The impact of veterinary medicine and animal husbandry on the biophysical characteristics of soils in neotropical agroecosystems

Los agroecosistemas neotropicales son áreas importantes en el escenario mundial en términos de producción ganadera. Por lo tanto, una buena conservación de sus suelos es crucial para garantizar la inocuidad de los alimentos y reducir el impacto de los procesos de degradación de la tierra. La conservación de los suelos neotropicales utilizados para las actividades agropecuarias podría obtenerse utilizando la medicina veterinaria y adoptando nuevos sistemas de pastoreo en los últimos decenios. Se realizó una amplia revisión bibliográfica que ilustra las cuestiones actuales de los agroecosistemas neotropicales, la importancia de sus propiedades del suelo, destacando el papel que desempeñan los escarabajos peloteros dentro de la edafofauna, y los efectos de las prácticas antiparasitarias más comunes, así como algunas alternativas naturales. Por último, presentamos los sistemas de pastoreo adoptados comúnmente y cómo están afectando a las propiedades del suelo y al bienestar de los animales. La conversión de bosques en tierras agrícolas y de pastoreo está alterando la calidad bioquímica de los suelos. Además, el uso de la ivermectina está reduciendo peligrosamente la cantidad total de escarabajos peloteros que son un elemento clave en los procesos de reciclaje de nutrientes. La aplicación de nuevos sistemas de pastoreo (por ejemplo, Voisin, Savory) está fragmentando progresivamente el hábitat de muchas especies. No obstante, también hay algunos beneficios en este tipo de prácticas y se están probando algunas alternativas naturales a los antihelmínticos.The neotropical agroecosystems are important areas in the global scene in terms of livestock production. Therefore, a good conservation of their soils is crucial in order to both guarantee food safety and reduce the impact of land degradation processes. Conservation of neotropical soils used for farming activities could be obtained using veterinary medicine and adopting new grazing systems in the last decades. A wide bibliographical review was carried out which illustrates current issues in neotropical agroecosystems, the importance of their soil properties highlighting the role played by dung beetles within the edaphofauna, and the effects of the most common anti-parasitic practices as well as some natural alternatives. Finally, we present commonly adopted grazing systems and how they are affecting soil properties and animal welfare. The conversion of forest into agricultural and pasture land is altering the biochemical quality of soils. Furthermore, the use of ivermectin is dangerously reducing the total amount of dung beetles that are a key element in nutrient recycling processes. The implementation of new grazing systems (e.g., Voisin, Savory) is progressively fragmenting the habitat of many species. Nevertheless, there are also some benefits in this kind of practices and some natural alternatives to anthelmintics are being tested.• Comisión Europea, IRSES FP7. Proyecto de investigación EcoDrypeerReviewe

Effect of dried leaves of Leucaena leucocephala on rumen fermentation, rumen microbial population, and enteric methane production in crossbred heifers

The effects of dietary inclusion of dried Leucaena leucocephala leaves (DLL) on nutrient digestibility, fermentation parameters, microbial rumen population, and production of enteric methane (CH4) in crossbred heifers were evaluated. Four heifers were used in a 4 × 4 Latin square design consisting of four periods and four levels of inclusion of DLL: 0%, 12%, 24%, and 36% of dry matter (DM) intake. Results showed that DM intake (DMI), organic matter intake, and gross energy intake (GEI) were similar (p > 0.05) among treatments. Apparent digestibility of organic matter, neutral detergent fiber, and energy decreased with increasing levels of DLL in the ration (p 0.05) rumen pH and total volatile fatty acids. Rumen microbial community was not affected (p > 0.05) by treatment. There was a linear reduction (p < 0.05) in CH4 emissions as the levels of DLL in the ration were increased. Results of this study suggest that an inclusion of 12% DM of ration as DLL enhances digestible CP and reduces daily production of enteric CH4 without adversely affecting DMI, rumen microbial population, and fermentation parameters

Emisión de metano en ovinos alimentados con Pennisetum purpureum y árboles que contienen taninos condensados

