It's difficult to say without a photo or two but it doesn't sound to me as if it's a disease.
You say you take two heavy silage cuts which leads me to ask if you are replenishing the Potash offtake?
Potash, in deficient situations, will make the tips of the leaves go yellow.
Our main UK trial site is Cropvale Farm in Worcestershire, a 15 acres site for both amenity and agricultural, first established in 2008. It is one of 21 research and breeding stations throughout the world for the Royal Barenbrug Group. Cropvale farm is still a working farm...
Dr Gillian Young, AFBI grass breeder
Improving grass varieties increases profitability on farm
Reseeding with improved ryegrass varieties has been shown to increase on-farm production efficiencies year on year in terms of grass utilization and livestock output. The AFBI ryegrass breeding...
Herbage Seed Production - Rooted in the UK
Herbage seed production is a high-risk, high reward crop that can yield gross margins of more than £1,000/Ha for good mixed farmers with a keen eye for detail. Over 8,000 Ha of herbage seed is grown annually in the UK for the agricultural and amenity...
I can get mostly anything mixed, we mixed large & small seeds separately for a Stewardship mixture last year so they could be sown a different depths!
Call me next week & we can discuss the other questions, it could turn into a rather large essay.
As long as the GS4 mix adheres to the recommended prescription laid down by Defra you can have any grass you desire.
It would be probably easiest to have a mix put together, it's no more money than buying your own straights & mixing.