Finishing diets in intensive beef production systems are mainly based on cereals, which does not take advantage of the capacity of the ruminant digestive system to digest fibrous feeds, cannot be considered sustainable and does not contribute to the circular bioeconomy. Our aim was to investigate the effects of an alternative concentrate rich in agro-industrial by-products for finishing crossbred Limousine heifers. Four pens with 12 heifers and four pens with 13 heifers were randomly allocated to one of two treatments: control (CON), a commercial concentrate with a 43.3% cereal composition, and alternative (ALT), a concentrate with a composition of 26% cereals and up to 73.5% agro-industrial by-products. Growth performance data were collected along the 91 days of the experimental period. Carcass characteristics were collected after slaughter and 24 h later. Vacuum-packaged samples from longissimus muscle were aged for 7, 21 or 28 days to study meat quality traits. Feed intake was higher and feed conversion rate was lower in the ALT treatment, but no differences were found in average daily gain and feeding costs. Treatment had no effects on any of the measured carcass traits (grading, hot and cold carcass weight, dressing out, chilling losses, subcutaneous fat depth, pH, temperature and lean and fat colour) nor on the meat quality traits (drip loss, cooking loss, shear force, oxidative stability, chromatic indices and pigment contents). Ageing time decreased drip loss and shear force, increased lightness and did not affect redness or surface colour stability. In conclusion, feeding crossbred Limousine heifers a finishing diet rich in agro-industrial by-products did not have any negative effects on performance, carcass and meat quality traits, which might be considered positive from the point of view of sustainability of beef production. Under the conditions assayed, ageing for 21 and 28 days improved tenderness of meat, without detrimental effects on oxidative stability or traits related to visual acceptability.

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Características de la canal y rendimiento en cortes comerciales en novillos Criollo Argentino y Braford criados en sistemas extensivos ecológicos RESUMENSe estudiaron las características de las canales y el rendimiento en cortes comerciales de novillos de raza Criollo Argentino y Bradford criados en un sistema extensivo ecológico sin suplementación. Los novillos se sacrificaron a una edad media de 898 días y un peso de 401 kg. La valoración de las canales de novillos Braford fue superior a la de novillos Criollo Argentino, lo que repercutió en el precio (1.47 dólares.kg -1 vs. 1.42 dólares.kg -1 canal, respectivamente). Las canales de novillos Criollo Argentino proporcionaron porcentajes superiores de cortes de Primera categoria (51.0% vs. 49.4%) y menores para las piezas de Segunda (26.9% vs. 27.6%) y Tercera categoria (22.1% vs. 23.2%). Así mismo, las canales de novillos Criollo Argentino presentaron menor cantidad de grasa (3.9% vs. 5.5%) y mayor porcentaje de carne vendible (86.7% vs. 85.6%), lo que motivo un mayor precio medio de la carne (2.78 dólares.kg -1 carne vs. 2.76 dólares.kg -1 carne). En sistemas extensivos sin suplementación y en las condiciones de la experiencia, las canales de novillos Braford presentaron un mayor rendimiento y nivel de engrasamiento, mientras que las canales de novillos Criollo Argentino proporcionaron mayor porcentaje de carne vendible. En conjunto, los ingresos obtenidos con novillos Braford fueron superiores a los registrados con novillos Criollo Argentino. Palabras clave: bovinos, despieceCarcass characteristics and commercial meat yield in Criollo Argentino and Braford steers reared in extensive ecologic system AB S TR ACTWe studied carcass characteristics and commercial joints of Criollo Argentino and Braford steers reared in an extensive ecologic system, without supplementation. Steers were slaughtered at an average age of 898 days and weighing 401 kg. The Braford steers had higher scores for carcass assessments and higher percentages for carcass yield and excess fat on the carcass than Criollo Argentino steers, which resulted in the price (1.47 dollars.kg -1 vs. 1.42 dollars.kg -1 channel, respectively). The carcasses of Criollo Argentino steers had higher percentages of prime category cuts (51.0% vs. 49.4%) and lower of second (26.9% vs. 27.6%) and third category cuts (22.1% vs. 23.2%). The carcasses of Criollo Argentino steers had less fat (3.9% vs. 5.5%) and highest percentage of salable meat (86.7% vs. 85.6%), which cause a higher purchase prices of meat (2.78 dollars.kg -1 meat vs. 2.76 dollars.kg -1 meat). In extensive systems without supplementation and the terms of the experience, the carcasses from Braford steers had a higher yield and fatness, while the carcasses from Criollo Argentino steers provided greater percentage of salable meat. Overall, revenue from Braford steers were higher than those registered with Criollo Argentino steers.

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Resumen -El objetivo de este trabajo fue utilizar el metaanálisis para estudiar los resultados productivos de ovejas y cabras de ordeño, alimentadas con aceites y semillas ricas en ácidos grasos insaturados. Se utilizaron 22 experimentos con ovejas (63 tratamientos) y 21 con cabras (76 tratamientos). El consumo medio de grasa extra fue de 83,6±33,6 g por día en ovejas y 73,4±38,7 g por día en cabras. En ovejas, la grasa extra no afectó al consumo de materia seca, pero aumentó la producción de grasa (de 91,4 a 98,8 g por día) y redujo el contenido proteico (de 5,41 a 5,24%) de la leche. No hubo diferencias en el extracto quesero. En cabras, la inclusión de grasa en la dieta redujo el consumo de materia seca (de 2,13 a 2,08 kg por día) y aumentó el porcentaje de grasa láctea (de 4,11 a 4,43%) y el extracto quesero (de 7,41 a 7,76%). La respuesta productiva de ovejas y cabras al consumo de dietas ricas en ácidos grasos insaturados es diferente. Sin embargo, el valor comercial de la leche no se ve afectado, debido a la ausencia de efectos negativos sobre el extracto quesero en ambas especies.Términos para indexación: ácidos grasos insaturados, grasa, leche, producción animal, proteína. Meta-analysis of the use of oilseeds and oils in ewe and goat dietsAbstract -The objective of this work was to use meta-analysis to study the productive results of ewe and goat fed oil and seed, rich in unsatured fat acid. Twenty-two experiments with ewes (63 treatments) and 21 experiments with goats (76 treatments) were used. Average extra fat intake was 83.6±33.6 g per day in ewes, and 73.4±38.7 g per day in goats. In ewes, extra fat intake did not affect dry matter intake, but increased milk fat yield (from 91.4 to 98.8 g per day) and reduced milk protein content (from 5.41 to 5.24%). There were no differences in the sum of fat and protein contents. In goats, extra fat included in the diet reduced dry matter intake (from 2.13 to 2.08 kg per day), and increased milk fat percentage (from 4.11 to 4.43%) and the sum of fat and protein contents (from 7.41 to 7.76%). The yield responses to the intake of diets enriched with unsaturated fatty acids differ between ewes and goats. However, milk commercial value is not affected because of the absence of negative effects on the sum of fat and protein contents in both species.