You are not doing so bad, they is a but, like I have, if your fields are ex rice fields, they could be prone to water logging? Mulatto II is a very good grass, but does not like waterlogging, I have had Purple Guinea, a good grass again it does like a lot of water logging.
Forget Ruzi that grass has been about in Thailand for years, about the only grass Thais know, the other grasses you have are a lot better.
You would be better letting them graze that cut and cart, but that, as have found during the wet season the field can get poached, leading to a lost time before the grass recovers.
They are no truth in they taste being overwhelmed, what the big problem is Thias go for quantity, not quality, they will cut grass that is old and in flower? not palatable at all, grass here n Thailand if the conditions are right i.e. rain at the right time you can get a 45-day cycle of grass, grass then will still be palatable, and they should eat it all.
If you are grazing grass, grass needs to be no more that wellington boot height, sometimes if that, cattle will eat it down to the ground, then it will grow back again quickly, I have done a strip grazing system using eclectic fence, works well, but as said, be wear of poaching.
Something I have seen on here before ,I do not know how many cattle you have17-18 rie of land all of that down to grass ,that is a lot of grass you will have that palatability problem, grass will grow old and cattle will not eat it ,and with old grass you will not get the cattle growth rates and, cows will not be fertile to get in calf.
Or, as we do grow a few rie of Nappier grass, make it in to bagged silage, and feed it during the dry season, but that can be labor intensive.