S.M.
Colorado
Answer: A couple of articles and a publication listed below deal with using amaranth as emergency forage for livestock. These resources note that high nitrate levels might be a concern.
Resources:
Anon. 2006. Current research projects: Forage amaranth. 2 p.
Sleugh, Byron B., et al. 2001. Forage nutritive value of various amaranth species at different harvest dates. Crop Science. March-April. p. 466-472.
Watson, Steve L., et al. 1993. Emergency and supplemental forage. (PDF / 233K) Kansas State University Department of Agronomy. MF-1073. 8 p.
Weibye, Cheryl. 1990. Amaranth: High-protein emergency forage. Hay & Forage Grower. August. p. 8, 11.