This study aimed to assess the effect of different breeds and crosses of broiler chickens and sex on growth, carcass characteristics, and tissue composition. The experimental design was a completely randomized design in a 6 × 2 factorial scheme, with six genotypes (New Hampshire – NHS, Jersey Black Giant – JBG, Rodhe Island Red – RIR, Indigenous Giant – IG, and the hybrids IG × NHS and IG × JBG) and two sexes (male and female). Each treatment was composed of five replications with three broiler chickens, totaling 180 broiler chickens. Zootechnical performance and growth were assessed through the Gompertz equation parameters. After slaughtering at 105 days, the characteristics of carcass and main cuts were determined by means of weight, yield, and proportion of tissue constituents (meat, bone, and skin). Regarding the Gompertz equation parameters, the genotype NHS presented a higher growth potential. Males presented higher live weight and carcass weights, except for IG. No difference was observed between genotypes and sexes (P > 0.05) for carcass yield. The genotype JBG presented the highest average for breast yield (24.4%). Males presented the highest average for leg yield (30.5%). The genotype IG presented the highest value of breast meat yield (71.2%), being similar to the genotypes from the crosses IG × NHS, and IG × JBG (68.9 and 68.3%, respectively). For meat to breastbone ratio, the genotype IG presented the highest value (3.4) and, considering the sex, females presented a higher average (3.2) for this characteristic. Regarding the proportion of leg meat, an effect was observed for genotype and sex (P < 0.05) with the highest values observed for the hybrid IG × JBG and females (66.3 and 66.0%, respectively). For meat to leg bone ratio, the genotypes NHS, JBG, RIR, and IG × NHS presented the highest values (2.6, 2.7, 2.6, and 2.6, respectively), with females presenting the highest value (P < 0.05) (2.7). The genotypes IG, IG × NHS and IG × JBG presented the best growth and carcass characteristics, being recommended to be reared under an alternative system. Females presented the highest breast yield and, proportionally, the highest amount of leg meat, which are important attributes in a chicken meat production system.

COST-BENEFIT ANALYSIS OF A MILK PRODUCTION SYSTEM WITH CROSSBRED ANIMALS IN NORTHERN MINAS GERAISABSTRACT: A simulation study was conducted to estimate the production costs of animals with different proportions of Holstein genes and annual return per cow in a herd from the northern region of Minas Gerais. Data from the zootechnical archive of Fazenda Queluz, Francisco Sá, MG, Brazil, comprising the period from 2007 to 2012 were used. The production system consists of crossbred Holstein x Zebu (HZ) cows with a genetic composition ranging from 1/4 HZ to 7/8 HZ.Total revenue per animal, annual profit per cow and variation in profitability were estimated over the years according to genetic composition. The revenue from milk production was greater for 7/8 HZ cows, but the estimated annual profit per cow was only 7.75% of total revenue, followed by 3/4 HZ cows which also exhibited low profit (4.11%). The highest profit was observed for 3/8 HZ cows, followed by 1/4 HZ and 1/2 HZ animals. Inversion of the genetic composition of the herd was observed over the years. In 2007, 64% of cows of the herd were 7/8 HZ, while in 2012, 7/8 HZ cows had been replaced with 1/4 HZ, 3/8 HZ and 1/2 HZ animals, accounting for 90% of all genotypes. Despite the greater production of animals with a higher proportion of Holstein genes, the change to cows with a higher proportion of genes of dairy Zebu breeds increased profitability, a fact that might be attributed to the greater economic efficiency of this genotype.

