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.

RESUMO: A busca por animais com características específicas é evidenciada na comercialização em leilões, em que, ao analisar os animais, compradores consideram as características individuais (musculosidade, frame, composição racial, peso) como preditor de qualidade e ajustam seus lances conforme suas preferências. Dessa forma, o presente estudo buscou avaliar o impacto de características fenotípicas e de padrão racial na composição do preço final de venda de bezerros comercializados em feiras oficiais na fronteira oeste do Rio Grande do Sul. Foram avaliados 507 lotes de bezerros comercializados nas feiras de terneiros de cinco municípios da região da Fronteira Oeste do estado do Rio Grande do Sul. Para a atribuição de escores visuais, considerou-se grupo genético, frame, musculosidade e pelagem dos animais. Foi realizada a análise de variância e a comparação dos preços finais médios pelo teste de Tukey a 5% de significância. As variáveis de maior impacto no preço foram grupo genético e tamanho dos animais. Animais de raças sintéticas obtiveram valorização superior nos três anos Estudados, considerável desvalorização e queda na oferta de animais sem definição racial. Os menores valores foram atribuídos a animais de tamanho grande.

ABSTRACT: The demand for beef cattle with specific traits is evident from sales in auctions. While purchasing, buyers consider individual traits (e.g., muscularity, frame, racial composition, and weight) as predictors of quality, and adjust their bids according to their preferences. The present study aimed to evaluate the effect of phenotypic and racial characteristics in determining the final sale price of calves of beef cattle in official auctions at the western border of the state of Rio Grande do Sul, Brazil. Five-hundred and seven lots of calves sold in calf auctions from five cities on the western border of Rio Grande do Sul were evaluated. The assignment of visual scores was based on their genetic group, frame, muscularity, and coat. Analysis of variance and the Tukey test at 5% significance level were performed for comparing the final average prices. Variables with the greatest impact on price were the genetic group and the size of the animals. Animals of synthetic breeds obtained higher value in the three years studied and animals without racial definition showed considerable devaluation and a decrease in supply. Larger animals had less value.