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Fifty Ethiopian Menz ewes maintained on pasture grazing with uncontrolled mating showed ovarian cyclicity at all times of the year. Conception rates to first, second and third service were 78, 18 and 4%, respectively. Mean post-partum anoestrous interval was 76-1 (s.e. 4-6) days. Two-thirds of ewes conceived before lamb weaning at 90 days and had 8 month lambing intervals. Twice weekly progesterone determinations showed that 67% of ewes exhibited a silent ovulation 66-4 (s.e. 10-5) days post partum, 12% of oestrous cycles were longer than 20 days and 8% of heats were false or anovulatory. It was concluded that Menz ewes have the natural potential for three lambings in 2 years, under adequate nutrition. Their better management and genetic improvement should further reduce current lambing intervals and increase annual reproductive rates.