I've had a couple of horses of late who halfway through a season will not recover at all after a race. The green bar will drop and stay at a certain level throughout the rest of the campaign, considerably lower than the red bar.

At first I guessed that horse is now knackered for the season but after looking at its breeding history, I'm now wondering if it just means he'll compete over a shorter distance? His sire was a G1 over 1m2, the dam a G1 over 1m4 and its been over 1m4 where the colt has had success so far.

no they are done for the season its a breeding problem i noticed one of my sires kept passing the gene on and they were done after 2 or 3 races everyone of his 2yo had the same issue so i had to retire him

Yeah, I checked the Head Boy for the first time in god knows how long and he said the horse is being over raced.