Evaluation of an on-farm fecal particle size separator

This study aims to validate an on-farm fecal particle size separator by comparing its performance against a laboratory method as the reference standard. Additionally, the device's applicability across different age groups (calves and adult cows) is evaluated. Fecal samples of 150 g each from calves and cows are dissolved in water and sieved through the on-farm device under water flow. Similarly, 15 g of the same samples are analyzed in the laboratory using an automatic sieve shaker. In both methods, the retained material is assessed. The analysis revealed a higher average percentage of retained material with the on-farm device. This is likely due to human error during operation: the on-farm method lacks a shaking component in order to remove access water, and the sieving duration is subjectively determined. Beyond human factors, the composition of the feces appears to influence the results. The overall better alignment between both methods in calves may be attributed to the underdeveloped gastrointestinal tract and differences in diet, which include milk feeding. In adult animals with developed rumination behavior and ingestion of larger particles, the increased number of microorganisms and soluble particles contained in the access water seem to cluster, thereby increasing the retained percentage in the on-farm method. Despite the observed differences, the development of standardized guidelines for implementation could make the device a cost-effective on-site tool for evaluating and optimizing calf feeding.