As inovações tecnológicas e os avanços das fronteiras agropecuárias promoveram para o Brasil uma posição de destaque no mercado internacional da carne bovina. Entretanto, no estado Rio Grande do Sul a produção de bezerros de corte apresenta baixos índices reprodutivos e financeiros. Deste modo, cabe ao pecuarista aprimorar sua capacidade tecnológica e gerencial para otimizar a produção. Nesse contexto, os programas de fomento à pecuária são desafiados a prestarem serviços de informação e alinhamento técnico para que os pecuaristas progridam na atividade. Esse trabalho está divido em dois objetivos centrais. Primeiramente, foram analisados os fatores que diferenciam os pecuaristas em relação à taxa de desmame e tecnologias adotadas. Participaram da pesquisa 73 pecuaristas e foram avaliadas 48 tecnologias. A metodologia estatística foi composta por análise multivariada de dados, constituída pelo procedimento GLIMMIX complementada pelo teste de Tukey, procedimento FASTCLUS, análise discriminante (DISCRIM e STEPDISC) e teste qui-quadrado (P<0.05). Foram formados três grupos de pecuaristas distintos entre si (R²= 0.9), nomeados como Baixa (BTD), Média (MTD) e Alta (ATD), Taxa de Desmame. Os pecuaristas BTD apresentaram maior taxa de adoção para a tecnologia sal comum em comparação com os grupos MTD e ATD (P<0.05). Os pecuaristas ATD demonstram maior taxa de adoção para as tecnologias sal proteinado, inseminação artificial em tempo fixo, ultrassonografia, seleção dos bezerros pelo peso ao nascer, melhoramento do campo nativo e ajuste de carga animal, quando comparado com o grupo BTD (P<0.05). Os pecuaristas MDT e ATD adotam com maior frequência as tecnologias relacionadas com os aspectos nutricionais e reprodutivos do rebanho. Entretanto, 52% dos pecuaristas não realizam o gerenciamento econômico na fazenda. Em decorrência disso, o segundo objetivo central foi analisar as características dos 73 pecuaristas que afetam a adoção do gerenciamento econômico. A análise dos dados foi realizada através do modelo Probit. Os pecuaristas que possuem maiores áreas de terra destinadas à produção de bovinos de corte (P<0.10) e que apresentam uma produção agropecuária diversificada (P<0.05) são menos propensos em adotar. Por outro lado, os pecuaristas que acessam a Internet com maior frequência (P<0.10), participam de um maior número de associações de produtores (P<0.05), recebem assistência técnica com maior frequência (P<0.10), acasalam um maior número de vacas ao ano (P<0.05), possuem o sistema produção do tipo ciclo completo (P<0.05) e apresentam taxa de desmame igual ou maior que 70% (P<0.05) estão associados positivamente com a adoção. Estas informações podem ser utilizadas na formulação de programas de extensão, com o propósito de fomentar a adoção das práticas de gerenciamento econômico. Os pecuaristas mais propensos em adotar podem servir como agentes difusores, colaborando com a disseminação de tecnologias propícias para maximizar os lucros e minimizar os riscos enfrentados pela atividade. / Technological innovations and agricultural advances have included Brazil as a leading position in the international beef market production. However, in Rio Grande do Sul State, production of cow-calf have low reproductive and financial indexes. In this way, farmers should improve their technological and management capacity to optimize its production. Furthermore, programs to promote high livestock production are routinely challenged in beef cattle production to yield substantial information for farmers to be used form its well development in the system activity. This work is divided into two main goals. In the first study, factors that differentiate the farmers were compared in relation to weaning rate and to adopt technologies. This survey comprehends 73 farmers and 48 technologies. We used multivariate data analysis, comprising the GLIMMIX procedure, Tukey test, FASTCLUS procedure, discriminant analysis (DISCRIM and STEPDISC) and chi-square test to evaluate the collected data. The level of significance was set at P<0.05. Three distinct groups of farmers (R² = 0.9), named as Low (LWR), Medium (MWR) and High (HWR) Weaning Rate were formed. LWR presented higher adoption rate for common salt technology in comparison to MWR and HWR (P<0.05). HWR demonstrated higher adoption rate for protein salt technologies, artificial insemination, ultrasonography, selection of calves at birth weight, improving native pasture and adjusting stocking rate, when compared with the LWR group (P<0.05). MWR and HWR adopt more frequently the technologies related with nutritional and reproductive aspects of the herd in comparison to LWR (P<0.05). Furthermore, 52% of farmers do not