Few studies have been conducted in sub-Saharan Africa where multiple recordings of heart girth and body weight were made for the same cattle population. In this study, monthly measurements were taken of working oxen on 24 smallholder farms in the Ethiopian highlands for 1 year. The overall yearly mean body weight of oxen across working and nonworking periods was 281 ± 37 kg. No significant differences in mean monthly body weights were observed, except for December and January compared to August (297 ± 36 and 296 ± 37, and 271 ± 35 kg, respectively, P2values for the monthly equations ranged from 0.63 to 0.87 and the R2 value for the entire year was 0.75. The single equation for the year predicted body weight of oxen as a group to within ± 27 kg of mean monthly weighbridge values, whereas for a single animal the predicted body weight was ± 37 kg of the actual weight (C.I. 95%). The single equation can be used to monitor mean body weight of the oxen population equally well across working and nonworking periods of the year
