I have no idea about Rio Tubs, but if it sounds too good to be true.....it probably is.
Mineral does not stay disbursed in lick tubs. The ones we sell we recommend free choice mineral be fed along with it, so I think
the Rio salesmen is.....selling...
. When mineral is heated it loses some of it's nutrition. Which brings me to ask, is the Rio tub a cooked tub or a chemical tub?
I have a crude protein comparison chart that I saved from years back. They compared alfalfa hay to other protein sources.
Alfalfa hay at $100/ton was by far the cheapest source of protein. Plus you get some dry matter with it and we are finding more and more how important DRY MATTER is in a diet.
Remember when you are figuring protein, take the moisture out. For instance you stated 10# of 19% alfalfa. Figure the moisture at 12% You now have 8.8# of dry matter x 19% = 1.67# crude protein. That's adequate depending on what stage of gestation your cattle are in. We normally feel you can feed your own home raised feedstuffs cheaper than what you can buy. Protein is fairly easy
to meet the requirements, in our country it is energy requirements that is hard to meet.
All protein isn't created equal. Soybean meal is the highest form of protein.http://www.feedipedia.org/node/674
Soybean meal is the most important protein source used to feed farm animals. It represents two-thirds of the total world output of protein feedstuffs, including all other major oil meals and fish meal (Oil World, 2015). Its feeding value is unsurpassed by any other plant protein source and it is the standard to which other protein sources are compared (Cromwell, 1999). While it has been an accepted part of livestock and poultry diets in the United States since the mid-1930s (Lewis et al., 2001), soybean feed production took off in the mid-1970s and then accelerated in the early 1990s due to a growing demand from developing countries. The expansion of aquaculture and prohibitions on the feed use of slaughterhouse by-products have also fueled the demand for this high-quality source of protein (Steinfeld et al., 2006).
Soybean meal is the by-product of the extraction of soybean oil. Several processes exist, resulting in different products. Soybean meal is usually classified for marketing by its crude protein content or by the sum of protein + oil. There are two main categories, the “high-protein” soybean meal with 49-50% of protein + oil and 3% crude fiber, obtained from dehulled seeds, and the “low protein” meal, with 44-46% protein + oil and 6-7% crude fibre, that contain the hulls. In solvent-extracted soybean meals, oil content is typically lower than 2% while it exceeds 3% in mechanically-extracted meals
FWIW~I think you are on the right track to question what you are questioning.