PSVII-14 - Evaluation of Precision Feeding on Production Efficiency Responses in Finishing Beef Cattle

Abstract: Angus heifers (n = 60; initial shrunk BW = 460 ± 26.2kg in n = 10 pens; 5 replicate pens/treatment) were used in a 112-d feedlot finishing experiment to evaluate animal growth performance outcomes, efficiency measures, and carcass characteristics when varying degrees of ingredient inclusion tolerances were imposed. Treatments included: 1) Normal feeding with 1lb tolerance for all ingredients (FIXED). 2) Variable inclusion strategy where each ingredient was randomly increased or decreased but the targeted as-fed quantity for the daily delivery was met (VAR). All heifers were fed once daily with all bunks managed using a slick bunk approach. Monensin sodium was fed at 33mg/kg and ractopamine HCl was fed (300mg per head daily) the final 28d. Individual BW measures were captured at processing and every 21d. Diets consisted of earlage, dried distiller’s grains, and a liquid supplement. Ingredient inclusions were randomized by assigning independently a random integer to DDGS and LS with each integer corresponding to the deviation from targeted inclusions. Earlage inclusion was adjusted so that the targeted as-fed amount of the diet was delivered. As-fed inclusion rates varied from formulated targets by -20, -15, -10, -5, 0, +5, +10, +15, or +20%. Actual DM inclusion was within 5% of expectations 72% of the time in FIXED (13periods/18periods) and only 27% of the time in VAR (5periods/18periods). Ingredient inclusion accuracy did not affect ADG, DMI, or feed conversion efficiency in this experiment (P ≥ 0.15). DMI and liquid inclusion rates showed an inverse relationship. There were no differences (P ³ 0.35) detected between treatments for carcass characteristics. No differences were noted between dietary treatments for liver abscess prevalence or severity. Under the conditions of this experiment, randomly altering ingredient proportions did not affect live animal performance, efficiency measures, or carcass characteristics.