Marine reserves, fisheries ban, and 20 years of positive change in a coral reef ecosystem.

By 2004, Belize was exhibiting classic fishing down of the food web. Groupers (Serranidae) and snappers (Lutjanidae) were scarce and fisheries turned to parrotfishes (Scarinae), leading to a 41% decline in their biomass. Several policies were enacted in 2009-2010, including a moratorium on fishing parrotfish and a new marine park with no-take areas. Using a 20-year time series on reef fish and benthos, we evaluated the impact of these policies approximately 10 years after their implementation. Establishment of the Southwater Caye Marine Reserve led to a recovery of snapper at 2 out of 3 sites, but there was no evidence of recovery outside the reserve. Snapper populations in an older reserve continued to increase, implying that at least 9 years is required for their recovery. Despite concerns over the feasibility of banning parrotfish harvest once it has become a dominant fin fishery, parrotfishes returned and exceeded biomass levels prior to the fishery. The majority of these changes involved an increase in parrotfish density; species composition and adult body size generally exhibited little change. Recovery occurred equally well in reserves and areas open to other forms of fishing, implying strong compliance. Temporal trends in parrotfish grazing intensity were strongly negatively associated with the cover of macroalgae, which by 2018 had fallen to the lowest levels observed since measurements began in 1998. Coral populations remained resilient and continued to exhibit periods of net recovery after disturbance. We found that a moratorium on parrotfish harvesting is feasible and appears to help constrain macroalgae, which can otherwise impede coral resilience.

Reservas Marinas, Vedas Pesqueras y 20 Años de Cambios Positivos en un Ecosistema de Arrecife de Coral Resumen Para el año 2004, Belice estaba exhibiendo la clásica pesca de los niveles más bajos de las cadenas alimenticias marinas. Los meros (Serranidae) y los pargos (Lutjanidae) eran escasos y las pesquerías comenzaron a consumir a los peces loro (Scarinae), lo que resultó en una declinación del 41% de su biomasa. Entre el 2009 y el 2010 se promulgaron varias políticas, incluyendo una moratoria para la pesca del pez loro y un nuevo parque marino con zonas de no consumo. Mediante una serie temporal de 20 años para los peces de arrecifes y el bentos, evaluamos el impacto de estas políticas aproximadamente diez años después de su implementación. La creación de la Reserva Marina del Cayo Southwater resultó en la recuperación del pargo en dos de tres sitios, pero no hubo evidencias de la recuperación fuera de la reserva. Las poblaciones de pargos en una reserva más vieja continuaron su incremento, lo que implica que se requieren al menos nueve años para su recuperación. A pesar de la preocupación por la viabilidad de la veda para el pez loro una vez que se haya convertido en una pesquería dominante, los peces loro regresaron al sitio de pesca y excedieron los niveles de biomasa previos a la pesquería. La mayoría de estos cambios involucró un incremento en la densidad de los peces loro; la composición de especies y la talla corporal adulta generalmente exhibieron pocos cambios. La recuperación ocurrió equitativamente bien en las reservas y en las áreas abiertas a otras formas de pesca, lo que implica un estricto cumplimiento de las restricciones. Las tendencias temporales en la intensidad de pastoreo de los peces loro estuvieron fuertemente asociadas de manera negativa con la cobertura de macroalgas, la cual para el 2018 había caído a los niveles más bajos observados desde que se comenzó a medir en 1998. Las poblaciones coralinas permanecieron resilientes y continuaron exhibiendo periodos de recuperación neta después de la perturbación. Descubrimos que una moratoria para la pesca de pez loro es viable y parece ayudar a restringir las macroalgas, las cuales de otra forma pueden impedir la resiliencia del coral.

Conserving Himalayan birds in highly seasonal forested and agricultural landscapes.

The Himalayas are a global biodiversity hotspot threatened by widespread agriculture and pasture expansion. To determine the impact of these threats on biodiversity and to formulate appropriate conservation strategies, we surveyed birds along elevational gradients in primary forest and in human-dominated lands spanning a gradient of habitat alteration, including forest-agriculture mosaics, mixed agriculture mosaics, and pasture. We surveyed birds during the breeding season and in winter to account for pronounced seasonal migrations. Bird abundance and richness in forest-agriculture and mixed agriculture mosaics were equal to or greater than in primary forest and greater than in pasture at local and landscape scales during both seasons. Pasture had greater abundance and richness of birds in winter than primary forest, but richness was greater in primary forest at the landscape scale during the breeding season. All 4 land-use types held unique species, suggesting that all must be retained in the landscape to conserve the entire avifauna. Our results suggest forest-agriculture and mixed agriculture mosaics are particularly important for sustaining Himalayan bird communities during winter and primary forests are vital for sustaining Himalayan bird communities during the breeding season. Further conversion of forest-agriculture and mixed agriculture mosaics to pasture would likely result in significant biodiversity losses that would disproportionately affect breeding species. To ensure comprehensive conservation, strategies in the western Himalayas must balance the protection of intact primary forest with the minimization of pasture expansion.

The perpetual state of emergency that sacrifices protected areas in a changing climate.

A modern challenge for conservation biology is to assess the consequences of policies that adhere to assumptions of stationarity (e.g., historic norms) in an era of global environmental change. Such policies may result in unexpected and surprising levels of mitigation given future climate-change trajectories, especially as agriculture looks to protected areas to buffer against production losses during periods of environmental extremes. We assessed the potential impact of climate-change scenarios on the rates at which grasslands enrolled in the Conservation Reserve Program (CRP) are authorized for emergency harvesting (i.e., biomass removal) for agricultural use, which can occur when precipitation for the previous 4 months is below 40% of the normal or historical mean precipitation for that 4-month period. We developed and analyzed scenarios under the condition that policy will continue to operate under assumptions of stationarity, thereby authorizing emergency biomass harvesting solely as a function of precipitation departure from historic norms. Model projections showed the historical likelihood of authorizing emergency biomass harvesting in any given year in the northern Great Plains was 33.28% based on long-term weather records. Emergency biomass harvesting became the norm (>50% of years) in the scenario that reflected continued increases in emissions and a decrease in growing-season precipitation, and areas in the Great Plains with higher historical mean annual rainfall were disproportionately affected and were subject to a greater increase in emergency biomass removal. Emergency biomass harvesting decreased only in the scenario with rapid reductions in emissions. Our scenario-impact analysis indicated that biomass from lands enrolled in the CRP would be used primarily as a buffer for agriculture in an era of climatic change unless policy guidelines are adapted or climate-change projections significantly depart from the current consensus.

Desert pastoralists' negative and positive effects on rare wildlife in the Gobi.

In arid regions of the developing world, pastoralists and livestock commonly inhabit protected areas, resulting in human-wildlife conflict. Conflict is inextricably linked to the ecological processes shaping relationships between pastoralists and native herbivores and carnivores. To elucidate relationships underpinning human-wildlife conflict, we synthesized 15 years of ecological and ethnographic data from Ikh Nart Nature Reserve in Mongolia's Gobi steppe. The density of argali (Ovis ammon), the world's largest wild sheep, at Ikh Nart was among the highest in Mongolia, yet livestock were >90% of ungulate biomass and dogs >90% of large-carnivore biomass. For argali, pastoral activities decreased food availability, increased mortality from dog predation, and potentially increased disease risk. Isotope analyses indicated that livestock accounted for >50% of the diet of the majority of gray wolves (Canis lupus) and up to 90% of diet in 25% of sampled wolves (n = 8). Livestock composed at least 96% of ungulate prey in the single wolf pack for which we collected species-specific prey data. Interviews with pastoralists indicated that wolves annually killed 1-4% of Ikh Nart's livestock, and pastoralists killed wolves in retribution. Pastoralists reduced wolf survival by killing them, but their livestock were an abundant food source for wolves. Consequently, wolf density appeared to be largely decoupled from argali density, and pastoralists had indirect effects on argali that could be negative if pastoralists increased wolf density (apparent competition) or positive if pastoralists decreased wolf predation (apparent facilitation). Ikh Nart's argali population was stable despite these threats, but livestock are increasingly dominant numerically and functionally relative to argali. To support both native wildlife and pastoral livelihoods, we suggest training dogs to not kill argali, community insurance against livestock losses to wolves, reintroducing key native prey species to hotspots of human-wolf conflict, and developing incentives for pastoralists to reduce livestock density.

