Correlation between physical measurements and dietary energy values of wheat for poultry and pigs

A number of wheat samples were obtained for evaluation: for young poultry, 50 wheats (10 varieties each grown at ®ve sites) with bushel weights/thousand grain weights ranging from 69.5 to 80.0 kg/hl and 34.6 to 59.3 g, respectively; for pigs (8 different varieties each grown at 2 sites) with bushel weights/thousand grain weights ranging from 71.0 to 81.5 kg/hl and 40.9 to 56.7 g, respectively. Apparent metabolisable energy (AME) and coef®cient of metabolisability of gross energy (CAME) were determined with young broilers; Digestible energy (DE) and coef®cient of total tract apparent digestibility (CTTAD) of gross energy were determined with growing ®nishing pigs. Wheat was added at a rate of 750 and 900 g/kg diet for poultry and pigs, respectively, in a series of metabolism trials. AME values ranged from 8.49 to 12.45 MJ/kg DM and CAME from 0.491 to 0.702. DE values ranged from 14.55 to 16.07 MJ/kg DM and CTTAD from 0.848 to 0.890. There were signi®cant differences between variety and site (together with interaction terms) in both, the physical and biological measurements, but not in a structured fashion. There were no signi®cant relationships between the two physical measurements and any dietary energy value (either in terms of concentration or coef®cient), con®rming previous work. The two lowest bushel weight wheats had among the highest AME values for poultry, con®rming that evaluation of the variability in nutritional value of wheat for poultry should only proceed against a background of detailed knowledge of genotype. Comparisons on the basis of variety name alone appear inappropriate as individual varieties do not seem to respond in a uniform fashion. # 2000 Elsevier Science B.V. All rights reserved.