I was only poking the borax FM

The only real difference is whether one subscribes to the American Holstein or the more traditional British Friesian.
However, look carefully at NZ genetics too. During the 70's and 80's NZ farmers got carried away on a wave of breeding American Holsteins - just look at all that milk!!! - and then lived to rue the day for reasons that you pointed out Up North. They took an enormous amount of feed to maintain milk production and cow condition, their weight destroyed paddocks particularly in wetter areas and they suffered metabolic problems. One of the biggest problems was the high rate of MT cows - one neighbour had 22% of his 600 cow herd pregnancy tested as MT. The greed for higher milk production cost dearly and it's taken a decade to right it. There is a marked swing back to Jerseys and British Friesians but there is still a lot of American genetics out there.
I'm surprised that you find the Jersey a hard doer on grass alone. I find them far better foragers than many other breeds and my little Jerseys will often keep on producing until I deliberately dry them off. As you are probably aware, I am 100% grassland farming with the exception of maintenance hay during the winter for the dry cows and molasses, palm kernal and hay for any I'm milking through the winter. BTW, what are the MF problems you refer to? I decided that if I thought about it long enough, it would become obvious but it hasn't

I use an Angus bull over all my cows and once weaned, they finish on grass and do very well.
I have never heard of the Montbelaird so will go and have a look for that and had never heard of the Swedish Red until recently and now I can't remember where I heard/read about it so will have to look for that too.
Cheers,
Ronnie