Gained a number of new 'do-follow' links - Good or Bad?

[soapmed]

So, my client's site is on a subdomain of the parent site and there were a number of links previously pointing to the subdomain site from the main site which were all no-follow so were purely for referral/traffic benefits.

Around the end of February, the main site changed all the links to 'do-follow'. Is this likely to have caused the decline we've recently seen in organic traffic to the site and a drop in rankings? I'm curious as to how that could have affected the site as we didn't know and have only just found out about it but I'm not sure how to show that it's led to a decline.

Any help is appreciated!

[SergioB1717]

If the links are of quality, it is always good to win new ones