Effect of Defoliation Frequency on Forage Yield from Intensive Silvopastoral Systems Compared to a Monoculture Grassland

Livestock production in the tropical regions of the world faces serious constraints as a result of climate change. Monoculture based pastures require the use of large amounts of nitrogen fertilizers to sustain production throughout the year. In general terms, tropical grasses are of low quality and when consumed by ruminant species, contribute to the emission of greenhouse gases (methane, carbon dioxide and nitrous oxide) (Herrero et al. 2009; Place et al. 2009). The establishment of intensive silvopastoral systems (iSPS) with associated shrubs legumes and grasses can increase the yield and quality of forage as well as fixation and transfer of atmospheric nitrogen (N) (Murgueitio et al. 2011). Therefore, the costs of nitrogen fertilizers and the emissions of greenhouse gases under practical conditions can be reduced. The intensive silvopastoral system is a kind of agroforestal practice that it is environmentally friendly and at the same time improves productivity of livestock systems. However, several aspects of its management have not been fully evaluated. This is the case of the response to defoliation, which is an important management factor associated to the overall biomass productivity (Solorio 2005)

Raiva em herbívoros no estado do Pará, Brasil: estudo descritivo (2004 a 2013)

PARC/PROPESP and PAPQ/ PROPESPUniversidade Federal do Pará. Instituto de Medicina Veterinária. Laboratório de Epidemiologia e Geoprocessamento. Castanhal, PA, Brazil.Instituto Federal de Educação do Tocantins. Palmas, TO, Brazil.Universidade Federal do Pará. Instituto de Medicina Veterinária. Laboratório de Epidemiologia e Geoprocessamento. Castanhal, PA, Brazil.Universidade Federal de Mato Grosso. Graduate Program in Health Sciences. Sinop, MT, Brazil.Museu Paraense Emílio Goeldi - Campus de Pesquisa. Programa de Capacitação Institucional. Coordenação Ciências da Terra e Ecologia. Belém, PA, Brazil.Agência de Defesa Agropecuária do Pará. Belém, PA, Brazil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Laboratório de Geoprocessamento. Ananindeua, PA, Brasil.Universidade Federal do Pará. Instituto de Medicina Veterinária. Laboratório de Epidemiologia e Geoprocessamento. Castanhal, PA, Brazil.Rabies is an important zoonosis to public health associated with lethal encephalitis and economic losses. Analysis of its spatial distribution is a meaningful tool in understanding its dispersion, which may contribute to the control and prophylaxis of the disease. This study analyzed the spatial-temporal distribution of rabies outbreaks in livestock in Pará state, Brazil, from 2004 to 2013. We used records of neurological syndromes obtained from the state’s livestock authority (Adepará). The analysis recorded 711 neurological syndromes reports in livestock, of which 32.8% were positive for rabies. In 8% of the neurological syndromes (n=57) was not possible to perform the analysis because of bad-packaging conditions of the samples sent. Outbreaks involved at least 1,179 animals and cattle were the most affected animal species (76.8%). The numbers of reported neurological syndromes and of rabies outbreak shad strong positive correlation and exhibited decreasing linear trend. Spatially, most outbreaks occurred in two mesoregions in Pará (Northeast and Southeast). One of the justifications for this spatial distribution may be related with the distribution of the animals in the state, since these mesoregions are the largest cattle producers in Pará and have most of their territory deforested for pasture implementation

Binding Mechanism of Metal⋅NTP Substrates and Stringent-Response Alarmones to Bacterial DnaG-Type Primases

SummaryPrimases are DNA-dependent RNA polymerases found in all cellular organisms. In bacteria, primer synthesis is carried out by DnaG, an essential enzyme that serves as a key component of DNA replication initiation, progression, and restart. How DnaG associates with nucleotide substrates and how certain naturally prevalent nucleotide analogs impair DnaG function are unknown. We have examined one of the earliest stages in primer synthesis and its control by solving crystal structures of the S. aureus DnaG catalytic core bound to metal ion cofactors and either individual nucleoside triphosphates or the nucleotidyl alarmones, pppGpp and ppGpp. These structures, together with both biochemical analyses and comparative studies of enzymes that use the same catalytic fold as DnaG, pinpoint the predominant nucleotide-binding site of DnaG and explain how the induction of the stringent response in bacteria interferes with primer synthesis

