19 research outputs found

    Rich Information in the Acoustic Signals from Feeding and Grazing in Ruminants

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    Because of their impact on productivity and the environment, feeding behaviour, ingestion and rumination are critical to understand intake in grazing ruminants. Many systems, mainly mechanical, have been developed to measure ingestive behaviour. However, these systems have problems, including mechanical failure and the inability to distinguish between the complex jaw movements of prehension and ingestion (Laca et al., 1994). The sounds generated by these behaviours are rich in information that holds potential not only to distinguish and count behaviours, but also identify aspects of the nature of the foods ingested

    The Sound of Chewing

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    Acoustic biotelemetry has been proposed as a way to count ingestive bites and chews of grazing animals. Recent work has indicated the possibility that detailed analysis of \u27sounds of chewing\u27 contains information about other characteristics of the ingestive process that can be used to study grazing behaviour of free ranging animals (Laca & Wallis DeVries, 2000), or to monitor stall-fed animals in more detail

    Resource heterogeneity and foraging behaviour of cattle across spatial scales

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    BackgroundUnderstanding the mechanisms that influence grazing selectivity in patchy environments is vital to promote sustainable production and conservation of cultivated and natural grasslands. To better understand how patch size and spatial dynamics influence selectivity in cattle, we examined grazing selectivity under 9 different treatments by offering alfalfa and fescue in patches of 3 sizes spaced with 1, 4, and 8 m between patches along an alley. We hypothesized that (1) selectivity is driven by preference for the forage species that maximizes forage intake over feeding scales ranging from single bites to patches along grazing paths, (2) that increasing patch size enhances selectivity for the preferred species, and that (3) increasing distances between patches restricts selectivity because of the aggregation of scale-specific behaviours across foraging scales.ResultsCows preferred and selected alfalfa, the species that yielded greater short-term intake rates (P < 0.0001) and greater daily intake potential. Selectivity was not affected by patch arrangement, but it was scale dependent. Selectivity tended to emerge at the scale of feeding stations and became strongly significant at the bite scale, because of differences in bite mass between plant species. Greater distance between patches resulted in longer patch residence time and faster speed of travel but lower overall intake rate, consistent with maximization of intake rate. Larger patches resulted in greater residence time and higher intake rate.ConclusionWe conclude that patch size and spacing affect components of intake rate and, to a lesser extent, the selectivity of livestock at lower hierarchies of the grazing process, particularly by enticing livestock to make more even use of the available species as patches are spaced further apart. Thus, modifications in the spatial pattern of plant patches along with reductions in the temporal and spatial allocation of grazing may offer opportunities to improve uniformity of grazing by livestock and help sustain biodiversity and stability of plant communities

    The Proportion of the Ungrazed Area of the Pasture (PUP) Determines When Forage Intake and Diet Quality Decline in Grazing Systems

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    Grazing management has to deal with the spatial and temporal heterogeneity of pastures. In this context it is desirable to have a grazing management strategy that can be applied in a wide range of pasture conditions to control daily forage intake, diet quality and thus, animal performance. Sward height has been extensively studied and has been found not to be universally applicable to control the animal response as its relationship with intake changes with sward structure (Prache and Peyraud, 2001; Sollenberger and Burns, 2001) . Selective grazing is a universal phenomenon where, independently of pasture condition, cattle prefer the more nutritious and easily ingested top stratum of the pasture before consuming the deeper strata that impose a lower diet quality and greater restrictions on selective grazing. This study tested the hypothesis that forage intake and diet quality significantly decreases when the top selected stratum is removed across the entire area of the pasture (i.e. the proportion of pasture ungrazed)

    Handling Time and Bite Mass Mechanisms in Large Herbivores: Contrasts between Sward Structure and Grazing Methods

