“It still makes economic sense” to put on as much weight on as efficiently as you can, to minimize losses” feedlot owner Tom Fanning told Bloomberg.
https://www.voanews.com/a/mht-good-news-for-burger-lovers-beef-prices-fall/3092061.html
here:
to put on as much weight on as efficiently as you can
the second "on" here makes me confused!