In my circle it seems like every other horse is F-line. Florestan I is staunchly represented here, and don’t forget Fidertanz is in the top ten of WBFSH rankings. Furstenball is #12. That’s up from #56 in 2021. He has enjoyed immense popularity with breeders and that has impacted the pool of available young horses. I think he has something close to 200 premium daughters and 90 approved sons.
When breeders are breeding to the Stallion Du Jour, and many of them are Furstenball or a Furstenball son, there’s a lot of them hitting the ground or on the market. Right now in my area there’s a trend towards breeding what sells as a young horse, which I can’t blame them for. Breeding is not cheap, and you want to breed what sells. I speak from experience being on the heels of helping a friend with a serious budget find a dressage bred horse on the east coast. There were lots of Furstenballs. He wasn’t on the exclusion list, but concerns came up for given reasons.
I’m sure you know this but soft or weak pasterns in a dressage horse are not indicative of ESPA/DSLD. In Hanoverians there has been a trend in the last ten years for softer, more elastic horses and that includes in the topline and pastern. I wouldn’t assume soft pasterns immediately means ESPA/DSLD. It can be a symptom, but there are horses with soft pasterns who never develope ESPA.
That is even assuming that’s what sidelined Furstenball. We don’t understand the inheritance of ESPA/DSLD at all. We can look at his pedigree and guess it came from him, but his sire died at 7, his dam has another licensed son who is making his own waves in dressage, his pedigree is packed with stallions everyone knows. There are breeders on this forum that have mentioned Donnerhall as a suspected source too. It’s not so cut and dry at this time as “avoid this stallion/mare” because there’s no understanding of where it comes from. And if you want to avoid him, you’ll want to avoid his pedigree – and good luck avoiding Donnerhall or Weltmeyer in a horse today.
My guess is it has a multifactoral genetic component, and I don’t think it’s as simple as one copy from either parent.