Effects of past and present livestock grazing on herpetofauna in a landscape-scale experiment.

Livestock grazing is the most widespread land use on Earth and can have negative effects on biodiversity. Yet, many of the mechanisms by which grazing leads to changes in biodiversity remain unresolved. One reason is that conventional grazing studies often target broad treatments rather than specific parameters of grazing (e.g., intensity, duration, and frequency) or fail to account for historical grazing effects. We conducted a landscape-scale replicated grazing experiment (15,000 km2 , 97 sites) to examine the impact of past grazing management and current grazing regimes (intensity, duration, and frequency) on a community of ground-dwelling herpetofauna (39 species). We analyzed community variables (species richness and composition) for all species and built multiseason patch-occupancy models to predict local colonization and extinction for the 7 most abundant species. Past grazing practices did not influence community richness but did affect community composition and patch colonization and extinction for 4 of 7 species. Present grazing parameters did not influence community richness or composition, but 6 of the 7 target species were affected by at least one grazing parameter. Grazing frequency had the most consistent influence, positively affecting 3 of 7 species (increased colonization or decreased extinction). Past grazing practice affected community composition and population dynamics in some species in different ways, which suggests that conservation planners should examine the different grazing histories of an area. Species responded differently to specific current grazing practices; thus, incentive programs that apply a diversity of approaches rather than focusing on a change such as reduced grazing intensity should be considered. Based on our findings, we suggest that determining fine-scale grazing attributes is essential for advancing grazing as a conservation strategy.

The importance of agricultural lands for Himalayan birds in winter.

The impacts of land-use change on biodiversity in the Himalayas are poorly known, notwithstanding widespread deforestation and agricultural intensification in this highly biodiverse region. Although intact primary forests harbor many Himalayan birds during breeding, a large number of bird species use agricultural lands during winter. We assessed how Himalayan bird species richness, abundance, and composition during winter are affected by forest loss stemming from agriculture and grazing. Bird surveys along 12 elevational transects within primary forest, low-intensity agriculture, mixed subsistence agriculture, and intensively grazed pastures in winter revealed that bird species richness and abundance were greatest in low-intensity and mixed agriculture, intermediate in grazed pastures, and lowest in primary forest at both local and landscape scales; over twice as many species and individuals were recorded in low-intensity agriculture than in primary forest. Bird communities in primary forests were distinct from those in all other land-use classes, but only 4 species were unique to primary forests. Low-, medium-, and high-intensity agriculture harbored 32 unique species. Of the species observed in primary forest, 80% had equal or greater abundance in low-intensity agricultural lands, underscoring the value of these lands in retaining diverse community assemblages at high densities in winter. Among disturbed landscapes, bird species richness and abundance declined as land-use intensity increased, especially in high-intensity pastures. Our results suggest that agricultural landscapes are important for most Himalayan bird species in winter. But agricultural intensification-especially increased grazing-will likely result in biodiversity losses. Given that forest reserves alone may inadequately conserve Himalayan birds in winter, comprehensive conservation strategies in the region must go beyond protecting intact primary forests and ensure that low-intensity agricultural lands are not extensively converted to high-intensity pastures.

Using empirical models of species colonization under multiple threatening processes to identify complementary threat-mitigation strategies.

Approaches to prioritize conservation actions are gaining popularity. However, limited empirical evidence exists on which species might benefit most from threat mitigation and on what combination of threats, if mitigated simultaneously, would result in the best outcomes for biodiversity. We devised a way to prioritize threat mitigation at a regional scale with empirical evidence based on predicted changes to population dynamics-information that is lacking in most threat-management prioritization frameworks that rely on expert elicitation. We used dynamic occupancy models to investigate the effects of multiple threats (tree cover, grazing, and presence of an hyperaggressive competitor, the Noisy Miner (Manorina melanocephala) on bird-population dynamics in an endangered woodland community in southeastern Australia. The 3 threatening processes had different effects on different species. We used predicted patch-colonization probabilities to estimate the benefit to each species of removing one or more threats. We then determined the complementary set of threat-mitigation strategies that maximized colonization of all species while ensuring that redundant actions with little benefit were avoided. The single action that resulted in the highest colonization was increasing tree cover, which increased patch colonization by 5% and 11% on average across all species and for declining species, respectively. Combining Noisy Miner control with increasing tree cover increased species colonization by 10% and 19% on average for all species and for declining species respectively, and was a higher priority than changing grazing regimes. Guidance for prioritizing threat mitigation is critical in the face of cumulative threatening processes. By incorporating population dynamics in prioritization of threat management, our approach helps ensure funding is not wasted on ineffective management programs that target the wrong threats or species.

Effects of landscape transformation on bird colonization and extinction patterns in a large-scale, long-term natural experiment.

Conversion of agricultural land to forest plantations is a major driver of global change. Studies on the impact of forest plantations on biodiversity in plantations and in the surrounding native vegetation have been inconclusive. Consequently, it is not known how to best manage the extensive areas of the planet currently covered by plantations. We used a novel, long-term (16 years) and large-scale (30,000 ha) landscape transformation natural experiment (the Nanangroe experiment, Australia) to test the effects of land conversion on population dynamics of 64 bird species associated with woodland and forest. A unique aspect of our study is that we focused on the effects of plantations on birds in habitat patches within plantations. Our study design included 56 treatment sites (Eucalyptus patches where the surrounding matrix was converted from grazed land to pine plantations), 55 control sites (Eucalyptus patches surrounded by grazed land), and 20 matrix sites (sites within the pine plantations and grazed land). Bird populations were studied through point counts, and colonization and extinction patterns were inferred through multiple season occupancy models. Large-scale pine plantation establishment affected the colonization or extinction patterns of 89% of studied species and thus led to a comprehensive turnover in bird communities inhabiting Eucalyptus patches embedded within the maturing plantations. Smaller bodied species appeared to respond positively to plantations (i.e., colonization increased and extirpation of these species decreased in patches surrounded by plantations) because they were able to use the newly created surrounding matrix. We found that the effects of forest plantations affected the majority of the bird community, and we believe these effects could lead to the artificial selection of one group of species at the expense of another.

Direct effects of cattle on grassland birds in Canada.

Effects of grazing on grassland birds are generally thought to be indirect, through alteration of vegetation structure; however, livestock can also affect nest survival directly through trampling and other disturbances (e.g., livestock-induced abandonment). We extracted data on nest fates from 18 grazing studies conducted in Canada. We used these data to assess rates of nest destruction by cattle among 9 ecoregions and between seasonal and rotational grazing systems. Overall, few nests were destroyed by cattle (average 1.5% of 9132 nests). Nest destruction was positively correlated with grazing pressure (i.e., stocking rate or grazing intensity), but nest survival was higher in more heavily grazed areas for some species. Because rates of destruction of grassland bird nests by cattle are low in Canada, management efforts to reduce such destruction may not be of ecological or economic value in Canada.

