Start reading with the professional trade magazine „Pig Topics“ number 4 (2008) on page 23:

Options for flooring and penning - Attentions to details makes for a better floor 

Another article in number 4 (2009) on page 19:

Options for flooring and penning – Unique quality floors for pig comfort

Furthermore enjoy the clear statement in “The HOG Gazette” Vol. 9:

Schonlau cast iron

This is an absract of the convention journal of one of our customers
(World Proc Expo 2010 Des Moines, Iowa, USA):

Schonlau cast iron

Schonlau Industrieguss