Feed intake response of feedlot cattle following single-dose treatment of ceftiofur crystalline free acid sterile suspension or florfenicol

Abstract

Healthy feedlot cattle were injected with either ceftiofur crystalline free acid (CCFA-SS) or florfenicol at the label dosage in a replicated, three treatment, 21-day study. Daily dry matter intake (DDMI), average daily gain (ADG) and feed efficiency (F:G) were compared between untreated controls and calves injected with CCFA-SS or florfenicol. The study was conducted at Mississippi State University (MSU) and the Pfizer Animal Health Research Farm (PAH). At MSU, 48 steers (630 lb; 286 kg) were individually fed in four pens with 12 Calan gates in each pen, while 192 steers and heifers (847 lb; 385 kg) were group fed in 24 pens, each holding eight head at PAH. Steers and heifers were fed separately during the trial. Treatments were randomly assigned to animals at MSU and to pens at PAH. DDMI for cattle treated with CCFA-SS was similar to controls on all days at both locations. Dry matter intake for calves treated with florfenicol was lower (P<0.05) than controls on days 2, 4, 5, 8 and 9 at MSU, and days 1-13 at PAH. ADG of calves treated with CCFA-SS at MSU was significantly greater than controls (4.37 and 3.45 lb; 1.99 and 1.57 kg, respectively) during the 21-day study, while ADG (2.04 lb; 0.93 kg) of calves treated with florfenicol was lower (P<0.01). There were no differences in ADG between treatment groups at the PAH study location. Feed:gain (feed efficiency) of calves treated with CCFA-SS was similar to control calves at both study locations (P=0.77). Feed:gain of cattle treated with florfenicol was similar (P=0.50) to controls at PAH, but was higher (less efficient) than control cattle at MSU (F:G 8.57 vs 3.71, P<0.01).