Evaluation of corn and barley varieties in backgrounding grazing programs for beef calves

Abstract Text: A study evaluated the effects of grazing either swathed barley (Hordeum vulgare; cv. Ranger) or standing corn (Zea mays; cv. Pioneer P7443R) as compared to drylot calves fed barley hay on forage quality, dry matter intake (DMI), calf backgrounding and feedlot performance, and backgrounding production costs.  Each year, 120 spring born Angus calves (278.2 ± 5 kg) were fall weaned, stratified by body weight and randomly allocated to 1 of 3 replicated (n = 2) backgrounding systems: 1) field grazing standing whole plant corn (CORN); 2) field grazing swathed whole plant barley (BAR); or 3) dry lot (DL) bunk fed processed barley hay.  CORN and BAR calves were limit grazed in 4-ha paddocks for 3 d grazing periods using electric fencing for 68 d, with all groups receiving a pelleted supplement (78% TDN, 16% CP) daily at 0.8% BW.  Forage samples were collected every 21 d to determine CP, TDN, ADF, and NDF.  DMI was estimated using the herbage weight disappearance method.  After backgrounding, replicates of calves were divided into 2 and placed in a feedlot.  Calves were fed a barley silage based diet with either barley or corn grain for 203 d to a target weight of 615 kg at which point they were slaughtered and carcass data was collected.  Data were analyzed as a one-way ANOVA using the Proc Mixed Model procedure of SAS.  Protein content was greatest (P<0.05) for DL and BAR (12.6% and 12.3%, respectively) compared to CORN (8.0%).  Forage TDN, ADF, NDF, and forage DMI did not differ (P>0.02) among backgrounding systems.  Final BW and ADG were greatest (P<0.05) for DL calves compared to CORN and BAR (331.7 vs 311.9 and 311.2 kg, respectively) and (0.9 vs 0.6 and 0.6 kg/d, respectively).  There was no difference in costs of gain among systems but the total cost of production was greatest (P<0.05) for DL calves ($2.20/calf/day).  Feedlot performance and carcass characteristics did not differ among systems, suggesting that backgrounding calves by field grazing either standing whole plant corn or swathed barley can result in lower backgrounding production costs compared to feeding in drylot.

Keywords: backgrounding, barley, corn