Ergot alkaloid exposure during gestation: I. Impacts on ewe milk production, lamb birth weight and pre-weaning growth rate

Authors: BRITT, JESSICA - Clemson University; GREENE, MASLYN - Clemson University; WILBANKS, SARAH - Clemson University; BERTRAND, J. KEITH - Clemson University; Klotz, James; BRIDGES, JR., W - Clemson University; AIKEN, GLEN - University Of Florida; ANDRAE, JOHN - Clemson University; DUCKETT, SUSAN - Clemson University

Submitted to: Animals
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/17/2020
Publication Date: 12/3/2020
Citation: Britt, J.L., Greene, M.A., Wilbanks, S.A., Bertrand, J., Klotz, J.L., Bridges, Jr., W.C., Aiken, G.E., Andrae, J.G., Duckett, S.K. 2020. Ergot alkaloid exposure during gestation: I. Impacts on ewe milk production, lamb birth weight and pre-weaning growth rate. Animals. 10(12). Article 2291. https://doi.org/10.3390/ani10122291.
DOI: https://doi.org/10.3390/ani10122291

Interpretive Summary: Ergot alkaloids are mycotoxins produced by endophyte-infected tall fescue. This study was conducted to examine how ergot alkaloid exposure during specific stages of gestation in ewes with different dopamine receptor 2 genotypes altered ewe and lamb performance. Exposure to ergot alkaloids during late gestation reduced lamb birth weight; however, exposure to ergot alkaloids during gestation, regardless of stage, reduced milk production. Lambs born to dams exposed to ergot alkaloids during mid gestation had slower growth rates and lower weaning weights. These results demonstrate that the exposure to ergot alkaloids during gestation in sheep can negatively impact lactation, growth of offspring and birth and weaning weights. Recommendations would include strategies to mitigate the negative impact of endophyte-infected tall fescue on ewes during gestation to improve production. This work will be of value to producers by providing more information on how to manage reproductive livestock on tall fescue pastures.

Technical Abstract: Tall fescue [Lolium arundinaceum (Schreb.) Darbysh; Schedonorus phoenix (Scop.) Holub] is the primary cool season perennial grass utilized in the eastern U.S. and most contains an endophyte (Epichloë coenophiala) that produces ergot alkaloids. Ergot alkaloids are mycotoxins that act as dopamine agonists to suppress prolactin and induce vasoconstriction. The experiment was designed as a 3 x 2 x 2 factorial with DRD2 genotype (AA, AG, GG), fescue seed treatment (E- or E+), stage of gestation (MID, d 35 – 85; LATE, d 86 – parturition) and all interactions in the model. Pregnant Suffolk ewes (n = 60) were stratified by genotype and fed a total mixed ration containing E- or E+ fescue seed during MID and/or LATE gestation according to treatment assignment. Serum prolactin concentrations were lower (p < 0.05) in ewes when consuming E+ seed but did not differ by maternal DRD2 genotype or two-way interaction. Lamb birthweight was lower (p < 0.05) in ewes fed E+ seed during LATE gestation. Pre-weaning growth rate, milk production and total weaning weight was reduced (p < 0.05) in ewes fed E+ fescue seed during MID and LATE gestation. Ergot alkaloid exposure during LATE gestation reduces lamb birth weight; however, exposure during MID and LATE gestation reduced lamb growth rate, milk production and total weaning weight.