about 25 years ago the Standardbred breeding season was changed from a commencement date of August 1 to September 1, the main reason being the fertility rates in mares and in many places August foals were being born in the snow. Significant research was done with regards to the overall performances of foal born in August Vs those later as many people were a bit "hung up" about the advantages of an early foal for juvenile racing. The research showed that foals born later actually had better lifetime stats than August foals.
The change was implemented, our cousins in the thoroughbred world were invited to come along but declined and I'm pretty sure most people would agree that the change was indeed a wise move.
To move the breeding season to January 1 would bring difficulties like foals being born on 40 degree days meaning we had gone from one extreme to another, so personnally I think a hell of a lot of research would be required and where would that research come from with so few foals born January 1 onwards.
Foals being born in January is one thing keep in mind we now have a breeding season where foals are born from September through to Jan/feb, so about 5 months, if you had foaling starting January then foaling would end say May?
If you left the breeding season as is and changed the racing season then I think racing 2 and 3yo's for big stakes before December 30 is short changing the horses and their connections. An alternative would be extend their "year" to the following December and then you have 3yo's racing for 2yo classics and 4yo's racing for 3yo classics and that, to me would be open to ridicule.
Not saying we should just keep on doing what we always have and an adjustment that assists our game in any sustainable way would be welcome, just highlighting some of the things people need to take into consideration.
Cheers,
Dan