ABSTRACT The main objective of this study was to evaluate the effects of phenotypic, genotypic, and auction characteristics that may influence the selling prices of bulls. Data from 1,540 Braford and 1,179 Brangus bulls sold at auctions in the state of Rio Grande do Sul, Brazil, were collected and evaluated individually. Body condition score (BCS), muscularity, frame, foreskin size, presence or absence of horns, and data regarding the auction such as name/venue, event edition, forms of payment, among others, were considered. Information such as weight at the time of sale, scrotal circumference (SC), expected profit differences, selection indexes, and date of birth were collected from the catalogs supplied at the auctions. To obtain the influence of the selected explanatory variables throughout the conditional distribution of bull prices, a quantile regression was used, and the quantiles were established as follows: 10th, 25th, 50th, 75th, and 90th. The buyers of Braford and Brangus bulls valued characteristics such as age, weight, and SC in relation to frame, muscularity, BCS, and foreskin size. In addition, the price behavior at different auctions was positively related to the operation time of the auction in this market and with the reputation of the seller. Regarding genetic variables of Brangus bulls, these had little or no influence on the selling price. There was a positive influence on the weaning index in the 90th quantile and on the final index in the 50th and 75th quantiles. Buyers of synthetic bull breeds at auctions value the phenotypic characteristics of bulls more than they do genetic characteristics, which may not reflect permanent gains in the cattle herd.

Abstract This research determines which factors most influence the purchase price of bulls in livestock auctions in the State of Rio Grande do Sul, Southern Brazil. Hence, 760 beef bulls sold in eleven different auctions between August and November 2013 were analysed. The data consists of: breed, muscularity (MUSC), frame (FRAME), body condition score (BCS), scrotal circumference (SC) and body weight (BW). Other data such as the animal entry order and the purchase price of the bulls was collected during the auction. A linear generalized model was used to evaluate the interaction of each variable with the purchase price of the bulls. An ANOVA with Tukey post-hoc was used to compare the differences between the categories that influenced the purchase price of bulls and were realized in the software SPSS 20.0. All breeds presented declining prices from the first to the second entry order and increasing purchase prices from the order third to forth. Bulls with large frame received higher purchase prices independent of the auction order, except for the second order of entry, in which medium and small animals were more valued. Angus bulls obtained the highest prices in relation to the breeds Brangus and Hereford. The frame and breed constituted the main phenotypic characteristics that influence in price. In addition, the order of entry of bulls in the ring influence the purchase price.

Resumen Esta investigación determina qué factores influyen más en el precio de compra de los toros en las subastas de ganado en el estado de Rio Grande do Sul, en el sur de Brasil. Por lo tanto, se analizaron 760 toros de carne que se vendieron en 11 subastas diferentes entre agosto y noviembre de 2013. Los datos consisten en: raza, musculatura (MUSC), marco (MARCO), puntaje de condición corporal (PCC), circunferencia escrotal (CE) y peso corporal (PC). Otros datos, como la orden de entrada de animales y el precio de compra de los toros, se recopilaron durante la subasta. Se utilizó un modelo lineal generalizado para evaluar la interacción de cada variable con el precio de compra de los toros. Se aplicó un ANOVA con Tukey post-hoc para comparar las diferencias entre las categorías que afectaron el precio de compra de los toros y se utilizó el software SPSS 20.0. Todas las razas registraron precios decrecientes desde el primer al segundo orden de entrada, y los precios de compra aumentaron desde el tercer orden al siguiente. Los toros con constitución grande recibieron precios de compra más altos independientemente del orden de entrada en la subasta, a excepción del segundo, en el que los animales medianos y pequeños fueron más valorados. Los toros Angus obtuvieron los precios más altos en relación con las razas Brangus y Hereford. La constitución y la raza constituyeron las principales características fenotípicas que inciden en el precio. Además, el orden de entrada de los toros en la pista influye en el precio de compra.

ABSTRACT The objective of this study was to evaluate the characteristics of carcass and non-carcass components of lambs and hoggets finished in the feedlot with high-concentrate corn or sorghum grain-based diets. Thirty-two animals were finished, comprising 16 lambs (milk teeth) and 16 hoggets (two teeth), which were distributed in a completely randomized design in a 2 × 2 factorial arrangement (two sheep categories × two grains). For the variables final live weight, live weight at slaughter, hot carcass weight, cold carcass weight, hot carcass yield, cold carcass yield, carcass compactness index, subjective color, loin-eye area, fasting losses, external organs, internal organs, and for the weights, in kilograms, of neck, shoulder, ribs, and leg, there was a significant difference between categories. In the variables studied for the high-concentrate diets, significant differences were found for the ribs, expressed in relative values. Lambs have much higher fasting losses, a greater proportion of internal organs, and lighter-colored meat compared with hoggets. Hot and cold carcass yields, meat subjective color, and percentage of ribs are higher in feedlot-finished lambs and hoggets fed high-concentrate sorghum-based diets compared with those fed corn-based diets.