The effects of pre- and post-transit potassium levels, feedlot receiving diets, and levamisole injection on stressed bull and steer calves

In a March 1983 trial, 125 bulls and 139 steer calves were used to compare bulls castrated at feedlot (FL) arrival (BULLS) with steers, to evaluate feeding supplemental potassium (K) at the order-buyer barn (OBB) for three days before shipment or at FL, to compare a 40% concentrate (CONG) receiving diet with a hay (HAY) diet, and to evaluate the effect of injection with levamisole (LEV) at OBB and FL arrival. Mortality was higher (P<.05) in BULLS (13.2%) than in steers (7.7%) and higher in CONG bulls than in HAY bulls.

Steers gained more (P<.10) (12.1 kg) from purchase to FL-28, had higher (P<.10) antibody titers for Bovine Viral Diarrhea (BVD) at OBB, and greater (P<.10) change in serum lymphocyte blastogenesis from OBB to FL-28 than BULLS. Calves fed a 1.5% K diet at OBB had less shrink during the 24-hour transit than those fed a 1.1% K diet. FL gains of calves fed a 1.1% K and a 1.7% K receiving diet were similar (P>.10).

Calf breed type affected mortality. Mortality of white-faced, feather-necked, red, medium-frame calves (WF) (18.3%) was higher (P<.10) than that of black, medium-frame calves (BL) (2.8%). WF calves required 30% more clinical treatments and had higher temperatures than did BL and large-frame calves. Injection of LEV at OBB or FL reduced mortality 6.6% and increased BVD and IBR antibody titers. Gains during the 28-day receiving period were similar for the GONG and HAY calves but the GONG calves gained more (P<.05) during the subsequent silage period. Mortality tended to be higher in CONC calves (12.3%) than in HAY calves (8.5%).