Intake, digestibility, and rumen fermentation by lactating beef cows offered bermudagrass hay with different sources of dried distillers grains

Authors: Nieman, Christine; COFFEY, KENNETH - University Of Arkansas; YOUNG, ASHLEY - Simmons Foods; KEGLEY, ELIZABETH - University Of Arkansas; HORNSBY, PAUL - University Of Arkansas; HOLLENBACK, JIMMIE - Arkansas Cooperative Extension Service; PHILIPP, DIRK - University Of Arkansas

Submitted to: Applied Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/5/2022
Publication Date: 5/30/2022
Citation: Nieman, C.C., Coffey, K.P., Young, A.N., Kegley, E.B., Hornsby, P., Hollenback, J., Philipp, D. 2022. Intake, digestibility, and rumen fermentation by lactating beef cows offered bermudagrass hay with different sources of dried distillers grains. Applied Animal Science. https://doi.org/10.15232/aas.2021-02236.
DOI: https://doi.org/10.15232/aas.2021-02236

Interpretive Summary: Lactating beef cattle in the mid-south require protein and energy supplementation when the majority of the diet is low quality forages, such as bermudagrass hay. Dried distillers’ grains with solubles (DDGS), a co-product of the ethanol industry, can provide adequate nutrition for lactating beef cows consuming bermudagrass hay. Nutrient composition and availability, as well as animal performance and ruminal and intestinal degradability vary due to different DDGS processing methods and heating. The aim of the experiment was to evaluate bermudagrass hay intake, digestibility, and in situ forage and DDGS disappearance in diets of lactating beef cows consuming different sources of DDGS. Four, 8-year-old, multiparous, ruminally-cannulated lactating beef cows (535 ± 6.3 kg) were offered 4 experimental diets in an experiment with a 4 × 4 Latin Square Design. Cows were offered diets of bermudagrass hay for ad libitum consumption, either with no supplementation (control) or bermudagrass hay supplemented with DDGS at 4.5 g/kg BW from source one, source two, or DG2 heated. Supplementation of DDGS at 0.45 % BW did not reduce bermudagrass hay intake or in situ degradability of hay regardless of the source of DDGS.

Technical Abstract: Objective: Supplements of protein co-products, such as dried distillers grains with solubles (DDGS) are often offered to lactating beef cattle consuming bermudagrass [Cynodon dactylon (L.) Pers.]. The quality of DDGS can vary greatly by source which could potentially influence hay intake and digestibility. The aim of the experiment was to evaluate bermudagrass hay intake, digestibility, and in situ forage disappearance for lactating beef cows consuming DDGS from different sources. Materials and Methods: Four 8-year-old multiparous, ruminally-cannulated lactating beef cows (535 ± 6.3 kg) were offered each of four diets during 1 of the 4 periods in an experiment with a 4 × 4 Latin Square Design. Diets consisted of bermudagrass hay without supplement (CON), or supplementation with 0.45% of BW (DM basis) from either DDGS source one (DG1), DDGS source two (DG2), or DG2 that was heated (HDG2). Results and Discussion: Hay DM and neutral detergent fiber (NDF) intake (g/kg BW) were greater (P = 0.04) from CON compared to DG1 and DG2; HDG2 was intermediate and not different from any treatment. Ruminal ammonia concentrations were greater (P = 0.05) from DG1 and DG2 compared to the CON, and DG1 was greater than HDG2, but HDG2 was intermediate and did not differ from DG2 or CON. Ruminal acetate (P = 0.03) and butyrate (P = 0.01) had diet by time interactions and propionate was less (P < 0.05) in CON compared to the other diets. The water-soluble (A) fraction for bermudagrass hay was greater (P = 0.05) from cows offered DG1 than DG2 and HDG2 but not different from that of cows offered CON. Implications and Applications: Different DDGS sources and DDGS of 41.3 acid detergent insoluble nitrogen (ADIN) % of N did not affect total intake or digestibility of bermudagrass for lactating beef cows.