Seasonal quality of milk from Creole grazing goats, stabled Saanen and French-Alpine goats / Calidad estacional de leche de cabras Criollas en pastoreo vs cabras estabuladas Saanen y Alpina-Francesa / Qualidade sazonal do leite de cabras Crioulas em pastagem vs cabras estábuladas Saanen e Franco-alpina

Abstract Background: Goat milk production has been increasing in northern Mexico; however, there is little information available about its quality. Objective: To compare goat milk quality during three seasons among creole goats in a traditional grazing system and stabled Saanen and French-Alpine goats. Methods: An experiment was performed in a completely randomized nested design with seasonality factor (fixed effects) with three levels (rain, transition, and drought) and breed factor (fixed effect with three levels (Creole, Saanen and French-Alpine)) nested within the season-of-the-year factor. Fifteen goats were randomly selected: five Creole in the extensive grazing system, five stabled Saanen, and five stabled French-Alpine. The factors assessed in milk were fat content, non-fat solids, protein, lactose, salts, density, freezing point, conductivity, and pH (using a Lactoscan® device). Results: With respect to season for all the breeds: fat, non-fat solids, protein, lactose, and salt contents were higher (p≤0.05) for goats sampled in the rainy season, followed by drought and transition seasons, respectively. The variables related to milk quality by breed and season showed that milk fat content of creole goats was greater (p≤0.05) in the drought season; salt and non-fat content (p≤0.05) in the three seasons of the year; density and protein increased (p≤0.05) in the transition and rainy seasons, while lactose was greater (p≤0.05) in drought and rainy seasons; protein was greater (p≤0.05) in transition and rainy seasons; and the freezing point was lower (p≤0.05) in the transition season. Regarding conductivity, French-Alpine milk was greater (p≤0.05) in the drought season. Conclusion: Season of the year significantly affects milk quality, with increased quality during the rainy season in creole grazing goats.

Resumen Antecedentes: La producción de leche de cabra se ha venido incrementando en el norte de México,; sin embargo, existe poca información sobre su calidad. Objetivo: Comparar la calidad de la leche de cabra durante tres épocas del año para cabras criollas en pastoreo y cabras puras de dos razas diferentes bajo estabulación. Métodos: El experimento se realizó mediante un diseño anidado completamente aleatorizado, con el factor época del año (efecto fijo) con tres niveles (lluvia, transición y sequia) y el factor raza (efecto fijo) con tres niveles (Criolla, Saanen y Alpino-Francesa) anidado dentro del factor época del año. En el sistema de pastoreo extensivo se eligieron al azar cinco cabras de raza Criolla, en el sistema estabulado se eligieron al azar cinco cabras de la raza Saanen y cinco de la raza Alpino-Francesa. La variables medidas fueron: contenido de grasa, sólidos no grasos, proteína, lactosa, sales, densidad, punto de congelación, conductividad y pH (utilizando el dispositivo Lactoscan®). Resultados: Respecto a la temporada del año para las tres razas se encontró que los contenidos en leche de grasa, sólidos no grasos, proteína, lactosa y sales fueron mayores (p≤0,05) en la época de lluvias, seguido por la leche muestreada en sequía y transición. Las variables por raza y temporada del año arrojaron que la grasa fue mayor (p≤0,05) en cabras criollas en sequía, solidos no grasos fue mayor (p≤0,05) en las tres temporadas del año en cabras criollas, la densidad aumentó (p≤0,05) en cabras criollas en transición y lluvia. La proteína fue mayor (p≤0,05) en cabras criollas en transición y lluvia, mientras que la lactosa fue mayor (p≤0,05) en cabras criollas en sequía y lluvia. El menor punto de congelación (p≤0,05) se presentó en cabras criollas en transición, la conductividad fue mayor (p≤0,05) en cabras Alpina-Francesa en sequía y la concentración de sales fue mayor (p ≤0,05) en cabras criollas durante las tres temporadas. Conclusión: Existe un marcado efecto de la temporada sobre la calidad de la leche, siendo la epoca de lluvias cuando se presenta mejor calidad en cabras criollas en pastoreo.

Resumo Antecedentes: No norte do México a produção de leite de cabra aumentou; no entanto, a qualidade do leite é desconhecida. Objetivo: Comparar a qualidade do leite de cabra durante três estações do ano com cabras crioulas em sistema de pastoreio tradicional e cabras Saanen e franco-alpinas em estábulos. Métodos: O experimento foi realizado através de um delineamento completamente casualizado com o fator de sazonalidade (efeitos fixos) com três níveis (chuva, transição e seca) e fator de raça (efeito fixo com três níveis (crioulo, Saanen e franco-alpino) aninhados dentro do fator estação do ano quinze cabras foram selecionadas aleatoriamente, cinco no sistema de pastejo extensivo, cinco Saanen e cinco Franco-Alpino no sistema estábulo. Os fatores avaliados no leite foram teor de gordura, sólidos desengordurados, proteína, lactose, sais, densidade, ponto de congelamento, condutividade e pH pelo aparelho Lactoscan®. Resultados: Em relação às estações do ano, nas três raças, mostrou que os teores de gordura, sólidos desengordurados, proteínas, lactose e sal foram maiores (p≤0,05) nas cabras cujo leite foi amostrado na ocasião um de chuvas seguido por aquele amostrado nas estações de seca e transição, respectivamente. As variáveis relacionadas à qualidade do leite de cabra por raça e ano, mostraram que nas cabras crioulas o teor de gordura foi maior (p≤0,05) na estação seca; teor de sal e gordura (p≤0,05) nas três estações do ano; a densidade aumentou significativamente e o teor de proteína foi maior (p≤0,05) nas estações de transição e chuvas, enquanto o valor de lactose foi maior (p≤0,05) nas estações seca e chuvosa; o teor de proteína foi maior (p≤0,05) nas estações de transição e chuvas; e o ponto de congelamento foi menor (p≤0,05) na estação de transição. Em relação à condutividade, o leite de cabra franco-alpino apresentou valor significativamente superior (p≤0,05) na seca. Conclusão: A qualidade do leite tem um efeito significativo por estação, sendo que a estação chuvosa aumentou a qualidade do leite em cabras crioulas em pastejo.

Effect of tropical forage species in silvopastoral arrangements on methane production and in vitro fermentation parameters in a RUSITEC system / Efecto de especies forrajeras tropicales en arreglos silvopastoriles sobre la producción de metano y parámetros de fermentación in vitro en un sistema RUSITEC / Efeito de espécies forrageiras tropicais em arranjos silvipastoris sob a produção de metano e parâmetros de fermentação in vitro em um sistema RUSITEC

Abstract Background: Supplementation of grazing cattle with native and naturalized forages using silvopastoral systems has been suggested as an affordable strategy to reduce methane production and improve nutrition, diminishing the environmental impact of cattle production. Objective: To evaluate the effect of three tropical forage species in a silvopastoral arrangement on methane production and fermentation parameters using an in vitro ruminal simulation system (RUSITEC). Methods: Four diets were evaluated. The control treatment was a basal diet of colosuana grass (COL; Bothriochloa pertusa), while the other diets consisted of 70% COL complemented with 30% shrub forage from either Leucaena leucocephala (CL), Guazuma ulmifolia (CG), or Crescentia cujete (CT). A randomized complete block design with repeated measurements over time was used. Results: The inclusion of shrub forage did not affect pH, organic matter degradation (OMD) or volatile fatty acids (VFA). The inclusion of shrub forage affected the degradation of structural components. The concentration of N-NH3 increased in the CL diet compared to COL (p<0.05). In general, methane production in terms of mL/day, mL/g DMi, mL/g DMd, and mL/gOMd was reduced for CL compared to COL (p<0.05). Conclusions: Based on these results, inclusion of Leucaena leucocephala, Guazuma ulmifolia or Crescentia cujete on B. pertusa-based diets improves ruminal fermentation parameters and reduces in vitro methane production.

