PSII-1 Adapting to the new normal: Feedlot cattle circadian rhythm and behavior-based management

Abstract

Abstract Every organism has evolved patterned responses to its temporal and physical surroundings. Rhythmicity is a central regulator of life and a sentinel for animal health and metabolism, thus chronic stress and disease can disrupt behavioral patterns. Feedlot cattle may exhibit irregularities in circadian rhythms due to social, environmental, and nutritional stressors and may benefit from behavior-based management strategies. This study characterized the hourly behavioral patterns of feedlot cattle with and without environmental enrichment, established behavioral expectations for animal managers, and proposed practical interventions. Fifty-four crossbred steers were shipped to Texas A&M AgriLife Feedlot in Bushland, Texas, blocked by weight, and assigned to one of six pens (n = 9 steers/pen), half of which had a cattle brush and half did not. Frequency of headbutting, mounting, bar licking, tongue rolling, allogrooming, and brush usage was decoded from video recordings of cattle from 08:00h to 17:30h on d -2, -1, 0, 1, 2, 4, 8, 16, 32, and 64 relative to brush implementation. The impact of time (hour), treatment, and their interaction on cattle behavior were evaluated using PROC MIXED in SAS. Brush use (P < 0.0001), allogrooming (P < 0.0001), and mounting (P < 0.0001) were performed at lower frequencies during early hours of the day and at higher frequencies in the afternoon. Both tongue rolling (P < 0.0001) and bar licking (P < 0.0349) occurred most often during daylight hours in accordance with a diurnal pattern. Major periods of headbutting (P < 0.0001) were observed in the morning and afternoon. Behavioral expectations were characterized so that stockpeople could observe the prevalence of each behavior during morning, midday, and evening to facilitate the implementation of best management practices. Proposed interventions include medical treatment, modified pen surface or bunk management, altered stocking density, and/or introduction of environmental enrichment.