adoption the economic management in farm. Due to this low adoption rate, the second objective of this study was to analyze the characteristics of the 73 farmers that affect the uses of economic management. Data analysis was performed by Probit model. Farmers with large size of the land (P<0.10) and diversity of the production system (P<0.05) are not likely to adopt an ideal economic management. On the other hand, farmers who access the Internet more frequently (P<0.10), participate in a greater number of associations (P<0.05), receive technical assistance more frequently (P<0.10), have a larger number of cows mated per year (P<0.05), possess a complete cycle system production (P<0.05), and have a weaning rate equal or greater than 70%, are positively associated with economic management in the farm (P<0.05). This information can be used to develop extension programs to promote new advances in the economy management of the production system. Farmers are more likely to adopt this approach to serve as diffusers agents, collaborating with the dissemination of key technologies to maximize profits and to minimize the risks faced by the activity.

As inovações tecnológicas e os avanços das fronteiras agropecuárias promoveram para o Brasil uma posição de destaque no mercado internacional da carne bovina. Entretanto, no estado Rio Grande do Sul a produção de bezerros de corte apresenta baixos índices reprodutivos e financeiros. Deste modo, cabe ao pecuarista aprimorar sua capacidade tecnológica e gerencial para otimizar a produção. Nesse contexto, os programas de fomento à pecuária são desafiados a prestarem serviços de informação e alinhamento técnico para que os pecuaristas progridam na atividade. Esse trabalho está divido em dois objetivos centrais. Primeiramente, foram analisados os fatores que diferenciam os pecuaristas em relação à taxa de desmame e tecnologias adotadas. Participaram da pesquisa 73 pecuaristas e foram avaliadas 48 tecnologias. A metodologia estatística foi composta por análise multivariada de dados, constituída pelo procedimento GLIMMIX complementada pelo teste de Tukey, procedimento FASTCLUS, análise discriminante (DISCRIM e STEPDISC) e teste qui-quadrado (P<0.05). Foram formados três grupos de pecuaristas distintos entre si (R²= 0.9), nomeados como Baixa (BTD), Média (MTD) e Alta (ATD), Taxa de Desmame. Os pecuaristas BTD apresentaram maior taxa de adoção para a tecnologia sal comum em comparação com os grupos MTD e ATD (P<0.05). Os pecuaristas ATD demonstram maior taxa de adoção para as tecnologias sal proteinado, inseminação artificial em tempo fixo, ultrassonografia, seleção dos bezerros pelo peso ao nascer, melhoramento do campo nativo e ajuste de carga animal, quando comparado com o grupo BTD (P<0.05). Os pecuaristas MDT e ATD adotam com maior frequência as tecnologias relacionadas com os aspectos nutricionais e reprodutivos do rebanho. Entretanto, 52% dos pecuaristas não realizam o gerenciamento econômico na fazenda. Em decorrência disso, o segundo objetivo central foi analisar as características dos 73 pecuaristas que afetam a adoção do gerenciamento econômico. A análise dos dados foi realizada através do modelo Probit. Os pecuaristas que possuem maiores áreas de terra destinadas à produção de bovinos de corte (P<0.10) e que apresentam uma produção agropecuária diversificada (P<0.05) são menos propensos em adotar. Por outro lado, os pecuaristas que acessam a Internet com maior frequência (P<0.10), participam de um maior número de associações de produtores (P<0.05), recebem assistência técnica com maior frequência (P<0.10), acasalam um maior número de vacas ao ano (P<0.05), possuem o sistema produção do tipo ciclo completo (P<0.05) e apresentam taxa de desmame igual ou maior que 70% (P<0.05) estão associados positivamente com a adoção. Estas informações podem ser utilizadas na formulação de programas de extensão, com o propósito de fomentar a adoção das práticas de gerenciamento econômico. Os pecuaristas mais propensos em adotar podem servir como agentes difusores, colaborando com a disseminação de tecnologias propícias para maximizar os lucros e minimizar os riscos enfrentados pela atividade. / Technological innovations and agricultural advances have included Brazil as a leading position in the international beef market production. However, in Rio Grande do Sul State, production of cow-calf have low reproductive and financial indexes. In this way, farmers should improve their technological and management capacity to optimize its production. Furthermore, programs to promote high livestock production are routinely challenged in beef cattle production to yield substantial information for farmers to be used form