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Da Silva G.M.,State University of Southwest Bahia | Da Silva F.F.,UESB | Silva R.R.,UESB | Teixeira F.A.,UESB | And 8 more authors.
Semina:Ciencias Agrarias | Year: 2015

This study aimed to evaluate the inclusion of crude glycerin (CG) in the diet of Nellore heifers grazing Brachiaria brizantha during the dry season, on nutrients intake and digestibility, performance, reproductive efficiency and economic viability. Sixty Nelore heifers with initial average weight of 285.89 ± 18.74 kg and approximately 19 ± 2 months of age, were distributed in a completely randomized design with five diets containing 0.0; 4.0; 8.0; 12.0 and 16.0% of CG inclusion in the diet. The average dry matter (DM) daily intake showed decreasing linear effect (P <0.05), whereas for one % inclusion of GB decreased to 0.097 kg of DM intake day-1. The DM digestibility of the diet, had no significant effect (P>0.05), with a mean value of 50.93%. The average daily gain (ADG) of heifers showed decreasing linear effect (P<0.05). For one % of GB included in the diet was reduced 0.0065 kg day-1 of gain. The reproductive rates (rate of pregnant and semen doses by pregnant), were not affected (P>0.05) by dietary inclusion of GB, with average values of 75% and 1.29 doses pregnant-1, respectively. The economic viability indicators were not positive in the short and medium term. Supplements for over 0.7% of the PC in animals maintained in Brachiaria brizantha with low nutritional quality, it is not recommended to include GB, since its inclusion in any level reduced around 15% weight gain. However, depending on the cost of coproduct, it can be includes up to 16% in the diet, even considering this drop in performance.


Da Cunha D.N.F.V.,Pos doutorando em Zootecnia | Martuscello J.A.,Pos doutorando em Zootecnia
Revista Brasileira de Zootecnia | Year: 2010

The objective of this study was to develop and to evaluate a dynamic simulation model, with stochastic components in order to assess milk production systems. The simulation model was developed by using STELLA 9.0, ZooCalc 1.0 and electronic data sheets. The physical structure of the herd was divided into 15 interlinked modules that represented categories or subdivisions of categories. Mathematical models obtained from the literature were used to simulate the body weight of growing and lactating animals and milk production and milk composition. Electronic data sheets were used to calculate the nutritional requirements and dietary balance. After cost minimization, each feed was evaluated by using ZooCalc 1.0. Some average responses of farm size, zootechnical and economic index, the change in the area used for corn silage production, the calving interval and age at first insemination were obtained to evaluate whether the simulation model was working consistently with the expected. To assess the capacity of the model to generate simulated values that approach reality, the degree of linear association was measured between the values generated by the model and the values observed in practice. Sensitivity analyses showed that the values produced by the simulation model were in agreement with the expected results, in response to changes in the area of corn crop used for corn silage production, the calving interval and the age at first insemination. There was correlation between the values generated by the simulation model and the values observed in practice and the degree of linear association for the variables could be considered high. © 2010 Sociedade Brasileira de Zootecnia.


Da Cunha D.N.F.V.,Pos doutorando em Zootecnia | Martuscello J.A.,Pos doutorando em Zootecnia
Revista Brasileira de Zootecnia | Year: 2010

The objective of the study was to compare through simulation Holstein and Jersey breed herds, considering the farm size, zootechnical and economic indexes and profitability of the activity, by using different systems of bonus payment for milk price based in percentage of fat and protein in the milk. The comparisons were made, initially, disregarding the bonus payment for milk price based on the increase in the fat and protein percentage in milk. After that, the profitability of the activity was compared considering bonus payment for milk price of the Jersey breed herd, for each unit increment in fat and protein percentage in milk above those obtained with the Holstein breed herd. Finally, the profitability of the activity was compared by using the bonus payment for milk price based on quality of that used by company A systems. When there was no bonus payment for milk price based in the percentage of fat and protein in the milk, the profit obtained with the Holstein breed was higher because of the lower production costs. In order to make the activity more profitable with the Jersey breed, a bonus payment of 5% for milk price would be needed for each percentage unit of fat above the percentage of that obtained with the Holstein breed, or a bonus payment of 10% in the milk price for each percentage unit of protein above the percentage obtained with the Holstein breed. By using the bonus payment system proposed by Gimenes and Ponchio, the annual profit with the Jersey breed was higher than the profit obtained with the Holstein breed. However, with the application of the bonus payment system used by company A, the Holstein breed became more profitable than the Jersey breed. © 2010 Sociedade Brasileira de Zootecnia.


Da Cunha D.N.F.V.,Pos doutorando em Zootecnia | De Campos O.F.,PESAGRO RJ | Martuscello J.A.,Pos doutorando em Zootecnia
Revista Brasileira de Zootecnia | Year: 2010

The objective of this study was to select models of lactation curves with a better adjustment to the observed data in models of milk production simulation systems. A data base on 6,459 recordings of daily milk production was used. These data were obtained from monthly and fortnightly controls of milk between 2004 and 2007, from 472 lactations of animals from ten different milking cow herd farms. Based on rolling averages of milk production (MP-L/day) per cow, the ten herd farms were divided into low (L < 15), medium (15 20). Data were also divided according to the lactation numbers in first, second, third or greater. Eight lactation curve models commonly used in literature were compared. The models were individually adjusted for each lactation. The goodness of fit used for comparison of those models was the coefficient of determination, mean square error, mean square prediction error and the Bayesian information criterion. The values for the goodness of fit obtained in each model were compared by using 95% probability confidence interval. Wilmink (1987) model showed a better adjustment for cows of the first lactation numbers, whereas the Wood (1967) model showed a better adjustment for cows of the third or greater lactations numbers for the low milk production groups. Wood model showed a better adjustment for all the lactation numbers for the medium milk production group. Dijkstra (1997) model showed a better adjustment for all lactation numbers for the high milk production group. Despite of being more recent, the model by Pollott (2000), mechanist based and with a higher number of parameters, showed a good convergence for the used data. © 2010 Sociedade Brasileira de Zootecnia.

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