clinical surveys. Risk factors were determined through binary logistic regression. Seroprevalence was 7.24% in humans and 6.9% in canines. Positive serological status was positively associated with the Rhodnius prolixus vector, age, maternal history of Chagas disease, tobacco chewing, presence of mammals and birds in the household, household disarray, mud-and-wattle outbuildings, and animal nests and burrows in the peridomicile, and negatively associated with tobacco and alcohol consumption, history of cancer, and storage deposits in the peridomile. In conclusion, Chagas disease in this rural area is an old phenomenon transmitted by R. prolixus or by the transplacental route, associated with socio-cultural habits related to poverty, sylvatic surroundings, and the host's medical history.

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