Raúl R. Vera
Pontifical Catholic University of Chile
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Featured researches published by Raúl R. Vera.
Chilean Journal of Agricultural Research | 2009
Raúl R. Vera; Claudio Aguilar; Rodrigo Lira; Paula Toro; Luis Barrales; Iván Peña; Fernando Squella; Patricio Pérez; Javiera Quenaya; Hanja Yutronic; Ignacio Briones
The purpose of this experiment was to determine the extent to which lamb carcass quality and fat composition could be altered by applying a dry olive cake-based ration instead of a conventional ration or pasture feeding. Three treatments were compared in a completely randomized experiment using 36 single male Suffolk Down lambs with an initial age and live weight of 80 d and 25 kg, respectively. The three treatments were: (a) suckling lambs kept with their mothers on annual Mediterranean grassland (GRAZE); (b) weaned stall-fed lambs on a control ration (CONC); and (c) weaned stall-fed lambs on an olive cake-based ration (CAKE). At the end of the 28-d experimental period, lambs were slaughtered, carcass quality evaluated, and samples of subcutaneous fat analyzed for fatty acids. Treatments did not differ in weight gain or carcass weight and quality, but highly significant differences were found in several fatty acid contents. CAKE animals had reduced palmitic acid as well as increased oleic and stearic acid contents. Atherogenic and thrombogenic indices improved with cake feeding. Principal component and discriminant analyses clearly differentiated treatments suggesting they could be applicable for traceability purposes. A laboratory experiment demonstrated that with or without added vitamin E, the dry olive cake did not alter its lipid properties with increased storage time.
Ciencia E Investigacion Agraria | 2009
Raúl R. Vera; Claudio Aguilar; Rodrigo Lira
Traditional sheep production for meat and wool for meat and wool among small and medium-sized Chilean farmers has low profi tability. Therefore, there is interest in producing value-added, differentiated products. One alternative is the production of sheep milk and cheese. This article analyzes and discusses existing alternatives for modifying milk and cheese compositions with the aim of differentiating these products. Also, analytical techniques that allow the chemical characterization of milk and cheese are briefl y mentioned. The main international thrusts are focused on the modifi cation of the content and composition of milk fatty acids and on the identifi cation of volatile compounds, terpenes, polyphenols and other analytes that allow differentiation of cheese types on the basis of aroma, taste and fl avor and that would help in ensuring traceability. La rentabilidad de la produccion ovina tradicional entre productores pequenos y medianos es muy baja, razon por la cual es deseable buscar alternativas con mayor valor agregado y diferenciacion. Una alternativa de interes es la produccion de leche ovina para la elaboracion de quesos. El articulo analiza y discute las alternativas para modifi car la composicion de la leche y quesos de forma de diferenciarlos. Se discute como es posible cuantifi car objetivamente dichos cambios y se mencionan brevemente algunas de las tecnicas analiticas disponibles con ese fi n. En general, los esfuerzos que se estan realizando a nivel mundial se focalizan en la modifi cacion del contenido y perfi l de los acidos grasos, asi como la identifi cacion y cuantifi cacion de compuestos volatiles, terpenos, polifenoles y otros que permitirian diferenciar quesos y leche por sabor y olor, y que permiten asegurar la trazabilidad.
Animal Production Science | 2013
Raúl R. Vera; Claudio Aguilar; Paula Toro; Fernando Squella; Patricio Pérez
Three lamb feeding strategies were compared, including finishing of suckling lambs on an annual Mediterranean pasture (GRAZE), weaned followed by a concentrate plus hay diet (CONC), or weaned and fed a concentrate with 33% dry olive oil cake plus hay (CAKE). Grazing lambs averaged a liveweight gain of 334 g/day during the 28-day experimental period, which was higher (P < 0.05) than that of CONC and CAKE (283 and 276 g/day, respectively); however, there were no differences in empty body or dressed carcasses weights due to dietary treatment. The feed conversion of the olive seed cake supplement (kg supplement/kg gain) was lower (P < 0.01) than that of the maize-based supplement. Despite some significant differences between carcasses traits, all were small and of little commercial consequence. Simulation modelling of whole-system performance suggested that early weaning of lambs followed by concentrate feeding would reduce the finishing period, marginally increase the liveweight of ewes and would have little effect on pasture availability. It was further concluded that olive oil cake can be a large proportion of concentrate diets without negatively affecting carcass quality.
