The United States Department of Agriculture ran a series of PSA's in the 70's, dating back to about 1973 according to one source, but I can't be sure of that.
In these short bits, a pair of puppets, one being a banjo playing Farmer Brown, would do a short song about various things. In this spot, Farmer Brown and Fred, a horse, sing about energy generated from bread and rice.
There are others, one with a goose, and one with a cow. Used to see these all the time on WSBK back in the day.