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    Grazing is a time-dependent process where jaw movements of prehension, handling and chewing compete with them (Laca et al. 1994; Ungar et al. 2006). The grazing efficiency is dependent of bite mass and time per bite. Bite mass has been related to sward structure by forage height, structural components (Cangiano et al. 2002). In rotational stocking this effect becomes more pronounced, especially under high grazing down levels. Consequently, there is a progressive reduction in short-term intake rate (Fonseca et al. in press). New management targets should be proposed based on the predominant influence of sward structure in short-term intake rate by grazing animals (Carvalho et al. 2007). We hypothesise that intake potential of animals grazing tropical pastures will be reduced due to higher constraints in bite formation when compared to temperate pastures. This study aimed to investigate the intake process of heifers under the influence of different sward heights and grazing down levels in two contrasting - tropical and temperate - forage species

    Uso del sonido para discriminar las especies consumidas por vacas

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    El objetivo de este trabajo fue evaluar el potencial uso del sonido para determinar la composición de la dieta de vacas en pastoreo. La hipótesis fue que es posible identificar con precisión las diferentes especies forrajeras consumidas a través del análisis del espectro y otras variables complementarias de los sonidos producidos durante la ingestión. Se utilizaron registros de sonido de cuatro vacas Holando Argentino (620±18,3 kg) pastoreando cuatro especies forrajeras: alfalfa (Medicago sativa), trébol blanco (Trifolium repens), avena (Avena sativa) y festuca alta (Festuca arundinacea) en estado vegetativo. Las especies se ofrecieron en grupos de macetas, de a una especie por vez. Las sesiones de pastoreo se realizaron en forma individual y ordenadas al azar durante seis días consecutivos.Fil: Galli, J.. Universidad Nacional de Rosario; ArgentinaFil: Milone, Diego Humberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigación en Señales, Sistemas e Inteligencia Computacional. Universidad Nacional del Litoral. Facultad de Ingeniería y Ciencias Hídricas. Instituto de Investigación en Señales, Sistemas e Inteligencia Computacional; ArgentinaFil: Cangiano, Carlos Alberto. Universidad Nacional del Litoral; ArgentinaFil: Pece, Mariela Alejandra. Universidad Nacional del Litoral; ArgentinaFil: Larripa, M.. Universidad Nacional del Litoral; ArgentinaFil: Rufiner, Hugo Leonardo. Universidad Nacional del Litoral; ArgentinaFil: Laca, E. A.. University of California; Estados Unido

    Uso del sonido para discriminar los eventos masticatorios de vacas en pastoreo.

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    El objetivo de este trabajo fue obtener información básica para evaluar el potencial uso del sonido para discriminar los eventos masticatorios de vacas en pastoreo. La hipótesis fue que es posible identificar con precisión los diferentes tipos de eventos masticatorios a través del análisis del espectro y otras variables características de los sonidos. Se registraron los sonidos ingestivos cuatro vacas Holando Argentino (596±26,2 kg) pastoreando alfalfa (Medicago sativa) o raigrás anual (Lolium multiflorum) en lotes separados y sembrados en forma convencional.Fil: Galli, Julio Ricardo. Universidad Nacional de Rosario; ArgentinaFil: Milone, Diego Humberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigación en Señales, Sistemas e Inteligencia Computacional. Universidad Nacional del Litoral. Facultad de Ingeniería y Ciencias Hídricas. Instituto de Investigación en Señales, Sistemas e Inteligencia Computacional; ArgentinaFil: Cangiano, Carlos Alberto. Instituto Nacional de Tecnologia Agropecuaria. Centro Regional Buenos Aires Sur. Estacion Experimental Agropecuaria Balcarce. Agencia de Extension Rural Balcarce.; ArgentinaFil: Pece, Mariela Alejandra. Instituto Nacional de Tecnologia Agropecuaria. Centro Regional Buenos Aires Sur. Estacion Experimental Agropecuaria Balcarce. Agencia de Extension Rural Balcarce.; ArgentinaFil: Larripa, M.. Instituto Nacional de Tecnologia Agropecuaria. Centro Regional Buenos Aires Sur. Estacion Experimental Agropecuaria Balcarce. Agencia de Extension Rural Balcarce.; ArgentinaFil: Martínez, C.. Instituto Nacional de Tecnologia Agropecuaria. Centro Regional Buenos Aires Sur. Estacion Experimental Agropecuaria Balcarce. Agencia de Extension Rural Balcarce.; ArgentinaFil: Laca, E. A.. University of California; Estados Unido

