Ttt.

As stated above what species are present at this time. If you have a good sod and good ground cover with good forage species I would not dig that up. Another thought are you going to hay it or graze it?

Different species will respond differently to a couple hay cuttings versus rotational grazing, but most likely those present will respond and grow well. If you hay it then fertilizing will be needed to maintain yields.
If you decide to change the mixture there are options without tearing things up. No till drilling deciduous or legume pasture mixes many times do better going into a sod than trying to the no till with grass based mixtures.

If your contract is over in September one thing you could do is cut the fields and round bale and sell for mulch or use for bedding etc. That will get the fields warming and growing faster next spring.

Bryce