Effects of Sericea Lespedeza supplementation on steers grazing wild-type endophyte-infected tall fescue [abstract]

Authors: POUDEL, SANJOK - Virginia Tech; PENT, GABRIEL - Virginia Tech; FIKE, JOHN - Virginia Tech; Davis, Brittany; Zeller, Wayne

Submitted to: American Society of Animal Science Southern Section Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 1/30/2024
Publication Date: 3/2/2024
Citation: Poudel, S., Pent, G.J., Fike, J.H., Davis, B.E., Zeller, W.E. 2024. Effects of Sericea Lespedeza supplementation on steers grazing wild-type endophyte-infected tall fescue [abstract]. In: Journal of Animal Science. American Society of Animal Science Southern Section Meeting, January 27-30, 2024, Louisville, Kentucky. p. 48-49.

Interpretive Summary:

Technical Abstract: Fescue toxicosis poses a significant challenge to the United States beef industry, resulting in considerable economic losses. This syndrome arises from the consumption of tall fescue (Schedonorus arundinaceous) infected with the wild-type endophyte (WE; Epichloe coenophiala), which produces toxic alkaloids. The most effective solution for mitigating fescue toxicosis is renovating WE tall fescue pastures to novel endophyte-infected (NE) tall fescue. However, this pasture renovation is costly and may not be feasible under certain conditions, with the economic profitability taking up to three years. While the potential of condensed tannins (CTs) in specific leguminous forages to reduce the absorption of toxic alkaloids is recognized, their use as supplements remains underexplored. This study aims to investigate the potential of CT-containing feed supplements, specifically sericea lespedeza (Lespedeza cuneata) pellets, in reducing the post-ingestive effects of fescue toxicosis in steers. Over two summers, twelve steers were assigned to either sericea lespedeza (LES) or LES mixed with polyethylene glycol (LES + PEG) as a positive control for 12 weeks. Body weight, hair retention score, rectal and extremities temperatures, cortisol level, and lumen area of caudal arteries were collected at four-week intervals. Data were analyzed using a mixed effect ANOVA test in SAS Studio 3.5. Steers on the LES diet exhibited significantly lower (p < 0.05) hair retention scores compared to those on the LES + PEG diet. In 2021, steers on the LES diet showed higher (p = 0.0101) ADG, while in 2022, there was no difference (p = 0.9916) in ADG between the treatments. Steers on the LES diet displayed higher (p = 0.0332) tail skin temperatures and lower (p < 0.0001) rectal temperatures compared to those on the LES + PEG diet. Hair cortisol levels were higher (p < 0.05) in steers on the LES + PEG diet than in those on the LES diet. Additionally, steers supplemented with the LES + PEG diet showed a 21.2% smaller caudal artery lumen area compared to those on the LES diet (p < 0.01). These findings underscore the potential of CTs in reducing the post-ingestive effects of fescue toxicosis. However, further research is needed to explore the complex mechanisms underlying these effects, establish the long-term efficacy of such interventions, and extend the investigation to include a broader range of physiological parameters affecting livestock health and performance.