Seasonal variation of meat duck manure production characteristics

This study aimed to explore the characteristics of the manure of meat duck, and to assess its characteristics of pollutant emission in different seasons, so as to provide a basis for waste disposal and resource utilization of meat duck farms. Feeding experiments were conducted in 4 seasons and 100 Pekin type Z meat ducks were raised in each season for 37 days. Their food intake and manure production were recorded daily, and the relevant components in the feed and manure were measured regularly. Results showed that the Zn content in duck manure was the highest in autumn, whereas TN, P, and Cu contents were the highest in winter. In winter, TN content in manure was significantly higher than that in summer and autumn. P and Cu contents in winter were significantly higher than that in all other seasons. Cu and Zn contents in manure were the lowest in spring. Average moisture content of duck manure was 84.61%, being the highest in summer and lowest in spring. Average content of organic matter was 83.38%, and the seasons ranked winter > spring > autumn > summer. Manure productions were 338.3 g·d^-1·head^-1, 275.9 g·d^-1·head^-1, 317.6 g·d^-1·head^-1, and 327.0 g·d^-1·head^-1 in spring, summer, autumn, and winter, respectively. Excretion coefficients of TN, P, Cu, and Zn were 2.13 g·d^-1·head^-1, 2.48 g·d^-1·head^-1, 2.56 mg·d^-1·head^-1, and 21.10 mg·d^-1·head^-1, respectively. Daily excretion of TN in spring and winter was significantly higher than that in summer and autumn, daily excretion of P was significantly higher in winter than in the other seasons, and daily excretion of Cu in summer was not significantly different from that in spring but significantly lower than that in autumn and winter. TN excretion accounted for the lowest proportion in autumn and the highest in spring, whereas P excretion accounted for the highest proportion in autumn and the lowest in spring. There was a highly significant positive correlation between the excretion of TN, P, Cu, and Zn and the intake of the corresponding elements. This research showed that seasonal (dietary) factors can significantly affect moisture content, organic matter, TN, P, Cu, and Zn contents in the manure of meat duck. There were significant differences in feed intake, manure production, and TN, P, Cu, and Zn excretion among the seasons, and the excretion of each element in each season was significantly correlated with the intake of the corresponding element.