Fermentation characteristics and nutritional value of different proportions of alfalfa and wheat straw ensiled with and without different additives

Experiments were conducted to investigate the fermentation characteristics and nutritional value of mixtures containing different proportions of alfalfa (Medicago sativa L.) and wheat (Triticum aestivum L.) straw ensiled with and without molasses, microbial inoculant and molasses + microbial inoculant.;In experiment 1, urea treatment of the 0:100 mixture (wheat straw) increased pH. Overall lower pH occurred when molasses was added, compared to untreated and inoculated silages. Lactic acid concentration decreased linearly with decreased level of alfalfa, over all additives. Molasses increased lactic acid concentration. Overall, water soluble carbohydrates (WSC) in pre-ensiled mixtures increased linearly with increases in alfalfa. The WSC decreased after ensiling. Microbial inoculant did not affect pH or lactic acid content in the silages. In vitro dry matter digestibility (IVDMD) increased linearly with level of alfalfa, and molasses increased IVDMD.;In experiment 2, increased proportions of wheat straw to alfalfa increased DM content and lactic acid concentration, and decreased pH and total VFA content. The CP, Ca, P, Mg and K contents decreased with increases in wheat straw. Addition of molasses to alfalfa increased WSC and lactic acid, and decreased pH and total VFA. Urea treatment of wheat straw increased pH and acetic acid, and decreased lactic acid, compared to untreated wheat straw. The NDF and hemicellulose were decreased with urea treatment.;Two metabolism trials were conducted, each with 21 crossbred wethers. The diets were alfalfa and wheat straw silages made as in experiment 2. Wheat straw ensiled alone was supplemented with soybean meal because of insufficient consumption when the straw was fed alone. Linear increases in DM, OM, and CP digestibilities were observed with increased level of alfalfa. Adding molasses increased DM digestibility. A linear increase in N retention was observed with increasing alfalfa level. Ruminal NH...