Article History
Received: 4 September 2018
Accepted: 12 February 2019
First Online: 13 March 2019
Compliance with ethical standards
: Care and treatment of pigs in this study were approved by the Institutional Animal Care and Use Committee of the U.S. Department of Agriculture, Beltsville Agricultural Research Center, Beltsville, MD.
: The authors declare that they have no conflict of interest.