Browsing by Author "Toro, Paula"

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    FEEDING DRY OLIVE CAKE MODIFIES SUBCUTANEOUS FAT COMPOSITION IN LAMBS, NOTING CAKE RESISTANCE TO DEGRADATION AND PEROXIDATION
    (INST INVESTIGACIONES AGROPECUARIAS, 2009) Vera, Raul; Aguilar, Claudio; Lira, Rodrigo; Toro, Paula; Barrales, Luis; Pena, Ivan; Squella, Fernando; Perez, Patricio; Quenaya, Javiera; Yutronic, Hanja; Briones, Ignacio
    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.
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    MODELLING SUPPLEMENTATION STRATEGIES FOR BEEF STEER REARING AND FATTENING SYSTEMS IN SOUTHERN CHILE
    (INST INVESTIGACIONES AGROPECUARIAS, 2009) Toro, Paula; Catrileo, Adrian; Aguilar, Claudio; Vera, Raul
    A mathematical model was developed to analyze beef production systems in Southern Chile. The study considered the identification of the main components of systems under different beef steer management strategies, using pasture with or without supplementation and back grounding cattle on pasture followed by a winter period of confined feeding with pasture silage and concentrates. Validation of model outputs using 200 kg LW Hereford steers against real experimental data showed no significant differences (P >= 0.01) between simulated and observed final weights. In order to analyze the interaction between the stocking rate (SR) and supplementation, three SR of 2, 2.5 and 3 steers ha(-1) with and without pasture silage supplementation at the rate of 5 kg DMd(-1) steer(-1) for the length of the entire period were simulated. Means were compared by the least significant difference (LSD, P <= 0.05). Significant differences were found in terms of final weights, which decreased with increasing SR regardless of the supplementation level, although silage supplementation tended to reduce differences between SR. A second set of simulation runs was carried out to simulate on-farm finishing of the steers through a final phase of confined feeding based on a ration of silage and concentrates. Final weights differed between SR and systems and results showed that the optimum corresponded to 2.5 steers ha(-1), since at this SR the largest income corresponded to the smallest mean cost. It is concluded that a stocking rate of 2.5 steers ha(-1) is feasible if winter supplementation is available, independently of a finishing period in feedlot.