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Agronomic and nutritional parameters of a set of 28 accessions of Megathyrsus maximus established in Colombia during the rainy season were evaluated to identify accessions with differences in nutritional quality and characterize germplasm of M. maximus. ANOVA and multivariate analysis showed differences among accessions. Agronomic variables such as plant height, dry matter yield and green fresh weight were not correlated with nutritional variables. Flowering affected nutritional quality (neutral detergent fiber, acid detergent fiber and relative feed value). Flowering, fiber content, digestibility and crude protein content had the most influence on forage quality of M. maximus. The integral evaluation of biomass and nutritional parameters showed that the set of 28 M. maximus accessions contained 2 accessions with high nutritional quality and competitive biomass production. Heterogeneity of the collection in nutritional and agronomic assessments supports plant-breeding and offers alternatives for cattle producers in the tropics.

La propagación eficiente de especies vegetales con alto potencial alimenticio juega un papel fundamental en su adopción y utilización por parte de los productores. Es importante, por tanto, desarrollar métodos económicos y rápidos para el establecimiento exitoso de sistemas más productivos. Con el objetivo de conocer algunos aspectos reproductivos de diferentes genotipos destacados de T. diversifolia y así favorecer su propagación y mejorar su uso en la alimentación animal, se evaluó su potencial de germinación, producción de semilla y duración del ciclo reproductivo. Se usaron 42 parcelas en un diseño de bloques completos al azar con siete genotipos de T. diversifolia y dos niveles (sin y con fertilización). Los genotipos tuvieron diferencias en todas las variables agronómicas y de producción de semilla a excepción del tiempo de secado de aquenios y en el porcentaje de semillas rudimentarias (P

There are few reports on dual-purpose cattle systems characterization in Latin America and Colombia based on large datasets. This limits our understanding of their dynamics, and the establishment of public policies and government programs to improve their productive performance, promotion and rural development. This study aimed to characterize very small, small, medium, and large dual-purpose farms in Colombia from technical and environmental perspectives. The data analysed were obtained from the Ganadería Colombiana Sostenible and the LivestockPlus projects, which gathered information from a total of 1313 dual-purpose farms in Colombia. Farms were classified as being either very small (1 to 30 bovines), small (31 to 50 bovines), medium (51 to 250 bovines), or large farms (more than 251 bovines). Numerical and categorical variables were distributed into five components: (1) General Farm Information, (2) Herd Composition and Management, (3) Pasture Management, (4) Production Information, and (5) Environmental Information. Each component was analysed using the factorial analysis of mixed data (FAMD) method. According to FAMD, for the components General Farm Information, Herd Composition and Management, Pasture Management, and Production Information, the distribution of variables led to a spatial separation of the centroid from each category of producers. For the component Environmental Information, there was no separation of the centroid. In general, medium-sized and large farms showed better infrastructure, better machinery and equipment, and better reproductive practices; however, this was not reflected in a significant improvement of productive parameters, except for a lower mortality rate. Larger livestock producers need to plan their livestock husbandry activities properly, based on their better available infrastructure and livestock management practices, with the purpose of increasing productivity. The main features identified for each livestock producer category can be the basis to guide and establish policies and programmes for their technological development. The development of better livestock management practices and the implementation of technology, as well as technical assistance, should focus on small- and medium-sized livestock producers, which could lead to reaching a better productive and reproductive performance of dual-purpose systems.

The purpose of this study was to determine the in vitro fermentation and methane (CH4) production in the grass Brachiaria brizantha (B) alone or when mixed with Gliricidia sepium forage (G) and/or Enterolobium cyclocarpum pods (E). Theses substrates were incubated in the following proportions: B100 (B100%), B85E15 (B85% + E15%), B85G15 (B85% + G15%), B85GE15 (B85% + G7.5% + E7.5%), and B70GE30 (B70% + G15% + E15%). Dry matter degradation (DMD), volatile fatty acid (VFA) concentration, and CH4 production were measured at 12, 24, and 48 h of incubation. Experimental design was a randomized complete block. At 48-h incubation, DMD ranged between 46.5 and 51.2% (P = 0.0015). The lowest cumulative gas production (CGP) was observed in B85E15 and B85G15 (160 mL CGP/g organic matter, on average). At 48 h, B85G15 and B100 produced 28.8 and 30.2 mg CH4/g DMD, respectively, while B85E15 or the mixtures, 33.5 mg CH4/g DMD, on average (P ≤ 0.05). B85E15 and B70G30 had the highest concentration of total VFA (P ≤ 0.05). Results showed that B85E15 and B70GE30 favor DMD and increased total production of VFA and CH4 at 48 h. Supplementing livestock feed with legume forages and pods allows improves the nutritional quality of the diet and the fermentation patterns.

En Colombia, la cría bovina representa el 15% del inventario ganadero, siendo un eslabón importante en la cadena de producción de carne. La carencia de estudios de caracterización limita la adecuada planificación técnica y ambiental de esta actividad. El objetivo de este estudio fue caracterizar los parámetros técnicos y ambientales de fincas de cría con doble utilización de la vaca, pertenecientes a muy pequeños (MPG), pequeños (PG), medianos (MG) y grandes productores (GG). La información se obtuvo de los proyectos Ganadería Colombiana Sostenible y Livestock – Plus. La muestra total fue de 2618 fincas, que fueron clasificadas de acuerdo con su orientación productiva: cría, ceba, doble propósito, lechería especializada e integral. Las 251 fincas de cría se estratificaron en MPG (1 a 30 bovinos), PG (31 a 50), MG (51 a 250) y GG (más de 251). Se consideraron variables numéricas y categóricas, las cuales fueron clasificadas en cinco componentes: información general, composición y manejo del hato, manejo de potreros, información productiva y reproductiva e información ambiental. Cada componente se analizó mediante un Análisis Factorial para Datos Mixtos (AFDM). En los primeros cuatro componentes, las variables conllevaron a una separación espacial del centroide de cada categoría de productores. Los MG y GG estuvieron asociados con variables que indicaron la existencia de mejor infraestructura, maquinarias y equipos, y mejores prácticas y parámetros reproductivos y productivos. No existieron diferencias en el desarrollo de prácticas ambientales. Las características identificadas pueden servir para el establecimiento de políticas públicas de desarrollo tecnológico y gestión ambiental.