Resumen Antecedentes: Suplementar ganado en pastoreo con forrajes nativos y naturalizados en sistemas silvopastoriles se ha sugerido como estrategia para reducir la producción de metano y mejorar la nutrición, disminuyendo el impacto ambiental de la ganaderia. Objetivo: Evaluar el efecto de tres especies forrajeras tropicales en arreglos silvopastoriles sobre la producción de metano y parámetros de fermentación utilizando un sistema de simulación ruminal in vitro (RUSITEC). Métodos: El tratamiento control consistió en una dieta basal de pasto Colosuana (COL; Bothriochloa pertusa), mientras que las demás dietas consistieron de 70% COL complementado con 30% de forraje arbustivo de Leucaena leucocephala (CL), Guazuma ulmifolia (CG) ó Crescentia cujete (CT). Se utilizó un diseño de bloques completos al azar con mediciones repetidas en el tiempo. Resultados: La inclusión de forrajes arbustivos no afectó (p>0.05) el pH, la degradación de la materia orgánica (DMO), ni los ácidos grasos volátiles (AGV). La inclusión de recursos arbóreos afectó la degradación de los constituyentes estructurales. La concentración de N-NH3 aumentó en la dieta CL en comparación con el control (p<0.05). En general, la producción de metano en términos de mL/día, mL/g DMi, mL/g DMd y mL/g OMd se redujo en CL respecto a COL (p<0.05). Conclusiones: Con base en estos resultados, la inclusión de Leucaena leucocephala, Guazuma ulmifolia o Crescentia cujete en dietas a base de B. pertusa mejora algunos parámetros de fermentación ruminal y reduce la producción in vitro de metano.

Resumo Antecedentes: A suplementação do gado em pastejo com forragens nativas e naturalizadas usando sistemas silvipastoris, tem sido sugerida como uma estratégia acessível para reduzir a produção de metano e melhorar a nutrição, diminuindo os impactos ambientais da produção de gado. Objetivo: Avaliar o efeito de espécies forrageiras tropicais de arranjo silvipastoril na produção de metano e parâmetros de fermentação usando um sistema de simulação ruminal in vitro (RUSITEC). Métodos: O controle do tratamento (COL) consistiu em uma dieta basal de Colosuana (Botrhiochloa pertusa) sozinha, enquanto as outras dietas, CL, CG e CT, foram complementadas com 30% de Leucaena leucocephala, 30% Guazuma ulmifolia ou 30% Crescentia cujete, respectivamente. Um desenho de blocos completos randomizados com medições repetidas ao longo do tempo foi aplicado. Resultados: A inclusão de forragem arbustiva não afetou o pH (p>0,05), a degradação da matéria orgânica (OMD) e os ácidos graxos voláteis (AGV). A degradação dos componentes estruturais foi afetada pela inclusão de forragem arbustiva. A concentração de N-NH3 aumentou no CL em comparação ao COL (p<0,05). Em geral, a produção de metano em termos de CH4 (mL/dia), CH4 (mL/g DMi), CH4 (mL/g DMd) e CH4 (mL/gOMd) reduziu (p<0,05) no CL em relação ao COL. Conclusões: Com base nos resultados e considerando as condições experimentais avaliadas, a inclusão de Leucaena leucocephala, Guazuma ulmifolia ou Crescentia cujete em dietas à base de B. pertusa melhora alguns parâmetros de fermentação ruminal e reduz a produção de metano in vitro.

Evaluación de tres especies de Brachiaria spp con pastoreo rotacional para ceba bovina / Evaluation of three species of Brachiaria spp with rotational grazing methods for bovine fattening / Avaliação de três espécies de Brachiaria spp com de pastejo rotativo para engorda bovina

Resume El Objetivo de este trabajo fue evaluar el desempeño de bovinos de carne con pastoreo rotacional en las gramíneas Brachiaria humidicola, B. brizantha cv. marandú y B. decumbens. El ensayo fue realizado en la finca Agua Claras, en el piedemonte del municipio de Tame - Arauca, a 430 msnm, con temperatura media de 28 °C, precipitación anual de 2.890 mm/año y distribución mono modal, brillo solar de 1.800 horas luz/año y humedad relativa de 83%. Fueron utilizados 75 bovinos de 22±2 meses de edad y 300±40 kg de peso, distribuidos en un diseño experimental totalmente al azar con tres tratamientos (métodos de pastoreo) y 25 repeticiones por tratamiento para un total de 75 unidades experimentales, los métodos de pastoreo experimentales fueron 1. método de pastoreo en B. humidicola alojados en 44 potreros de 0,5 ha. 2. método de pastoreo en B. brizantha cv. marandú, alojados en 15 potreros de 1,4 ha., y 3. El método de pastoreo en B. decumbens alojados en potreros de 1, 2 y 2,5 ha, los potreros contaban con acceso a agua a voluntad y suministro de sal mineralizada, los animales fueron pesados en ayuno al inicio y final del ensayo, las variables estudiadas incluían la disponibilidad de forraje, cantidad de materia seca, de proteína cruda, fibra detergente neutra, fibra detergente ácida, actividad ureásica, concentración de los minerales calcio, fosforo y magnesio, la fase experimental tuvo una duración de 80 días previo acostumbramiento de 60 días. En los resultados no hubo diferencia significativa en la ganancia diaria de peso. Los métodos de pastoreo influenciaron (p<0,05) el contenido de proteína cruda, fibra en detergente neutra y fibra en detergente acida, calcio, fósforo, magnesio y la actividad ureásica. En conclusión, el pastoreo rotacional en brachiaria spp no afecta el desempeño de bovinos en ceba.

Abstract This work was aimed at evaluating beef cattle performance regarding rotational grazing on Brachiaria humidicola, B. brizantha cv. Marandu and B. decumbens tropical forage grasses. The experiment was carried out on the Água Claras Farm in the piedmont municipality of Tame in Colombia's Arauca department; the area is 430 masl, has 8°C average temperature, 2,890 mm/year annual rainfall, 1,800 light hours/year monomodal distribution and 83% relative humidity. Seventy-five 22±2 month-old beef cattle, weighing 300±40 kg were used in this study; a completely randomised design was used involving three treatments (grazing methods) and 25 repetitions per treatment (i.e. giving 75 experimental units.) The experimental grazing methods involved cattle grazing on in forty-four 0.5 ha pastures, cattle grazing on d cv. Marandu on fiftee1.4 ha pastures and cattle grazing on B. decumbens in 1, 2 and 2.5 ha pastures. The pastures enabled cattle to have access to water at will and a mineralised salt supply was provided; the cattle were weighed while fasting at the beginning and the end of the trial. Forage availability, the amount of forage dry matter (FDM), crude protein (CP), neutral detergent fibre (NDF), acid-detergent fibre (ADF), urease activity (UA) and calcium, phosphorus and magnesium concentration/intake were the variables studied. The cattle had a 60-day adaptation period, followed by the 80-day experimental phase. The results revealedeefregarding daily weight gain. The grazing methods did influence (p<0.05) CP, NDF, ADF, calcium, phosphorus and magnesium content, as well as UA. Grazing on Brachiaria spp. thus does not affect fattening cattle's performance.

