PS13-2. Effect of Olive Oil By-Product Inclusion on Ingestive Behavior and Intake Dynamics in Finishing Brangus Beef Cattle.

Abstract Olive oil by-product (olive cake) has a high lipid content, which may alter ruminal dynamics and feeding patterns. Therefore, this study aimed to evaluate the effects of increasing levels of olive cake inclusion on ingestive behavior and intake dynamics in beef cattle. The experiment was conducted in a feedlot system using 32 castrated Brangus steers (36 months old), distributed in a completely randomized design with four treatments over an 85-day period. Animals were assigned to four treatments and fed diets composed of pre-dried silage and ryegrass hay, combined with isoproteic and isoenergetic concentrates. The concentrates included 0%, 5%, 10%, and 20% olive cake, replacing corn. Dry matter intake and daily feeding behavior (24 h) were monitored using automated feeding systems (Ponta Agro®, Minas Gerais, Brazil). The following variables were evaluated: intake, total feeding time, intake rate, frequency of feeder visits, meal size, and meal duration. Significant effects of treatment, day, and treatment × day interaction were observed for feeding frequency, total feeding time, meal size, and meal duration (P < 0.001), indicating that behavioral responses varied over time and among inclusion levels. Dry matter intake (kg DM/day) was influenced by treatment, day, and their interaction (P < 0.001). Higher intake was observed in the 20% (11.82 kg DM/day) and 0% (11.38 kg DM/day) treatments, intermediate values in 5% (10.69 kg DM/day), and the lowest intake in 10% (10.03 kg DM/day) (P < 0.05). Intake rate was affected only by treatment (P = 0.001), with no effect of day or interaction (P > 0.05). Animals receiving 5% olive cake showed lower feeder visit frequency (55.9 visits/day) and higher intake rate (0.41 kg/min), along with greater meal size (0.396 kg/visit) and longer meal duration (1.72 min) (P < 0.05), indicating fewer but more intense feeding events. In contrast, animals fed 20% olive cake exhibited greater total feeding time (88.4 min/day) and longer meal duration (1.57 min), as well as lower intake rate (0.15 kg/min) and smaller meal size (0.214 kg/visit) (P < 0.05), suggesting slower and more distributed intake throughout the day. Animals receiving 10% olive cake showed intermediate responses, with higher feeder visit frequency and more balanced intake patterns. These results demonstrate that lower inclusion levels promote a rapid and concentrated feeding pattern, whereas higher inclusion levels result in slower and more distributed intake without compromising total intake. These changes suggest a reorganization of intake dynamics, possibly associated with the effects of dietary lipids on intake regulation in ruminants.