Urinary Excretion of Mimosine Derivatives by Cows with and without Experience in Consumption of \u3cem\u3eLeucaena leucocephala\u3c/em\u3e

Leucaena leucocephala is a leguminous tree widely distributed in the tropical regions of the world. In Mexico, it has been incorporated into silvopastoral systems and is highly regarded, owing to its high content of crude protein. Nonetheless, L. leucocephala contains secondary metab-olites, such as mimosine, a non-protein free amino acid, which may induce toxic effects in unadapted ruminants that consume the forage (Hammond 1995). Although Synergistes jonesii, an anaerobic bacterium, has the ability to degrade 3,4-DHP and 2,3-DHP to non-toxic compounds (Allison et al. 1992), in Mexico its presence has not yet been confirmed. Recent work has suggested the occurrence of sub-clinical toxicity to 3,4-DHP and 2,3-DHP in cattle grazing L. leucocephala in Australia and Thailand (Graham 2007; Dalzell et al. 2012; Phaikaew et al. 2012). Several options such as the transfer of rumen liquor and the adaptation of ruminants to the intake of L. leucocephala have been studied in an attempt to reduce the excretion of mimosine and its metabolites (Palmer et al. 2010). The aim of the present work was to evaluate the effect of the experience of consumption of L. leucocephala on excretion of mimosine derivatives (3,4-DHP and 2,3-DHP) in the urine of cattle

Productive Performance of Growing Cattle Grazing a Silvopastoral System with \u3cem\u3eLeucaena leucocephala\u3c/em\u3e

In tropical regions, the feeding of cattle is usually based on the grazing of medium to low quality grasses. Low fertility of soils, changing climatic conditions and the poor management of pastures, have further reduced the quality and forage yield of pastures. The low availability and quality of grasses gives modest weight gains for grazing cattle and this in-turn causes low economical efficiency of cattle production systems (Campos et al. 2011). Silvopastoral systems represent a sustainable option for meat and milk production in the tropics. The association of grasses with legumes such as Leucaena leucocephala (leucaena) supply forage with high concentration of crude protein (Barros et al. 2012). There are reports in the scientific literature which show that intake of leucaena can result in good rates of growth in cattle (e.g. Shelton and Dalzell 2007); however the presence of the free amino acid mimosine and its metabolites (3,4-DHP and 2,3-DHP) in leucaena when the anaerobic bacteria Synergistes jonesii (Allison et al. 1992) is absent from the rumen, may induce subclinical toxicity in grazing ruminants (Graham 2007; Dalzell et al. 2012; Phaikaew et al. 2012). There are no reports in Mexico regarding the rate of growth of cattle grazing silvopastoral systems with leucaena. The aim of the present work was to evaluate the rate of growth of cattle grazing an association of Panicum maximum and leucaena compared to that of cattle fed a high grain ration (feedlot)

Urinary Excretion of Mimosine Metabolites by Hair Sheep Fed Foliage of \u3cem\u3eLeucaena leucocephala\u3c/em\u3e