Latin America and Caribbean (LAC) is a developing region characterized for its importance for global food security, producing 23 and 11% of the global beef and milk production, respectively. The region's ruminant livestock sector however, is under scrutiny on environmental grounds due to its large contribution to enteric methane (CH4) emissions and influence on global climate change. Thus, the identification of effective CH4 mitigation strategies which do not compromise animal performance is urgently needed, especially in context of the Sustainable Development Goals (SDG) defined in the Paris Agreement of the United Nations. Therefore, the objectives of the current study were to: 1) collate a database of individual sheep, beef and dairy cattle records from enteric CH4 emission studies conducted in the LAC region, and 2) perform a meta-analysis to identify feasible enteric CH4 mitigation strategies, which do not compromise animal performance. After outlier's removal, 2745 animal records (65% of the original data) from 103 studies were retained (from 2011 to 2021) in the LAC database. Potential mitigation strategies were classified into three main categories (i.e., animal breeding, dietary, and rumen manipulation) and up to three subcategories, totaling 34 evaluated strategies. A random effects model weighted by inverse variance was used (Comprehensive Meta-Analysis V3.3.070). Six strategies decreased at least one enteric CH4 metric and simultaneously increased milk yield (MY; dairy cattle) or average daily gain (ADG; beef cattle and sheep). The breed composition F1 Holstein × Gyr decreased CH4 emission per MY (CH4IMilk) while increasing MY by 99%. Adequate strategies of grazing management under continuous and rotational stocking decreased CH4 emission per ADG (CH4IGain) by 22 and 35%, while increasing ADG by 22 and 71%, respectively. Increased dietary protein concentration, and increased concentrate level through cottonseed meal inclusion, decreased CH4IMilk and CH4IGain by 10 and 20% and increased MY and ADG by 12 and 31%, respectively. Lastly, increased feeding level decreased CH4IGain by 37%, while increasing ADG by 171%. The identified effective mitigation strategies can be adopted by livestock producers according to their specific needs and aid LAC countries in achieving SDG as defined in the Paris Agreement. Fil: Congio, Guilhermo Francklin de Souza. Universidade do Sao Paulo. Escola Superior de Agricultura Luiz de Queiroz; Brasil. Corporación Colombiana de Investigación Agropecuaria; Colombia Fil: Bannink, André. University of Agriculture Wageningen; Países Bajos Fil: Mayorga Mogollón, Olga Lucía. Corporación Colombiana de Investigación Agropecuaria; Colombia Fil: Jaurena, Gustavo. Universidad de Buenos Aires. Facultad de Agronomia. Departamento de Producción Animal. Cátedra de Nutrición Animal; Argentina Fil: Gonda, Horacio Leandro. Uppsala Universitet; Suecia Fil: Gere, José Ignacio. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Patobiología Veterinaria - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Patobiología Veterinaria; Argentina Fil: Cerón Cucchi, María Esperanza. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Patobiología; Argentina Fil: Ortiz Chura, Abimael. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Patobiología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Tieri, María Paz. Universidad Tecnológica Nacional. Facultad Regional Rafaela; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigación de la Cadena Láctea. - Instituto Nacional de Tecnología Agropecuaria. Centro Regional Santa Fe. Estación Experimental Agropecuaria Rafaela. Instituto de Investigación de la Cadena Láctea; Argentina Fil: Hernandez, Olegario. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Tucuman-Santiago del Estero; Argentina Fil: Ricci, Patricia. Instituto Nacional de Tecnologia Agropecuaria. Centro Regional Buenos Aires Sur. Estacion Experimental Agropecuaria Balcarce. Instituto de Innovación Para la Producción Agropecuaria y El Desarrollo Sostenible. Grupo Vinculado Estacion Experimental Agropecuaria Cuenca del Salado Al Ipads | Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Mar del Plata. Instituto de Innovación Para la Producción Agropecuaria y El Desarrollo Sostenible. Grupo Vinculado Estacion Experimental Agropecuaria Cuenca del Salado Al Ipads.; Argentina Fil: Juliarena, María Paula. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires; Argentina Fil: Lombardi, Banira. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires; Argentina Fil: Abdalla, Adibe Luiz. Universidade de Sao Paulo; Brasil Fil: Abdalla Filho, Adibe Luiz. Universidade de Sao Paulo; Brasil Fil: Berndt, Alexandre. Ministerio da Agricultura Pecuaria e Abastecimento de Brasil. Empresa Brasileira de Pesquisa Agropecuaria; Brasil Fil: Oliveira, Patrícia Perondi Anchão. Ministerio da Agricultura Pecuaria e Abastecimento de Brasil. Empresa Brasileira de Pesquisa Agropecuaria; Brasil Fil: Henrique, Fábio Luis. Colegios Asociados de Uberaba; Brasil Fil: Monteiro, Alda Lúcia Gomes. Universidade Federal do Paraná; Brasil Fil: Borges, Luiza Ilha. Universidade Federal do Paraná; Brasil Fil: Ribeiro Filho, Henrique Mendonça Nunes. Universidade Federal de Santa Catarina; Brasil Fil: Ribeiro Pereira, Luiz Gustavo. Ministerio da Agricultura Pecuaria e Abastecimento de Brasil. Empresa Brasileira de Pesquisa Agropecuaria; Brasil Fil: Tomich, Thierry Ribeiro. Ministerio da Agricultura Pecuaria e Abastecimento de Brasil. Empresa Brasileira de Pesquisa Agropecuaria; Brasil Fil: Campos, Mariana Magalhães. Ministerio da Agricultura Pecuaria e Abastecimento de Brasil. Empresa Brasileira de Pesquisa Agropecuaria; Brasil Fil: Machado, Fernanda Samarini. Ministerio da Agricultura Pecuaria e Abastecimento de Brasil. Empresa Brasileira de Pesquisa Agropecuaria; Brasil Fil: Marcondes, Marcos Inácio. Universidade Federal de Viçosa.; Brasil Fil: Mercadante, Maria Eugênia Zerlotti. Agencia de Tecnología Agroindustrial de Sao Paulo; Argentina Fil: Sakamoto, Leandro Sannomiya. Agencia de Tecnología Agroindustrial de Sao Paulo; Argentina Fil: Albuquerque, Lucia Galvão. Universidade Estadual Paulista Julio de Mesquita Filho; Brasil Fil: Carvalho, Paulo César de Faccio. Universidade Federal do Rio Grande do Sul; Brasil Fil: Hristov, Alexander Nikolov. State University of Pennsylvania; Estados Unidos. University of Agriculture Wageningen; Países Bajos. Universidade de Sao Paulo; Brasil. Corporación Colombiana de Investigación Agropecuaria; Colombia

