ECONOMIC DETERMINISTIC ANALYSIS OF TWO YEARS OLD STEERS PRODUCTION SYSTEMS

The objective of this study was to realize the economic deterministic analysis of steers production system in full cycle, finished in feedlot or cultivated pasture at twenty-four months old, utilizing or not the quality bonus from slaughterhouses. The study was realized using data from meta-analytic survey of studies in the central region of Rio Grande do Sul state, Brazil, in Microsoft Excel® spreadsheets. The systems were simulated considering the male and female calves weaned early, at the tree months of age, and finished at the 24 months of age in feedlot or cultivated pasture. After the slaughter, it was realized the economic deterministic analysis. According to financial return indicators net present value (NPV), benefit:cost index (IB:C) and additional return on investment (ROI) only the system in pasture show return at the end of planning horizon, and the internal return rate (IRR), modified internal return rate (MIRR) and discounted payback (PBd), show that this system possesses a higher risk of investment. The feedlot system show negative results as a investment project. The bigger cost center was depreciation, feeding supply and taxes, and the quality bonus shows up an interesting alternative of return, but was not sufficient to render the feedlot system a viable project.Keywords: bioeconomic; economic indicators; economic viability; productive systems; risk analysis

GANHO DE PESO PRÉ E PÓS-DESMAME NO DESEMPENHO REPRODUTIVO DE NOVILHAS DE CORTE AOS QUATORZE MESES DE IDADE

The objective of this experiment was to study the development and reproductive performance of sixty-six Charolais crossbred beef heifers bred at fourteen months of age, classified in four groups according to pre and postweaning average daily weight gain (ADG): AA= heifers that showed ADG > .54 kg and .73 kg, respectively; AB= heifers that showed ADG > .54 kg and .73 kg, respectively; BB= heifers that showed ADG < .54 kg and < .73 kg, respectively. Weight at the beginning and end of the breeding period, and the reproductive performance were influenced by ADG of the heifers during pre and postweaning phase. AA heifers showed better development in relation to the other groups, without difference between AB and BA. The AA group was superior to the others except for the reproductive performance of the group AB. Heifers that became cyclical showed higher development during the growing phase and mating period than acyclic heifers. Reproductive performance of heifers was positively correlated with weight and body condition at beginning and end of the mating period. Greater weight during pre and post-weaning improve the reproductive performance of beef heifers

ANÁLISE ECONÔMICA, RENDIMENTOS DE CARCAÇA E DOS CORTES COMERCIAIS DE VACAS DE DESCARTE 5/8 HEREFORD 3/8 NELORE ABATIDAS EM DIFERENTES GRAUS DE ACABAMENTO

O objetivo deste trabalho foi estudar o efeito do grau de acabamento sobre os rendimentos de carcaça e dos cortes comerciais de vacas de descarte 5/8 Hereford 3/8 Nelore, bem como realizar a análise econômica da comercialização desses cortes pela indústria frigorífica. Foram utilizadas 42 vacas adultas, todas com oito dentes ao abate, e peso corporal médio de 530 kg. O delineamento experimental utilizado foi o inteiramente casualizado. Após o abate, as carcaças foram classificadas em relação à gordura de cobertura, separadas em gordura 1 (ausente), gordura 2 (escassa), gordura 3 (mediana) e gordura 4 (uniforme), conforme o Sistema Nacional de Tipificação e Classificação de Carcaças Bovinas. Os pesos corporais na origem foram maiores para as vacas classe de gordura 4 em relação às classes 2 e 1, sendo de 571,9; 517,6; e 488,1 kg, respectivamente, não diferindo da classe de gordura 3 (536,6 kg). Os rendimentos de carcaça quente aumentaram em função da elevação do grau de acabamento de carcaça, com valores médios de 44,4; 46,1; 47,9 e 47,8%, para as classes de gorduras 1, 2, 3 e 4, respectivamente. A ponta-de-agulha é o corte com maior incremento de peso quando crescem as classes de gordura. Se fossem considerados os preços dos cortes comerciais nos mercados atacadistas de São Paulo e do Rio Grande do Sul, a indústria poderia remunerar melhor vacas com acabamento 2 em relação às demais. O ponto de equilíbrio da indústria frigorífica seria de R$6,21/kg de carcaça para vacas com gordura 2, contra R$ 6,02/kg, R$5,99/kg e R$ 5,98/kg, respectivamente, para vacas com gorduras 1, 3 e 4. PALAVRAS-CHAVE: Braford; espessura de gordura; rendimento de ponta-de-agulha; rendimento de traseiro especial; vacas de corte

Genetic association of conformation scores with growth traits in Angus breed cattle

O objetivo deste trabalho foi determinar a associação genética entre escores visuais de conformação e as características de ganho de peso médio diário e de velocidade de crescimento em bovinos da raça Angus à desmama e ao sobreano. Os componentes de covariância foram estimados por modelo animal de análise tetracaracterística, com uso do método de inferência bayesiana, tendo-se assumido o modelo linear para: ganho de peso médio diário do nascimento à desmama (GMD) e da desmama ao sobreano (GMS); e velocidade de ganho de peso do nascimento à desmama (VD) e da desmama ao sobreano (VS). Um modelo não linear (de limiar) foi utilizado para os escores de conformação à desmama (CD) e ao sobreano (CS). As médias a posteriori, para a herdabilidade direta, foram: 0,12±0,023 (CD), 0,15±0,020 (GMD), 0,15±0,024 (VD), 0,17±0,020 (CS), 0,17±0,023(GMS), e 0,17±0,023 (VS). A correlação genética variou de -0,09±0,11 a 0,60±0,06, entre os escores CD e CS e as características de ganho médio diário de peso e velocidade de ganho de peso. A correlação entre CD e CS foi 0,52±0,089. A seleção direta para escores visuais de conformação, ganho médio diário e velocidade de ganho responde de forma lenta à seleção, tanto à desmama como ao sobreano.The objective of this work was determine the genetic association between visual scores of conformation and the traits of daily average weight gain and weight gain rate in Angus breed cattle at weaning and yearling. The components of covariance were estimated by a multitrait animal model using the Bayesian inference method, assuming a linear model for: daily average weight gain from birth to weaning (BWG) and from weaning to yearling (WYG); and weight gain rate from birth to weaning (BWR) and from weaning to yearling (WYR). A nonlinear model (threshold) was used for conformation scores at weaning (WC) and at yearling (YC). The a posteriori means for heritability were: 0.12±0.023 (WC), 0.15±0.020 (BWG), 0.15±0.024 (BWR), 0.17±0.020 (YC), 0.17±0.023 (WYG) and 0.17±0,023 (WYR). The genetic correlations ranged from -0.09±0.11 to 0.60±0.06, between WC, YC, and the daily average weight gain and weight gain rate. The correlation between WC and YC was 0.52±0.089. The direct selection for visual scores of conformation, average daily gain and weight gain rate respond slowly to selection, both at weaning and yearling