185 Effect of ad Libitum Versus Limit-Feeding Program at Receiving on Morbidity and Performance of Feedlot Calves

Abstract

Abstract Despite advancements in both vaccine technology and antibiotic therapy, bovine respiratory disease complex (BRD) remains the primary health challenge for cattle feeding operations in the United States. The strategy of limit-feeding calves during the early receiving period (first 28 days) has been proposed as a method to mitigate BRD risk, but limited data are available despite this strategy becoming more common. The objective of this study was to evaluate limit-feeding as a receiving protocol to determine impact on pull rates, receiving performance, and subsequent (Post-receiving) finishing performance. Steers (initial BW = 262 kg; n = 704) were blocked by arrival day (7 blocks) and housed in 44 open-lot pens. Pens were assigned to either limit-fed at approximately 75% of ad libitum or fed ad libitum for the 28-day receiving period. A subset of 216 steers in 14 pens was followed through finishing to evaluate carry-over effects in the finish period (192 days). Dry matter intake (DMI; P < 0.01), average daily gain (ADG; P < 0.01) and ending body weight (P < 0.01) were less for the limit-fed treatment compared with ad libitum due to the limitation of intakes as designed. Intake averaged 70.1% for limit-fed versus ad libitum whereas ADG was 72.6% for limit-fed compared with ad libitum. Because both DMI and ADG were decreased by similar amounts, G:F was not affected (P = 0.28). Numerically better G:F was observed for limit-fed cattle versus ad libitum but this 3.4% difference was not significant (P = 0.28). Morbidity rates for BRD were not statistically different, with ad libitum morbidity of 16.3% compared with 14.3% for limit-fed steers (P = 0.58) Low mortality for the receiving period was observed with 0.84% (3 steers) on limit-fed treatment, and 0% for the ad libitum treatment. For the subset of pens that were followed through finishing, there were no differences (P > 0.18) in ADG or DMI. While not statistically different, there was a 2.2% increase in ADG for steers that were limit-fed during the receiving period, which allowed for similar HCW and final BW (P = 0.39) at slaughter. Other carcass characteristics were also similar (P > 0.74) between steers received with an ad libitum or limit-fed program. No statistical difference (P = 0.29) in the rate of liver abscess occurrence was noted. In conclusion, there was no statistical difference between treatments in early-period morbidity or finishing performance between ad libitum and limit-fed receiving management.