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Effect of pelleted byproducts on performance when fed to growing cattle
An 84-d growing trial was conducted utilizing 300 heifers (initial BW = 279 kg; SD = 22) to determine the effects of supplementing a pellet consisting of 54% corn stover treated with calcium oxide, 32% dried distillers grains, 14% solubles, and 1% urea, on the performance of growing cattle fed either a high (brome silage, sorghum silage, alfalfa hay blend) or low quality (bromegrass hay) forage. The experiment was arranged in a 2 x 3 factorial with low quality (LQ) or high quality (HQ) forage as one factor and level of supplement (0, 0.5, or 1.0% of BW) as the other. Heifers were blocked by BW (n = 3) and stratified by BW within block. Heifers were limit fed 5-d and weighed on 2 consecutive days at beginning and end of trial. A forage x supplement interaction existed for final BW (FBW), ADG, and G:F (P < 0.01). For the HQ forage diet there was a linear increase in BW, ADG, and G:F as supplement level increased (P < 0.01), while for the LQ forage diet there was a quadratic response (P < 0.04) as supplement level increased; FBW, ADG, and G:F increased at a decreasing rate. In the LQ diet, as supplement level increased from 0 to 0.5% there was a 96% increase in ADG and a 77% increase in G:F. As supplement increased from 0.5 to 1%, ADG and G:F only increased by 24 and 15%, respectively. The ADG and G:F response between 0.5 and 1% in LQ forage was similar to relative increases in HQ diet between 0.5 and 1% levels of supplementation (19 and 7% for ADG and G:F, respectively). The larger increase in the LQ diet from 0 to 0.5% of BW supplementation suggests a protein response, while the rate of increase from 0.05 to 1% of BW is more in concert with the response seen in the HQ forage diets suggesting an energy response as supplement level increased further. Forage DMI and total DMI had linear responses as supplement increased, with forage DMI decreasing and total DMI increasing (P < 0.01). However, forage quality did not affect either forage or total DMI (P > 0.17). These data suggest that use of a corn residue-based pellet increases performance in growing animals when fed either a low or high quality roughage diet, although there is a greater response when fed in a low quality forage diet.
Keywords: growing, pellet, by-products