Fermentation characteristics, digestibility and performance of ensiled swine waste, wheat straw and cane molasses fed to sheep

Abstract

In four full-scale bunker silos were ensiled 16·5 tons of different mixtures of swine waste, wheat straw and cane molasses. One mixture had 22% swine waste, and the other one 44% (DMB). Swine waste was collected from an open concrete growing-finishing swine feedlot. During the first six weeks samples were taken from the silos and analyzed for pH, lactic acid, total coliforms, clostridia and aerobic and lactic acid bacteria. After three months, silos were opened and evaluated for physico-chemical, microbiological and nutritional characteristics. Two performance trials on sheep were conducted, one to determine the nutritive value of the silages with 22 and 44% of swine waste and the other one to evaluate the inclusion of the silage with 44% swine waste at 20, 40, 60 and 80% (DMB) in sheep diets. Dry matter, crude protein, acid detergent fiber and neutral detergent fiber digestibilities were determined for silages with 22 and 44% swine waste in eight sheep. Evaluation of storage stability in samples from different levels in bunker silos indicated low stability in surface, bottom and side wall samples and fairly good stability in samples from 50 cm depth. Those samples had a pleasant aroma and appearance similar to that of a good quality haylage. Typical manure aroma was not present in waste silages. Twenty-two percent swine waste silage reached an average pH 4·4 while 44% swine waste silage reached an average pH4·6. After 7 days of fermentation, total coliforms were completely destroyed. Clostridia and aerobic bacteria tended to be decreased by ensiling. Average daily gain and digestibility of crude protein were higher for sheep fed 44% swine waste silage than sheep fed 22% swine waste silage, but lower than sheep fed basal diet (P < 0·01). Feed efficiency was different for the three diets (P < 0·01). Dry matter intake was similar for sheep fed 44 and 22% swine waste silage (P > 0·01) but lower than sheep fed basal diet (P < 0·01). Average daily gain and dry matter intake decreased with increasing levels of 44% swine waste silage (P < 0·01). Feed efficiency was not different between the four treatments (P < 0·01).