Beet pulp as an alternative roughage source for feedlot steers fed feedlot diets based on dry-rolled corn containing 30% modified distillers grains with solubles

Authors: Neville, Bryan; PICKINPAUGH, W - North Dakota State University; MITTLEIDER, L - North Dakota State University; CATON, J - North Dakota State University

Submitted to: Applied Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/23/2023
Publication Date: 8/1/2023
Citation: Neville, B.W., Pickinpaugh, W.J., Mittleider, L.J., Caton, J.S. 2023. Beet pulp as an alternative roughage source for feedlot steers fed feedlot diets based on dry-rolled corn containing 30% modified distillers grains with solubles. Applied Animal Science. 39(4):236-243. https://doi.org/10.15232/aas.2022-02379.
DOI: https://doi.org/10.15232/aas.2022-02379

Interpretive Summary: The effects of replacement of corn silage or grass hay with beet pulp as a roughage in finishing diets containing 30% modified distillers grains with solubles was explored. Steers fed beet pulp in the feedlot study had decreased carcass weight and backfat potentially indicating that beet pulp when include at a 1:1 substitution for corn silage may not support sufficient animal performance. Signs of acidosis observed in the feedlot study resulted in inclusion of 3% wheat straw to the beet pulp fed steers potentially indicating that beet pulp may not be providing sufficient roughage to maintain appropriate ruminal pH when fed as the sole source of roughage in high concentrate feedlot diets. Small improvements in digestibility seen with diets containing beet pulp indicate further research would need to be explored at what point beet pulp can affectively replace other roughage sources while still supporting rumen function and beef cattle performance.

Technical Abstract: Objectives: These studies evaluated the impacts of roughage source when fed in combination with modified distillers grains with solubles on digestion, ruminal fermentation, and pH; as well as growth performance of steers. Materials and Methods: Three ruminally and duodenally cannulated steers were used the digestibility experiment. One-hundred sixty-five steer calves were randomly assigned to feedlot pens (n = 5/treatment) were utilized for the feedlot experiment. Treatments were based on roughage source and consisted of 1) 20% DM inclusion of corn silage (CS), and 2) 20% DM inclusion of beet pulp (BP), or 3) 10% DM inclusion of grass hay (GH). In the feedlot study 3% wheat straw was added to BP following observations of acidosis. Results and Discussion: Intake (percentage of BW basis) was less for steers fed either CS or GH compared to steers fed BP (P /= 0.34). Hot carcass weight was greater for steers fed either GH or CS (P /= 0.16). Implications and Applications: The decreased carcass weight and backfat reported in the feedlot study may indicate that beet pulp, when include at a 1:1 substitution for corn silage, may not support similar animal performance to more traditional roughage sources. Research evaluating starch digestibility and physically effective fiber of beet pulp may also prove beneficial when fed in combination with modified distillers grains with solubles.