Improving animal’s robustness will contribute to overcome current and future economic, environmental and societal challenges in the small ruminant sector in Europe. The ability of ewes to mobilize and to restore body reserves (BR) is a key mechanism to cope with quantitative and qualitative variations in feed resources. The aims of this work were to characterize the different patterns of BR changes throughout productive cycles and to analyze the genetic variability of such changes in French meat sheep. Temporal changes in BR dynamics were investigated using Body Condition Score (BCS) measured frequently throughout repeated entire productive cycles in ewes reared exclusively outdoors in harsh conditions. The analysis showed three different clusters for BCS variations whatever the productive cycle. Major clusters were mainly characterized by BR accretion during dry-off period and early pregnancy and BR mobilization during mid-pregnancy and suckling. Clusters differed in the BCS level and profiles of variation. The heritability values were low to medium for BCS variations (h2=0.06 to 0.15). High negative genetic correlations for BCS variations between dry-off period and pregnancy and/or suckling indicated BR mobilization and accretion were two genetically correlated processes. These results showed that BR variations could be used in selection to increase robustness.