The £7.4million 22-year-old forward, who arrived at Old Trafford from Portuguese club Guimaraes in 2010, has secured a temporary contract at Rio Ave until the end of June.
"We feel the boy has got to get good experience at a better level than our reserve team," Ferguson told MUTV.
"He's gone to Rio Ave who are fifth in the Portuguese league at the moment - they have a young coach [Nuno] who has a very good reputation.
"Bebe has done quite well in the last two or three months. He got a cruciate knee injury when he was on loan in Turkey last season and that derailed him for a bit.
"Coming back from these injuries takes time but he's started to develop quite well. Hopefully his spell in Portugal, where he is from anyway, could help him."
Having made the move at the end of 2012, Bebe said: "I'll give it everything while I'm here and try to help the team to continue occupying the places that they have been in the table.
"Obviously something went wrong in the last phase of my career, I had a serious injury which thankfully I have fully recovered well from.
"I'm fine physically - I was always training and playing. It's good to come here and I want to show what I can do."