In Colombia, cattle-fattening farms account for 20.7% of the Colombian cattle herd and play an important role in terms of economic and social benefits for rural communities. However, few characterization studies have been conducted on these production systems, which limit our understanding of their production dynamics and environmental impacts. This study aimed to characterize very small, small, medium, and large cattle-fattening farms from technical and environmental perspectives. The data analyzed were obtained from the Ganadería Colombiana Sostenible and the LivestockPlus projects, which gathered information from a total of 2618 farms, classified according to their cattle production orientation. From those, 275 cattle-fattening farms were classified as being either very small (1–30 bovines), small (31–50 bovines), medium (51–250 bovines), or large farms (more than 251 bovines). Numerical and categorical variables were distributed into five components: (1) general farm information, (2) composition and management of the herd, (3) pasture management, (4) production information, and (5) environmental information. Each component was analyzed using the factorial analysis of mixed data (FAMD) method. According to FAMD, for the components general farm information, herd composition and management, pasture management, and production information, distribution of variables led to a spatial separation of the centroid from each category of producers. For the component environmental information, there was no separation of the centroid. Better infrastructure, machinery and equipment, better pasture management, and better productive parameters and practices were observed in larger farms. This suggests that those public policies aimed at improving productive and environmental performance of the livestock sector should give priority to small- and medium-sized livestock producers considering their farm characteristics.

Incorporation of foliage and pods of tropical legumes in ruminant rations is an alternative to mitigate enteric methane emissions. The objective of this research was to evaluate the effect of adding increasing levels of ground pods of Enterolobium cyclocarpum (Jacq.) Griseb. mixed with foliage of Gliricidia sepium (Jacq.) Steud. on emissions of ruminal methane (CH4), volatile fatty acid proportions, rumen pH and microbial population in cattle. Four heifers (218 ± 18 kg LW) were fed (13 days) 0, 15, 30, and 45% of pods of E. cyclocarpum mixed with foliage of G. sepium, which were supplemented to a basal ration of Brachiaria brizantha (Hochst. ex A. Rich.) Stapf. Data were analyzed as a 4 × 4 Latin square. After three days of CH4 measurements in open-circuit respiration chambers, rumen fluid was collected to determine volatile fatty acid (VFA) molar proportions and quantify the microbial population. Samples of ration ingredients, refusals and feces were collected to evaluate nutrient composition. Foliage and pods of legumes provided crude protein (CP), condensed tannins (CT) and saponins, while grass was characterized by higher concentrations of neutral detergent fiber (NDF). Dry matter intake (DMI) was 5.35 kg/day on average (P = 0.272). Apparent fiber digestibility was reduced (81 g/kg) and digestible CP intake (13 g/kg) increased when E. cyclocarpum mixed with G. sepium in rations were given (P 0.05). Substitution of 15 and 30% of pods of E. cyclocarpum mixed with foliage of G. sepium in the ration, decreases annual methane emissions per unit product, without affecting dry matter intake or rumen microbial population, on the contrary, digestible CP intake and animal productivity increased due to supply of CP, CT and saponins.

Forage grass nutritional quality directly affects animal feed intake, productivity, and enteric methane (CH4) emissions. This study evaluated the nutritional quality, in vitro enteric CH4 emission potential, and optimization of diets based on two widely grown tropical forage grasses either alone or mixed with legumes. The grasses Urochloa hybrid cv. Cayman (UHC) and U. brizantha cv. Toledo (UBT), which typically have low concentrations of crude protein (CP), were incubated in vitro either alone or mixed with the legumes Canavalia brasiliensis (CB) and Leucaena diversifolia (LD), which have higher CP concentrations. Substitution of 30% of the grass dry matter (DM) with CB or LD did not affect gas production or DM degradability. After 96 h of incubation, accumulated CH4 was 87.3 mg CH4 g−1 DM and 107.7 mg CH4 g−1 DM for the grasses alone (UHC and UBT, respectively), and 100.7 mg CH4 g−1 DM and 113.2 mg CH4 g−1 DM for combined diets (70% grass, 15% CB, and 15% LD). Diets that combined legumes (CB or LC) and grass (UHC or UBT) had higher CP contents, gross, and metabolizable energy (GE, ME, respectively) densities, as well as lower concentrations of neutral detergent fiber (NDF) and acid detergent lignin (ADL). The ME and nutritional variables such as NFD, tannins (T), and CP showed a positive correlation with in vitro net gas production, while ruminal digestibility was affected by CP, ADL, T, and GE. Optimal ratios of components for ruminant diets to reduce rumen net gas production and increase protein content were found with mixtures consisting of 60% grass (either UHC or UBT), 30% CB, and 10% LD. However, this ratio did not result in a decrease in CH4 production.