its well development in the system activity. This work is divided into two main goals. In the first study, factors that differentiate the farmers were compared in relation to weaning rate and to adopt technologies. This survey comprehends 73 farmers and 48 technologies. We used multivariate data analysis, comprising the GLIMMIX procedure, Tukey test, FASTCLUS procedure, discriminant analysis (DISCRIM and STEPDISC) and chi-square test to evaluate the collected data. The level of significance was set at P<0.05. Three distinct groups of farmers (R² = 0.9), named as Low (LWR), Medium (MWR) and High (HWR) Weaning Rate were formed. LWR presented higher adoption rate for common salt technology in comparison to MWR and HWR (P<0.05). HWR demonstrated higher adoption rate for protein salt technologies, artificial insemination, ultrasonography, selection of calves at birth weight, improving native pasture and adjusting stocking rate, when compared with the LWR group (P<0.05). MWR and HWR adopt more frequently the technologies related with nutritional and reproductive aspects of the herd in comparison to LWR (P<0.05). Furthermore, 52% of farmers do not adoption the economic management in farm. Due to this low adoption rate, the second objective of this study was to analyze the characteristics of the 73 farmers that affect the uses of economic management. Data analysis was performed by Probit model. Farmers with large size of the land (P<0.10) and diversity of the production system (P<0.05) are not likely to adopt an ideal economic management. On the other hand, farmers who access the Internet more frequently (P<0.10), participate in a greater number of associations (P<0.05), receive technical assistance more frequently (P<0.10), have a larger number of cows mated per year (P<0.05), possess a complete cycle system production (P<0.05), and have a weaning rate equal or greater than 70%, are positively associated with economic management in the farm (P<0.05). This information can be used to develop extension programs to promote new advances in the economy management of the production system. Farmers are more likely to adopt this approach to serve as diffusers agents, collaborating with the dissemination of key technologies to maximize profits and to minimize the risks faced by the activity.

This thesis explores the zooarchaeology of cattle management and production at the 19th-century Hacienda El Progreso, on San Cristóbal Island, Galápagos, Ecuador. Many cattle products were exported, including salted meat, leather, and fat. In order to examine cattle commodification, comparative literature was reviewed, and the sequential steps that were undertaken to turn cattle into a product were assessed. The results were then compared to the faunal analysis of the Carpintero assemblage from Hacienda El Progreso using the chaîne opératoire framework in order to examine the possibility of interpreting the sequential production of cattle commodification from zooarchaeological specimens. Historical cattle from Hacienda El Progreso were a likely small bodied Criollo variety. While there was evidence of cattle management and production, there was limited opportunity to identify the hacienda’s operational sequence of cattle production for export as the Carpintero assemblage likely represented locally consumed animals. / Graduate

<p>Fat supplementation has potential to improve reproductive performance and increase pregnancy rates in cattle by increasing the energy density of the diet. However, some of the positive effects of fat seem to be influenced by the type of fatty acid fed. Supplementation of omega-3 (n-3) fatty acids increase uptake of n-3 fatty acids into tissue phospholipids and can mitigate immune and inflammatory responses in favor of pregnancy maintenance in cattle. However, n-3 fatty acid supplementation in ruminants has been associated with a decrease in circulating PGF_2α, which may delay CL regression, extend an animal’s time in diestrus, and prevent ovulation. Prostaglandin F_2α is a series 2 prostaglandin, synthesized from omega-6 (n-6) fatty acids, which is inhibited by production of series 3 prostaglandins from n-3 fatty acids. Docosohexaenoic acid (DHA, 22:6n-3) and eicosapentaenoic acid (EPA, 20:5n-3) are long-chain n-3 poly-unsaturated fatty acids (PUFA) that have important biological effects on reproduction through their involvement in hormone and series 3 prostaglandin synthesis. Ruminant tissues are naturally almost devoid of n-3 long-chain PUFA, specifically EPA and DHA. Fish oil is the most common ration additive used to provide very long chain n-3 fatty acids to ruminants. However, marine fish do not synthesize n-3 fatty acids; they