Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)

Department / School

Agricultural Engineering


Continued and increased use of confinement methods for fattening beef cattle in South Dakota _are inevitable for many· reasons: surface runoff from feedlots is practically eliminated, the cost and labor required for bedding are decreased, problems with adverse surface conditions and manure accumulation are reduced, diseases are usually decreased, and national and worldwide demands for red meat are augmenting. When animal densities are increased maximum utilization can be made of the labor saving devices obtainable with increased capitalization. However, as animal densities increase environmental maintenance within a confinement structure becomes an increasingly important design consideration. Therefore, accurate and pertinent information is needed that will allow livestock producers to employ ventilation system designs that will improve environmental relations and allow the maximum economic production efficiencies. Various university experiments, both winter and summer, show only slight advantages in rate of gain and feed efficiency for controlled environment confinement systems as compared to open front confinement buildings which have natural ventilation systems. It is generally believed that the marginal profits realized from this slight advantage do not cover the amortized investment. This suggests the need for increased emphasis on improving the design of open front or cold confinement beef buildings that are becoming increasingly popular in many areas. Proper design of confinement structures, which utilize natural ventilation systems; are dependent upon the availability of representative data that describe the relationships. between environmental, climatic, and structural characteristics of livestock housing systems. Southermation, ridge vents, and eave inlets are current design inclusions of open front confinement barns. Ridge vent design is one of the most controlling aspects of such· a system. Research instituted towards. the development of an optimum ridge vent and the description of the performance of various ridge vents has been minimal and inconclusive. Additionally, many of the studies have been laboratory tests and do not reflect responses under actual weather conditions. Therefore, a model study, employing the techniques of dimensional analysis, ,was initiated in the spring of 1973 at South Dakota State University with the following objectives: 1) Evaluation of the effects of ridge vent design on airflow characteristics and temperature in a model of an open front beef confinement building under actual weather conditions. 2) Determination of prediction equations for the relationships between wind velocity and outlet velocity in a model of an open front beef confinement building.

Library of Congress Subject Headings

Barns -- Heating and ventilation

Farm buildings

South Dakota State University Theses



Number of Pages



South Dakota State University