Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)


Agricultural Engineering

First Advisor

Dr. Donald P. Froehlich


An animal's environment is affected by all surrounding conditions. The thermal environment; the effects of air temperature, moisture, and velocity balanced with animal heat and moisture production, is part of the total environment. It is one of the most important influences of an animal's surroundings since 25 to 40 percent of an animal's gross feed energy is converted to heat and moisture loss to the environment. Poor livestock thermal environments occur because of poor livestock structures. A structure with the correct thermal environment will provide conditions such that the homeothermic animal will be in a zone of thermal comfort. If the animal’s thermal environment falls below the zone of thermal comfort, cold stress takes place and the animal increases heat production which decreases animal weight gain. To achieve proper conditions, the building must be correctly constructed and ventilated. The building construction and ventilation system are interdependent between them to provide a zone of livestock structures, presently, are harmony must occur thermal comfort constructed under design generalities. Specifications in ventilation type and construction remain virtually the same throughout a climatic area. Design temperatures and animal heat production values are generalized to constant values. Seasonal temperature and moisture highs and lows can cause stress to an animal in a structure designed for a region's general climate. A simulation of interior environmental conditions throughout the animal's life span would aid in the proper construction and ventilation of an individual structure by considering the varying effects of animal heat and moisture production. in conjunction with climatic variation. These effects change quickly through the animal's life span. Better control is needed to follow these variables to properly match building construction with the ventilation system. A simulation considering the rapidly changing environmental effects would develop structural ventilation curves, predict interior environmental temperature, estimate supplemental heating/cooling, and produce other desired parameters, such as required feed intake, as the animal grows. Additionally, a simulation maybe used as the program statement for the controller of the ventilation system. These simulations, however, neglected the effects of animal growth and seasonal climatic changes throughout the animal's lifecycle. Research was, thus, initiated with the following specific objectives: 1) Develop a simulation to predict interior environmental conditions, in a livestock structure, as animal growth and climatic conditions change throughout a segment of the animal's life cycle. 2) Evaluate the simulation performance and sensitivity for a specific geographic location, climate, construction, and occupant.

Library of Congress Subject Headings

Livestock -- Housing

Livestock -- Housing -- Heating and ventilation

South Dakota State University Theses



Number of Pages



South Dakota State University