consume microscopic algae or other algae-consuming fish to obtain n-3 fatty acids. Algae biomass provides a consistent source of DHA and EPA that could be fed to alter hormonal profiles and improve reproduction of beef heifers. Eighty-eight Angus × Simmental heifers (427 ± 1.8 kg) were blocked by BW and allotted to 2 treatments (44/treatment, 4 pens/treatment, 11 heifers/pen). Control heifers were fed a diet that contained (DM basis) 52.8% mixed grass silage, 32% corn silage, and 15.2% concentrate. DHAgold™ (49% fat; 21.8% DHA; DSM Inc.) was included in the algae diet at 1.65% of DM, replacing equal parts of corn and DDGS. Diets were formulated to contain 12% CP and 0.79 Mcal/kg NEg. Heifers were fed treatment diets from 54 d prior to the breeding season through the first trimester. Follicular fluid was collected on day 47 for hormonal analysis. Artificial insemination (AI) was from d 55 to 98, after which open heifers were removed to 1 control and 1 algae pen and placed with a bull. The study ended on d 180. Performance data were analyzed using the MIXED procedure and conception data were analyzed using the GLIMMIX procedure of SAS. Dominant follicle diameter and follicular estrogen concentration were unaffected by treatment (<i>P</i>≥0.12). Follicular insulin-like growth factor-1 was greater in algae compared to control heifers (<i>P</i>=0.03). During the pre-breeding period, algae supplemented heifers had lesser DMI (<i>P</i>=0.006), and greater ADG (<i>P</i>=0.03) during the breeding period, while BW tended to be greater compared to control heifers on d 98 and 180 (<i>P</i>≤0.07). First service conception rate did not differ between treatments (<i>P</i>=0.67); however, second service tended (<i>P</i>=0.08) and overall conception was (<i>P</i>=0.03) lesser in algae compared to control heifers. These data suggest supplementing DHA-rich algae improved growth, but decreased conception rates of primiparous beef females.</p>

The production of cattle in the United State is a very large business. Production begins at the cow-calf level, where a calf is born and raised to a specific weight. This weight is the weaning weight and averages between 300-600 pounds. The calf is then typically shipped to a feedlot, where it is fed a high corn ration which increases the weight of animal quickly and cost effectively to reach a sufficient slaughter weight. Cattle production takes place primarily in 5 different geographical locations which include the North Central, Southeast, Northern Plains, Southern Plains, and West regions. Due to the relationships between fed cattle prices, feeder cattle prices and feed costs, lighter weight feeder cattle typically sell for a higher price per pound than heavier weight feeder cattle. This decrease in price per pound for heavier feeders is often referred to as a feeder cattle price slide. This study is to determine how price slides have reacted over time and space due to the relative changes in fed and feeder cattle prices and the cost of feed. Weekly data was obtained from the Livestock Marketing Information Center (LMIC) on the auction price for feeder cattle at different weights for both steers and heifers. Weekly data on the futures price of live cattle and corn were also obtained from the LMIC. To determine if feeder cattle price slides had changed over time, regression analysis was used to evaluate the relationship between feeder cattle prices at varying weights with the price of fed cattle and the price of corn. Two different time periods were used for the same location: the first period was from 1992 to 1996 and the second period was from 2005 to 2015. Price slides were also examined across space. There were five different geographical locations analyzed: Oklahoma, Nebraska, Georgia, Kansas, and Montana. Each region was regressed individually and then compared. Prices slides were calculated as the difference in the regressed feeder cattle price at each weight. A combination of the time and space was used to evaluate changes in the same model. Results from the regression models returned feeder cattle prices at varying weights for steers and heifers and price slides were calculated from those estimated prices. It was found that price slides are not constant over time and that price slides are geographically specific. In the third objective, it is shown that time and space are both factors in determining price slides for feeder cattle. The implications of this study are to help cattle producers be more aware of market conditions specific to changes in feeding cost. It is also to make aware that price slides are not constant over time and space and therefore, must be reevaluated on a consistent basis.