Leucaena leucocephala is an adapted legume widely distributed in the tropical regions of Mexico. The high crude protein content of leucaena leaves renders it appropriate for ruminant feeding under commercial conditions. However, the foliage contains the non-protein amino acid mimosine, which, if consumed in high amounts, may induce toxicity in animals which have not previously consumed the legume or without microorganisms capable of degrading mimosine and its derivatives 2,3-DHP (dihydroxypyridine) and 3,4-DHP (Hammond 1995, Palmer et al. 2010, Dalzell et al. 2012). Barros-Rodríguez et al. (2012) found that dry matter intake and weight gain were reduced when sheep grazed paddocks with 55,000 plants of leucaena per hectare. Early work in Australia led to the isolation of Synergistes jonesii, an anaerobic bacterium able to degrade 3,4-DHP and 2,3-DHP to non-toxic compounds (Allison et al. 1992). In Mexico, the presence of this microorganism in the rumen has not yet been confirmed. Inoculation of non-accustomed animals with rumen liquor of ruminants adapted to the consumption of leucaena can reduce the impact of mimosine and its metabolites on animal health (Ghosh et al. 2009; Palmer et al. 2010). The aim of the present work was to evaluate the effects of transferring rumen liquor of cows adapted to the consumption of L. leucocephala to sheep without experience of consumption, on urinary excretion of 3.4-DHP and 2.3-DHP by means of a colorimetric technique

Review: Strategies for enteric methane mitigation in cattle fed tropical forages

Methane (CH4) is a greenhouse gas (GHG) produced and released by eructation to the atmosphere in large volumes by ruminants. Enteric CH4 contributes significantly to global GHG emissions arising from animal agriculture. It has been contended that tropical grasses produce higher emissions of enteric CH4 than temperate grasses, when they are fed to ruminants. A number of experiments have been performed in respiration chambers and head-boxes to assess the enteric CH4 mitigation potential of foliage and pods of tropical plants, as well as nitrates (NO3−) and vegetable oils in practical rations for cattle. On the basis of individual determinations of enteric CH4 carried out in respiration chambers, the average CH4 yield for cattle fed low-quality tropical grasses (>70% ration DM) was 17.0 g CH4/kg DM intake. Results showed that when foliage and ground pods of tropical trees and shrubs were incorporated in cattle rations, methane yield (g CH4/kg DM intake) was decreased by 10% to 25%, depending on plant species and level of intake of the ration. Incorporation of nitrates and vegetable oils in the ration decreased enteric CH4 yield by ∼6% to ∼20%, respectively. Condensed tannins, saponins and starch contained in foliages, pods and seeds of tropical trees and shrubs, as well as nitrates and vegetable oils, can be fed to cattle to mitigate enteric CH4 emissions under smallholder conditions. Strategies for enteric CH4 mitigation in cattle grazing low-quality tropical forages can effectively increase productivity while decreasing enteric CH4 emissions in absolute terms and per unit of product (e.g. meat, milk), thus reducing the contribution of ruminants to GHG emissions and therefore to climate change

Evaluar los enemigos naturales de "Leucaena Psyllid" y Onion Thrips en los procesos de cosecha en diferentes genotipos de Leucaena