Dual-purpose cattle systems (DPS) include more than 75% of all dairy cows in Latin America and produce 40% of total milk production. Colombia has the fourth largest cattle herd in Latin America, and DPS account for 39% of the cattle population, and 58% of national milk production. Therefore, focusing on reducing the carbon footprint (CF) of DPS can have a huge contribution on mitigating the environmental impacts of the cattle farming sector. The present study aimed to estimate, based on a farm gate life cycle assessment (LCA) approach, the environmental impact of 1313 dual-purpose farms in Colombia. The study also aimed at identifying the main hotspots of negative environmental impacts and proposing possible mitigation options and their cost-effectiveness. The impact categories such as CF, non-renewable energy use, and land use were estimated using the 2019 Refinement to 2006 IPCC, databases, and locally estimated emission factors. Three methods of allocating environmental burdens to meat and milk products were applied. A principal component multivariate analysis (PCA) and a Hierarchical Clustering on Principal Components (HCPC) were performed. The largest source of greenhouse gas (GHG) in dual-purpose cattle systems comes directly from enteric fermentation, and manure deposited on pasture. The proportion of environmental burdens allocated to meat differed, with the economic method assigning the greater burden (36%), followed by energy content (30%) and mass production (13%). Four farms clusters and two production strategies were identified, a more intensive strategy with high proportion of improved pastures and higher fertilizer application rates (Clusters 1 and 2), and a more extensive with low input of fertilizers and grazing on natural pastures (Clusters 3 and 4). The CF values ranged between 2.1 and 4.2 CO2-eq per kg fat and protein corrected milk (FPCM) and between 9.0 and 18.3 CO2-eq per kg meat among clusters. CF, land use, and non-renewable energy use were lowest for clusters 1 and 3. Concerning cost-effectiveness, the adoption of improved pastures is a negative-cost measure and a promising climate change mitigation option. Overall, the CF could be reduced by around 25 to 48% for milk and meat. Therefore, our results suggest that it is possible to reduce GHG emissions by adopting improved pastures, better agricultural management practices, efficient fertilizer usage, and using the optimal stocking rate. It is expected that these reductions can be achieved with at negative costs.

In Colombia, the beef production chain accounts for approximately 11.6 million cattle heads and annually produces 933 million kg of the beef carcass. There are no life cycle assessment (LCA) studies that have evaluated the environmental performance of Colombian beef systems. The present study aimed to estimate the carbon footprint (CF), non-renewable energy use, and land use of 251 cow-calf and 275 fattening farms in Colombia. The study also aimed to identify the main hotspots of adverse environmental impacts and propose possible mitigation options and their cost-effectiveness. The impact categories were estimated using the 2006 IPCC and the 2019 Refinement to 2006 IPCC guidelines, databases, and locally estimated emission factors. The functional units used were 1 kg fat and protein corrected milk (FPCM) and 1 kg live weight gain (LWG), leaving the farm gate. Three methods of allocating environmental burdens to meat and milk products were applied: economic, energy, and mass allocation. The adoption of improved pastures was considered a mitigation measure, and an economic assessment was performed to estimate the relative cost-effectiveness of its establishment. A principal component multivariate analysis and a Hierarchical Clustering on Principal Components were performed. The economic allocation method assigned a greater environmental burden to meat (83%), followed by energy content (80%) and mass production (73%). The largest sources of GHG emissions were enteric fermentation and manure deposited on pasture. Both cow-calf and fattening systems had a cluster of farms with better productivity, pasture and cattle management practices, and environmental performance. The CF for meat could be reduced by 33 to 56% for cow-calf and 21 to 25% for fattening farms, by adopting improved pastures. Therefore, our results suggest that GHG emissions can be reduced by adopting improved pastures, better agricultural management practices, efficient fertilizer usage, using the optimal stocking rate, and increasing productivity.

En este artículo se presenta un análisis descriptivo y valorativo de los beneficios productivos y ambientales de los SSPi con Leucaena leucocephala (Lam.) de Wit, con énfasis en los aspectos de calidad nutricional, producción de biomasa, consumo voluntario, productividad animal y emisiones de gases de efecto invernadero. Para ello se hizo una revisión bibliográfica acerca de las investigaciones durante los últimos 15 años, referentes a los sistemas de producción animal en condiciones tropicales, con énfasis en las realizadas en Colombia. Se comprobó que la oferta forrajera en SSPi con leucaena tiene un contenido de proteína superior al 22 % y un menor contenido de fibra (20-30 %) respecto a la mayoría de los pastos tropicales. Adicionalmente, la leucaenatiene la capacidad de soportar el ramoneo intenso, y su presencia incrementa la productividad vegetal y animal. Los animales producen al menos dos o tres veces más carne y leche ha-1 año-1 como resultado de un mayor consumo de nutrientes y una mayor oferta forrajera, dado que con esta leguminosa el consumo de materia seca (MS) puede ser 1,3 veces mayor que el observado en sistemas convencionales, y la producción forrajera puede incrementarse de 5 a 18 t de MS ha-1 año-1.Por otra parte, la inclusión de L. leucocephala permite disminuir las emisiones entéricas de CH4 en cantidades cercanas a un 20 % por kilogramo de carne o leche producida y por kilogramo de materia seca consumida. En comparación con los sistemas tradicionales, en los que se incluye L. leucocephala, se incrementa la eficiencia en la producción y disminuyen los efectos ambientales negativos de la ganadería.

The purpose of this study was to determine the in vitro fermentation and methane (CH

In the last decades, strategies have been evaluated to reduce rumen methane (CH4) production by supplementing tropical forages rich in secondary compounds; however, most of these beneficial effects need to be validated in terms of their persistence over time. The aim of this study was to assess CH4 emissions over time in heifers fed with and without Gliricidia sepium foliage (G) mixed with ground pods of Enterolobium cyclocarpum(E). Two groups of 4 crossbred (Bos taurus x Bos indicus) heifers (284 ±17 kg initial weight) were fed with 2 diets (0% and 15% of a mixture of the pods and foliage [E + G:0 and E + G:15, respectively]) over 80 d, plus 2 wk before the experiment, in which every animal was fed a legume and pod-free diet. Every 14 d, CH4 production, apparent digestibility, volatile fatty acids (VFA), and microbial population were quantified for each animal. The experiment was conducted with a repeated measurements design over time. Diets fed differed in terms of their crude protein (CP), condensed tannins, and saponins content supplied by E. cyclocarpum and G. sepium. For most of the experiment, dry matter intake (DMI) and digestible dry-matter intake (DDMI) were 6.3 kg DMI/d and 512 g DDMI/kg, respectively, for both diets (diet: P > 0.05). Apparent digestible crude protein (DCP) was reduced by 21 g DCP/kg DM when the diet was supplemented with E + G:15 (P = 0.040). Molar proportions of VFA's in the rumen did not differ between diets or in time (P > 0.05). Daily methane production, expressed in relation to DMI, was 23.95 vs. 23.32 g CH4/kg DMI for the diet E + G:0 and E + G:15, respectively (diet: P = 0.016; Time: P > 0.05). Percent gross energy loss as CH4 (Ym) with grass-only diets was above 8.1%, whereas when feeding heifers with the alternate supplementation, Ym values of 7.59% (P = 0.016) were observed. The relative abundance of total bacterial, protozoa, and methanogenic archaeal replicates was not affected by time nor by the incorporation of legume and pods into the diet (P > 0.05). Results suggest that addition of G. sepium mixed with E. cyclocarpum pods can reduce CH4 production in heifers and this response remains over time, without effect on microbial population and VFA concentration and a slight reduction in CPD digestibility.

