Levels, sources and methods of nitrogen supplementation of maize silage for beef production

Abstract Results from some trials concerning protein supplementation of maize silage in beef cattle fattening are reported. With 1% LW/day of concentrate in the diet no technical differences have been found between 11%, 13% and 15% crude protein content in the DM of the diet. The protein levels (from 11 – 15%) proved to be independent of the energy content of the diet, giving similar results both in all-maize-silage diets and with the addition of 0.5 or 1% LW/day of concentrates. Equal technical results are also found with traditional nitrogen supplementation with soya bean meal, and with urea given at feeding; there is a tendency for higher performances to be obtained by mixing the urea in the forage before ensiling. With regard to this last subject, the comparison between two commercial NPN chemical additives (Pro-sil and Maisol-plus) and two experimental mixtures showed substantially similar results, slightly unfavourable to Pro-sil. On the whole these results confirm the possibility of eliminating the vegetable proteins from beef cattle production and substituting them completely with NPN.