El objetivo fue evaluar el efecto de los taninos condensados (TC) contenidos en el follaje de arbóreas tropicales, sobre el consumo de materia seca y orgánica (CMS, CMO), la digestibilidad de la materia seca (DMS) y emisiones de metano (CH4) en ovinos alimentados con una ración basal de pasto Pennisetum purpureum. Cuatro ovinos de pelo con un peso vivo promedio de 21.6±2.0 kg se sometieron a cuatro tratamientos en un diseño cuadro latino 4 x 4. Los tratamientos fueron P. purpureum (PP), P. purpureum + Havardia albicans (PPHA), P. purpureum + Bursera simaruba (PPBS), y P. purpureum + Acacia pennatula (PPAP); el follaje de las arbóreas se incluyó en 300 g/kg de MS de la ración. El consumo, la digestibilidad y la producción total de metano entérico se midieron por periodos de 23 h. La producción de metano se midió en cajas de respiración de circuito abierto. El consumo y digestibilidad de la MS y materia orgánica (MO) entre los tratamientos PP, PPHA, PPBS y PPAP no se afectaron por la inclusión de los follajes de arbóreas en la ración (P>0.05). Cuando la producción de CH4 se expresó en L/kg del CMS, CMO o consumo de fibra detergente neutro los resultados fueron similares entre tratamientos (PP, PPHA, PPBS y PPAP) (P>0.05). Se concluye que los TC contenidos en el follaje de Havardia albicans, Acacia pennatula y Bursera simaruba no afectaron las emisiones de CH4 al nivel de incorporación de 30 % de la MS; tampoco se observaron efectos en el CMS, CMO, DMS y concentración molar de ácidos grasos volátiles

Role of secondary plant metabolites on enteric methane mitigation in ruminants

The rumen microbiome plays a fundamental role in all ruminant species, it is involved in health, nutrient utilization, detoxification, and methane emissions. Methane is a greenhouse gas which is eructated in large volumes by ruminants grazing extensive grasslands in the tropical regions of the world. Enteric methane is the largest contributor to the emissions of greenhouse gases originating from animal agriculture. A large variety of plants containing secondary metabolites [essential oils (terpenoids), tannins, saponins, and flavonoids] have been evaluated as cattle feedstuffs and changes in volatile fatty acid proportions and methane synthesis in the rumen have been assessed. Alterations to the rumen microbiome may lead to changes in diversity, composition, and structure of the methanogen community. Legumes containing condensed tannins such as Leucaena leucocephala have shown a good methane mitigating effect when fed at levels of up to 30–35% of ration dry matter in cattle as a result of the effect of condensed tannins on rumen bacteria and methanogens. It has been shown that saponins disrupt themembrane of rumen protozoa, thus decreasing the numbers of both protozoa and methanogenic archaea. Trials carried out with cattle housed in respiration chambers have demonstrated the enteric methane mitigation effect in cattle and sheep of tropical legumes such as Enterolobium cyclocarpum and Samanea saman which contain saponins. Essential oils are volatile constituents of terpenoid or non-terpenoid origin which impair energy metabolism of archaea and have shown reductions of up to 26% in enteric methane emissions in ruminants. There is emerging evidence showing the potential of flavonoids as methane mitigating compounds, but more work is required in vivo to confirm preliminary findings. From the information hereby presented, it is clear that plant secondary metabolites can be a rational approach to modulate the rumen microbiome and modify its function, some species of rumen microbes improve protein and fiber degradation and reduce feed energy loss as methane in ruminants fed tropical plant species

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

Composición química de ensilajes mixtos de gramíneas y especies arbóreas de Yucatán, México

