PSII-1 Evaluation of Precision Feeding on Animal Behavior in Finishing Beef Cattle

Abstract

Abstract Charolais × Angus cross steers (n = 80; initial shrunk BW = 505 kg ± 31.6 kg; n = 10 pens; 5 replicate pens/treatment) were used in two 24-hour observations to evaluate animal behavior based on varying degrees of daily feed inclusion over a 28-day period (d 14 and d 42 on feed). Treatments included: 1) A fixed diet inclusion rate for each individual ingredient with a tolerance of 0.454 kg, and 2) Variable inclusion rates (VAR) of diet ingredients that were randomly increased or decreased while maintaining the targeted daily as-fed delivery. Steers were fed twice daily with a slick bunk approach used to manage feed bunks. Diets composition (DM basis) was 48% high moisture corn (HMC), 21% dry-rolled corn (DRC), 5% liquid supplement (LS), 14% dried distillers’ grains plus solubles (DDGS), and 12% grass hay (GH). In the VAR treatment inclusions of HMC, DRC, and DDGS varied independently by assigning a random integer with each integer corresponding to a specific deviation from target. Dietary inclusion of LS was fixed. Inclusion of GH was altered so that the targeted as-fed amount was delivered each day. Inclusion rates of ingredients (HMC, DRC, and DDGS) on an as-fed basis varied from the formulated diet by -20, -15, -10, -5, 0, +5, +10, +15, or +20%. Data from the two 24-hour observations were analyzed using the GLIMMIX procedure of SAS 9.4 (SAS Inst. Inc., Cary, NC) with pen as the experiment unit. Treatment was analyzed as a fixed effect and block (pen location) was a random effect in the model. Varying ingredient inclusion did not affect cattle activity, time spent drinking, resting, eating, or ruminating, or chewing behaviors (P ≥ 0.24) during the initial d 14 observation. Treatment did affect DMI the week preceding that observation period (P = 0.04). During the second 24-hour observation period activity, resting, ruminating, and chewing behaviors along with DMI were unaffected by variation in inclusion of diet ingredients (P ≥ 0.33). Varying inclusion rates of diet ingredients increased time spent drinking (P = 0.05) by 33.3% and decreased time spent eating behaviors (P = 0.01) by 9.4% at the d 42 observation point. Under the conditions of the present experiment, altering dietary ingredient proportions in a finishing diet may influence time spent drinking and eating after 42 d on feed.