O objetivo do trabalho foi avaliar o ganho de peso diário (GPD) e os níveis séricos de Zn e Se em resposta à suplementação mineral injetável (SMI) contendo Zn, Cu, Se e Mn, fornecida antes e após o desmame de 174 bezerros da raça Nelore (88 machos e 86 fêmeas), divididos em três grupos e submetidos aos tratamentos: C - Controle (sem SMI); M1 - Suplementado com SMI na desmama e M2 - Suplementado SMI 28 dias antes e na desmama. Os animais permaneceram em pastagem de Brachiaria e receberam sal mineral proteinado comercial ad libitum. Foram realizadas pesagens aos 28 dias anteriores ao desmame, ao desmame, e 28, 56, e 84 dias após o desmame, e colhidas amostras de sangue de 12 animais machos de cada tratamento. A pastagem e o sal foram amostrados para determinação da composição bromatológica e mineral. O delineamento experimental adotado foi inteiramente ao acaso, com três tratamentos com 58 animais cada. Os teores médios de Zn, Cu, Mn e Se na pastagem foram: 9,7; 2,6; 194 e 0,045 mg/kg, comprovando só não haver deficiência de Mn. Os resultados indicaram que não houve efeito significativo da SMI no GPD dos animais, possivelmente porque a ingestão de minerais presentes no sal proteinado foi suficiente para complementar a pastagem. Os níveis séricos de Zn não foram influenciados pela SMI e permaneceram elevados durante todo o período, comprovando que os animais não estavam deficientes. Entretanto, a suplementação M2 provocou aumento do Se no sangue aos 28 dias após o desmame e também propiciou níveis superiores aos do grupo controle. / The experiment was conducted to evaluate the daily weight gain (DWG) and serum levels of Zn and Se in response to an injectable inorganic mineral supplementation (IMS) provided before and after weaning from 174 Nelore calves (88 males and 86 females) divided into three groups and distributed to treatments: C - Control (without IMS), M1- supplemented with IMS at weaning and M2- supplemented with IIS 28 days before and at weaning. IIS contained Zn, Cu, Se and Mn. The animals remained in pasture of Brachiaria and received commercial mineral protein ad libitum. Weighings were made at 28 days prior to weaning, at weaning, and 28, 56 and 84 days after weaning, and blood sampled from 12 animals males of each treatment. The pasture and salt were sampling to determine the chemical and mineral composition. The experimental design was completely randomized, with tree treatments with 58 animals each. The average levels of Zn, Cu , Mn and Se in the pasture were 9.7, 2.6 , 194 and 0.045 mg/kg, that evidence mineral deficiency for Zn, Cu and Se. The results indicated that there was no significant effect of IIS in the DWG of the animals, possibly because the intake of zinc, copper and Se in mineral salt was sufficient to complement the pasture. Serum Zn levels were not affected by IIS and remained high throughout the period, showing that the animals were not in deficiency. However, the M2 supplementation increased the Se levels at 28 days after weaning and also provided higher levels than the control group.