Reducir la vulnerabilidad a los desastres, adaptar los sistemas de producción agropecuaria a los cambios ambientales y mitigar las emisiones de gases con efecto de invernadero son acciones urgentes para enfrentar el cambio climático. En ganadería bovina de pastoreo, la investigación aplicada realizada en empresas y familias pioneras de varios países, ha permitido notables avances en agroforestería, especialmente con el sistema silvopastoril intensivo (SSPi), un uso de la tierra caracterizado por aplicar simultáneamente varios principios agroecológicos orientados a la maximización de la transformación de la energía solar en biomasa, la fijación biológica del nitrógeno, la solubilización del fósforo, la acumulación de materia orgánica en el suelo, el pastoreo rotacional, el uso inteligente del agua, la conservación de la diversidad biológica y el bienestar animal. Con estos arreglos, en los SSPi se aumenta la carga animal hasta cuatro o cinco veces en comparación al pastoreo extensivo pasando de 200 hasta 800-1200 kg ha-1 año-1, a la par que se reducen los costos en sistemas intensivos al reemplazar el alimento concentrado (40% en vacas lecheras tropicales) y evitar el uso de fertilizantes nitrogenados (bajan de 300 ha-1 año-1 de N2 hasta cero). La producción de carne y leche por hectárea se incrementa ostensiblemente sin aumentos en las emisiones de metano entérico ni aumentos en las emisiones de óxido nitroso. De esta manera, la implementación de SSPi permite intensificar sosteniblemente la producción de carne y leche bovina en el trópico y subtrópico.

A rapid growth of the meat production industry is necessary to satisfy increased demand for this commodity, which might have negative impacts on the environment. The objective of this study was to assess enteric methane (CH 4 ) emissions when a forage legume is introduced in the diet of animals consuming a tropical grass. Eight Lucerna heifers, 218±18 kg live weight with an average age of 19±3 months were used in two experiments following a changeover design. The diets evaluated were 100% star grass ( Cynodon plectostachyus, S ) or 76% star grass plus 24% leucaena ( Leucaena leucocephala , S+L). Throughout the experiment, animals were housed in two chambers, in which the diet was offered four times daily. Each chamber had a small wind tunnel, which housed a fan set to a constant speed of extraction. Air samples were obtained every hour during 24 h both inside and outside (ambient) the tunnel. Methane concentration in these samples was determined by gas chromatography. Temperature and relative humidity both inside and outside the tunnel were recorded using a thermo-hygrometer. The S+L diet had greater protein content whereas the S diet had greater content of neutral detergent fiber. Average intake (kg/d) of fresh forage and dry matter (DM) was significantly greater (23.7 and 5.6) for the S+L than for the S diet (18.9 and 4.7), respectively ( P P =0.32). These results suggest that while increasing animal productivity by increasing dry matter intake, the inclusion of leucaena does not increase methane emission per animal, thus significantly decreasing methane emissions per kg of meat or milk produced.

In the last decades, strategies have been evaluated to reduce rumen methane (CH(4)) production by supplementing tropical forages rich in secondary compounds; however, most of these beneficial effects need to be validated in terms of their persistence over time. The aim of this study was to assess CH(4) emissions over time in heifers fed with and without Gliricidia sepium foliage (G) mixed with ground pods of Enterolobium cyclocarpum(E). Two groups of 4 crossbred (Bos taurus x Bos indicus) heifers (284 ±17 kg initial weight) were fed with 2 diets (0% and 15% of a mixture of the pods and foliage [E + G:0 and E + G:15, respectively]) over 80 d, plus 2 wk before the experiment, in which every animal was fed a legume and pod-free diet. Every 14 d, CH(4) production, apparent digestibility, volatile fatty acids (VFA), and microbial population were quantified for each animal. The experiment was conducted with a repeated measurements design over time. Diets fed differed in terms of their crude protein (CP), condensed tannins, and saponins content supplied by E. cyclocarpum and G. sepium. For most of the experiment, dry matter intake (DMI) and digestible dry-matter intake (DDMI) were 6.3 kg DMI/d and 512 g DDMI/kg, respectively, for both diets (diet: P > 0.05). Apparent digestible crude protein (DCP) was reduced by 21 g DCP/kg DM when the diet was supplemented with E + G:15 (P = 0.040). Molar proportions of VFA’s in the rumen did not differ between diets or in time (P > 0.05). Daily methane production, expressed in relation to DMI, was 23.95 vs. 23.32 g CH(4)/kg DMI for the diet E + G:0 and E + G:15, respectively (diet: P = 0.016; Time: P > 0.05). Percent gross energy loss as CH(4) (Ym) with grass-only diets was above 8.1%, whereas when feeding heifers with the alternate supplementation, Ym values of 7.59% (P = 0.016) were observed. The relative abundance of total bacterial, protozoa, and methanogenic archaeal replicates was not affected by time nor by the incorporation of legume and pods into the diet (P > 0.05). Results suggest that addition of G. sepium mixed with E. cyclocarpum pods can reduce CH(4) production in heifers and this response remains over time, without effect on microbial population and VFA concentration and a slight reduction in CPD digestibility.

