79. Interval from Feedlot Arrival to Initial Processing: An Overlooked Management Decision to Improve Health and Performance of High-risk Receiving Cattle

Abstract This experiment compared different rest periods upon arrival (0 h, 24 h, or 72 h), and their subsequent effects on health and productive responses of feedlot cattle. One hundred and twenty Angus-influenced steers were obtained from 4 different cow-calf herds (30 steers/herd) and road transported for 1,200 km (18 h) to stimulate the stress of road-transport. Steers were weaned immediately prior to transport. Upon arrival at the experimental receiving yard, steers were ranked by source and weaning body weight (BW) and assigned to 1 of 3 treatments: 1) initial processing upon arrival (NOREST), 2) rest for 24 h prior to initial processing (24REST), and 3) rest for 72 h prior to initial processing (72REST). Steers were housed in 12 drylot pens (10 steers/pen, with 2 or 3 steers/source; 4 pens/treatment) after initial processing for a 56-d receiving period. The initial processing included tagging, vaccination, deworming, and application of growth-promoting implant. Steers assigned to NOREST immediately received the initial processing upon arrival. The 24REST and 72REST steers were maintained in 4 separate paddocks (2 paddocks/treatment) for 24 or 72 h, respectively, prior to initial processing with free-choice access to long-stem hay, water, and mineral-vitamin supplement. All steers were revaccinated against respiratory pathogens on d 14. Steer BW was recorded upon arrival, added 8% to account for shrink, and used as initial BW. Final BW was the average of steer unshrink BW on d 56 and 57. Pen feed intake and symptoms of bovine respiratory disease (BRD) were evaluated daily. Results were analyzed using pen as experimental until and orthogonal contrasts. Initial and final BW did not differ (P ≥ 0.44) among NOREST, 24REST, and 72REST (266, 267, and 261 kg of initial BW, SEM = 5.2; 328, 332, and 333 of final BW, SEM = 5.7). A linear effect was detected for average daily gain, which increased linearly according to length of rest period (1.09, 1.15, and 1.22 kg/day for NOREST, 24REST, and 72REST, respectively; SEM = 0.04). No differences among NOREST, 24REST, and 72REST were detected (P ≥ 0.16) for feed intake (7.29, 7.37, and 7.73 kg/d, respectively; SEM = 0.21), gain:feed ratio (0.150, 0.158, and 0.158, respectively; SEM = 0.006), and incidence of BRD symptoms (20, 20, and 35%, respectively; SEM = 7.6). In summary, length of rest period upon feedyard arrival was positively associated with ADG of high-risk receiving cattle.