Evaluation of High-intensity and Low-intensity Preconditioning Systems
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Steer calves n = 345 (year 1 n = 183; 253 ± 35 kg, year 2 n = 162; 241 ± 36 kg initial BW) were used to evaluate 56-d preconditioning systems in each of two years. Angus- and Charolais-sired calves out of crossbred dams were assigned to systems within breed and BW strata. The systems consisted of ad libitum access to a self-fed milo-based diet in drylot (DL); ad libitum access to the same self-fed diet while grazing dormant warm season pasture (SF); and hand-fed 20 precent CP pellets (2.1 kg 3 times/wk; equivalent to 0.89 kg/steer per d) while grazing dormant warm season pasture (HF). Steers were weighed after overnight shrink on d 0, 28, and 56. The economic analysis was based on current local prices for cattle and inputs. Morbidity and mortality rates were similar among treatments. In year 1, one steer was removed from SF (mechanical) and one from DL (chronic bloat). In year 2, two steers were treated for respiratory disease (DL and HF) and mortalities occurred in DL (1 steer, digestive), HF (1 steer, unknown) and SF (1 steer, mechanical). Shrink from weaning to d 0 averaged 4.45 percent across years and was similar (P = 0.70) among treatments. Across years, ADG was lower in HF vs. SF or DL-fed steers (P < 0.01), which had similar rates of gain (P = 0.29; 0.13, 0.98, and 0.96 ± 0.03 kg/d yr 1; P = 0.13; 0.14, 0.73, 0.79 ± 0.06 kg/d for HF, SF, and DL, respectively). In year 1, daily feed intake was similar (9.03 vs. 10.0 ± 0.96 kg/steer; P = 0.17) among SF and, DL systems. In year 2, intake was greater for DL than SF (10.1 vs. 8.3 ± 0.25; P < 0.01). Feed efficiency (G:F) was greater for HF steers vs. SF or DL steers in year 1 (P < 0.01). (P=0.91; 0.04, 0.11, 0.09, ± 0.04 for year 1 HF, SF, and DL respectively). In year 2, G:F did not differ among treatments (P= 0.50; 0.16, 0.09, 0.08 HF, SF, DL respectively). Forage utilization was not quantified; these values represent gain per unit of purchased feed delivered, a metric favoring groups fed at lower rates. Preconditioning costs were 73.50, 175.12 and 167.20 $/steer (year 1) and 53.58, 152.72, and 141.68 $/steer (year 2; HF, SF, and DL respectively). These systems resulted in losses of -57.89, -67.59, and -58.80 $/steer (SE = 4.99; P= 0.38) in year 1, and -28.35,-80.00, and -64.55 $/steer (SE = 17.39; P = 0.18) in year 2 for HF, SF, and DL. Price premiums of 10.61, 10.51, and 9.18 $/45.4 kg (SE = 0.85; P=0.46) in year 1 and 5.79, 14.01, and 11.31 $/45.4 kg (SE = 3.25; P=0.27) in year 2 would be required for HF, SF, and DL to be par with sale at weaning. Overall preconditioning was unprofitable for both years and would require substantial price premiums. Although a lower intensity pasture system reduced overall input cost, it did not result in profitability. Providing ad libitum access to a diet while on pasture did not result in any advantages over drylot based systems.
Orsak, Andrew Nathan (2010). Evaluation of High-intensity and Low-intensity Preconditioning Systems. Master's thesis, Texas A&M University. Available electronically from