Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

Se determinó la prevalencia de Cryptosporidium spp. en bovinos de tres regiones ecológicas del centro del estado de Veracruz, México. Se realizó un estudio transversal en 72 becerros de 3 a 12 meses de edad de seis unidades de producción de los municipios de Zentla, Tlacotalpan y Manlio F. Altamirano. Se colectaron muestras de heces de los becerros y se analizaron con la tinción de Kinyoun. La prevalencia general de criptosporidiosis fue 73.6 %, y por municipio fue 66.7 % en Zentla, 75 % en Tlacotalpan y 79.2 % en Manlio F. Altamirano. La prevalencia por edad fue 72.4 % en becerros de 3 meses y 74.4 % en becerros de 6 a 12 meses. Hubo mayor prevalencia en hembras (78.7 %) que en machos (45.5 %). La prevalencia por raza fue 78.8 % en Suizo Pardo/cebú, 83.3 % en Suizo Pardo, 50 % en Holstein/cebú y 50 % en Suizo Pardo/Holstein, sin diferencia entre las cruzas (P > 0.05). No hubo asociación entre la infección por Cryptosporidium spp. y el sexo, raza, edad y zona ecológica. Se concluyó que Cryptosporidium spp. está presente en los sistemas de producción de becerros de doble propósito en los tres municipios estudiados ubicados en el centro de Veracruz, México.

Social olfactory signals, often known as pheromones, are powerful regulators of reproductive function. These chemosignals can be detected by two olfactory systems, namely the main or the accessory olfactory systems. While initially anatomically segregated, both systems converge functionally as they can detect and process overlapping sets of chemosignals. This convergence also takes place at the level of their central projections in the hypothalamus. It is probably at this level that future investigations will be needed. Indeed, if the physiology of both olfactory system and reproductive function are now quite well characterized, the interrelation between both systems is unclear. Among the many cell populations that can serve as targets or relays for the pheromonal information in the hypothalamus are GnRH cells or the recently discovered Kispeptin population which have been showed to be activated after pheromonal activation. However, many works will be needed before having a definitive picture.

Se comparó la cantidad de carbono (C) que secuestra un potrero arbolado (P+Ar) respecto a los potreros convencionales sin árboles (P) y al bosque caducifolio (BC), en la región de Huatusco, Veracruz, México. El total de C secuestrado por los sistemas evaluados fue de 49.9, 63.0 y 469.8 ton ha-1 para P, P+Ar y BC, respectivamente. El sistema con mayor cantidad de C secuestrado fue el BC, con casi igual proporción en la parte aérea (268.4 ton ha-1) y en la subterránea (201.4 ton ha-1). La cantidad de C secuestrado por los sistemas ganaderos representó aproximadamente la décima parte de la secuestrada en el BC, siendo mayor la proporción en el P+Ar (13.4 %) que en el P (10.6 %). En ambos sistemas ganaderos fue notoriamente mayor la cantidad de C secuestrado en la materia orgánica del suelo en comparación con la biomasa aérea, con 59.7 y 3.29 ton ha-1 en P+Ar, y con 48.2 y 1.78 ton ha-1 en P, respectivamente. Se espera que conforme los árboles del sistema P+Ar ganen volumen, el secuestro de C sea cada vez mayor, especialmente en la biomasa aérea.

The study was carried out during the dry season (March to May) in three dual-purpose cattle farms located in Tepalcatepec, Michoacan, Mexico, in order to evaluate the forage offer and intake, and milk production in Brown Swiss cows. Two farms had silvopastoral systems with Leucaena leucocephala cv. Cunningham associated with Panicum maximum cv. Tanzania, and one of them also included mango trees (Mangifera indica); the third farm had a traditional system with Cynodon plectostachyus in monoculture. In the traditional system, cows were offered 8 kg animal-1 day-1 of concentrate feed during the milking period, and only 1.5 kg animal-1 day-1 in the silvopastoral systems. Edible forage offer in the silvopastoral farms was 2470 and 2693 kg DM ha-1 grazing-1, and in the traditional system it was 948 kg DM ha-1 grazing-1. Forage intake in the silvopastoral systems was 8.25 and 11.81 kg DM animal-1 day-1, whereas in the traditional system it was 3.63 kg DM animal-1 day-1. Milk production in the silvopastoral system was 9.0 and 9.2 kg animal-1 day-1, while in the traditional system it was 10.4 kg animal-1 day-1. The silvopastoral systems with L. leucocephala cv. Cunningham associated with P. maximum cv. Tanzania produced high edible forage offer and allowed to obtain milk yield similar to that of the traditional system with C. plectostachyus in monoculture, but on a lower concentrate feed intake.

The Moringa (Moringa oleifera Lam.) is a tree species with the known value of food, medicine and water treatment, and is promising for bioenergy use. Our objective was to evaluate, using RAPD markers, the genetic diversity of sixteen accessions from Germplasm Bank (BAG) of Embrapa Coastal Tablelands, Sergipe, Brazil. We estimate the diversity indices, and genetic similarity between accessions. The Shannon index and the index of genetic diversity (H) were 0.33 and 0.22, respectively. We observed by Jaccard similarity that, the accessions MO1 and MO12 are the most similar (0.27), and MO13 and MO16 are the most divergent (0.69). By UPGMA and PCoA groupings, we identified that MO1, MO2, MO12 and MO13 are genetically isolated. The results are important in designing strategies for conservation, but because of low diversity detected in this investigation, new activities of collection should be realized, with integration and characterization of new accessions, to ensure the ever increasing diversity of the collection.

