Two prevailing trends in livestock production include increasing farm sizes and higher recycling rates of manure. Using beef cattle farms in China as a case study, we examine the impact of farm size on farmers' choice of manure disposal modes. Three forms of manure disposal modes are identified: (1) selling to neighboring farmers, (2) giving away to neighboring farmers and (3) self-use. Based on primary data from a field survey of beef cattle farmers in China, we estimate the choice of the above-mentioned three disposal modes using the constrained singular Seemingly Unrelated Regression (SUR) model. We find a significant and nonlinear impact of farm size on farmers' choice of manure disposal modes. Specifically, there is a significant and inversed U-shaped relationship between farm size and manure giving away, and a significant U-shaped relationship between farm size and manure selling or self-use. We additionally find several other factors that affect farmers' choice of manure disposal: the educational level of a farmer has a positive impact on manure selling; the better a farmer's physical health condition, the more likely the farmer self uses manure and less likely gives it away; land acquisition, as well as engagement in crop farming, increases manure self-use and reduces manure giving away and selling; the availability of manure treatment facilities reduces manure self-use; and the willingness of nearby crop growers to accept manure significantly decreases manure self-use and increases manure selling and giving away. Policy implications are also discussed.

Livestock rations are formulated to minimize feed cost subject to nutritional requirements for a target performance level, which ignores the potentially substantial cost of disposing of nutrients fed in excess of nutritional requirements. We incorporate nutrient disposal costs into a modified least-cost ration formulation model to arrive at a joint least-cost decision that minimizes the sum of feed and net nutrient disposal costs. The method is demonstrated with phosphorus disposal costs on a representative dairy farm. Herd size, land availability and proximity, crop rotation, and initial soil phosphorus content are shown to be important in determining phosphorus disposal costs.