Genetic and nutritional effects on swine excreta

The objective of this study was to investigate genetic and nutritional effects on swine excreta. Two studies were used. Study I was a 3 x 2 x 2 factorial design with three genetic groups, two diets, and two sexes. Genetic groups were a maternal line (WL), paternal line (BL) and their F1 progeny. Corn-soybean meal diets with either 18 or 14% CP, differing only by substitution of soybean meal for corn, were used in both studies. Study II was a 2 x 2 factorial design with two genetic groups and two diets. High testosterone (D2) and low testosterone (D1) Duroc lines were used. Solid and liquid wastes were collected for 3 d. A total of 108 pens in Study I and 50 pens in Study II were sampled twice. Total excreta were measured and samples collected for chemical analysis of N, NH3N, P, Ca, Cu, K, Zn, and Fe. Measures were adjusted for pig weight and feed disappearance. Maternal-line pigs excreted significantly less P, Ca, Cu, Zn, and Fe than F1 or BL pigs and numerically smaller quantities of all nutrients than BL pigs. In study II, differences were found between lines ofthe same breed. Line D2 pigs had greater output of P, Ca, and Cu (P< 0.05) than D1 pigs and numerically larger quantities of all other nutrients except NH3N and Fe. Pigs fed 14% CP excreted less N, NH3N, and K (P < 0.01) in both studies and excreted significantly less P in Study I. Pigs on a 14% CP diet excreted numerically smaller amounts of all nutrients in both studies except Ca in Study II. In Study I, gilts excreted smaller (P < 0.05) amounts of all nutrients than barrows. Genetic, nutritional, and gender differences influenced waste output.