Animal Science Department


First Advisor

Paul J. Kononoff

Date of this Version



A THESIS Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of Requirements For the Degree of Master of Science, Major: Animal Science, Under the Supervision of Professor Paul J. Kononoff. Lincoln, Nebraska: May, 2018

Copyright (c) 2018 Mickayla Ann Marie Myers


Byproducts have played a major role in dairy nutrition by providing a cheaper protein and fiber source, while also utilizing a product that would otherwise be waste from the human perspective. Use of byproducts in the dairy industry should allow for continued and overall increases in production and efficiency of the dairy industry. Two of the more popular byproducts in the dairy industry today are dried distillers grains and solubles and canola meal.

In the first experiment, 12 multiparous lactating Jersey cows were used evaluate the feeding value of dried distillers grains and solubles (DDGS) or canola meal. A replicated 4 × 4 Latin square design was used to compare four different dietary treatments. Treatments were composed of a control (CON) containing no byproducts, a treatment diet containing 10% (DM basis) reduced fat DDGS (pDDGS), a 10% DDGS treatment with an alternative distillers grains source (aDDGS), and a 10% canola meal (CanM) treatment. Results suggest that milk production can be maintained when feeding these byproducts. However, energy utilization differences are observed, specifically in gross energy, digestible energy, metabolizable energy and energy balance (Mcal/kg of DM). The alternative source of DDGS contained the greatest amount of gross energy, digestible energy, and metabolizable energy. The control and the alternative source of DDGS contained the greatest energy balance. Dry matter, organic matter, crude protein, and neutral detergent fiber digestibility differences were also observed between treatments, specifically the control and the DDGS treatments had the greatest digestibility.

In the second experiment, a comparison of sample preparation methods of urine to be analyzed for energy content by bomb calorimetry was conducted. The two methods to be tested included a lyophilization and oven drying method. Results of this study suggest that there were significant differences in gross energy content and total urine energy depending on which sample preparation method was used. The lyophilization method resulted in a greater gross energy and total urine energy compared to oven drying method, creating a negative method difference.

Advisor: Paul J. Kononoff

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Dairy Science Commons