Location: Forage-animal Production ResearchTitle: Ergovaline disappearance from a ruminally incubated buffer) Author
Submitted to: Joint Meeting of the ADSA, AMSA, ASAS and PSA
Publication Type: Abstract only
Publication Acceptance Date: 3/6/2012
Publication Date: 7/15/2012
Citation: Foote, A.P., Kristensen, N.B., Klotz, J.L., Brown, K.R., Strickland, J.R., Kim, D.H., Koontz, A.E., Mcleod, K.R., Bush, L.P., Harmon, D.L. 2012. Ergovaline disappearance from a ruminally incubated buffer. J. Anim. Sci. Vol. 90, Suppl. 3:94. Interpretive Summary:
Technical Abstract: Ergovaline (ERV) is an alkaloid present in endophyte-infected tall fescue (Lolium arundinaceum) that is thought to contribute to fescue toxicosis in cattle. To determine the disappearance of ERV in the temporarily washe reticulorumen, steer (n=8) were pair-fed alfalfa cubes at 1.5× NEM and received ground endophyte-infected tall fescue seed (E+) or endophyte-free tall fescue seed (E-) via rumen cannula 2× daily for 7 d at thermoneutral (TN; 21 °C) and heat stress (HS; 32°C) conditions. On d 8 rumen contents were removed and the rumen was emptied and rinsed. Buffer containing VFA was incubated in the following sequence +0.015 mg ergovaline/kg BW (1×EXT), and +0.045 mg ergovaline/kg BW (3×EXT). ERV was supplied as a seed extract. For each buffer there were 2 30-min incubations. There was a 30 min incubation of a treatment buffer with no sampling followed by removal of the buffer and incubation of an identical sampling buffer with the addition of Cr-EDTA and. Analysis of ERV was conducted using UPLC with tandem mass spectrometry detection. Disappearance of ERV was calculated by changes in the pool size in the buffer corrected for dilution by physiological water and passage out of the rumen. In this model, ERV disappearance is the sum of absorption into the blood, adsorption to the rumen wall or residual particles, and metabolism. Treatment of steers with seed had no effect on ERV disappearance (P=0.64). The interaction of temperature and buffer (P=0.08) indicated that ERV disappearance increased at HS (P=0.01) but not at TN (P=0.19). Data indicate that increasing the ERV ruminal dose increases ERV disappearance in steers at high ambient temperatures which could be caused by increased absorption rate, metabolism, or binding of ERV.