Date Available


Year of Publication


Degree Name

Master of Science (MS)

Document Type

Master's Thesis


Agriculture, Food and Environment


Animal and Food Sciences

First Advisor

Dr. David L. Harmon


Eight steers were used in a replicated 4 x 4 Latin square design experiment to study the rumen metabolism of polyunsaturated fatty acids. The animals were fed a concentrate diet based on cracked corn grain, corn silage and hay fescue (K31). The dietary fat treatments were a negative control, tallow added at 60g/day, fish oil at 60g/day and heterotrophically grown microalgae high in DHA at 100g/day. Treatments were incorporated immediately prior to feeding each day and dosed through a ruminal fistula mixed with 0.45kg of the diet. Animals were fed at 1.75 x NEm once daily during adaptation then switched to twice daily during sample collection. Samples rumen, reticulum and omasal contents were used to determine ruminal digestion and metabolism of fatty acids while urine and feces were collected to determine diet digestibility and N balance. The experiment was analyzed as a Latin Square design with a 2 x 2 factorial using mixed models in SAS. There was no difference among treatments for DMI, urine or fecal excretion, N balance, total VFA concentrations, omasal or reticular flow, and apparent digestibility. Fat treatments had lower blood plasma C18:0 than control. Algae increased flow of C18:1 isomers and increased DHA in plasma.

Digital Object Identifier (DOI)