This study aimed to evaluate levels of yerba mate (Ilex paraguariensis) extract (YME), as a feed additive in the diets of growing lambs on serum biochemical parameters and hematological indices, animal performance, body metrics and carcass traits. Thirty-six entire (nine per treatment), male growing lambs, weighing 23.8 ± 3.7 kg, were fed the experimental diets which were treatments consisting of increasing levels of YME (0, 1, 2, and 4% inclusion on a dry matter [DM] basis) during an experimental period of 53 days. The experiment was carried out in a randomized block design, which initial body weight was used as blocking factor and the results were analyzed by orthogonal contrasts (linear, quadratic, and cubic). Yerba mate extract did not change the general health status of the animals; however, inclusions of up to 2% of the extract increased globulins (p = 0.05) and white blood cell count, as segmented neutrophils (p = 0.02) and lymphocytes (p = 0.04). Additionally, inclusion of up to 2% YME increased dry matter intake, final weight gain, total and daily gain (p < 0.05), also tended to increase ribeye area and reduce fat thickness (p < 0.10); however, YME above 2% of inclusion reduced animal productive parameters (p < 0.05). In conclusion, levels up to 2% of YME were beneficial to the health and productive parameters of growing lambs.

The present study investigated the inclusion of yerba mate extract (YME) in the lamb’s diet on meat quality traits, antioxidant activity, and shelf-life. Thirty–six lambs were distributed according to a block design with the following groups: control group without YME (0%) and three treatment groups with 1, 2, and 4% YME inclusion in the dry matter. The animals were fed these diets for 53 days. Samples were collected from the Longissimusthoracis (LT) muscle to analyze antioxidant activity and meat quality. Samples were placed on a counter display simulating a retail environment for 0, 3, and 6 days at 4 ± 2 °C. All data were analyzed using a MIXED model with orthogonal contrasts. Inclusion of 1 and 4% YME in the diet changed the yellow (b*) and the chroma (C*) of the meat (p ≤ 0.05). The pH, colour, thiobarbituric acid reactive substances, and carbonyl values were influenced by the retail display time for all the evaluated treatments (p ≤ 0.03). However, neither diet nor the retail display time influenced the oxidation of proteins or the antioxidant enzyme activities of catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPX) and glutathione activity (GSH) in meat. Therefore, the inclusion of 4% YME showed positive results in the yellow and colour stability parameters of the meat without increasing the lipid peroxidation values or altering the normal meat quality parameters in lambs.

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The aim of this study was to analyze the influence of the zootechnical performance indicators and the price main cost items on the total production cost of feedlot beef cattle. We used a mathematical model of the production cost, which considered the cost of the items according to the Economic Theory. Costs were allocated into: i) variable costs, ii) fixed costs, and iii) factor income. A survey was carried out in 2015, with ten farmers in the state of São Paulo, to define the technical indicators of production. The representative property was defined with 27 thousand animals slaughtered per year. The spot prices used in our analysis were collected in December 2019. Elasticity was calculated and expressed as a relationship between two interrelated functional variables. We estimated elasticities for the variables: animals purchase of 355 kg ($1.78/kg), feed price ($0.17/kg of dry matter), interest rate (4.5%), average daily gains (1.616 kg), and carcass yield (55.46%). This way we compared the variation of total cost per carcass kilo caused by increases of 1% in each of the considered variables. In the base scenario, production cost was US$ 3.11/kg and the variable cost of the activity represented 94.9% of the total costs, which of purchase animals, feed and variable taxes were 69.5%, and 20.6% and 3.8%, respectively. Increases of 1% in each of those variables caused variations of, respectively, +0,71%, +0,21%, 0,01%, -0,98%, and -0,98% on production cost unit. In conclusion, the purchase price of animals for feedlot activity is interrelated to the total cost. The average daily gains and carcass yield is also a zootechnical performance that presented a direct relation with the reduction of total costs. Thus, this demonstrates that farmers should improve management practices in the purchase of inputs and the performance of animal production.