Effects on Intake of Supplementing Low-Quality Roughage with Protein-Rich Feeds

Intake responses of ruminants to supplementation with protein-rich concentrates or legume hays have been related to the ratio of nitrogen (N) content and organic matter digestibility (OMD) of the basal feed. Marginal intake effect of supplements, i.e. change of organic matter intake (OMI) from the basal feed per unit OMI from supplement, decreased on average from 1.7 to 0 and -0.8 g. g-1 at N/OMD of 0.010, 0.016 and \u3e 0.030 g. g-1, respectively. Marginal effect of supplements defined as change of total digestible organic matter intake (DOMI) per g DOMI from supplement was 2.5, 1 and 0.3 g. g-1 for N/OMD of 0.010, 0.017 and \u3e 0.030 g. g-1, respectively. From these effects, marginal productivity of a protein-rich concentrate, i.e. increase in liveweight gain (kg) per kg dry matter of supplement, was estimated to decline from 0.9 kg. kg-1 to less than 0.2 kg. kg-1 when N/OMD is raised from 0.010 to values \u3e 0.030 g. g-1

Uncertain Time to Completion in a Sequential Investment Problem:a Theoretical and Empirical Analysis

We develop a real options framework for a sequential oil project in which the oil company has to complete its development stage before it is able to start its production stage. Both the oil price and the duration of the development stage are uncertain. For each stage we determine the associated optimal price threshold that reflects an optimal investment timing. The goal of the article is to study the determination of these two thresholds from both a theoretical and empirical perspective. Because the oil price and the time to completion are uncertain, it is imperative to coordinate the thresholds in such a way that upon completion of the development stage it is more probable that the oil company can immediately start its production stage. Our numerical analysis is based on Uganda’s oil project in the Albertine Graben region. We show that changes in the characteristics of the oil price have a more pronounced effect on the development price threshold because it depends also on the production price threshold. Interestingly, we observe that it could be optimal for the oil company to start its development stage later in case of a shorter expected time to completion. This happens when it expects the oil price to grow relatively quickly