Nutritive Evaluation of a Waste Wood Pulp in Diets for Finishing Lambs

Abstract

Diets containing wood pulp fines (WPF) were evaluated in lamb digestion and finishing trials. WPF was a residue from a hardwood ammonia base sulfite tissue mill and contained 1.2% crude protein, 95.4% neutral detergent fiber (NDF), 86.4% acid detergent fiber (ADF), 4.1% acid detergent lignin and 1.5% ash on a dry matter (DM) basis. The six diets evaluated in both trials were a 50% hay, 50% corn control; 20, 40 or 60% WPF, plus equal amounts of hay and concentrate (conc.; corn, soybean meal and minerals); 67% WPF, 23% conc, 10% hay and 23% WPF, 67% conc, 10% hay. Diets did not affect DM intake (per Wkg75) during the ad libitum intake phase of the digestion trial. Apparent dry matter digestibility (DDM) was highest (P<.01) for the 23%WPF diet and lowest (P<.01) for the 67% WPF diet. NDF and ADF digestibility were highest (P<.01) for the 60% WPF diet and lowest (P<.01) for the control diet. Nitrogen retention was highest (P<.05) in lambs that received the control diet and lowest (P<.05) in lambs fed the 67% WPF diet. Crude protein digestibility was not significantly affected by diet. In a 54-day finishing trial (eight lambs per treatment; avg initial wt 35.5 kg), final weight and average daily gain were lowest (P<.05) for lambs fed the 60% WPF diet with no differences among the remaining treatment groups. Carcass traits were not affected by diet and there were no adverse effects from feeding diets containing WPF on blood serum composition (blood urea nitrogen, protein or mineral levels) or rumen and liver histopathology.