An experiment was carried out to assess the nutritional value and quality of silages prepared from different combinations of grass and forage trees. Taiwan grass 144-A (Pennisetum purpureum) and four forage trees (Guazuma ulmifolia, Piscidia piscipula, Lisyloma latisiliquum, Albizia lebbeck) and a combination of the four trees were tested in a randomized design with factorial arrangement. Forage trees were included in the silage at 15, 30 and 45 % w/w fresh grass weight. Sugarcane molasses 4 % diluted in water (1:1 w/v) was added to ensure an adequate fermentation. Micro silages were prepared in 1.8 l plastic containers and opened after 90 d. Grass silage (0 % tree) was used as control. Differences were found (P0.05) for silage DM (27.8 vs 27.9 %), CP (7.2 vs 8.6 %), pH (3.88 vs 3.87), ammonia nitrogen/total nitrogen (7.5 vs 7.8 %), acetic acid (3.3 vs 2.9 %) and butyric acid (1.0 vs 0.4 %). It can be concluded that the inclusion of forage trees in tropical grass silages improves their quality but not their nutritive value. Differences in the chemical composition of these silages reflect variations in the proportion of each ingredient (% grass/tree).Se llevó a cabo un experimento para determinar la calidad y el valor nutritivo de ensilajes mixtos (gramínea y especies arbóreas) utilizando pasto Taiwán 144-A (Pennisetum purpureum), cuatro especies arbóreas (Guazuma ulmifolia, Piscidia piscipula, Lisyloma latisiliquum, Albizia lebbeck) y una mezcla de las cuatro especies, en un diseño completamente al azar con arreglo factorial. Las especies arbóreas fueron incluidas al 15, 30 y 45 % del peso en fresco del forraje picado, adicionando todos los ensilajes con un 4 % de melaza diluida 1:1 con agua, utilizando microsilos de plástico de 1.8 l de capacidad, los cuales fueron abiertos a los 90 días. El ensilaje de pasto fungió como testigo (0 %). Se encontraron diferencias (

Evaluación de ecuaciones alométricas de biomasa epigea en una selva mediana subcaducifolia de Yucatán

The objectives of this study were to develop and compare allometric equations of aboveground biomass (AGB) for a semi-deciduous tropical forest of the ejido (system of communal or cooperative farming) San Agustin, Yucatan, Mexico, and to compare them to existing equations. Forty seven trees of 18 different species with diameters between 2.5 cm and 41.5 cm were selected. The diameter of each tree was measured before felling, and the height was estimated before and measured after felling. Fresh weight of each component (stem, branches, leaves) was measured in the field, and samples were taken to determine dry weight in the laboratory and to extrapolate to the whole individual. Six allometric equations with different functional forms were explored, and tested using the Akaike information criterion (AIC), adjusted R2 value and cross validation. The best equation yielded an AIC value of 48.36 and an adjusted R2 of 0.96. Cross-validation showed an adjusted R2 value of 0.72 and a coefficient of agreement of 0.56. Unexpectedly, this equation is less precise than others used in the forests of the Yucatan Peninsula, including equations developed locally and in other continents, with very contrasting sample sizes. However, the best equation obtained in this study allows adequate estimates of AGB of the semideciduous tropical forests of Yucatan, especially for the largest trees, which are the most influential.Los objetivos del estudio fueron elaborar y cotejar ecuaciones alométricas para estimar la biomasa epigea (BE) en una selva mediana subcaducifolia del ejido San Agustín, Yucatán, México, y compararlas con ecuaciones existentes. Se seleccionaron 47 árboles de 18 especies con diámetros normales entre 2.5 cm y 41.5 cm. Se midió el diámetro de cada árbol y la altura se estimó antes y se midió después de derribarlo. Se obtuvo el peso fresco de cada componente (fuste, ramas, hojas) en el campo y se tomaron muestras para determinar su peso seco en el laboratorio y extrapolar a todo el individuo. Se elaboraron seis ecuaciones alométricas evaluadas a través del criterio de información de Akaike (AIC), el valor de R2 ajustado y validación cruzada. La mejor ecuación tuvo un valor de AIC de 48.36 y un R2 ajustado de 0.96. La validación cruzada mostró un valor de R2 ajustado de 0.72 y un coeficiente de concordancia de 0.56. Contrario a lo esperado, esta ecuación es menos precisa que algunas otras utilizadas para las selvas de la Península de Yucatán, incluyendo ecuaciones locales y de otros continentes, con tamaños de muestra muy contrastantes. Sin embargo, la mejor ecuación elaborada en este estudio permite obtener estimaciones de la BE de las selvas medianas subcaducifolias de Yucatán adecuadas, especialmente para los individuos de mayor tamaño, que son los más influyentes

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