Resumo de corte em pastejo rotacionado em gramíneas Brachiaria humidicola, B. brizantha cv. marandú e B. decumbens. O experimento foi realizado na Fazenda Água Claras, no piedemonte do município de Tame - Arauca, a 430 metros de altitude, temperatura média de 28 ° C, precipitação anual de 2.890 mm / ano e distribuição monomodal , 1.800 horas-luz / ano e umidade relativa de 83%. Foram utilizados 75 bovinos de 22 ± 2 meses de idade e 300 ± 40 kg de peso, distribuídos em delineamento experimental totalmente casualizado com três tratamentos (métodos de pastejo) e 25 repetições por tratamento, totalizando 75 unidades experimentais. 1. método de pastejo em B. humidicola alojada em 44 piquetes de 0,5 ha. 2. método de pastejo em B. brizantha cv. marandú, alojado em 15 piquetes de 1,4 ha., e 3. O método de pastejo em B. decumbens alojado em piquetes de 1, 2 e 2,5 ha, os piquetes tinham acesso à água à vontade e fornecimento de sal mineralizado, os animais eram pesadas em jejum no início e no final do ensaio, as variáveis estudadas incluíram a disponibilidade de forragem, quantidade de matéria seca, proteína bruta, fibra em detergente neutro, fibra em detergente ácido, atividade da urease, concentração de minerais de cálcio, fósforo e magnésio, a fase experimental durou 80 dias após a adapatação de 60 dias. Nos resultados não houve diferença significativa no ganho de peso diário. Os métodos de pastejo influenciaram (p<0,05) o teor de proteína bruta, fibra em detergente neutro e fibra em detergente ácido, cálcio, fósforo, magnésio e atividade da urease. Em conclusão, o pastejo rotacionado em Brachiaria spp não afeta o desempenho de bovinos em engorda.

Effects of the submerged macrophyte Ceratophyllum demersum (Ceratophyllaceae) and the cladoceran Moina micrura (Cladocera: Moinidae) on microalgal interactions / Efectos de un macrófito sumergido Ceratophyllum demersum (Ceratophyllaceae) y un cladócero Moina micrura (Cladocera: Moinidae) sobre las interacciones de microalgas

Abstract Introduction: Cyanobacterial blooms in tropical water bodies are increasingly common, because of eutrophication and rising temperatures. Consequently, many freshwater systems are affected, by reducing water quality, biodiversity, and ecosystem services. With the increased frequency of harmful algal blooms, the development of biological tools to improve water quality is an urgent issue. Objective: To evaluate the effects of a submerged macrophyte and a cladoceran on the microcystin-producing cyanobacteria Microcystis aeruginosa (NPLJ-4) and the chlorophyte Raphidocelis subcapitata (BMIUFRPE-02) in mixed cultures. Methods: Two parallel experiments were carried out for ten days to evaluate the effects of the submerged macrophyte Ceratophyllum demersum and the cladoceran Moina micrura on microalgal interactions. Microalgal strains were cultivated in the ASM1 culture medium, under controlled laboratory conditions. The first experiment presented four treatments: M (C. demersum), Z (M. micrura), MZ (C. demersum and M. micrura), and C (control). Meanwhile, the second experiment consisted of five treatments, in which the microalgae were cultivated together at different Microcystis:Raphidocelis ratios: 1:0, 3:1, 1:1, 1:3, and 0:1. Biomass and growth rates of the strains were evaluated every two days, which were statistically treated with three-way or two-way repeated-measures ANOVA. Results: In the first experiment, M. aeruginosa was significantly inhibited in M and MZ treatments from the second day, and Z from the fourth, while R. subcapitata showed no reduction in its biomass in any treatment. On the other hand, R. subcapitata was stimulated from the eighth and tenth days in M treatment and only on the eighth day in Z treatment. In the second experiment, M. aeruginosa was significantly inhibited when cultivated with R. subcapitata in low ratios (Microcystis:Raphidocelis ratio of 1:3) throughout the experiment, while the chlorophyte was stimulated in that treatment. Conclusions: The coexistence of a cyanobacterium with a green alga did not alter the main negative response of M. aeruginosa to the submerged macrophyte and zooplankton but stimulated the green alga. Accordingly, the introduction of submerged macrophytes and cladocerans already adapted to eutrophic conditions, both isolated and combined, proved to be a good method to control cyanobacterial blooms without negatively affecting other coexisting phytoplankton species.

Resumen Introducción: Las proliferaciones de cianobacterias en los cuerpos de agua tropicales son cada vez más comunes, debido a la eutrofización y al aumento de las temperaturas. En consecuencia, muchos sistemas de agua dulce se ven afectados por la reducción de la calidad del agua, la biodiversidad y los servicios de los ecosistemas. Con el aumento de la frecuencia de la proliferación de algas nocivas, el desarrollo de herramientas biológicas para mejorar la calidad del agua es urgente. Objetivo: Evaluar los efectos de una macrófita sumergida y un cladócero sobre la cianobacteria productora de microcistina llamada Microcystis aeruginosa (NPLJ-4) y la clorofita Raphidocelis subcapitata (BMIUFRPE-02) en cultivos mixtos. Métodos: Se realizaron dos experimentos paralelos durante diez días para evaluar los efectos de la macrófita sumergida Ceratophyllum demersum y el cladócero Moina micrura sobre las interacciones microalgales. Se cultivaron cepas de microalgas en el medio de cultivo ASM1, en condiciones controladas de laboratorio. El primer experimento presentó cuatro tratamientos: M (C. demersum), Z (M. micrura), MZ (C. demersum y M. micrura) y C (control). El segundo experimento consistió en cinco tratamientos, en el que las microalgas se cultivaron juntas en diferentes proporciones de Microcystis:Raphidocelis: 1:0, 3:1, 1:1, 1:3 y 0:1. La biomasa y las tasas de crecimiento de las cepas se evaluaron cada dos días, y se trataron estadísticamente con ANOVA de medidas repetidas de dos o tres factores. Resultados: En el primer experimento, M. aeruginosa se inhibió significativamente en los tratamientos M y MZ a partir del segundo día, y en Z a partir del cuarto, mientras que R. subcapitata no mostró reducción de su biomasa en ningún tratamiento. Por otro lado, R. subcapitata fue estimulada a partir del octavo y décimo día en el tratamiento M y solo en el octavo día en el tratamiento Z. En el segundo experimento, M. aeruginosa se inhibió significativamente cuando se cultivó con R. subcapitata en proporciones bajas (proporción de Microcystis:Raphidocelis de 1:3) durante todo el experimento, mientras que la clorófita se estimuló en ese tratamiento. Conclusiones: La coexistencia de una cianobacteria con un alga verde no alteró la principal respuesta negativa de M. aeruginosa a la macrófita sumergida y al zooplancton, sino que estimuló al alga verde. En consecuencia, la introducción de macrófitos y cladóceros sumergidos ya adaptados a las condiciones eutróficas, tanto aislados como combinados, resultó ser un buen método para controlar las proliferaciones de cianobacterias sin afectar negativamente a otras especies de fitoplancton coexistentes.

Efecto de la edad de rebrote sobre el desarrollo morfológico y la composición química del pasto kikuyo (Cenchrus clandestinus) en el trópico alto colombiano / Effect of regrowth period on morphological development and chemical composition of kikuyu grass (Cenchrus clandestinus) in Colombian's highlands / Efeito da idade de rebrota no desenvolvimento morfológico e composição química do capim kikuyo (Cenchrus clandestinus) nos altos trópicos colombianos

Resumen El conocimiento de la dinámica composicional y de crecimiento del pasto kikuyo (Cenchrus clandestinus) permite establecer estrategias de manejo para maximizar la producción animal. El objetivo de este trabajo fue evaluar el efecto de la edad de rebrote sobre la variables morfológicas, composicionales y productivas del pasto kikuyo en las cuencas lecheras Alto Chicamocha (AC), Sabana de Bogotá (SB) y Ubaté-Chiquinquirá (UC) durante las épocas de lluvia y sequía. Se seleccionaron dos fincas por cuenca y se evaluó el crecimiento del forraje a través de un muestreo longitudinal del kikuyo desde el día 7 al 70 de rebrote. En cada muestreo se determinó la altura de la planta, la longitud y el ancho de las hojas y el ancho del estolón. Además, se midió el rendimiento y la composición química del forraje. Los datos se analizaron como un diseño completo al azar con medidas repetidas (10 etapas de rebrote). La altura de la planta fue superior (p<0,05) en época de lluvias a partir del día 14, 42 y 49 en AC, SB y UC, respectivamente. El número de hojas aumentó con la edad de rebrote (p<0,05), independiente de la época en SB y UC. El rendimiento de forraje seco fue mayor (p<0,05) en la época de lluvias, desde el día 42 en AC y UC y desde el 49 en SB. La proteína cruda disminuyó (p<0,05) con la edad de la planta y presentó los mayores valores en la época de lluvias en las cuencas AC y SB. El rendimiento y la composición química del kikuyo fue afectada por la edad de rebrote y la época de corte, lo cual hace necesario ajustar los esquemas de alimentación de acuerdo con las características del forraje y el requerimiento nutricional de los animales en cada región.

