Managing Dairy Heifer Growth Investment

Accelerated prepubertal growth rates can lower heifer raising costs but may put heifers at risk for impaired mammary development and have been found to be detrimental decreased to milk production in the first lactation. The tradeoff between heifer raising costs and milk production loss is examined in a capital budgeting model. Monthly annuity net present value of a heifer investment through the first lactation is assessed for heifers calving at 20, 22, 24, 26 and 28 months of age. A 24 mo AFC base case strategy with 9009.5 kg subsequent first lactation milk yields $7.34 in returns per month. Accelerated growth resulted in higher returns ($12.77/mo for 20 mo AFC; $9.86/mo for 22 mo AFC) when milk production is not affected as total raising costs decline relative to the base case. Slower growth resulted in lower returns ($5.12/mo for 26 mo AFC; $3.15/mo for 28 mo AFC). When milk production declines, revenues decline as do feed and marketing costs which are a function of milk produced. Adjusting for factors, breakeven milk production losses were 10.6 % for 20 mo AFC and 5.3 % for 22 mo AFC relative to the 24 mo AFC base. These results were not sensitive to the assumed discount rate, heifer feed costs or discount rate. Other operation-specific heifer management factors including calving season, reproduction, herd size/expansion considerations and, in the longer-term, heifer facilities investments may be more significant economically than the differences found in this analysis.Heifer growth, Economics, Investment, Livestock Production/Industries,

Kinetic modelling of methanol synthesis over commercial catalysts: A critical assessment

Kinetic modelling of methanol synthesis over commercial catalysts is of high importance for reactor and process design. Literature kinetic models were implemented and systematically discussed against a newly developed kinetic model based on published kinetic data. Deviations in the sensitivities of the kinetic models were explained by means of the experimentally covered parameter range. The simulation results proved that an extrapolation of the working range of the kinetic models can lead towards significant simulation errors especially with regard to pressure, stoichiometric number and CO/CO$_{2}$-ratio considerably limiting the applicability of kinetic models frequently applied in scientific literature. Therefore, the validated data range for kinetic models should be considered when detailed reactor simulations are carried out. With regard to Power-to-Methanol processes special attention should be drawn towards the rate limiting effect of water at high CO$_{2}$ contents in the syngas. Moreover, it was shown that kinetic models based on data measured over outdated catalysts show significantly lower activity than those derived from state-of-the-art catalysts and should therefore be applied with caution for reactor and process simulations. The plausible behavior of the herein proposed kinetic model was demonstrated by a systematic comparison towards established kinetic approaches within both, an ideal kinetic reactor and an industrial steam cooled tubular reactor. Relative to the state-of-the-art kinetic models it was proven that the herein proposed kinetic model can be applied over the complete industrially relevant working range for methanol synthesis

Managing Dairy Heifer Growth Investment

Accelerated prepubertal growth rates can lower heifer raising costs but may put heifers at risk for impaired mammary development and have been found to be detrimental decreased to milk production in the first lactation. The tradeoff between heifer raising costs and milk production loss is examined in a capital budgeting model. Monthly annuity net present value of a heifer investment through the first lactation is assessed for heifers calving at 20, 22, 24, 26 and 28 months of age. A 24 mo AFC base case strategy with 9009.5 kg subsequent first lactation milk yields $7.34 in returns per month. Accelerated growth resulted in higher returns ($12.77/mo for 20 mo AFC; $9.86/mo for 22 mo AFC) when milk production is not affected as total raising costs decline relative to the base case. Slower growth resulted in lower returns ($5.12/mo for 26 mo AFC; $3.15/mo for 28 mo AFC). When milk production declines, revenues decline as do feed and marketing costs which are a function of milk produced. Adjusting for factors, breakeven milk production losses were 10.6 % for 20 mo AFC and 5.3 % for 22 mo AFC relative to the 24 mo AFC base. These results were not sensitive to the assumed discount rate, heifer feed costs or discount rate. Other operation-specific heifer management factors including calving season, reproduction, herd size/expansion considerations and, in the longer-term, heifer facilities investments may be more significant economically than the differences found in this analysis

Multicenter, International Assessment of the Eighth Edition of the American Joint Committee on Cancer Cancer Staging Manual for Conjunctival Melanoma

MTG4Molecular tumour pathology - and tumour genetic