The Effect of a Preassembly Zeranol Implant and Post-transit Diet on the Health Performance and Metabolic Profile of Feeder Calves3

Abstract

A total 262 Angus steer calves averaging 207 kg from none (trial 1) and five farms (trial 2) were identified on the farm of origin and one-half of the calves on each farm was implanted with 36 mg of zeranol before entering the feeder calf assembly and marketing system. Calves were assembled, fasted for 24 h and fed hay for 72 h, then shipped 1,368 km. Upon arrival, the following receiving diets were fed for 4 wk to one-third of the calves from each farm and implant group: 1) control diet, 2) high-potassium diet, 3) escape-protein diet using corn gluten meal, which can escape ruminal degradation as a protein source. Implanted calves gained more weight (P less than .10) than nonimplanted calves while on the farm, but changes in weight during assembly, transit and the 28-d receiving period were not different (P more than .10). Plasma glucose and total protein concentrations were higher (P less than .05), while urea nitrogen concentration was lower (P less than .05) for implanted calves following transit. Increasing the potassium concentration of the receiving diet increased (P less than .05) post-transit weight gains, but had no affect on dry matter consumption. Corn gluten meal replaced soybean meal in the escape-protein diet and resulted in similar weight gains. Plasma urea nitrogen concentrations were higher (P less than .05) at 2 wk post-transit in the escape-protein diet group as compared with the control group. Receiving diet had no effect on the incidence or severity of bovine respiratory disease, but affected (P less than .05) performance during the subsequent 69-d stocker phase of ad libitum access to medium quality hay and 2.27 kg of supplement per day.

Effects of Calving Season on Stocker and Feedlot Performance

“…Steers with greater BW would accumulate GI tract fill faster than steers with less BW because absolute amounts of DMI would be greater. However, the BW gains observed in this study were similar to those reported by Phillips et al (1986) for calves shipped in the fall from Tennessee to Oklahoma. Steers shipped in January did not go through a receiving period but were placed on wheat pasture shortly after arrival.…”

Intake and digestion of wheat forage by stocker calves and lambs

“…Greater dietary concentration of CP would increase ruminal ammonia, plasma protein, and plasma urea-N concentrations. However, our observations agree with previous reports for stocker calves consuming a typical growing diet that has a balance of protein and energy concentrations (Phillips et al, 1986(Phillips et al, , 1991. On the basis of these observations, we concluded that after 14 d of grazing wheat pasture and 7 d of being fed freshly harvested wheat forage, the lambs and steers in the nonadapted group were digesting and metabolizing N as efficiently as the lambs and steers in the adapted group.…”

Effect of a trainer cow on health, behavior, and performance of newly weaned beef calves.

“…Average daily gain over the first 3 d in the feedlot was negatively influenced by the presence of a trainer cow (−.27 kg/d vs 1.23 kg/d; P < .001). Differences in apparent gain over this short time period are strongly influenced by fill (Cole et al, 1982;Phillips et al, 1986). Thus, these data may indicate that Trainer calves were consuming less feed during the first 3 d of the experiment.…”