Characterization of nutrient content, yield, and gross return to cattle feeding at three corn crop endpoints

Abstract Text: Data collected at 3 reproductive stages and at harvest from 11 corn fields (8.5 ha/field; 4 as corn grain and 7 as corn grain/corn silage traits) were utilized to measure yields, nutrient concentrations and simulated gross return from feeding cattle on 40 ha of corn harvested as corn silage (CS), corn earlage (E), or whole corn (WC).  Field sample (3.72 m² plot) collection began at silking (R1) 73 d after planting, and ensued for corn reproductive stages R5 (CS), R6 (E) and harvest (WC). Stages R5, R6 and harvest occurred 49, 56, and 86 d following the onset of R1. Plant DM at R1, R5 or R6 was evaluated using Pearson’s correlation coefficients as possible predictor of DM content of alternative endpoint crops.  Correlations of corn grain yield at harvest with WC residue yield, E and E residue yield were also tested as predictors of various endpoint yields given WC yield.  Gross return of crop harvest for sale to simulated enterprises: grain market or cattle feeding using WC, as CS, or E was determined.  Each enterprise valued corn grain at market price ($0.14/kg).   Credit for crop residue (market price for corn stover) removed for feed or bedding was given but adjusted to debit caused by residue removal based on fertilizer value (market prices for urea, diammonium phosphate and potash).  Fertilizer value of manure (pricing same as for residue) was credited when cattle feeding was simulated.  Corn trait effect on DM, CP, NDF, and ADF at CS, E, and WC was not significant (P > 0.05).  Total plant DM at R1 was a poor predictor of crop DM as CS, E, or WC (P > 0.05).  Additionally, total plant DM as CS was not highly correlated with crop DM as E or WC (P > 0.05). Yield of E, E residue, or CS were not correlated (P > 0.05) to WC yield.  However, WC yield was correlated (0.878; P = 0.003) to WC harvest residue.    Simulated gross returns from cattle feeding were greater (P > 0.05) than marketing corn grain. Simulated gross returns were greatest (P < 0.05) when feeding cattle WC, intermediate (P < 0.05) when feeding cattle E, and lowest (P < 0.05) when feeding cattle CS.        

Keywords: Feedlot, Corn, Crops