The study was conducted in 2013 and 2014, at Xmatkuil Merida, Yucatan, Mexico to survey natural enemies and their effects on the population dynamics of Leucaena leucocephala (Lam.) de Wit pests: Leucaena Psyllids, Heteropsylla cubana, Crawford (1914) (Homoptera: Psyllidae) and Onion Thrips, Thrips tabaci, Lindeman (1889) (Thysanoptera: Thripidae) on four Leucaena genotypes: Cunningham, K636, Nativa and KX2. The juvenile leaves were collected, examined and the natural enemy’s counts were correlated with each pest numbers. Nine predators related to 5 orders, and one parasitoid controlled the populations of both pests. In the first season Nativa had the largest densities of Psyllid, and Cunningham for Thrips. In the second season, Nativa for both pests. The least numbers recorded in KX2 for both pests. The coefficient of correlation (r) was stronger between natural enemies and H. cubana than T. tabaci. In the first season three peaks of Psyllid were occurred, two before the first harvest during May and June and one after at December. Otherwise, four peaks of Thrips were recorded on Cunningham, Nativa, and K636 during May to Aug. and only two occurred on KX2 at May and June. In the second season the largest population of pests was recorded in Nativa, and the lowest were in KX2 for both pests (r) was negative between Thrips and natural enemies. Psyllid showed two peaks in February and April, and two for Thrips in April and June. Keywords: biological control, Leucaena Psyllid, Leucaena pest’s dynamics, onion thrips.El estudio se llevó a cabo en 2013 y 2014, en Xmatkuil, Mérida, Yucatán, México a la encuesta enemigos naturales y sus efectos sobre la dinámica poblacional de Leucaena leucocephala (Lam.) de plagas Wit: Leucaena Psílidos, Heteropsylla cubana Crawford (1914) (Homoptera: Psyllidae) y cebolla trips, Thrips tabaci Lindeman, 1889 (Thysanoptera: Thripidae) en cuatro genotipos de Leucaena: Cunningham, K636, Nativa y KX2. Se recogieron las hojas juveniles, examinaron y cuenta del enemigo natural, se correlacionaron con cada uno de los números de plagas. Nueve depredadores relacionados con 5 órdenes, y uno parasitoide controlan las poblaciones de ambas plagas. En la primera temporada Nativa tuvo las mayores densidades de Psyllid, y Cunningham para Thrips. En la segunda temporada, Nativa para ambas plagas. Los números de menos registran en KX2 para ambas plagas. El coeficiente de correlación (r) fue más fuerte entre los enemigos naturales y H. cubana que T. tabaci. En la primera temporada se produjeron tres picos del psílido, dos antes de la primera cosecha en mayo y junio y una después en diciembre. De lo contrario, cuatro picos de trips se registraron en Cunningham, Nativa y K636 durante mayo a agosto y sólo dos ocurrieron en KX2 en mayo y junio. En la segunda temporada de la mayor población de plagas se registró en Nativa, y la más baja se encontraban en KX2 para ambas plagas (r) fue negativa entre trips y enemigos naturales. Psyllid mostró dos picos en febrero y abril, y dos para los trips en abril y junio. Palabras clave: control biológico; dinámica de Leucaena plagas; Leucaena psílido; trips de la ceboll

Forage Yield and Quality of \u3cem\u3eLeucaena leucocephala\u3c/em\u3e and \u3cem\u3eGuazuma ulmifolia\u3c/em\u3e in Tropical Silvopastoral Systems

Low availability and quality of pastures during the dry season are common problems in tropical livestock production systems. However, several studies indicate that the use of trees and shrubs is a good alternative to overcome those problems (Ku-Vera et al. 1999). In fact, the nutritional value of tree foliage is often better than that of forage grasses. In addition, its use could con-tribute to reforestation and restoration of degraded land (Casanova-Lugo et al. 2010). Recently, several reports have focused on the incorporation of Leucaena leucocephala in silvopastoral systems (Murgueitio et al. 2012). Nevertheless, there is little information about other tropical tree species with high forage production potential, such as Guazuma ulmifolia, which is broadly used in Southeast Mexico. In addition, little is known about the effect of season on forage quality of these species under a particular management regime. Therefore, the aim of this study was to evaluate the yield and forage quality of L. leucocephala and G. ulmifolia in the sub-humid tropics during the dry and rainy seasons

Contribution of intensive silvopastoral systems to animal performance and to adaptation and mitigation of climate change

