Nutrient characterization of swine fecal waste and utilization of these nutrients by swine

Swine feces collected from finishing hogs was fed to 48 crossbred gilts averaging 125 kg in two total collection metabolism trials. Unprocessed feces (fresh) was used in one trial and dried feces was used in the other trial.

Feces from the gilts fed the feces substituted rations were significantly higher in crude fiber, ether extract, crude protein, magnesium, copper, and zinc content in both the unprocessed and dry trials. The fecal concentration of ash, NFE, calcium, phosphorus, and potassium tended to remain constant, Phosphorus was the only urinary mineral which significantly increased as the level of feces substituted in the basal ration increased. Output of feces increased as the amount of feces substituted for the basal ration was increased with no differences in urinary output.

Swine feces were found to be of less nutritive value than a basal corn-soybean meal ration, but nutrients were available. Digestion of dry matter, ash, crude fiber, ether extract, crude protein, and nitrogen-free extract was significantly reduced as either fresh or dried swine feces was substituted for the basal ration with digestion coefficients of (%): 52.3, 32.4, 50.5, 53.5, 62.7, and 48.5, respectively for the wet feces and 43.7, 30.7, 31.2, 54.7, 57.5, and 43.3, respectively for the dried feces, calculated by difference and regression, and averaged. The apparent absorption of most minerals analyzed was reduced as the level of feces substituted increased while the absorption and retention in grams per day was similar across treatments in most cases.