The experimental design for this experiment is a 5x5 Latin square. Treatments include source of dietary fat (commodity soybean oil or high oleic soybean oil) and concentration (3% or 6% of diet dry matter) arranged in a 2x2 factorial with the addition of a negative control (no added fat).

Ruminally cannulated steers (n = 5 total) will be utilized for this experiment. Cattle will be randomly assigned to a sequence of treatments so that they receive all treatments over a term of 5 periods. Cattle will be adapted to the respective diet for 14 days followed by a 5-day collection period. Diets will be fed ad libitum once daily. Rations and refusals will be sampled each day and composited by period. During the 5-day sample collection period, total feces and urine will be collected and sampled as previously described (Hales et al., 2017). By collecting total urine and feces, we will be able to estimate the digestion and metabolism of the rations (dry matter, organic matter, energy) and individual nutrients (fiber, starch, nitrogen, and fat). Additionally, to determine the effects of the source and amount of fat on rumen metabolism specifically, we will perform an in situ digestibility trial to measure rumen degradability of the rations using previously published guidelines (Vanzant et al., 1998) and established methods in our lab. Rumen fluid samples will be collected from the ventral rumen at increasing intervals following feeding to evaluate volatile fatty acid production (Foote et al., 2013).