O objetivo do trabalho foi avaliar o ganho de peso diário (GPD) e os níveis séricos de Zn e Se em resposta à suplementação mineral injetável (SMI) contendo Zn, Cu, Se e Mn, fornecida antes e após o desmame de 174 bezerros da raça Nelore (88 machos e 86 fêmeas), divididos em três grupos e submetidos aos tratamentos: C - Controle (sem SMI); M1 - Suplementado com SMI na desmama e M2 - Suplementado SMI 28 dias antes e na desmama. Os animais permaneceram em pastagem de Brachiaria e receberam sal mineral proteinado comercial ad libitum. Foram realizadas pesagens aos 28 dias anteriores ao desmame, ao desmame, e 28, 56, e 84 dias após o desmame, e colhidas amostras de sangue de 12 animais machos de cada tratamento. A pastagem e o sal foram amostrados para determinação da composição bromatológica e mineral. O delineamento experimental adotado foi inteiramente ao acaso, com três tratamentos com 58 animais cada. Os teores médios de Zn, Cu, Mn e Se na pastagem foram: 9,7; 2,6; 194 e 0,045 mg/kg, comprovando só não haver deficiência de Mn. Os resultados indicaram que não houve efeito significativo da SMI no GPD dos animais, possivelmente porque a ingestão de minerais presentes no sal proteinado foi suficiente para complementar a pastagem. Os níveis séricos de Zn não foram influenciados pela SMI e permaneceram elevados durante todo o período, comprovando que os animais não estavam deficientes. Entretanto, a suplementação M2 provocou aumento do Se no sangue aos 28 dias após o desmame e também propiciou níveis superiores aos do grupo controle. / The experiment was conducted to evaluate the daily weight gain (DWG) and serum levels of Zn and Se in response to an injectable inorganic mineral supplementation (IMS) provided before and after weaning from 174 Nelore calves (88 males and 86 females) divided into three groups and distributed to treatments: C - Control (without IMS), M1- supplemented with IMS at weaning and M2- supplemented with IIS 28 days before and at weaning. IIS contained Zn, Cu, Se and Mn. The animals remained in pasture of Brachiaria and received commercial mineral protein ad libitum. Weighings were made at 28 days prior to weaning, at weaning, and 28, 56 and 84 days after weaning, and blood sampled from 12 animals males of each treatment. The pasture and salt were sampling to determine the chemical and mineral composition. The experimental design was completely randomized, with tree treatments with 58 animals each. The average levels of Zn, Cu , Mn and Se in the pasture were 9.7, 2.6 , 194 and 0.045 mg/kg, that evidence mineral deficiency for Zn, Cu and Se. The results indicated that there was no significant effect of IIS in the DWG of the animals, possibly because the intake of zinc, copper and Se in mineral salt was sufficient to complement the pasture. Serum Zn levels were not affected by IIS and remained high throughout the period, showing that the animals were not in deficiency. However, the M2 supplementation increased the Se levels at 28 days after weaning and also provided higher levels than the control group.

O objetivo do trabalho foi criar um modelo para simular intervenções de manejo e analisar o resultado em sistemas de recria-terminação de bovinos de corte, servindo como Sistema de Apoio à Decisão (SAD). O modelo foi desenvolvido e é operado de forma integrada em planilhas dinâmicas do Microsoft Excel® e foi dividido em três módulos (Sistemas de Alimentação; Desempenho Animal; e Resumo e Análise Econômica). O SAD foi criado para gerenciar individualmente a alimentação dos animais, analisar a demanda por alimentação do rebanho e confrontar esta demanda com a capacidade de suporte e fornecer o resultado econômico do sistema. Foram simuladas duas alternativas de intensificação do Sistema de Produção Base (SPB) por meio do aumento da área de campo melhorado e da incorporação do confinamento na terminação (SPCT) ou na recria (SPCR). A intensificação proposta gerou aumento na produtividade (321, 314 e 274 kg/ha/ano) e redução na idade de abate (21, 23 e 26 meses), respectivamente para os sistemas SPCT e SPCR em relação ao SPB. Na análise econômica, o sistema SPB apresentou a maior margem bruta anual por hectare, seguido pelo SPCT e SPCR. Posteriormente, o SPB foi submetido a diferentes cenários por meio do incremento no ganho de peso médio diário (GMD 20% superior) combinado com três percentuais de deságio dos preços mensais de venda do novilho em relação ao preço de compra do bezerro (0%, 20% e 40%). O aumento no GMD promoveu uma redução da idade média de abate de 26 para 25 meses e um aumento no peso médio de venda ao abate de 470 kg para 490 kg. A margem bruta anual por hectare foi superior para os cenários com menor deságio de preços, sendo este o principal fator a influenciar no retorno econômico. O modelo proposto permite