Evaluation of Alkalis, Buffers, and Complementary Fiber Feeds to Increase Digestibility and Performance in Feedlot Steers Fed Corn Stover

The use of dried distillers grains with solubles (DDGS) has been shown to limit fiber digestibility due to the inherent acidity of the feedstuff. Three studies were conducted to evaluate the effect of alkalis, buffers and complimentary fiber feeds on ruminal pH, fiber digestibility, and animal performance. The first study was conducted to determine the effectiveness of calcium hydroxide (StoverCal; Ca(OH)2) and/or roughage on diet digestibility, performance and carcass characteristics of steers fed 60% DDGS. The addition of StoverCal to low corn silage diets, or the addition of corn silage or corn stover to a 60% DDGS ration did not impact steer DMI, gain:feed, or carcass characteristics. However, the addition of 2% StoverCal to diets containing 34% corn silage and 60% DDGS did decrease DM intake and the addition of StoverCal increased ADG in 60% DDGS diets when corn stover replaced a portion of corn silage. In the second study, addition of 1% CaO improved gain of steers fed soybean hull (SBH) free diets, but not steers fed 30% SBH. Calcium oxide addition increased hot carcass weight and yield grade and tended to increase backfat in steers fed SBH free diets, but not steers fed SBH. Total VFA concentrations were greater when either SBH or CaO was included in the diet, but they did not interact. Digestibility of DM, NDF and ADF were greater with CaO addition, while only NDF and ADF digestibilites were greater with SBH inclusion. The third study was performed to determine which alkali, buffer, or alkali/buffer combination is most effective at increasing performance of feedlot cattle fed a corn-based diet containing 20% corn stover and 30% DDGS. Addition of 1% CaO resulted in improved performance, while 1% calcium hydroxide (Ca(OH)2), 1% potassium carbonate (K2CO3), and a combination of 1% Ca(OH)2 and 1% K2CO3 had little impact on steer performance. Calcium oxide also maintained a greater in vitro ruminal pH for a longer duration, which suggests a potential for increased fiber digestibility. In summary, feeding 2% StoverCal improved digestibility and performance in cattle fed 20% corn stover and 60% DDGS, presenting similar performance to steers not fed corn stover. Use of complimentary fiber feedstuffs or addition of CaO to SBH free diets were effective at increasing animal performance, but SBH inclusion and CaO addition did not interact. Addition of 1% CaO to corn based rations with DDGS and corn stover seems to be most effective at improving feedlot performance compared to Ca(OH)2, K2CO3, or a combination of Ca(OH)2 and K2CO3, presumably by maintaining a greater ruminal pH and potentially increased fiber digestibility