Izhar Ali this is a very good question but not one that is easily answered I'm afraid. Mixing order is affected by four things, in my opinion - ingredients used, ingredient form, mixing and processing equipment and operator ability.
Ingredients, particularly forages are variable, particularly when it comes to particle size or chop. This also varies depending on the intended outcome or average particle size. Additionally, it can vary depending on the fragility of dried hays, such as alfalfa, which if very dry can "shatter" into much finer pieces if mixed too long. In general, a recommended order might be:
1) long stem, "tougher" forages - hays or silages
2) smaller chop silages (corn silage, chopped grass silage)
3) Died commodities - corn, DDGs, SBM, etc.
4) Liquid ingredients - molasses, liquid blends, wheys, water
5) mineral/vitamin premixes and additives
A key to this is to constantly evaluate the final product - the actual mix of the TMR. so sampling and analyses should be a regular activity as well as visual appraisal at the mixer and at the bunk.
I’m owner of farm siting far from the farm it’s totally hand of GM farm I’m always worried about the micro minerals and the others minerals mixing, it’s a challenging task to each Cow chew all the balance TMR.