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Knowledge about feed intake and adequate nutritional status of dairy cows is important to achieve high milk yield in grazing systems. A possible, but subjective, method to estimate changes in grazing intake could be rumen fill scoring. Thus, a novel flow chart, based on existing criteria for rumen fill scoring was developed to simplify this approach. The first objective of this study was to develop a flowchart to reduce training time for untrained observers and to support the observers in their decision-making process. Therefore, the quality of scoring of four trained observers that used the criteria, originally published by Zaaijer and Noordhuizen (2003), was assessed first. After that, the interobserver reliability of trained observers (control group) and untrained observers that used the novel flowchart was determined. The novel flowchart was tested twice. The second version of the flowchart included the feedback of the first round. To assess if rumen fill scoring is a suitable method for detecting changes in grazing intake was the second objective of this study. Therefore, it was investigated if rumen fill scores could be used to detect decreasing feed intake during a 6-d grazing period with limited feed allocation. The experiments demonstrated that overall agreement between trained observers who used the criteria originally published was moderate (κ F = 0.53). The overall agreement of untrained observers who used the novel flowchart increased from fair (κ F = 0.40) to substantial (κ F = 0.66) between the two versions of the flowchart. Finally, it was found that rumen fill scores decreased, according to decreasing feed allocation for this small sample. In conclusion, the novel flowchart simplified rumen fill scoring, thus facilitating the assessment of rumen fill as a potential method for estimating changes in pasture intake in research and practice.