Effects of housing, perches, genetics, and 25-hydroxycholecalciferol on keel bone deformities in laying hens

Several studies have shown a high prevalence of keel bone deformities in commercial laying hens. The aim of this project was to assess the effects of perch material, a vitamin D feed additive (25-hydroxyvitamin D(3); HyD, DSM Nutritional Products, Basel, Switzerland), and genetics on keel bone pathology. The study consisted of 2 experiments. In the first experiment, 4,000 Lohmann Selected Leghorn hens were raised in aviary systems until 18 wk of age. Two factors were investigated: perch material (plastic or rubber-coated metal) and feed (with and without HyD). Afterward, the hens were moved to a layer house with 8 pens with 2 aviary systems. Daily feed consumption, egg production, mortality, and feather condition were evaluated. Every 6 wk, the keel bones of 10 randomly selected birds per pen were palpated and scored. In the second experiment, 2,000 Lohmann Brown (LB) hens and 2,000 Lohmann Brown parent stock (LBPS) hens were raised in a manner identical to the first experiment. During the laying period, the hens were kept in 24 identical floor pens but equipped with different perch material (plastic or rubber-coated metal). The same variables were investigated as in the first experiment. No keel bone deformities were found during the rearing period in either experiment. During the laying period, deformities gradually appeared and reached a prevalence of 35% in the first experiment and 43.8% in the second experiment at the age of 65 and 62 wk, respectively. In the first experiment, neither HyD nor the aviary system had any significant effect on the prevalence of keel bone deformities. In the second experiment, LBPS had significantly fewer moderate and severe deformities than LB, and rubber-coated metal perches were associated with a higher prevalence of keel bone deformities compared with plastic perches. The LBPS laid more but smaller eggs than the LB. Again, HyD did not affect the prevalence of keel bone deformities. However, the significant effect of breed affiliation strongly indicates a sizeable genetic component that may provide a basis for targeted selection.

Government Influence and the Failure of Fannie Mae and Freddie Mac

In 2008 two government-sponsored enterprises, Fannie Mae and Freddie Mac, were placed into conservatorship due to insolvency. The financial bailout of the two publically traded corporations came at the expense of the American tax payer. This study investigates the relationship between direct and indirect government influence and the increasing risk taking of Fannie Mae and Freddie Mac from the late 1990’s through their conservatorship in 2008. As government-sponsored enterprises Fannie Mae and Freddie Mac have many special advantages that other publically traded companies did not possess. These advantages allowed Fannie Mae and Freddie Mac to increase their profitability. Theoretical literature regarding Congress and the bureaucracy suggests that the actions of bureaucrats can be linked to the preferences of Congressional members because bureaucrats are responsive to potential threats or perceived threats from the legislature. This theory is applicable to Fannie Mae and Freddie Mac, and is used to explain why the government was able to directly and indirectly influence the government-sponsored enterprises. Overall this investigation has determined that the United States government pursued a clear mission that determined to increase the availability of housing to all Americans, specifically to low-income and under-served individuals, through the use of the government-sponsored enterprises. Despite this link there is no conclusive data to show that the pursuit of this housing mission led Fannie Mae and Freddie Mac to operate in riskier business segments. This study has also found that motivation regarding profit-seeking and compensation structure provide a more plausible explanation for why the government-sponsored enterprises began to engage in riskier business practices that led to their insolvency.

The Choice of Expedient Regulatory Controls on Housing Market Using Short-Term Equilibria Model

Khutoretsky dealt with the problem of maximising a linear utility function (MUF) over the set of short-term equilibria in a housing market by reducing it to a linear programming problem, and suggested a combinatorial algorithm for this problem. Two approaches to the market adjustment were considered: the funding of housing construction and the granting of housing allowances. In both cases, locally optimal regulatory measures can be developed using the corresponding dual prices. The optimal effects (with the regulation expenditures restricted by an amount K) can be found using specialised models based on MUF: a model M1 for choice of the optimum structure of investment in housing construction, and a model M2 for optimum distribution of housing allowances. The linear integer optimisation problems corresponding to these models are initially difficult but can be solved after slight modifications of the parameters. In particular, the necessary modification of K does not exceed the maximum construction cost of one dwelling (for M1) or the maximum size of one housing allowance (for M2). The result is particularly useful since slight modification of K is not essential in practice.