Effect on manure characteristics of supplementing grower hog ration with clinoptilolite

Diet manipulation, such as zeolite (clinoptilolite) supplementation, can reduce manure nutrient content but may negatively affect manure handling properties. The objective of the study was to measure the impact on manure physico–chemical properties of supplementing grower hog rations with 4% zeolite (90% + clinoptilolite). The manure was produced by feeding each one of four experimental rations to three hogs for four weeks. During the last week, the hogs were placed in metabolic cages to individually collect, measure and analyze their manure for nutrient content. The four rations consisted of a control with 100% crude protein (CP) and energy requirements (R1), and three 4% zeolite (90% + clinoptilolite) supplemented rations with a CP and energy of 100%, 100%; 90%, 90% and; 90% and 85% of requirements (R2, R3 and R4), respectively. The manures were aged at 25 °C for 67 days and then analyzed for nitrogen and carbon, and tested for flow characteristics and odour emissions. Ration R2 resulted in the lowest fresh manure total carbon (TC), but was significantly more diluted by urines. Ration R2 also produced fresh manure with the lowest total nitrogen (TN), while ration R3 produced that with the lowest total phosphorous (TP) and total potassium (TK), but not significantly different from that of the control ration, R1, because of a large coefficient of variation among hogs. Ration zeolite supplementation improved aged manure flow characteristics, especially for rations R3 and R4 with a lower fat formulation. Zeolite added to manure once excreted had no effect on its viscosity even if its total solids were increased. Rations R3 and R4 produced an aged manure which emitted less odours, as compared to ration R1; ration R2 produced less odours than ration R1, although not statistically significant (P > 0.05). Thus, swine diets supplemented with a zeolite (clinoptilolite) can lower the manure nutrient content without altering its physico–chemical properties. The results require repeating with more hogs and rations containing a better nutrient balance.