1) Research data on changes in rumen fermentation and pH.
2) Research data on fiber digestibility.
3) Publication and presentation of results at scientific meetings.
4) Presentation of research to local constituents at field days and other events.

Update:

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Evaluation of soybean hulls as roughage sources in feedlot rations

Bryan Neville, Animal Scientist, Carrington REC


Goals/Objectives:
The overall objective of this research was to evaluate the fiber value provided by soybean hulls in feedlot diets.
Specific objectives included:
1) To evaluate performance of changes in ruminal fermentation and pH with increasing concentrations of soybean hull inclusion.
2) To evaluate changes in ruminal and duodenal fiber kinetics of high grain rations containing soybean hulls.

Results:
Intake was negatively impacted by increasing soyhull inclusion and decreased by 2.1 kg/d when corn silage was completely replaced with soyhulls. Intake and total tract digestibility of NDF were not affected by rate of soyhull inclusion or added straw. Further, duodenal flow of NDF was not affected by rate of soyhull inclusion but tended to decrease with added straw in the diet. In the current research replacing corn silage with soyhulls did not affect ruminal pH; however, adding wheat straw to the diet increased ruminal pH compared to the same diets without straw. The fact replacing greater amounts of corn silage with soyhulls did not impact ruminal pH is interesting. Based on lower expected effective fiber content of soyhulls we had anticipated that ruminal pH would have decreased with increasing soyhull replacement of corn silage. The response in ruminal fluid pH to the addition of 3% wheat straw to the diet was more traditional, and likely represents increases in rumination and addition of buffers from salvia to the rumen.

Presentations/Deliverables:
1) This data will be presented at the Western Section American Society of Animal Science Meetings in 2021.
2) A manuscript detailing the results of this project is being drafted and will be submitted to a peer-reviewed journal.

Production Outcomes:
In conclusion, decreases in intake observed in this study would likely decrease feedlot cattle performance and underscores the need for additional research prior to recommending utilizing soyhulls as a roughage source for feedlot cattle. Data evaluating soyhulls as a roughage source in high-concentrate diets are lacking and more research on the impacts of soyhull inclusion on performance of feedlot cattle would be needed to fully understand the impacts of utilizing this feed resource.