Se evaluo el efecto de la suplementacion de dos fuentes de vitamina D 3 , 1α-hidroxicolecalciferol (1α-OH-D3,) y 25-hidroxicolecalciferol (25-OH-D 3 ), en la presencia de fitasa, sobre los indicadores productivos, la composicion mineral osea y la calidad externa del huevo de gallinas de postura comercial durante las semanas 55 a la 68 de vida. Se utilizaron 360 gallinas Lohmann Brown, distribuidas entre cuatro tratamientos con seis replicas por tratamiento y quince aves por replica. Las dietas fueron: T1 ( dieta con 50 g ton -1 de fitasa), T2 (igual a T1 mas la adicion de 12,5 g ton -1 de 1α-OH-D 3 sin valorar los aportes de calcio y fosforo), T3 ( igual a T1 con la adicion de 12,5 g ton -1 de 1α-OH-D 3 considerando una liberacion de 0,05% del fosforo y calcio disponible), T4 (igual a T1 con la adicion de 5,52 g ton -1 de 25-OH-D 3 considerando una liberacion de 0,05% del fosforo y calcio disponible). Todas las aves tuvieron acceso a agua y alimento de acuerdo a la recomendacion para la linea comercial. Las variables porcentaje de postura, conversion acumulada, calidad de huevo, minerales en cascara, % de cascara en huevo, densidad de huevos y minerales en huesos no fueron influenciadas significativamente (p>0,05) por la fuente ni el tipo de inclusion de la vitamina D 3 . Sin embargo, el uso de la vitamina 1α-OH-D3 matrizada mostro un beneficio economico neto, representado en menor costo de produccion y mayor ingreso por ventas de huevo. En futuras investigaciones con ponedoras, es necesario verificar tanto el nivel de inclusion de vitamina D 3 como la concentracion de calcio de la dieta. DOI: http://dx.doi.org/10.21615/cesmvz.11.1.4

espanolResumen Introduccion. Los tiempos de espera ante mortem en Colombia son prolongados, el ayuno de los animales supera en promedio las 40 horas, provocando altos niveles de estres que afectan la calidad y cantidad de la carne. Objetivo. Analizar el efecto del tiempo de espera ante mortem sobre el rendimiento en canal y el pH en canales bovinas. Materiales y metodos. Se estudiaron 78 animales (Brahman comercial) provenientes del municipio de Monteria, Cordoba, Colombia; con edades entre 24 y 27 meses, y un peso promedio de 465 kg. Fueron sometidos a dos tiempos de ayuno: uno corto (20 horas) y uno prolongado (40 horas). Se registraron los pesos vivos, de canal caliente y canal fria, y se realizo la medicion de pH 24 horas post mortem. Resultados. Se analizo el efecto del tiempo de espera ante mortem sobre el rendimiento en canal y el descenso del pH 24 horas post mortem en canales bovinas; se hallaron diferencias significativas en el descenso del pH 24 horas post mortem, y se observo que la tasa de decrecimiento es casi el doble en los animales con ayunos prolongados y el nivel de estabilizacion es menor; con respecto al rendimiento en canal no se encontraron diferencias significativas entre los tratamientos. Conclusiones. Se concluye que los tiempos de espera ante mortemprolongados en los bovinos afectan el descenso normal del pH 24 horas post mortem, lo cual tiene repercusion sobre la calidad final de la carne. portuguesResumo Introducao. Os tempos de espera ante mortem na Colombia sao prolongados, o juejum dos animais supera em media as 40 horas, provocando altos niveis de estresse que afetam a qualidade e quantidade da carne. Objetivo. Analisar o efeito do tempo de espera ante mortem sobre o rendimento em canal e o pH em canais bovinas. Materiais e metodos. Se estudaram 78 animais (Brahman comercial) provenientes do municipio de Monteria, Cordoba, Colombia; com idades entre 24 e 27 meses, e um peso medio de 465 kg. Foram submetidos a dois tempos de jejum: um curto (20 horas) e um prolongado (40 horas). Se registraram os pesos vivos, de canal quente e canal fria, e se realizou a medicao de pH 24 horas post mortem. Resultados. Se analisou o efeito do tempo de espera ante mortem sobre o rendimento em canal e o descenso do pH 24 horas post mortem em canais bovinas; se encontraram diferencas significativas no descenso do pH 24 horas post mortem, e se observou que a taxa de decrescimento e quase o dobro nos animais com jejum prolongados e o nivel de estabilizacao e menor; com respeito ao rendimento em canal nao se encontraram diferencas significativas entre os tratamentos. Conclusoes. Se conclui que os tempos de espera ante mortem prolongados nos bovinos afetam o descenso normal do pH 24 horas post mortem, o qual tem repercussao sobre a qualidade final da carne. EnglishAbstract Introduction. The ante mortem lapses in Colombia are long, animals do not eat for more than 40 hours in average and this produces high stress levels that affect the quality and the quantity of the meat. Objective. Analyze the effect of the ante mortem waiting time on the performance in carcass and the pH in bovine carcasses. Materials and methods. 78 animals were studied (commercial Brahman) with ages between 24 and 27 months and an average weight of 465 kg. They were subjected to two fasting lapses: a short one (20 hours) and a long one (40 hours). The living weights were registered in hot and cold carcass conditions, and the pH was measured post mortem, after 24 hours. Results. The effect of the ante mortem time of wait on the performance in carcass and the decline of the pH 24 hours post mortem in bovine carcasses were analyzed. Significant differences in the pH decline 24 hours post mortem were found, and it was observed that the decrease rate is almost twice in animals with long fasting and the stabilization level is lower. As for the performance in carcass, there were no significant differences in the treatments. Conclusions. The long ante mortem waiting lapses affect the normal decline of the pH 24 hours post mortem, and this affects the meat´s quality.

A study was carried out to estimate the balance of metabolizable protein (MP), metabolizable energy (ME), calcium, and phosphorus in 12 recently calved (RC) and early lactation (EL, 42 – 50 days after calving) Gyr x Holstein dairy cows grazing in a Leucaena leucocephala and Cynodon plectostachyus intensive silvopastoral system (ISS) and receiving energy and protein supplementation. Dry matter (DM) availability from the grazing paddocks, nutrients offered and their balance were estimated. On average, the available forage DM per animal.day-1 was 44.7 kg for C. plectostachyus and 11.8 kg for L. leucocephala . EL cows had greater requirements of MP, ME, and minerals than RC cows. In RC cows, ME, MP, and mineral requirements were supplied by the total diet, while EL cows exhibited a negative energy balance. For both RC and EL cows, ME was the limiting dietary factor, whereas MP and P were found to be in excess. If cows were only to receive ISS forages with no supplementation, estimated daily milk yield would be 10 and 12 litters for RC and EL cows, respectively. Under tropical conditions, based on ISS forage intake, RC and EL cows can meet most of their ME, MP, calcium, and phosphorous requirements. Keywords: energy balance; Leucaena leucocephala ; nutrient requirements; phosphorus balance; protein balance.