que intervenções realizadas no gerenciamento da alimentação do rebanho, preços e desempenho animal de sistemas de recria-terminação sejam manejadas de forma conjunta e analisadas dentro de uma visão sistêmica. / The aim of this study was to create a model to serve as a Decision Support System (DSS) to simulate management intervention and analyze systems results. Model was developed and operated in Microsoft Excel® spreadsheet and was divided trough three components (Feeding Systems; Animal Performance; and Summary & Economic Analysis). DSS allows analysis of individual and herd’s feeding management, feed demand versus stock capacity and economic analysis. Intensification of the Pasture-Based System (PBS) was evaluated through the simulation of increasing areas of improved natural pasture and feedlot systems composing another two systems: Pasture/Feedlot-Based System for Finishing Cattle (FBSF) and Pasture/Feedlot-Based System for Stocker Cattle (FBSS). System’s intensification increases productivity (321, 314 and 274 kg/hectare/year) and decreases slaughter age (21, 23 and 26 months of age), for FBSF and FBSS compared to PBS. In the economic analysis, PBS showed higher annual gross margin per hectare, followed by FBSF and FBSS. In another analysis, PBS was tested through simulation of different scenarios for average daily gain (20% increasing in the ADG) combined with three levels of difference between the prices paid and received for cattle (0%, 20% and 40%). Increasing in ADG decreases the average slaughter ages from 26 to 25 months-old and increases selling weight from 470 to 490 kg. Annual gross margin per hectare was higher to the highest selling prices scenarios, which was the major factor that influenced on the economic return. Model provides an overview of integrated management, showing major results of interventions on herd’s feeding, purchase and selling prices and animal performance of stocker-finishing systems in beef cattle production.

Fundação de Amparo a Pesquisa no Estado do Rio Grande do Sul / This paper was the objective to identify some deciding factors of purchases of European and synthetic breeding bull at auctions in Rio Grande do Sul and its influence on the purchase price. Were viewed a total of 55 auctions, between television auctions and presential auctions. In total, were collected data of 4,569 Aberdeen Angus, Hereford, Brangus and Braford breeding bull, auctioned in several cities in the state of Rio Grande do Sul. Data were collected in two stages: the first consisted of the collection data catalogs related to phenotypic and genotypic information at auction or websites of the auction companies, the second stage was the collection of information marketing of animals. Data were tabulated in spreadsheets software and then analyzed using a statistical software. Braford bulls had higher value than Aberdeen Angus, Brangus and Hereford breeding cattle. Bulls of two years old were more valued than animals three years old in Aberdeen Angus, Brangus and Hereford breeds, while the opposite occurred to Braford breed. The trade of bulls take effect in the spring have higher sales value compared to trades in the fall. The weight of the bull influence on the best selling price, the same does not occur with scrotal perimeter. The red fur bull has higher value than the black fur, both in Angus as Brangus. / Este trabalho teve por objetivo identificar alguns fatores decisórios no processo de compra de reprodutores das raças europeias e sintéticas em leilões no Rio Grande do Sul e sua influência no preço de venda. Foram acompanhados um total de 55 leilões, sendo alguns televisivos e outros presenciais. Ao total foram coletados dados da oferta de 4.569 reprodutores de bovinos de corte das raças Aberdeen Angus, Hereford, Brangus e Braford, leiloados em diversos municípios do Rio Grande do Sul. Os dados foram obtidos em duas etapas: a primeira constou da coleta de dados dos catálogos referentes a informações fenotípicas e genotípicas distribuídos ao início dos leilões ou através dos sitios das empresas leiloeiras. A segunda foi a coleta de informações da comercialização dos animais. Os dados foram tabulados em planilhas eletrônicas e posteriormente analisados por meio de software estatístico. Touros da raça Braford tiveram maior valor comercial do que os Aberdeen Angus, Brangus e Hereford. Touros de dois anos foram mais valorizados do que os de três anos nas raças Angus, Brangus e Hereford, mas não os Braford. As comercializações efetivadas durante a primavera têm valor de venda superior quando comparada às do outono. O peso do touro influencia no melhor preço de venda, mas não o perímetro escrotal. Os touros de pelagem vermelha têm maior valor comercial do que os de pelagem preta, tanto na raça Aberdeen Angus quanto na Brangus.