Italian Journal of Animal Science | 2015
Paula Toro-Mujica; Antón García; Claudio Aguilar; Raúl R. Vera; José Perea; Elena Angón
Sheep production systems in regions with a Mediterranean climate are important in social, economic and environmental terms. Modeling these systems allows, among others, evaluation of the costs efficiencies which in turn permits assessing the expected effects of changes in production variables. This paper presents a prototype analysis of the economic sustainability of ecological dairy sheep systems of Castilla-La Mancha, Central Spain evaluated through the estimation of costs efficiencies. Costs functions were developed using data from 31 farms. Rate of supplementary feeding, labour use, and flock size were used to measure the cost efficiency. On average, cost efficiency was 61.7±15.5%, with significant differences among typological groups. High efficiency was found in only 29% of the farms. The economic analyses performed suggest that the continued existence of economically unsustainably farms is explained by the available subsidies, lack of amortization of fixed assets leading to progressive decapitalization, and subsistence incomes by family groups (gross family income).
Animal Production Science | 2009
A. R. Catrileo; Paula Toro; C. D. Aguilar; Raúl R. Vera
A simulation model was developed to evaluate the productive and economic effect of the variation in feed practices and stocking rate of a cow–calf system in Chile. Winter supplementation at grazing, stocking rate and economic aspects of the system were analysed. The supplementation of straw v. pasture hay at two different stocking rates was evaluated in the temperate pasture zone in La Araucania, Chile. Data were simulated using a decision support tool to help analyse the system. Simulations with the model involved 20 replicates of a factorial combination of two stocking rates (1.0 and 1.4 cows/ha) with differences in the initial weight (‘light’ v. ‘heavy’ with weights of heifers, primiparous and multiparous cows being 340 v. 380, 400 v. 450 and 440 v. 480 kg, respectively), at the same grazing pressure (kg liveweight/ha), two winter supplements (oat straw v. pasture hay) and two levels (6 v. 8 kg straw, and 5.1 v. 6.8 pasture hay). The model was validated with data collected from an experiment conducted with permanent pastures and a beef cattle cow–calf system from 1984 to 1989. The results indicate that there was a significant (P 0.05) the weight of female and male calves at the time of sale. Finally, supplementation with pasture hay, as opposed to oat straw, incurred a larger (P < 0.01) mean cost at an equivalent level of provision of metabolisable energy. Although difficult to analyse under real conditions, the economic and productive benefits of various feed practices and stocking rates were successfully evaluated in the present study using simulation tools.
Ciencia E Investigacion Agraria | 2014
Einar Vargas-Bello-Pérez; Raúl R. Vera; Claudio Aguilar; Rodrigo Lira; Iván Peña; Franco. A. Tello
The aim of this trial was to evaluate the effect of dietary supplementation of extruded linseed on the milk and cheese fatty acid (FA) profiles of ewes under extensive grazing conditions. Over 26 days, a group of nine lactating ewes (Latxa × Milchaf × Corriedale) in mid-lactation were managed under grazing conditions and given supplements during each manual milking (0830 and 1800 h) of 50% corn and 50% oats (500 g ewe -1 milking -1 ; control, TC) for the first 6 days. From day 7 to 20, the supplement was 25% corn, 25% oats and 50% extruded linseed (500 g ewe -1 milking -1 ) (extruded linseed; TEL). From day 21 to 26, the ewes were fed TC. The saturated FA content in milk was reduced (3.6%), and the monounsaturated, polyunsaturated and n-3 FA (7, 10 and 25%, respectively) were increased when the ewes were supplemented with extruded linseed. A correlation between rumenic acid with vaccenic acid (R 2 =0.68) was found in the milk fat from ewes fed TEL. In cheese obtained from TEL, the contents of n-3 and polyunsaturated FA were increased (21 and 7%, respectively). In conclusion, a supplement of extruded linseed in ewes under grazing conditions could be an alternative lipid source to produce cheese with additional nutritional value. However, the effect of extruded linseed supplementation in ewes under the same conditions with longer experimental periods and a more suitable statistical design must be investigated. El objetivo de este ensayo fue evaluar el efecto de suplementar extruido de linaza en el perfil de acidos grasos de leche y queso de ovejas en pastoreo extensivo. Durante 26 dias, un grupo de nueve ovejas lactantes (Latxa × Milchaf × Corriedale) fueron manejadas en pastoreo extensivo y suplementadas durante cada ordeno manual (830 y 1800 h) con 50% maiz + 50% avena (500 g oveja -1 ordeno -1 ) durante los primeros 6 dias (control; TC), de los dias 7 al 20 se suplementaron con 25% maiz + 25% avena + 50% extruido de linaza (500 g/oveja/ordeno) (extruido de linaza; TEL), y finalmente, del dia 21 al 26 las ovejas fueron alimentadas con TC. El contenido de acidos grasos saturados en leche fue reducido (3,6%) mientras que los acido grasos monoinsaturados, polinsaturados y n-3 fueron incrementados (7, 10 y 25%) en aquellas ovejas alimentadas con TEL. Se observo una correlacion de acido rumenico con acido vaccenico (R 2 =0,68) en leche de ovejas alimentadas con TEL. Los quesos elaborados de ovejas alimentadas con TEL, aumentaron su contenido de n-3 y acidos grasos poliinsaturados (21 y 7%). En conclusion, el suplementar ovejas en pastoreo extensivo con extruido de linaza puede ser una alternativa que puede resultar en la elaboracion de quesos con un valor nutricional mas saludable desde el punto de vista humano. Ademas resulta necesario investigar mas sobre el uso del extruido de linaza bajo las mismas condiciones con periodos mas largos de experimentacion usando un diseno estadistico mas apropiado.
