Digestibility and growth performance of feedlot cattle fed pelleted grain screenings
2016
Jancewicz, L.J. | Gibb, D.J. | Swift, M.L. | Penner, G.B. | McAllister, T.A.
The impact of two different grain screening pellets (GSP) on the chemical profile of feces, feed digestibility, growth performance, and carcass traits of feedlot heifers was measured. Near-infrared spectroscopy (NIRS) was used to predict differences in the chemical composition and energy content of GSP and feces. Heifers (445 ± 35.5 kg) were allocated to 15 pens (10 heifers pen⁻¹) and offered three diets: (1) 76% barley grain (dry matter basis; control); (2) light screening pellets (LSP); and (3) heavy screening pellets (HSP), where GSP replaced 20% barley grain. In controls, fecal starch tended to be higher (P = 0.09) and neutral detergent fiber (NDF) lower (P < 0.01) than heifers fed GSP diets. Fecal nitrogen (N) and ether extract (EE) were also higher (P < 0.05) in heifers fed the control compared with GSP diets. The average daily gain (ADG) of heifers fed LSP tended to be lower (P < 0.06) than the control diet. Gain:feed in controls was higher (P < 0.02) than in those fed GSP diets. Both ADG and G:F were positively associated with fecal N and starch, but negatively associated with NDF. Compared with direct measurements, NIRS over predicted total digestible nutrient (TDN) content of GSP, but did predict most differences in chemical composition.
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