    Atrasentan and renal events in patients with type 2 diabetes and chronic kidney disease (SONAR): a double-blind, randomised, placebo-controlled trial

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    Background: Short-term treatment for people with type 2 diabetes using a low dose of the selective endothelin A receptor antagonist atrasentan reduces albuminuria without causing significant sodium retention. We report the long-term effects of treatment with atrasentan on major renal outcomes. Methods: We did this double-blind, randomised, placebo-controlled trial at 689 sites in 41 countries. We enrolled adults aged 18–85 years with type 2 diabetes, estimated glomerular filtration rate (eGFR)25–75 mL/min per 1·73 m 2 of body surface area, and a urine albumin-to-creatinine ratio (UACR)of 300–5000 mg/g who had received maximum labelled or tolerated renin–angiotensin system inhibition for at least 4 weeks. Participants were given atrasentan 0·75 mg orally daily during an enrichment period before random group assignment. Those with a UACR decrease of at least 30% with no substantial fluid retention during the enrichment period (responders)were included in the double-blind treatment period. Responders were randomly assigned to receive either atrasentan 0·75 mg orally daily or placebo. All patients and investigators were masked to treatment assignment. The primary endpoint was a composite of doubling of serum creatinine (sustained for ≥30 days)or end-stage kidney disease (eGFR <15 mL/min per 1·73 m 2 sustained for ≥90 days, chronic dialysis for ≥90 days, kidney transplantation, or death from kidney failure)in the intention-to-treat population of all responders. Safety was assessed in all patients who received at least one dose of their assigned study treatment. The study is registered with ClinicalTrials.gov, number NCT01858532. Findings: Between May 17, 2013, and July 13, 2017, 11 087 patients were screened; 5117 entered the enrichment period, and 4711 completed the enrichment period. Of these, 2648 patients were responders and were randomly assigned to the atrasentan group (n=1325)or placebo group (n=1323). Median follow-up was 2·2 years (IQR 1·4–2·9). 79 (6·0%)of 1325 patients in the atrasentan group and 105 (7·9%)of 1323 in the placebo group had a primary composite renal endpoint event (hazard ratio [HR]0·65 [95% CI 0·49–0·88]; p=0·0047). Fluid retention and anaemia adverse events, which have been previously attributed to endothelin receptor antagonists, were more frequent in the atrasentan group than in the placebo group. Hospital admission for heart failure occurred in 47 (3·5%)of 1325 patients in the atrasentan group and 34 (2·6%)of 1323 patients in the placebo group (HR 1·33 [95% CI 0·85–2·07]; p=0·208). 58 (4·4%)patients in the atrasentan group and 52 (3·9%)in the placebo group died (HR 1·09 [95% CI 0·75–1·59]; p=0·65). Interpretation: Atrasentan reduced the risk of renal events in patients with diabetes and chronic kidney disease who were selected to optimise efficacy and safety. These data support a potential role for selective endothelin receptor antagonists in protecting renal function in patients with type 2 diabetes at high risk of developing end-stage kidney disease. Funding: AbbVie

    The epidemiology of renal replacement therapy in two different parts of the worldThe Latin American Dialysis and Transplant Registry versus the European Renal Association-European Dialysis and Transplant Association Registry

