ABSTRACT The study evaluated the average return on invested capital (ROIC) in function of the variations in the historical prices of beef cattle and the odds of return on that capital gain within the system of beef cattle fattening on a farm in the state of Minas Gerais, Brazil, from 2004 to 2007. To calculate the risk of ROIC, monthly data of beef cattle prices (BM&F) were used from July 1997 to December 2013, revised by the General Price Index of the Fundação Getúlio Vargas in December 2013. The corrected data were divided into five classes that correspond to the risk scenarios. In light of these classes, the observed frequencies and their respective probabilities were calculated. The cumulative and updated ROIC were -3.02 and 0.24%, respectively. The odds for obtaining returns above 8.4% (Brazilian Selic Rate) per year were median, corresponding to 32.0 and 34.94% for the calculation of operating profit (ROIC OP) and total profit (ROIC TP), respectively. The expected average annual return was 6.26 and 7.66% for ROIC OP and ROIC TP, respectively. The standard deviation and coefficient of variation showed a high risk of ROIC because the scale and extent of dispersion per unit of expected return were elevated in the accumulation period and the risk for 2013 was reduced according to the price of beef cattle. The expected risk of ROIC was considered high between 2004 and 2007 and average for 2013. The probability of return on capital invested in the intensification of fattening beef cattle is a function of the selling price of cattle and purchase of inputs, in which the high scenario ranching provides greater probability of getting a return above the bank interest rates.

Foram avaliados 24 touros da raça Guzerá, de 24 a 34 meses de idade, com o objetivo de estudar o perfil da concentração sérica de testosterona e sua variação relativa à idade, peso corporal e características andrológicas. A concentração média de testosterona foi de 1,36 ng/mL, com influência do horário de coleta nos níveis circulantes. A equação de regressão da concentração sérica de testosterona em função do peso corporal dos animais apresentou efeito linear, sugerindo que, para cada quilograma a mais no peso corporal, ocorre acréscimo de 0,0082 ng/mL nas concentrações de testosterona. A regressão da concentração sérica de testosterona e a circunferência escrotal (CE) também apresentou efeito linear indicando que, para cada centímetro a mais na CE nos touros Guzerá, ocorreu aumento de 0,2319 ng/mL na concentração de testosterona. A regressão da concentração espermática do sêmen em função da concentração sérica de testosterona apresentou efeito linear, os resultados mostram que, para cada 0,1 ng/mL a mais na concentração de testosterona circulante, ocorreu aumento de 9,29 x 10(6) espermatozoides/mL de sêmen. Os resultados indicam que os níveis circulantes de testosterona podem auxiliar na identificação e seleção de touros Guzerá, com maior potencial reprodutivo.

Twenty-four Guzerat bulls were evaluated from 24 to 34 months of age, aiming to determinate the bulls serum testosterone concentration profile and their variation according to age, body weight and andrologic traits. The average of testosterone concentration was 1.36 ng/mL, with effect of time at harvest on circulating levels. The regression equation of testosterone according to body weight showed linear effect, suggesting that for each kilogram added to the body weight, an increase of 0.0082 ng/mL on serum testosterone concentrations occurs; and the regression of testosterone according to scrotal circumference (SC) also showed a linear effect. The results show that for each centimeter added to SC in Guzerat bulls, an increase of 0.2319 ng/mL on testosterone concentrations occurs. The regression of sperm concentration according to serum testosterone showed a linear effect, the results show that for each 0.1 ng/mL added to serum testosterone concentration, an increase of 9.29x10(6) spermatozoa/mL of semen occurs. The results indicate that circulating levels of testosterone may help on identification and selection of Guzerat bulls with major reproductive potential.

In order to determine the profile of leptin and insulin values in seminal plasma and their correlations with sperm patterns during the peripuberty, a total of 16 crossbred Gyr dairy bulls were monitored from 60 days before to 60 days after puberty, separated into two groups, early and regular, according to the onset of puberty. Hormone values were determined by radioimmunoassay after gel filtration in fast performance liquid chromatography and semen patterns, according to the Brazilian College of Animal Reproduction. Insulin concentrations in seminal plasma did not differ between groups, nor between the ages, with the pooling of the data showing average of 35.15±16.93, 36.60±26.21, 26.82±09.81, and 43.56±31.71 32.24±16.71 U/mL for the pubertal period of -60, -30, 0, +30 and +60 days, respectively. These values were not correlated with sperm parameters, but differed in the group of animals with the highest percentage of major defects (31.08±18.58 U/mL) compared with those with lower percentage of these sperm defects (40.01±25.37 U/mL). Leptin was not correlated with sperm parameters and did not differ between groups or stage of sexual development, with concentrations of 23.10±10.43, 24.35±9.42, 22.41±9.90, 23.76±9.69 and 24.99±11.42 ng/mL for the periods of puberty aforementioned, respectively, after being grouped. These results demonstrated the binding of insulin to the structural quality of the sperm cell, and this hormone is indicated in andrologycal evaluation of future breeding soundness.

O objetivo deste trabalho foi estimar correlações genéticas e fenotípicas de características reprodutivas e ponderais em 579 touros Nelore, em criação extensiva. As características reprodutivas estudadas foram: circunferência escrotal, consistência, volume e forma testiculares, comprimento dos testículos esquerdo e direito, largura dos testículos esquerdo e direito, motilidade e vigor espermáticos, defeitos espermáticos maiores, menores e totais e classificação andrológica por pontos. As características foram analisadas pelo método de máxima verossimilhança restrita, com algoritmos livres de derivadas, sob modelo animal, com inclusão da matriz de numeradores dos coeficientes de parentesco entre os animais e seus ascendentes. As correlações genéticas entre circunferência escrotal e as características peso corporal, volume testicular, motilidade espermática, vigor espermático, defeitos espermáticos menores, defeitos espermáticos totais e classificação andrológica por pontos foram, respectivamente, 0,72, 0,99, 0,72, 0,60, -0,67, -0,12 e 0,64. As maiores correlações fenotípicas encontradas entre peso e circunferência escrotal, características físicas e morfológicas do sêmen, quando comparadas às correlações entre idade e as mesmas características, são indicativas de que o peso tem maior influência na condição reprodutiva. As correlações genéticas entre classificação andrológica por pontos e as características: peso, circunferência escrotal, volume testicular, defeitos espermáticos maiores e defeitos espermáticos totais foram, respectivamente, 0,19, 0,64, 0,71, -0,47 e -0,58.

The aim of this work was to estimate genetic and phenotypic correlations for sexual reproductive and productive traits using a Multiple Trait Derivative-Free Restricted Maximum Likelihood (MTDFREML) methodology in 579 Nelore bulls, raised under pasture. The reproductive traits analyzed were scrotal circumference, testicular consistency, testicular volume, testicular shape, length and width of right and left testicles, physical (motility and vigor) and morphological (major and minor, and total sperm defects) semen traits, and breeding soundness evaluation. Genetic correlations between scrotal circumference and body weight, testicular volume, motility, vigor, minor sperm defects, total sperm defects and breeding soundness evaluation were, respectively, 0.72, 0.99, 0.72, 0.60, -0.67, -0.12 e 0.64, showing favorable associations of scrotal circumference and the characteristics related. Phenotypic correlations of major magnitude found among ages and the above-related characteristics suggested to be the body weight the major factor affecting the reproductive performance of those animals. Genetic correlations among breeding soundness evaluation, body weight, scrotal circumference, testicular volume, major sperm defects and total sperm defects were, respectively, 0.19, 0.64, 0.71, -0.47 e -0.58.