Abstract Compositional and growth dynamics knowledge of Kikuyu grass (Cenchrus clandestinus) allows establishing strategies to maximize animal performance. The objective of this work was to evaluate the effect of the regrowth period on morphological, compositional, and productive variables of Kikuyu grass in Alto Chicamocha (AC), Bogotá savanna (SB) and Ubaté-Chiquinquirá (UC) dairying regions, during rainy and dry seasons. Two farms were selected per region and the forage growth was evaluated from 7 to 70 regrowth day. Plant height, leaf length and width, and stolon width were determined. Also, biomass production and chemical composition were defined. The data were analyzed as a randomized complete design with repeated measurements (10 regrowth stages). Plant height was higher (p <0.05) during the rainy season from day 14, 42, and 49 in AC, SB, and UC, respectively. Leaf number increased (p<0.05) during the forage regrowth, independently of the season in SB and UC. Dry matter production was higher (p <0.05) in the rainy season, from day 42 in AC and UC, and 49 in SB. Crude protein decreased (p <0.05) during the growth period and presented high values in the rainy season in AC and SB regions. The production and chemical composition of the Kikuyu grass was affected by regrowth age and season, which requires adjusting the feeding programs related to forage characteristics and animal nutrient requirements in each region.

Resumo O conhecimento da composição e da dinâmica de crescimento do capimkikuyo (Cenchrus clandestinus) permite estabelecer estratégias de manejo para maximizar a produção animal. O objetivo deste trabalho foi avaliar o efeito da idade de rebrota nas variáveis morfológicas, composicionais e produtivas do capim-kikuyo nas bacias leiteiras de Alto Chicamocha (AC), Sabana de Bogotá (SB) e Ubaté-Chiquinquirá (UC) durante a épocas de chuva e seca. Duas fazendas por bacia foram selecionadas e o crescimento da forragem foi avaliado por meio de uma amostragem longitudinal do kikuyu do 7º ao 70º dia de rebrota. Em cada amostragem, foram determinados a altura da planta, o comprimento e a largura das folhas e a largura do estolão. Além disso, foram medidos o rendimento e a composição química da forragem. Os dados foram analisados em um delineamento inteiramente casualizado com medidas repetidas (10 estágios de rebrota). A altura da planta foi maior (p <0,05) no período chuvoso a partir dos dias 14, 42 e 49 no AC, SB e UC, respectivamente. O número de folhas aumentou com a idade de rebrota (p <0,05), independente da estação do ano em SB e UC. A produção de forragem seca foi maior (p <0,05) no período chuvoso, a partir do dia 42 no AC e UC e a partir do dia 49 no SB. A proteína bruta diminuiu (p <0,05) com a idade da.planta e apresentou os maiores valores no período chuvoso nas bacias AC e SB. O rendimento e a composição química do kikuyo foram afetados pela idade de rebrota e época de corte, o que torna necessário ajustar os esquemas alimentares de acordo com as características da forragem e as exigências nutricionais dos animais de cada região.

Comportamiento ingestivo diurno y desempeño productivo de corderos suplementados con semilla de algodón y maíz molido / Daytime Ingestion Behavior and Performance in the Production of Lambs Supplemented with Cotton Seed and Ground Corn (GC) / Comportamento ingestivo diurno e desempenho produtivo de cordeiros suplementados com semente de algodão e molho moído

Resumen El estudio del comportamiento ingestivo es importante para conocer el desempeño de los animales y es especialmente imprescindible cuando se evalúan diferentes regímenes de alimentación. El objetivo del presente estudio fue evaluar la conducta ingestiva diurna y la respuesta productiva de corderos criollos suplementados con semilla de algodón (SA) y maíz molido (MM). Se emplearon 16 corderos criollos machos enteros con peso inicial de 16 ± 2 kg, los cuales fueron distribuidos aleatoriamente en cuatro tratamientos experimentales consistentes en: T0 = Pastoreo, T1 = Pastoreo + 25 % SA + 75 % MM, T2 = Pastoreo + 50 SA + 50 % MM y T3 = Pastoreo + 75% SA + 25 % MM. En los forrajes se determinó la composición nutricional y en los animales el consumo de materia seca a través de marcadores externos e internos, el comportamiento ingestivo y el desempeño productivo. El consumo de materia seca total presentó diferencias estadísticas (p < 0.05), con menor consumo para los animales del tratamiento control. Asimismo, se detectaron diferencias estadísticas (p < 0.05) entre los tratamientos para las actividades de pastoreo, rumia, consumo de agua y caminata para las variables número de bocados por minuto y total. El peso final y la ganancia de peso obtenida por los animales que recibieron suplementación fueron superiores en un 28.4 % y 50.3 %, respectivamente. La suplementación con SA y MM promovió un mayor consumo de nutrientes y, en consecuencia, mejoró el desempeño productivo de los corderos.

Abstract The study of the ingestion behavior is important to know the animal production performance and is a must when evaluating different feeding regimes. This work aims to evaluate the daytime ingestion behavior and the productive answer in criollo lambs receiving supplement with cotton seeds (CS) and ground corn (GC). Sixteen complete male criollo lambs were used having a starting weight of 16 ± 2 Kg. They were distributed randomly into four experimental treatments consisting in: T0 = shepherding, T1 = shepherding + 25% CS + 75% GC, T2 = shepherding + 50% CS + 50% GC, and T3 = shepherding + 75% CS + 25% GC. Using both external and internal markers, the nutritional composition of the forages and the dry mass consumption in the animals were determined, i.e., the ingestion behavior and the productive performance. The total dry mass consumption showed statistical differences (p < 0.05), with lower consumption among the control animals. Likewise, statistical differences were detected (p < 0.05) between the treatments for shepherding activities, cud, water consumption and walking regarding variables like mouthfuls per minute and total ingestion. The final weight and the weight gain in the animals receiving supplements were higher in 28.4 % and 50.3 %, respectively. The CS and GC supplements led to a greater consumption of nutrients and, therefore, improved the ovine production performance.