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    Publisher Copyright: © 2018 Pan American Health Organization. All rights reserved.Objective: To compare the epidemiology of renal replacement therapy (RRT) for end-stage renal disease (ESRD) in Latin America and Europe, as well as to study differences in macro-economic indicators, demographic and clinical patient characteristics, mortality rates, and causes of death between these two populations. Methods: We used data from 20 Latin American and 49 European national and subnational renal registries that had provided data to the Latin American Dialysis and Renal Transplant Registry (RLADTR) and the European Renal Association-European Dialysis and Transplant Association (ERA-EDTA) Registry, respectively. The incidence and prevalence of RRT in 2013 were calculated per million population (pmp), overall and by subcategories of age, sex, primary renal disease, and treatment modality. The correlation between gross domestic product and the prevalence of RRT was analyzed using linear regression. Trends in the prevalence of RRT between 2004 and 2013 were assessed using Joinpoint regression analysis. Results: In 2013, the overall incidence at day 91 after the onset of RRT was 181 pmp for Latin American countries and 130 pmp for European countries. The overall prevalence was 660 pmp for Latin America and 782 pmp for Europe. In the Latin American countries, the annual increase in the prevalence averaged 4.0% (95% confdence interval (CI): 2.5%-5.6%) from 2004 to 2013, while the European countries showed an average annual increase of 2.2% (95% CI: 2.0%-2.4%) for the same time period. The crude mortality rate was higher in Latin America than in Europe (112 versus 100 deaths per 1 000 patient-years), and cardiovascular disease was the main cause of death in both of those regions. Conclusions. There are considerable differences between Latin America and Europe in the epidemiology of RRT for ESRD. Further research is needed to explore the reasons for these differences.Peer reviewe

    Acoustic monitoring of short-term ingestive behavior and intake in grazing sheep

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    Acoustic monitoring of the ingestive behavior of grazing sheep was used to study the determinants of intake rate and to estimate dry matter intake (DMI) based on biting and chewing sounds. Each of three crossbred ewes (85±6.0kg body weight) were tested in 16 treatments resulting from the factorial combination of two forage species (orchardgrass and alfalfa), two levels of biomass depletion (tall=30±0.79cm and short=14±0.79cm) and four numbers of bites (20, 40, 60 and 80 bites). During each grazing session biting and chewing sounds were recorded with a wireless microphone placed on the ewe's forehead and connected to a digital video camera for synchronized audio and video recording of ingestive behavior. Dry matter (DM) intake rate was higher for alfalfa than orchardgrass (9.4±0.64 vs. 7.8±0.58g/min, P0.05), because sheep increased biting rate (from 17±1.6 to 28±1.6 bites/min, P<0.01) as bite mass declined from tall to short plants (from 0.54±0.02 to 0.31±0.01g DM, P<0.01). Sheep compensated for the reduction in bite mass by allocating fewer chews per bite (from 6.0±0.46 to 3.8±0.47, P<0.05) and increasing total jaw movement rate (from 95±6.3 to 122±6.3 movements/min, P<0.05). Compound jaw movements (chew-bites) were observed in every grazing session. The number of chew-bites was higher for tall than short plants (0.52±0.05 vs. 0.25±0.04 chew-bites/bite, P<0.05). The total amount of energy in chewing sound in a grazing session was linearly related to DMI (root mean square error=6.1g, coefficient of variation=27%); 79% of the total variation in total amount of energy in chewing sound was due to DMI. Dry matter intake was estimated accurately by acoustic analysis. The best model to predict DMI from acoustic analysis had a prediction error equal to 4.1g (coefficient of variation=18%, R2=0.92). Chewing energy per bite and total amount of energy in chewing sound were the most important predictors because they integrate information about eating time and intake rate of forages. The results demonstrate that ingestive sounds contain valuable information to remotely monitor feeding behavior and estimate dry matter intake in grazing ruminants.Fil: Galli, Julio Ricardo. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias; ArgentinaFil: Cangiano, Carlos Alberto. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce; ArgentinaFil: Milone, Diego Humberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigación en Señales, Sistemas e Inteligencia Computacional. Universidad Nacional del Litoral. Facultad de Ingeniería y Ciencias Hídricas. Instituto de Investigación en Señales, Sistemas e Inteligencia Computacional; ArgentinaFil: Laca, Emilio A.. University of California; Estados Unido
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