According to FAO, world demand for animal products will double in the first half of this century as a result of increasing population and economic growth. During the same period, major changes are expected in world climate. Food security remains one of the highest priority issues in developing Latin American countries, a region where livestock production plays a fundamental role. Agricultural activities seriously threaten natural resources; therefore, it is necessary to ensure that livestock production contributes to satisfy the demand for animal products in a sustainable manner. Intensive silvopastoral systems (ISS) are becoming the technology of choice for Colombian and regional livestock sectors because it can help reduce the seasonality of plants and animal production, and therefore contribute to mitigate and adapt to the effects of climate change. We have recently gained knowledge on the nutritional and productive attributes of these systems. However, in recent years, the low carbon approach acquired importance in animal agriculture, which seeks to primarily promote the adoption of programs running parallel activities aimed at adapting to and mitigating climate change. This review outlines projections on the effects of climate change on the livestock industry, presents concepts on Greenhouse Gas flow and highlights evidence in support of the conclusion that ISS is an interesting option to allow the livestock sector in the region to adapt to climate change and to mitigate some of its effects. The adoption of ISS may help to remove up to 26.6 tons of CO2 eq/Ha/yr from the atmosphere.Segundo a FAO, a demanda mundial de produtos de origem animal se duplicará durante a primeira metade deste século como resultado do aumento da população e dos recursos económicos; durante o mesmo período se esperam grandes mudanças no clima em todo o mundo. A segurança alimentar continua a ser uma das questões de maior prioridade no desenvolvimento dos países latino-americanos e a produção pecuária tem um papel fundamental em muitos destes. Todos estes elementos têm estreita relação com a enorme pressão sobre os recursos naturais, portanto, é necessário que a produção pecuária seja feita de uma maneira sustentável. Os sistemas silvipastoris intensivos (SSPi) estão se transformando em uma opção tecnológica de implementação progressiva na pecuária colombiana e da região porque podem reduzir a estacionalidade da produção vegetal e animal, portanto, podem mitigar os efeitos das mudanças climáticas e adaptar-se a eles. Nos últimos anos ocorreram avanços no conhecimento sobre os aspectos nutricionais e produtivos destes sistemas. No entanto, recentemente começou a ter importância o enfoque da agricultura com baixa produção de carbono que visa, principalmente, delinear programas de desenvolvimento onde se executem paralelamente atividades destinadas à adaptação e mitigação das mudanças climáticas. Esta revisão apresenta algumas projeções sobre os efeitos das mudanças climáticas na pecuária, apresenta alguns conceitos sobre o fluxo de gases do efeito estufa (GEEs) em sistemas de produção animal. Destaca algumas evidências para apoiar que os SSPi são uma opção interessante para permitir que a pecuária na região se adapte às mudanças climáticas e mitigue alguns dos seus efeitos, pois a adoção dos SSPi pode ajudar a remover até 26,6 tôn. CO2 eq/Ha/ano a partir da atmosfera.Según la FAO, la demanda mundial de productos de origen animal se duplicará durante la primera mitad de este siglo como resultado del incremento de la población y del crecimiento económico y durante el mismo período se esperan grandes cambios en el clima a nivel mundial. La seguridad alimentaria sigue siendo una de las cuestiones de más alta prioridad en el desarrollo de los países latinoamericanos y la producción ganadera tiene un papel fundamental en muchos de estos países. Todos estos elementos tienen estrecha relación con la enorme presión sobre los recursos naturales, por tanto, es necesario que la producción ganadera se realice de manera sustentable. Los sistemas silvopastoriles intensivos (SSPi) se están convirtiendo en una opción tecnológica de implementación progresiva en la ganadería colombiana y de la región porque pueden reducir la estacionalidad de la producción vegetal y animal; y por lo tanto pueden mitigar los efectos del cambio climático y adaptarse a ellos. En los últimos años se ha avanzado en el conocimiento sobre los atributos nutricionales y productivos de éstos sistemas. Sin embargo, ultimamamente empieza a tener importancia el enfoque de agricultura baja en carbono que busca principalmente, adelantar programas de desarrollo donde se ejecuten paralelamente actividades orientadas a la adaptación y a la mitigación del cambio climático. La presente revisión incluye algunas proyecciones sobre los efectos del cambio climático en la ganadería, presenta algunos conceptos sobre el flujo de los gases de efecto invernadero (GEI) en los sistemas ganaderos. Resalta algunas evidencias que permiten afirmar que los SSPi son una opción interesante para que la ganadería de la región se adapte al cambio climático y mitigue algunos de sus efectos, dado que con el establecimiento de SSPi se pueden remover hasta 26,6 ton de CO2 equivalentes/Ha/año