O objetivo do trabalho foi criar um modelo para simular intervenções de manejo e analisar o resultado em sistemas de recria-terminação de bovinos de corte, servindo como Sistema de Apoio à Decisão (SAD). O modelo foi desenvolvido e é operado de forma integrada em planilhas dinâmicas do Microsoft Excel® e foi dividido em três módulos (Sistemas de Alimentação; Desempenho Animal; e Resumo e Análise Econômica). O SAD foi criado para gerenciar individualmente a alimentação dos animais, analisar a demanda por alimentação do rebanho e confrontar esta demanda com a capacidade de suporte e fornecer o resultado econômico do sistema. Foram simuladas duas alternativas de intensificação do Sistema de Produção Base (SPB) por meio do aumento da área de campo melhorado e da incorporação do confinamento na terminação (SPCT) ou na recria (SPCR). A intensificação proposta gerou aumento na produtividade (321, 314 e 274 kg/ha/ano) e redução na idade de abate (21, 23 e 26 meses), respectivamente para os sistemas SPCT e SPCR em relação ao SPB. Na análise econômica, o sistema SPB apresentou a maior margem bruta anual por hectare, seguido pelo SPCT e SPCR. Posteriormente, o SPB foi submetido a diferentes cenários por meio do incremento no ganho de peso médio diário (GMD 20% superior) combinado com três percentuais de deságio dos preços mensais de venda do novilho em relação ao preço de compra do bezerro (0%, 20% e 40%). O aumento no GMD promoveu uma redução da idade média de abate de 26 para 25 meses e um aumento no peso médio de venda ao abate de 470 kg para 490 kg. A margem bruta anual por hectare foi superior para os cenários com menor deságio de preços, sendo este o principal fator a influenciar no retorno econômico. O modelo proposto permite que intervenções realizadas no gerenciamento da alimentação do rebanho, preços e desempenho animal de sistemas de recria-terminação sejam manejadas de forma conjunta e analisadas dentro de uma visão sistêmica. / The aim of this study was to create a model to serve as a Decision Support System (DSS) to simulate management intervention and analyze systems results. Model was developed and operated in Microsoft Excel® spreadsheet and was divided trough three components (Feeding Systems; Animal Performance; and Summary & Economic Analysis). DSS allows analysis of individual and herd’s feeding management, feed demand versus stock capacity and economic analysis. Intensification of the Pasture-Based System (PBS) was evaluated through the simulation of increasing areas of improved natural pasture and feedlot systems composing another two systems: Pasture/Feedlot-Based System for Finishing Cattle (FBSF) and Pasture/Feedlot-Based System for Stocker Cattle (FBSS). System’s intensification increases productivity (321, 314 and 274 kg/hectare/year) and decreases slaughter age (21, 23 and 26 months of age), for FBSF and FBSS compared to PBS. In the economic analysis, PBS showed higher annual gross margin per hectare, followed by FBSF and FBSS. In another analysis, PBS was tested through simulation of different scenarios for average daily gain (20% increasing in the ADG) combined with three levels of difference between the prices paid and received for cattle (0%, 20% and 40%). Increasing in ADG decreases the average slaughter ages from 26 to 25 months-old and increases selling weight from 470 to 490 kg. Annual gross margin per hectare was higher to the highest selling prices scenarios, which was the major factor that influenced on the economic return. Model provides an overview of integrated management, showing major results of interventions on herd’s feeding, purchase and selling prices and animal performance of stocker-finishing systems in beef cattle production.