Resumo O estudo do comportamento ingestivo é importante para conhecer o desempenho dos animais e é especialmente essencial quando se avaliar diferentes regimes alimentares. O objetivo do presente estudo foi avaliar a conduta ingestiva diurna e a resposta produtiva de cordeiros crioulos suplementados com semente de algodão (SA) e molho moído (MM). Foram usados 16 cordeiros crioulos machos inteiros com peso inicial de 16 ± 2 kg, os quais foram distribuídos aleatoriamente em quatro tratamentos experimentais consistentes em: T0 = Pastejo, T1 = Pastejo + 25% SA + 75% MM, T2 = Pastejo + 50% SA + 50% MM e T3 = Pastejo + 75% SA + 25% MM. Nas forrageiras determinou-se a composição nutricional e nos animais o consumo de matéria seca através de marcadores externos e internos, o comportamento ingestivo e o desempenho produtivo. O consumo total de matéria seca apresentou diferenças estatísticas (p < 0.05), com menor consumo nos animais do tratamento controle. Mesmo, detectaram-se diferenças estatísticas (p < 0.05) entre os tratamentos para as atividades de pastoreio, ruminação, consumo de agua e caminhada para a variável número de lanches por minuto e total. O peso final e o ganho de peso obtido pelos animais que receberam suplementação foram superiores em 28.4% e 50.3%, respectivamente. A suplementação com SA e MM promoveu maior consumo de nutrientes e consequentemente, melhorou o desempenho produtivo dos cordeiros.

Estimación del balance de metionina y lisina metabolizable en vacas de leche en pastoreo / Estimation of the balance of metabolizable lysine and methionine for grazing dairy cows

RESUMEN Objetivos. El objetivo de este trabajo fue estimar en vacas en pastoreo, tanto la reproducibilidad como la precisión del balance de metionina (Met) y lisina (Lis), aminoácidos más limitantes en la producción de leche, cuando se comparan los valores predichos versus los valores observados. Materiales y métodos. Se usaron 12 vacas durante un periodo de 20 días. Control: animales pastoreando y suplementados con alimento balanceado; Met-Lis: igual al control y el suplemento se ajustó con Lis y Met protegida. Para los valores predichos para la suplementación de Met y Lis, se tuvo en cuenta el promedio del consumo de materia seca (CMS) del hato, basado en la oferta y el consumo de pasto y los valores de proteína microbiana. Los valores observados se determinaron con base en el CMS individual usando marcadores externos e internos, además, la producción individual de proteína microbiana. Se realizó una prueba de t pareada y un modelo de predicción para determinar la eficiencia fue determinado usando el error cuadrático medio de predicción (ECMP) y el coeficiente de concordancia (CCC). Resultados. Se encontraron diferencias significativas entre la suplementación y el balance de Met y Lis, entre los valores predichos y los valores observados para el CMS del forraje, la digestibilidad de la proteína microbiana, la producción de proteína microbiana, el suministro y el balance de Lis y Met. El CCC del balance de Lis y Met fue bajo (0.10), el ECMP fue alto, excepto para el CMS, que tuvo una concordancia moderada (0.63) y un bajo ECMP(4.42). Conclusiones. Estos resultados demuestran la falta de precisión de las herramientas que se usan para balancear las raciones individuales de vacas en pastoreo, ya que subestiman la suplementación y el balance de los aminoácidos.

ABSTRACT Objective. The aim of this study was to determine in grazing cows, the reproducibility and accuracy of the balance between predicted values, when compared with the observed values for the most limiting amino acids in milk protein synthesis, the methionine (Met) and Lysine (Lys). Materials and methods. Twelve lactating cows were used for a 20-day experimental period. Control: animals grazing and supplemented with balanced food; Met-Lys: same as control and supplemented with adjusted rumen protected Met and Lys. For Met and Lys supply predicted values, it was taking in account the average of the dry matter intake (DMI) of the herd, based in offer and foraging control and values of microbial protein data. Observed values were determined based in the individual DMI intake, using external and internal markers and the individual microbial protein production. A t-paired-sample test was performed and the efficiency of the model's prediction was determined using the mean square prediction error (MSPE) and the concordance coefficient (CCC). Results. Significant differences were found between the predicted and observed values for DMI forage, digestible microbial protein and microbial protein production, supply and the balance of Lys and Met. The CCC for Lys and Met balance were low (0.10), the MSPE was high except for the total DMI with a moderate concordance (0.63) and low MSPE (4.42). Conclusions. These results indicate a lack of precision of the tools, which underestimates the supply and balance of amino acids in individual grazing cows.

Productividad y eficiencia de ganaderías lecheras especializadas en el Valle del Cauca (Colombia) / Productivity and efficiency of specialized dairy farms in the Valley of Cauca (Colombia)

RESUMEN El estudio caracterizó la productividad y eficiencia de 52 lecherías especializadas en el Valle del Cauca (Colombia). Se encontró que en promedio los predios fueron de 41,3 hectáreas y 133 animales, respectivamente. El cuadro reproductivo supuso: días abiertos (97-225), servicios por concepción (1,4-5,4) e intervalo entre partos en días (IPP) (382-520). Las pasturas básicas fueron estrella C.plestostachyusy guinea P. maximun, con rendimientos anuales de 18,6 Ton MS.ha-1, un consumo de MS de pasto por vaca de 9,44 kg y un total de 12,2 kg incluyendo los concentrados. Se determinó una relación lineal Y=Producción de leche (kg.día) = 5,6639 + 0,5513 X, R2=0,77, donde solo con pastoreo las vacas producen 5,66 l.vaca-1día y cada kg de concentrado adicional incrementó en 0. 5513 l.vaca-1día. Las vacas productivas fueron 84,8 vacas.hato-1 con 11,9 l.vaca-1día. La carga animal por finca fue 3,2 UGG.ha-1 con una productividad de 7965 litros.ha-1 año; donde por cada UGG que ingresa al sistema se mejora en 2816 l.ha-1año. De 34 variables analizadas las que determinaron la productividad de las fincas fueron: litros totales por lactancia (33,3%), vacas en ordeño (17,7%), hectáreas productivas (11,0%), 1. ha-1 año (7,8%), kilogramos de concentrado (5,3%) y MS del pasto en kg.ha-1(4,5%). Se identificaron cuatro sistemas de producción con base en pastoreo que dependen críticamente de los suplementos concentrados con asimetrías en componentes raciales que afectan negativamente la productividad.

ABSTRACT The study characterizes productivity and efficiency of 52 specialized dairies in Valle del Cauca (Colombia). It was found that, on average, the farms were 41.3 hectares and 133 animals respectively. The reproductive status was: open days (97-225), services by conception (1.4- 5.4), in interval between births in days (IPP) (382-520). The basic pastures were Stargrass C. plestostachyus and Guinea P. maximun, with yields per year of 18.6 DM.Ton.ha-1 year and dry matter intake (DMI) of cow pasture of 9.44 kg and total of 12.2 kg including supplements. A linear relationship was determined: Y = Milk yield (kg.day) = 5.6639 + 0.5513 X, R2 = 0.77, where with only grazing, cows produce 5.66 l.cow-1day and each kg of additional supplements increases by 0.5513 l.cow-1 day. The productive cows were 84.8 farm-1 cows with 11.9 l.cow-1day. The animal load per farm was 3.2 large livestock units (LLU)) per ha with a productivity of 7965 liters.ha-1year; where for each LLU that enters the system, is improved by 2816 l.Ha-1year. Of the 34 variables analyzed, those that determined the productivity of the dairies were: total litters per lactation (33.3%), milking cows (17.7%), Ha productive (11.0%), liters per Ha year (7.8%), supplements (5.3%) and pasture production DM kg.Ha-1 (4.5%). Four grazing-based production systems were identified that depend critically on concentrated supplements with severe asymmetries in racial components that negatively affect productivity.