Ciencia E Investigacion Agraria | 2014
Einar Vargas-Bello-Pérez; Claudio Aguilar; Paula Toro-Mujica; Raúl R. Vera; Matías Cerda; Ignacio Briones
A high demand for Chilean cheese has resulted in increased cheese production. This increase represents an opportunity to promote the development of new markets, such as for small ruminant cheeses. However, little has been discussed regarding the extent to which cheese consumers consider small ruminant cheeses. We hypothesized that price is the main determining factor for purchasing cheese. The present study examined this previously unexplored aspect. The objective of this study was to identify the factors that contribute to the purchaser’s response behavior, including purchase, usage and product possession. This study also aimed to provide preliminary information on cheese consumption in the Province of Santiago, Chile. A personal interview was conducted in a sample of 323 individuals in major supermarkets from five municipalities (Santiago, La Florida, Las Condes, Pudahuel, and Recoleta) of Santiago city between March and May 2012. The largest proportion of surveyed individuals were female (62%) who were between 20 to 25 years (34%). The main cheese purchaser of the household was more often the woman (52%; P<0.01). The brand and origin (70%; P≤0.01) and price (30%; P≤0.01) of the cheese were the main aspects considered before making a purchase. Cow’s milk cheese was the predominant cheese type consumed (77%), followed by goat’s milk cheese (6%), cow’s and goat’s milk cheese (15%) and cow’s, goat’s and sheep’s milk cheese (2%). Of the individuals surveyed, 35% consumed cheese three times per week as a sandwich ingredient. We conclude that consumer fidelity is driven by brand and origin and a preference to use the cheese in sandwiches (81%). Data from this study may be used to determine the most adequate strategy for promoting the sales of small ruminant cheeses. La produccion de queso en Chile esta creciendo debido a un alza en su demanda; este fenomeno podria representar una oportunidad para promover el desarrollo de nuevos mercados (quesos de rumiantes menores), sin embargo, poco se ha investigado sobre el consumo de quesos. La hipotesis que se contrasta es que los sujetos que compran queso en el mercado lo hacen con un grado debil de implicacion, donde el precio del producto es la variable mas importante en el comportamiento de compra. Este estudio tiene por objetivo identificar funciones de respuesta comportamental, para analizar los procesos de adquisicion, utilizacion, y posesion del producto en la Provincia de Santiago en Chile. Un cuestionario personal fue realizado a una muestra de 323 personas en supermercados de cinco comunas (Santiago, La Florida, Las Condes, Pudahuel y Recoleta) de la ciudad de Santiago entre marzo y mayo del 2012. La mayor proporcion de personas encuestadas resulto ser mujeres (62%) entre 20 y 25 anos de edad (34%). Las mujeres (52%; P≤0.01) resultaron ser las personas que se encargan de comprar el queso mientras que marca y origen (70%; P≤0.01) y precio (30%; P≤0.01) fueron los aspectos mas importantes que el consumidor considera antes de realizar la compra de queso. El queso de origen vacuno fue el queso que mas se consume (77%), la diferencia se distribuye en queso de cabra (6%), queso de vaca y queso de cabra (15%) y quienes consumieron queso de vaca, cabra y oveja (2%). Del total de encuestados, el 35% consume queso tres veces a la semana como un ingrediente en sandwiches. Se puede concluir que la accion de compra de queso tiene una debil implicacion, como generalmente se asume, con una aprehension complementaria entre racional y emocional. Ello se explica por una presumible alta tasa de fidelidad a marca/origen en quesos cuya principal caracteristica es ser suave, caracteristica que lo hace apropiado para el fin que se utiliza (81%): sandwich. Los resultados de este estudio podrian ser utilizados para encontrar la forma mas apropiada de ingresar al mercado de quesos de pequenos rumiantes: un uso practico y habitual.
Small Ruminant Research | 2011
P. Toro-Mujica; Antón García; A.G. Gómez-Castro; R. Acero; José Perea; V. Rodríguez-Estévez; Claudio Aguilar; Raúl R. Vera
Animal Feed Science and Technology | 2013
Einar Vargas-Bello-Pérez; Raúl R. Vera; Claudio Aguilar; Rodrigo Lira; Iván Peña; J. Fernández
Small Ruminant Research | 2006
Claudio Aguilar; Raúl R. Vera; R. Allende; Paula Toro