Animal Industry News, February 2004, Vol. 5, No. 1

Newsletter produced by Iowa Department of Agriculture and Land Stewardship.

Feeding and the Equilibrium Feeder Animal Price-Weight Schedule, June 2005

The feeder animal price is a derivative in the sense that its value depends upon the price of animals for the consumption market. It also depends upon the biological growth technology and feed costs. Daily maintenance costs are of particular interest to the husbander because they can be avoided through accelerated feeding. In this paper, the optimal feeding path under equilibrium feeder animal prices is established. This analysis is used to gain a better understanding of feeding decisions, regulation in feedstuff markets, and the consequences of genetic innovations. It is shown that days on feed can increase or decrease with a genetic innovation or other improvement in feed conversion efficiency. The structure of comparative prices for feeder animals at different weights, the early slaughter decision, and equilibrium in feeder animal markets are also developed. Feeder animal prices can increase over a weight interval if biological feed efficiency parameters are low over the interval.

Biosecurity and Infectious Animal Disease, November 2005

The spatial dimension of agricultural production is important when a communicable disease enters a region. This paper considers two sorts of biosecurity risk that producers can seek to protect against. One concerns the risk of spread: that neighboring producers do not take due care in protecting against being infected by a disease already in the region. In this case, producer efforts substitute with those of near neighbors. For representative spatial production structures, we characterize Nash equilibrium protection levels and show how spatial production structure matters. The other sort of risk concerns entry: that producers do not take due care in preventing the disease from entering the region. In this case, producer heterogeneity has subtle effects on welfare loss due to strategic behavior. Efforts by producers complement, suggesting that interfarm communication will help to redress the problem.

Animal Industry News, March 2008, Vol. 9, no. 1

Newsletter produced by Department of Agriculture and Land Stewardship about the animal industry in Iowa.

Animal Industry News, 2009, Vol. 10, no. 1

Newsletter produced by Department of Agriculture and Land Stewardship about the animal industry in Iowa.

Animal Industry News, February 2000, Vol. 1, No. 1

Newsletter produced by Iowa Department of Agriculture and Land Stewardship.

Animal Industry News, March 2007, Vol. 8, No. 1

Newsletter produced by Iowa Department of Agriculture and Land Stewardship.

Animal Industry News, 2010, Vol. 11, no. 1

Newsletter produced by Department of Agriculture and Land Stewardship about the animal industry in Iowa.

Animal Industry News, February 2001, Vol. 2, no. 1

Newsletter produced by Department of Agriculture and Land Stewardship about the animal industry in Iowa.

Animal Industry News, April 2002, Vol. 3, no. 1

Newsletter produced by Department of Agriculture and Land Stewardship about the animal industry in Iowa.

Animal Industry News, February 2005, Vol. 6, no. 1

Newsletter produced by Department of Agriculture and Land Stewardship about the animal industry in Iowa.

Animal Industry News, April 2006, Vol. 7, no. 1

Newsletter produced by Department of Agriculture and Land Stewardship about the animal industry in Iowa.

Iowa Animal Industry News, 2012, Vol. 13, no. 1

Newsletter produced by Department of Agriculture and Land Stewardship about the animal industry in Iowa. Previously titled Animal Industry News.

Iowa Animal Industry News, 2011, Vol. 12, no. 1

Newsletter produced by Department of Agriculture and Land Stewardship about the animal industry in Iowa. Previously titled Animal Industry News.

Sediment Control in Bridge Waterways, February 1990

The objective of this study was to develop guidelines for use of the Iowa Vanes technique for sediment control in bridge waterways. Iowa Vanes are small flow-training structures (foils) designed to modify the near-bed flow pattern and redistribute flow and sediment transport within the channel cross section. The structures are installed at an angleof attack of 15 - 25' with the flow, and their initial height is 0.2 - 0.5 times water depth at design stage. The vanes function by generating secondary circulation in the flow. The circulation alters magnitude and direction of the bed shear stress and causes a reduction in velocity and sediment transport in the vane controlled area. As a result, the river bed aggrades in the vane controlled area and degrades outside. This report summarizes the basic theory, describes results of laboratory and field tests, and presents the resulting design procedure. Design graphs have been developed based on the theory. The graphs are entered with basic flow variables and desired bed topography. The output is vane layout and design. The procedure is illustrated with two numerical examples prepared with data that are typical for many rivers in Iowa and the midwest. The report also discusses vane material. In most applications, the vane height will be between 30% and 50% of bankfull flow depth and the vane length will be two to three times vane height. The vanes will be placed in arrays along the bank of the river. Each array will contain two or more vanes. The vanes in an array will be spaced laterally a distance of two to three times vane height. The streamwise spacing between the arrays will be 15 to 30 times vane height, and the vane-to-bank distance will be three to four times vane height. The study also show that the first (most upstream) array in the vane system must be located a distance of at least three array spacings upstream from the bridge, and there must be at least three arrays in the system for it to be effective at and downstream from the third array.