OK, this is for the folks who have more than a hundful of cattle
Tub supplements provide a non-protein source of Nitrogen which the rumen microbes can convert into protein digestible by the rumenant
I am in central Texas and have seen several years of drought where only poor quality forage is available, the supplements will help the cattle consume the poor quality stockpiled forrage or poor quality grass hay, it can be economical depending on the opperation, and the perpose of supplementation
We had a huge stockpile of forage, with spoiled cattle who wanted to be picky, we fed the liquid feed, it forced them to consume the dry grass with good digestion and performance in terms of weight gain and lactation
I only use it on an as needed basis, the company I purchase my liquid feed from provides the feeders at no charge, base feeder size on number of head to be supplemented, they deliver as need requires, I would talk to a nutritionist and cost compare wether a non-protein nitrogen liquid feed or the natural protein type liquid feed that utilizes nutural protein sources in a molassass base
Good luck, hope that helps