Economic analysis of the finishing of beef cattle in feedlots in the state of Minas Gerais: a case studyThe objective of this study was to evaluate the profitability of the beef cattle finishing in feedlot. Particularly, it was also intended to identify the components of the total and effective operational cost of greater impact on the production of meat and estimate the breakeven point. Data collection was carried out from January to December of 2009 in two beef cattle production systems, located in Sete Lagoas -MG (feedlot 1) and Carmo de Minas -MG (feedlot 2). The electronic data processing as well as the profitability analysis were conducted using the Cu$to Bovino Corte ® software, considering the gross margin, the net margin and the result (either profit or loss) as economic efficiency indicators. Feedlot 1 showed positive net and gross margins, which points out that it can survive in the short and medium term; Objetivou-se, com este trabalho, estudar a rentabilidade da terminação de bovinos de corte em confinamento. Especificamente, pretendeu-se, ainda, identificar os componentes dos custos total e operacional efetivo, que foram mais relevantes no custo da arroba de carne produzida e estimar o ponto de equilíbrio. A coleta de dados foi de janeiro a dezembro de 2009, em dois sistemas de produção de bovinos de corte, localizados em Sete Lagoas -MG (confinamento 1) e Carmo de Minas -MG (confinamento 2). O processamento eletrônico dos dados e a análise de rentabilidade foram realizados, utilizando-se o software Cu$to Bovino Corte ® , considerando-se a margem bruta, a margem líquida e o resultado (lucro ou prejuízo) como indicadores de eficiência econômica. O confinamento 1 não apresentou viabilidade econômica, mas obteve margens líquida e bruta positivas, o que indica que a atividade pode sobreviver no curto e médio prazos; o confinamento 2, por apresentar margens bruta e líquida e resultado positivos, demonstra que a atividade tem possibilidade de manter-se no longo prazo e com possibilidade de expansão. Os itens que apresentaram maiores representatividades sobre o custo total da atividade foram, em ordem decrescente, para o confinamento 1: aquisição de animais, alimentação, mão de obra e depreciação; e, para o confinamento 2: aquisição de animais, alimentação, despesas diversas (aluguel de máquinas, principalmente) e depreciação. Em relação ao custo operacional efetivo, foram, em ordem decrescente, aquisição de animais, alimentação, mão de obra e energia; aquisição de animais, alimentação, despesas diversas (aluguel de máquinas, principalmente) e mão de obra, para os confinamentos 1 e 2, respectivamente.Palavras-chave: custo de produção, lucratividade, pecuária de corte.

RESUMOViabilidade econômica da terceira ordenha em sistemas de produção de leite com ordenhadeira de circuito fechadoObjetivou-se, com este trabalho, analisar a viabilidade econômica da terceira ordenha, em sistemas de produção de leite com ordenhadeira mecânica, do tipo circuito fechado, visando a fornecer aos técnicos e pecuaristas informações que os auxiliem nas tomadas de decisões. Especificamente, pretendeu-se, ainda: a) estimar o custo de uma ordenha; b) estimar o custo da terceira ordenha; c) desenvolver uma equação matemática que permita estimar a quantidade mínima de leite produzida em duas ordenhas, a partir da qual será viável economicamente a realização da terceira ordenha. Os dados foram coletados em três propriedades leiteiras, de novembro de 2010 a março de 2011, em uma rotina de duas ordenhas diárias, sendo realizadas três coletas de dados em cada uma, perfazendo um total de nove. Considerando-se os dados médios, seria viável a realização da terceira ordenha se a produtividade média diária das vacas em lactação, em duas ordenhas, fosse igual ou superior a 24,43 kg de leite.Palavras-chave: bovinocultura leiteira, custo de produção, economia, frequência de ordenhas. This study aimed to analyze the economic viability of the third milking in production systems using mechanical milking in a closed circuit, aiming to provide technicians and farmers with information to assist them in decisionmaking. Specifically, it intended: (a) to estimate the cost of one milking; (b) to estimate the cost of the third milking; (c) to develop a mathematical equation to estimate the minimum amount of milk produced with two milkings, from which it would be economically feasible to do the third milking. Data were collected from three dairy farms, from November 2010 to March 2011, keeping a twice-a-day milking frequency, with three data collections in each farm, totalizing nine collections. Considering the average data, it would be feasible to do the third milking if the average milk yield per day of lactating cows in a twice-a-day milking frequency was greater than or equal to 24.43 kg of milk.

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