PSXII-5 Simulation of feed restriction and anorexia during auction market and transportation and its effects on concentrate intake and body weight recovery of unweaned crossbred Angus-Holstein calves

Twenty unweaned Angus-Holstein bull calves (44.1 ± 2.0 kg and 14.7 ± 0.63 d) were used to evaluate the effects of feed restriction and anorexia (simulating auction market and transport) on concentrate intake (CI) and body weight (BW) recovery. Calves were randomly assigned to 1 of 4 treatments; Control (CT; n = 5): from d-4 to -1, 2.5 L of milk replacer (MR) twice daily, concentrate and straw ad libitum; Mild (MD; n = 5): only MR (d-4 to -1) as described for CT, and at the end of d-1 feed withdrawal for 9 h; Moderate (MO; n = 5): only MR as described for CT and at the end of d-1 feed withdrawal for 19 h; and Severe (SV; n = 5): only 2.5 L of a hydrate solution (HS) twice daily (d -4 to -1) and at the end of d-1 feed withdrawal for 19 h. Simulating the arrival to the farm, from d 0 all calves were fed MR, concentrate and straw ad libitum. The CI was recorded daily, and BW was measured on d-4, -1 (restriction day), 0, 2 and 7. Data were analyzed using mixed models with repeated measures. BW was greater (P < 0.001) for CT compared with the rest from d0 to 7, while BW of SV was lesser compared with the rest from d-1 to d7. At d1 CI did not differ among treatments; however, at d 2 CI of MD, MO and SV was lesser (P < 0.05) compared with CT. At d5, CI of SV was similar to that for CT, and it was greater (P < 0.05) than CI of MD and MO. Calves BW and CI recovery was affected by the degree of restriction (9 vs 19 h) and by the type of liquid feeding (MR or HS) offered in long restriction periods.