RESUMEN: La tripanosomiasis bovina es una enfermedad hemoparasitaria transmitida en Latinoamérica principalmente por moscas picadoras de la familia Tabanidae. El objetivo del estudio fue evaluar la infección por Trypanosoma vivax y Trypanosoma evansi en ganadería bovina especializada en producción de leche en una hacienda y sus potenciales vectores. Se realizó un estudio parasitológico y entomológico directo por técnicas de microscopia y reacción en cadena de la polimerasa (PCR) con dos marcadores moleculares para diferenciar especies de Trypanosoma en muestras de sangre de bovinos y moscas. La frecuencia de infección por Trypanosoma vivax y Trypanosoma evansi en bovinos fue de 3,6 y 0%, respectivamente. La caracterización de vectores muestra a Haematobia irritans como la mosca más frecuente en la zona de estudio (97,1%), seguida de Stomoxys calcitrans (2,8%). No se identificaron tabánidos. Se encontró T. vivax y T. evansi en probóscide y toráx-abdomen de las moscas picadoras Haematobia irritans y Stomoxys calcitrans, lo que representa un comportamiento epizoótico atípico al que sucede en países de Suramérica. Por su alta densidad poblacional, se sugiere la mosca Haematobia irritans como el principal potencial vector. ABSTRACT: Bovine trypanosomiasis is a hemoparasitic disease transmitted in Latin America mainly by biting flies of the family Tabanidae. The study aimed to evaluate infection by Trypanosoma vivax and Trypanosoma evansi in cattle specialized in milk production on a farm and their potential vectors. A direct parasitological and entomological study was performed using microscopy techniques and polymerase chain reaction (PCR) with two molecular markers to differentiate Trypanosoma species in blood samples of cattle and flies. Infection frequency with Trypanosoma vivax and Trypanosoma evansi in cattle was 3.6 and 0%, respectively. Characterization of vectors shows Haematobia irritans as the most frequent fly in the study area (97.1%), followed by Stomoxys calcitrans (2.8%). No horseflies were identified. T. vivax and T. evansi were found in proboscis and thorax-abdomen of biting flies Haematobia irritans and Stomoxys calcitrans, representing an epizootic behavior, atypical in South American countries. Due to its high population density, it is suggested that the Haematobia irritans fly is the main potential vector. RESUMO: A tripanossomíase bovina é uma doença causada por hemoparasitas e transmitida na América Latina principalmente por moscas picadoras da família Tabanidae. O objetivo do estudo foi avaliar a infecção por Trypanosoma vivax e Trypanosoma evansi em gado bovino especializada em produção de leite em uma fazenda e seus potenciais vectores. Se realizou um estudo parasitológico e entomológico direto por técnicas de microscopia e reação em cadeia da polimerase (PCR) com dois marcadores moleculares para diferenciar espécies de Typanosoma em amostras de sangue de bovinos e moscas. A frequência de infecção por Trypanosoma vivax e Trypanosoma evansi em bovinos foi de 3,6 e 0%, respectivamente. A caracterização de vetores mostra a Haematobia irritans como a mosca mais frequente na zona de estudo (97,1%), seguida de Stomoxys calcitrans (2,8%). Não se identificaram tabanídeos. Se encontrou T. vivax e T. evansi em proboscídea e tórax-abdômen das moscas picadoras Haematobia irritans e Stomoxys calcitrans, o que representa um comportamento epizoótico atípico ao que sucede em países da América do Sul. Por sua alta densidade populacional, se sugere a mosca Haematobia irritans como o principal potencial vetor. COL0021461

La fermentación y metanogénesis ruminal son procesos metabolicos vitales para los bovinos y son llevados a cabo por poblaciones microbianas, las cuales se afectan por factores como la presencia de metabolitos secundarios, la composición nutricional y la degradabilidad de la dieta. El objetivo de este trabajo fue monitorear las poblaciones de bacterias totales, metanógenos totales y Butirivibrio fibrisolvens en el rumen de novillas raza Lucerna, alimentadas con dietas típicas de un sistema silvopastoril intensivo y un sistema tradicional. Para ello, se colectó contenido ruminal (CR) por vía oral a ocho novillas que consumían 100% Cynodon plectostachyus (control) y 76% C. plectostachyus + 24% Leucaena leucocephala siguiendo un diseño de sobre-cambio. A partir del CR se extrajo y cuantificó ADN mediante PCR cuantitativa. Las poblaciones [Log10 (ng/g CR)] fueron 5.6 y 5.8 para bacterias totales (P= 0.5343), 3.6 y 3.5 para B. fibrisolvens (P= 0.4742), y 5.0 y 5.3 para metanógenos totales (P= 0.2661), para la dieta control y la dieta con leucaena respectivamente. Las poblaciones monitoreadas cuantitativamente no difirieron de manera significativa con la inclusión de L. leucocephala. Esto indica la importancia de investigar la estructura, función e interacciones de las poblaciones más allá del análisis cuantitativo para determinar cómo la dieta afecta las poblaciones microbianas ruminales y su función. Rumen fermentation and methanogenesis are vital metabolic processes in cattle and are carried out by microbial populations that are affected by dietary factors such as secondary metabolites, nutritional composition and degradability. The aim of this study was to monitor populations of total bacteria, total methanogens and Butirivibrio fibrisolvens in the rumen of Lucerne heifers fed on diets typical of intensive silvopastoral systems (ISS) or of a traditional (control) system. Rumen contents (RC) were collected orally from eight heifers consuming 100% Cynodon plectostachyus (control) and 76% C. plectostachyus + 24% Leucaena leucocephala (ISS) following a crossover design and DNA was extracted and quantified by quantitative PCR. Populations [Log10 (ng g-1 RC)] were 5.6 and 5.8 for total bacteria (p = 0.5343), 3.6 and 3.5 for B. fibrisolvens (p = 0.4742) and 5.0 and 5.3 for total methanogens (p = 0.2661) respectively in control and ISS diets. However, when measured in a separate parallel study, enteric methane emissions (g kg-1 of fermented dry matter) were significantly reduced with the inclusion of L. leucocephala. This fact indicated the importance of investigating the structure, function and interactions of populations beyond quantitative analysis to determine how diet affects rumen microbial populations and their function.

