AIM: Quantifying relative changes of milk yield of three dairy cattle breeds of different levels of productivity when grazing alpine pastures. MATERIALS & METHODS: ▪ Alpine summer pasture at 2000 m asl (Alp Weissenstein); ▪ 3x 18 days grazing rotations: Early (June), Mid (July) and Late (August); ▪ 3 vegetation quality types: high, medium and low quality; ▪ 3x dairy breeds: Hinterwaelder (low productivity), Original Brown (medium), Swiss Holstein (high productivity); ▪ Outcome variable: milk yield (energy corrected) at similar stocking density RESULTS: Extensive Hinterwaelder are lighter and produce less milk than highly-productive Swiss Holstein. Dual-purpose Original Brown show medium body weight and milk yield. Early summer grazing (June): milk yield in low-quality pastures is ~5% lower than in medium- or high-quality pastures, irrespective of the breed. Mid summer grazing (July): grazing low-quality pastures reduced ~6% milk production of Hinterwaelder and Swiss Holstein. Late summer grazing (August): +/-10% relative milk production change when grazing high- or low-quality pastures in Original Brown and Swiss Holstein (vs medium quality pastures). Late summer grazing (August): grazing low-quality pastures reduced ~5% milk production in Hinterwaelder. RECOMMENDATIONS: In late summer grazing, offering your high-quality pastures to the most productive cows boost their milk production, which otherwise fall slump on lowquality pastures. Instead, using Hinterwaelder cows in low-quality pastures result in relatively smaller losses of milk per cow. Breed-specific stocking rate offset milk yield per area. CONCLUSIONS: Highly production breeds respond strongly to forage quality differences towards the end of summer, with large loses (or gains) of milk yield when grazing low- (or high-) quality pastures. Hinterwaelder, a Black Forest old breed, as smaller loses of milk yield when grazing low-quality pastures all along summer grazing.