The effects of technology use in feedlot production systems on cattle behavior and mobility

Abstract Text: Crossbred steers (n = 336; initial BW = 379 ± 8 kg) were utilized in a randomized complete block design (24 pens; 8 pens/treatment; 14 steers/pen) to determine the effects of technology use in feedlot production systems on animal behavior and mobility.  Treatments consisted of an all-natural treatment (defined as cattle receiving no growth promoting technologies; NAT), a conventional treatment (implanted with 40 mg of estradiol and 200 mg of trenbolone acetate on d 0, and fed 33 and 9 mg/kg of monensin and tylosin daily, respectively; CONV), and a CONV treatment plus the addition of a beta-adrenergic agonist (zilpaterol hydrochloride at 6.76 g/ton for the last 20 days on feed with a 3-4 d withdrawal; CONV-Z).  Handling assistance, temperament, and exit scores at the chute and temperament in each home pen were collected every 28 d until d 112, and then every 10 d during the beta-agonist feeding period.  On the d of shipment, cattle mobility was scored prior to loading at the feedlot and while unloading at the abattoir.  There was no effect of treatment on cattle requiring assistance to enter the squeeze chute (P = 0.35).  There was a Treatment x Time interaction for chute temperament score (P = 0.03), with NAT cattle being more restless than CONV cattle at d 56 (2.24 vs. 1.98; P = 0.02) and CONV-Z cattle intermediary (2.14).  Pen temperament was not affected by treatment (P = 0.14). Overall temperament score resulted in CONV-Z cattle being numerically calmer than NAT cattle (1.47 vs. 1.61; P < 0.02) and CONV cattle intermediary (1.57).  Chute exit scores resulted in a Treatment x Time interaction (P < 0.01), with NAT cattle having a greater exit score than CONV and CONV-Z cattle (2.24 vs. 1.93 and 1.87; P < 0.03) on d 132.  There were no differences in exit velocity (P > 0.37).  Treatment displayed no effect on cattle mobility prior to loading or during unloading (P ≥ 0.14), but numerically, cattle had a more difficult time moving at the abattoir than at the feedlot.  The results of this experiment suggest that growth promoting technologies have no negative effects on cattle mobility and could potentially improve cattle temperament at the end of the finishing period.

Keywords: behavior, beta-adrenergic agonist, mobility