Thousands of Iowa farmers use grass or corn silage as feed for cattle. Under present feeding practices, this calls for many hours of labor; this can be practically by the use of self-feeding silos.
Armstrong, Ray E.
"Self-Feed Silage to Cut Labor,"
Iowa Farm Science: Vol. 8
, Article 3.
Available at: https://lib.dr.iastate.edu/farmscience/vol8/iss11/3