Maize meal supply in finishing bull farms: physical and chemical variability

摘要

Abstract The work was carried out in 15 associated beef farms with the aim of monitoring animal food quantity and quality starting from the chemical analysis of the components used to formulate the total mixed rations (TMR) for finishing Charolais (CH=9 farms) and Limousin bulls (LI=4). In particular cereal grains, mainly maize, constitute the 25.6% + 6.7 (as fed) of TMR. The samples of maize grains were collected for about three months (N=57) to perform chemical analysis: dry matter, crude protein, ether extract, ash, soluble polysaccharides (SC, by α-amylase treatment) and fibre fractions (α-NDF, ADF, ADL). The α-amylase treatment did not give values of fibrous fractions with a satisfying repeatability and there is not a good accord between SC (100- indigested residue) and calculated non fibrous carbohydrates (NFC) values; presumably because it, alone, is not able to degrade crystalline starch (slowly digestible starch). The performing of a heating pre-treatment, to gelatinize starch, improves amylase effectiveness, but it seems to remove some other analytical components, as protein and/or ash (SC =76.3 vs NFC =73.3).