Studies were conducted to investigate the fermentation and nutritive value of ensiled broiler litter and corn forage.
The non-processed broiler litter, containing a wood shaving base, contained 82.9% DM, 26.8% crude protein, 23.0% crude fiber and 16.7% ash. Corn forage was harvested at two stages of maturity, corresponding to 26 and 38% DM. Two studies, one designated "small-bag" and one designated "large-bag" were conducted. For the small-bag study the treatments at each maturity were: untreated; urea, 0.5%, wet basis; and litter at levels estimated to contribute 15, 30 and 45% of the total dry matter. For these, mixtures were mixed by hand in 2 kg amounts and packed into small polyethylene bags supported in cardboard food containers. For the large-bag study the treatments at reach maturity were: untreated; urea, 0.5%, wet basis; and levels of litter to contribute 15 and 30% of the total dry matter. The large-bag silages were mixed with shovels and ensiled in large polyethylene bags containing approximately 114 kg per bag.
Both the small-bag and the large-bag silages were evaluated on the basis of nutrient composition and characteristics of fermentations such as pH and organic acid concentration. Total bacteria and coliform counts were conducted on the small-bag silages to evaluate fermentation as a means of destroying microorganisms present in litter. The large-bag silages were fed to sheep in two metabolism trials and two palatability trials to study the digestibility, nitrogen utilization and voluntary intake of the ensiled mixtures.
The addition of broiler litter resulted in significant increases (P < .01) in dry matter, crude protein and ash for silages made from forage harvested at both maturities. Litter increased the crude protein from about 8% (dry basis) for the control treatment to about 11, 15 and 18%, respectively, for silages in which litter contributed 15, 30 and 45% of the total dry matter. Ammonia concentrations of silage were increased (P < .01) by each level of litter. Litter and urea appeared to buffer the organic acids of fermentation resulting in final concentrations of lactic acid that were higher than control silages. Total bacteria numbers were in excess of 3 million per gram; however, only the highest level of litter in maturity 2 silages and the two highest levels of litter in maturity 2 silages had significantly higher counts than controls. Coliforms were no higher in litter silages than controls.
When fed to sheep, dry matter digestibility was similar for all silages. Crude protein digestibility was depressed by advancing maturity of the corn plant, but significantly increased by each level of litter. Nitrogen retention data indicated that litter nitrogen was well utilized; however, increasing the level of litter from 15 to 30% of the dry matter depressed efficiency of dietary nitrogen utilization.
Dry matter intake was significantly greater (P < .01) for silages containing litter than for control and urea silages. There were no significant differences in dry matter intake associated with forage maturity.
Ph. D.