I just made a batch of feed with 7.5% of mix being dried distillers grains after reading a PDF file from U of Purdue, they recommend 10% or less due to such a fine particulate size causing ulcers.
As for the wet or spent brewers grains I don't believe I would bother seeing how much work and the quantity it would require and the low nutritional value for non ruminant livestock. But it apparently can be part of their diet.
Protein value
Brewers grain have a good protein value for ruminants and their protein is less ruminally degradable than that of other plant-derived feeds. Brewers grains are thus often used in ruminant productions with high requirements in by-pass protein, such as high-yielding dairy cows. The effective nitrogen degradability of brewers grains reported in feed tables and in the scientific literature is about-41-49% (Sauvant et al., 2004-;Batajoo et al., 1998-;-Nishiguchi et al., 2005-;-Volden, 2011-;-Promkot et al., 2007). These values are lower than those of soybean meal and cereal by-products (Sauvant et al., 2004;-Volden, 2011;-Nishiguchi et al., 2005), though in one case the protein of distillers dried grains was found less degradable (Batajoo et al., 1998). Nitrogen degradability depends on the amount of heat used during the drying process: in one experiment, the amount of protein by-pass doubled when temperature rose from 50° to 135°C (Pereira et al., 1998). Heating also decreases protein solubility while increasing the insoluble ADF-bound nitrogen fraction-(Enishi et al., 2005). Values for the intestinal digestibility of nitrogen range from 74% (Yue Qun et al., 2007) to 84% (Sauvant et al., 2004), which is much lower than the values reported by these authors for soybean meal, corn gluten meal and maize distillers grains (> 90%). As usual for cereal grains and their by-products, lysine is the first limiting amino acid in brewers grains used for high yielding ruminants, so it needs to be blended with sources of by-pass protein richer in lysine.
Pigs
Brewers grains can be fed to pigs, but their high fibre content and the low quality of the protein, which is deficient in lysine, threonine and tryptophan, make them more suitable to pigs with low energy requirements such as gestating sows and boars, rather than to growing pigs and lactating sows, particularly in intensive production systems (Holden et al., 1991;-Blair, 2007;-Boessinger et al., 2005). Brewers grains are usually fed dried to pigs, as they are easier to store and more stable (Blair, 2007;-Crawshaw, 2004), but they are also fed wet or ensiled (Boessinger et al., 2005).
All this info is found here.--
http://www.feedipedia.org/node/74