The objective of this study was to describe the trend of reproductive performance of primiparous and multiparous cows that grazed rice crop residues located in a Dry Tropical Forest of Colombia, taking into account the rainfall pattern of the place. In this study, 89 primiparous and 309 multiparous Cebu cattle records were analyzed. Mean, mean standard deviation for age at first calving and open days of primipar-ous Cebu cattle were 41.05± 1.85 months and 269.7±36.25 days respectively. Confidence intervals (95%) for both reproductive parameters were 36.8-45.3 months and 202.7-336.6 days respectively. For multiparous Cebu cattle, the mean and mean standard deviation for open days and calving interval were 245.6±36.8 days and 17.5±0.9 months respectively. Confidence intervals 207.1-366.9 days and 13.9-20.7 months respectively. The mean rainfall since 1999 until 2012 was1202 mmper year. The reproduc-tive trend of the primiparous cattle showed an increasing behavior of age at first calving since 1999 until 2012, that can possibly be explained due to the decreasing behavior of the rainfall throughout the years, that can affect the nutritional value and offer of the grass that can grow in the borders of the crop, such as Guinea and Star grass, and eventually affect the body condition and weight necessary to be ready for the first estrous. An inverse behavior of open days occurred, showing a decreased trend along the last years of research. This fact could have happened due to the intensive use of the enriched rice straw with urea and molasses lately. Regarding to the reproductive trend of the multiparous cattle, there is no an evident pat-tern of it. Factors such as rainfall, temperature, nutrition and management should have affected it. Further research on this topic is needed.

It is widely accepted that selection for high milk yield in dairy cows has negatively affected their reproductive performance. After calving, dairy cows experience a nutritional imbalance due to an asynchrony in the occurrence of the lactation and dry matter intake peaks. In the tropics, this situation is exacerbated due to poor quality and/ or availability of the diet. A study was carried out to describe the nutritional and reproductive behavior of two-to-four parturition crossbred cows (Gyr (Bos indicus) x Holstein (Bos taurus)) divided in two groups according to their calving to first service interval (CFSI): Group 1: ≤50 days CFSI, n=7; Group 2: ≥50 days CFSI, n=8. Animals were grazing in an intensive silvopastoral system (ISS) based on Leucaena leucocephala and Cynodon plectostachyus and also received protein, energy and mineral supplementation. Dry matter (DMI) and nutrient intake were individually estimated and correlations between reproductive and nutritional parameters were performed. Additionally, serum progesterone concentration was monitored. Group 2 had greater forage and total DMI and milk production than Group 1 (P

La percepción del cambio climático como uno de los grandes problemas ambientales del siglo XXI viene creciendo en las últimas décadas. La emisión de metano por fermentación ruminal es una pérdida de energía potencialmente utilizable. El objetivo fue estimar las emisiones de metano de forrajes usados en dietas para alimentar bovinos. Las dietas evaluadas provenían de un sistema silvopastoril intensivo (SSPi) con leucaena (Leucaena leucocephala; Leu) y pasto guinea (Megathyrsus maximus; Gui) y de confinamiento con matarratón (Gliricidia sepium; Mat) y pasto ángleton (Dichantium aristatum; Ang). Muestras representativas de los forrajes fueron analizadas por su contenido de nutrientes; las emisiones de metano de los forrajes solos y sus mezclas (90:10, 80:20 y 70:30, teniendo mayor participación las gramíneas) fueron medidas in vitro, mediante la técnica de producción de gas. La degradación de la materia seca se midió a las 24, 48, 72 y 96 h. Las leguminosas tuvieron mayores contenidos de proteína y grasa bruta; mientras que las gramíneas, mayores contenidos de fibra insoluble en detergente neutro y ácido y cenizas. La mayor producción de gas a las 96 h fue para Gui70-Leu30 (156 ml) y la menor fue Leu100 (P≤0,05; 121 ml). Para el sistema en confinamiento, la acumulación de gas de Ang70-Mat30 y Ang80-Mat20 a partir de a las 48 horas fueron superiores a los demás tratamientos (P

La determinación del consumo voluntario de materia seca (CMS) por los animales, es indispensable para determinar su capacidad productiva y su estado nutricional. Existen muchas técnicas para la estimación del CMS, siendo una de ellas la técnica de n-alcanos la cual permite además estimar la selectividad de los forrajes consumidos. El presente trabajo tuvo como objetivo estimar el consumo voluntario y la excreción fecal de nutrientes por novillos cebuínos alimentados en un sistema silvopastoril intensivo (SSPi). El estudio se realizó en el Centro Experimental Cotové, propiedad de la Universidad Nacional de Colombia. Se evaluaron seis novillos castrados con un peso promedio de 381±12 kg y se utilizó la técnica de alcanos para determinar CMS. El CMS promedio de forraje fue de 9,54 kg dia-1, del cual, el 75,24 % correspondió a consumo de gramíneas y el 24,76 % a consumo de leguminosa. En promedio, el consumo de nutrientes (kg) fue de 1,33; 5,8; 4,02; 1,13; 0,058 y 0,021 para PC, FDN, FDA, Cenizas, Ca y P respectivamente. Estos consumos fueron adecuados para el tipo de animales del estudio aportando una dieta de buena calidad nutricional. La digestibilidad fue del 53 % para el tratamiento sin inclusión del suplemento y del 58 % para el tratamiento con suplemento, lo que junto con el CMS, permite afirmar que los animales satisficieron sus requerimientos de los principales nutrientes. Las cantidades excretadas (kg) fueron 4,15; 0,44; 2,56; 1,78; 0,8; 0,054 y 0,02 para MS, PC, FDN, FDA, Cenizas, Ca y P, respectivamente. La excreción fecal de N por animal al año se calculó en 29,9 kg, contribuyendo a la producción de biomasa de las gramíneas acompañantes en el SSPi.