La caña de azúcar es una de los cultivos pilares en la economía de Tabasco, México, pues se cultivan 27,041 ha que contribuyen con el 4 % de la producción nacional de azúcar, ocupando el tercer lugar en superficie cultivada. Esta investigación tuvo como objetivo identificar los principales factores que impactan los rendimientos en el agroecosistema cañero del Ingenio Presidente Benito Juárez. Se entrevistaron a 150 productores y se analizó la información con estadística descriptiva. Entre las características socioeconómicas de los productores destacan la edad (51 % entre 50 y 70 años), escolaridad (40 % con estudios de primaria), la escasez de mano de obra familiar, entre otras. En cuanto a las tecnológicas destacan el cultivar MEX 79-431 sembrado en menor área pero con mayor rendimiento, de entre 50 y 60 t ha1; la fertilización comúnmente aplicada es triple 17 por 30 % de los productores y la mezcla 20-10-10 es a pliada por 26 %; 58 % de los productores reportó nulo acceso a asesoría técnica.

The dry matter partitioning of sesame with organic and inorganic fertilizers was assessed in a pot experiment. Treatments consisted of sole and combined applications of poultry manure and NPK 16-16-16. Complementary application enhanced dry matter yield. Shoot yield ranged from 1.2 to 2.8kg while root dry matter yield ranged from 0.5 to 0.9 kg. Total dry matter yield ranged from 1.7 to 3.5kg. Highest K content of 0.36% occurred in plants treated with sole 100 kg NPK ha-1 and the lowest of 0.03% from the control plants. Calcium content increased from 0.09% in control plants to 0.37% in plants treated with 5 tons ha-1 PM. Magnesium content ranged from 0.01% in the control plants to 0.04 % in plants treated with application of 100kg NPK ha-1. Sodium ranged from 0.07% to 0.13%. Phosphorous increased from 0.33 % to 0.83 % in plants treated with 50kg NPK ha-1.

The aim of this work was to evaluate the effect of supplementation with bypass fat on plasma concentrations of cholesterol (COL), tryglicerides (TG), high density lipoproteins (HDL), low density lipoproteins (LDL) and progesterone (P4), during the early postpartum period in Indobrasil cows in the dry tropics. Thirty five anestrous cows with 62.91±20.87 days postpartum, 3.24±0.43 body condition score and 486.17±72.54 kg liveweight, multiparous (four and six calvings) were used. Both groups of cows were given isoenergetic and isoproteic feed supplements and were divided in two groups, without supplementation (GC, n=17) and with supplementation with bypass fat (GG, n=18), equivalent to 4% of ration DM for 35 days. Plasma concentrations of COL, TG, HDL and LDL were assayed by enzymatic-colorimetric methods and concentrations of P4 by solid phase radioinmunoassay. Cows in group GG showed increased plasma concentration of COL (216.80±6.36 vs 168.32±7.46 mg/dl; P

Water quality testing (in situ and in laboratory) was conducted on 50 wells across the state of Campeche. Further to this (to aid in water quality management and policy), a GIS was implemented to i) approximate Zones of Contribution (ZOC) for well recharge which in turn supplies water for main cities in the state and ii) perform predictive land change modeling on these ZOC’s to predict the future effect of non-point source pollution. Due to natural geohydrological conditions, values of TDS, pH, and SO4 exceeded Mexican regulations in roughly one third of the wells. Although most wells do not exceed the permissible limits of nutrients and heavy metals, some wells show worryingly high levels of NO2-, TP, and Pb, indicators of pollution from anthropogenic sources. All wells were contaminated by coliform bacteria. Poor water quality in some of the main water sources in the state is mainly due to the proliferation of open dumps and the lack of sewage infrastructure, as well as the ongoing conversion of vegetated land to agriculture into the ZOC’s. It is shown that unless remedial measures are implemented, human activities will continue to extend into these areas, placing the state’s water supply at even higher risk of contamination. 

Mt. Marsabit forest is the only forest in Kenya where Coffea arabica L. (Rubiaceae) occurs naturally in wild populations. This forest however is highly fragmented and decreasing at a rapid rate due to anthropogenic activities. This study assesses the diversity and structure of species of conservation concern with reference to wild coffee as basis for management, conservation and use of wild genetic resources in Kenya. A botanical inventory and diversity study identified  52 species of trees and shrubs, 12 species of herbs and six species of climbers and lianas were recorded and belonged to 35 families and 64 genera. Rubiaceae (Coffee family) was the richest family with nine species followed by Euphorbiaceae with six species. Rinorea convallarioides (Bak.f.) Eyles ssp. marsabitensis Grey-Wilson (Violaceae), an endemic species, and Drypetes gerrardii Hutch. (Euphorbiaceae), were the two most important species, accounting for more than third of the combined importance value. Coffea arabica was dominant in the forest undergrowth with a higher density occurring in the open patches where it was competing with other shrubs and small trees in the undergrowth. The success and future management and conservation strategy of this forest depend on how to conserve the forest genetic resources especially of this wild species.