Characterization of the dual-purpose bovine system in northwest Mexico: producers, resources and problematic / Caracterización del sistema bovino doble propósito en el noroeste de México: productores, recursos y problemática

ABSTRACT Objective. The present study consisted in characterizing the dual-purpose cattle system and the factors that limit the productivity of this system in northern Sinaloa, Mexico. Material and Methods. We applied a survey to 214 producers and we analyzed the data with analyses of factors and conglomerate. Results. The analysis of factors identified five components: resources level, productivity, technological level, livestock management and socioeconomic aspects and these components explain 70.5% of the total cumulative variance. The conglomerate analysis identified three clusters: cluster 1 (52.5%, 105 producers) defined as a system focused on milk production. Cluster 2 (41.5%, 83 producers) defined as traditional farms of meat and milk production and Cluster 3 (6%; 12 producers) defined as farms focused on meat production. The three clusters present similar livestock management (p>0.05). The producers base their feeding strategies on grazing rangeland with seasonal supplementation of silage and commercial concentrate; however, each cluster differed (p<0.05) in the level of use of these resources. Conclusion. The present study identifies, in the dual-purpose cattle system in northern Sinaloa, low milk yield and limit forage resources as main problems that results in multiple strategies that the producers follow to solve it. The social aspects and the level of resources (land, animals, machinery and equipment and infrastructure) play an important role therefore they must be considered independently to help to define differentiated technological strategies.

RESUMEN Objetivo. El estudio consistió en realizar una caracterización del sistema bovinos de doble propósito y los factores que limitan la productividad de este sistema en el norte de Sinaloa, México. Materiales y Métodos. Se aplicó una encuesta a 214 productores y la información se analizó mediante un análisis de factores y de conglomerados. Resultados. El análisis de factores identificó cinco componentes; nivel de recursos, productividad, nivel tecnológico, manejo del ganado y aspectos socioeconómicos. Estos cinco factores explican el 70.5% del total de la varianza acumulada. El análisis de conglomerados identificó tres clústers o grupos: Clúster 1 (105 productores, 52.5%) se definió como sistema enfocado a la producción de leche, Clúster 2 (83 productores, 41.5%) definido como explotaciones tradicionales productoras de carne y leche y Clúster 3 (12 productores, 6%) definido como explotaciones enfocadas la producción de carne. Los tres clústers presentan un manejo similar del ganado (p>0.05). Los productores de los clústers basan sus estrategias de alimentación del ganado en el pastoreo con suplementación estacional de ensilaje y concentrado comercial, no obstante, cada clúster tiene diferentes (p<0.05) niveles de uso de recursos. Conclusiones. El presente estudio identifico, en los sistemas bovino de doble propósito del norte de Sinaloa, como problemas principales una baja producción de leche y escasez de forraje que se manifiesta en múltiples estrategias que siguen los productores para resolverla. Los aspectos sociales y el nivel de recursos (tierra, animales, maquinaria, equipo e infraestructura) juegan un papel importante por lo que deben de ser considerados de manera independiente para la definición de estrategias tecnológicas diferenciadas.

Etnobotánica y territorio en el pastal de Mulluri (Norte de Chile): las enseñanzas del pastoreo aymara / Ethnobotany and territory in Mulluri ́s pasture (Northern Chile): the teachings of aymara pastoralism

A partir de un trabajo etnográfico centrado en las memorias territoriales de la comunidad aymara de Mulluri (Región de Arica y Parinacota, Norte de Chile) se propone que el pastoreo, un modo de vida tradicional de origen prehispánico, tiñe fuertemente la percepción del espacio de sus habitantes y la clasificación que elaboran en relación al mundo de las plantas. Se realizaron entrevistas y observación participante guiadas por un enfoque etnobotánico y espacial orientado a relevar sistemas clasificatorios y manejos ganaderos. Se analizaron las categorías "cordillera", "costa" y "valle" usadas por los comuneros para nombrar las distintas regiones geográficas o pisos ecológicos de la gradiente occidental andina, definidas por ellos a partir de variables climáticas, ecológicas, simbólicas y prácticas. Simultáneamente, al interior de estas macro regiones los comuneros reconocen zonas específicas según las asociaciones botánicas existentes. Éstas fueron conceptualizadas por los comuneros como "etapas de pasto", coincidiendo con los pisos vegetacionales definidos por la botánica. En relación a las plantas, se registraron categorías genéricas de acuerdo a sus formas de crecimiento ("pastos del champeal", "pajas" o wichu, t ́olas, "montes", "pastos de lluvia" y otros) así como nomenclaturas específicas por especie.

From an ethnographic work focused on the territorial memories of the Aymara community of Mulluri (Region of Arica and Parinacota, Northern Chile) it is proposed that pastoralism, as a traditional way of life of prehispanic origin, strongly colors the perception and systematic of space and of the world of plants. Interviews and participant observation were conducted guided by an ethnobotanical and spatial approach aimed at relieving classification systems and livestock management. The categories "cordillera", "costa" and "valle" used by the comuneros were analyzed to name the different geographical regions or ecological zones of the western Andean gradient, which are defined by them from climatic, ecological, symbolic and practice variables. Simultaneously, within these macro-regions the comuneros recognize specific zones according to the existing botanical associations. These were conceptualized by the comuneros as "pasture stages", coinciding fully with the vegetational areas defined by botany. In relation to the plants, generic categories were registered according to their growth forms ("pastos del champeal", "pajas" o wichu, t ́olas, "montes", "pastos de lluvia", among others) as well as specific nomenclatures by species.

Determinación de la curva de crecimiento en ovinos criollos de pelo, mediante la utilización del modelo gompertz, en el trópico bajo colombiano / Growth curve determination for creole hair sheep using the gompertz model in the low colombian tropic

En Colombia existe una diversidad de ovinos, denominados ovinos criollos, resultado del cruce de diferentes razas, desde la época de la colonización y que se adaptaron a diferentes regiones del país. En el caso particular de este estudio, se hace referencia a los ovinos criollos de pelo, que se acomodaron a las condiciones biogeográficas de la Costa Caribe colombiana. Estos animales, por su adaptabilidad, han tenido un importante papel en el desarrollo de la ovinocultura del país; sin embargo, es muy poca la información que se tiene, a nivel nacional, sobre las características crecimiento de la raza o especie. El objetivo del presente estudio fue determinar la curva de crecimiento de dos poblaciones de ovinos criollos del trópico bajo colombiano, a través del uso del modelo no lineal Gompertz. Se utilizaron 55 animales, con 13 pesajes cada uno, perteneciente a dos sistemas de producción del departamento de Córdoba, Colombia. Se realizó un ajuste del modelo, mediante el procedimiento NLIN de Statistical Analysis Software (SAS), para la estimación de los parámetros del modelo. Se estimó β0, β1 y β2, cuyos valores fueron 25,97 ± 9,3, 2,1 ± 0,5 y 0,010 ± 0,004, respectivamente. Los estimados de madurez a los 4 y 6 meses fueron de 55,8 y 70,6%, respectivamente, y la edad al 75 de madurez fue de 7,0 meses y al 95% de madurez, de 13,1 meses. El modelo de Gompertz permitió describir el crecimiento de ovinos criollos, en condiciones de pastoreo, en el trópico bajo.

The Colombian Creole sheep has an important role in the development of sheep farming in the country, as this breed is distributed in most of the territory, being animals with significant features that make it widely used in farms with different productive purposes. To assess growth characteristics in animals have been used mathematical models, which describe the relationship between the age of the animal, its rate of growth and maturity. These models are equations that allow the construction of continuous curves of one biological variable according to another. This study aimed to determine the growth curve of two populations of crossbred sheep through the use of nonlinear Gompertz model. 55 animals with 13 measures of weight each were used, pertaining to two production systems of the department of Córdoba, Colombia. Estimaste for β0, β1 y β2 were 25.97 ± 9.3, 2.1 ± 0.5 and 0.010 ± 0.004, respectively. Estimates of maturity at 4 and 6 months were 55.8 and 70.6%, respectively; age 75% of maturity was of 7.0 months and at 95% of maturity was of 13.1 months. Gompertz model allowed describing the growth of creole sheep in conditions of grazing in the low tropics.