Improving Reproductive Efficiency in Semi-Arid Sheep Systems: The Red Maasai and Dorper Case

Reproductive efficiency is key to sustainable sheep production in any environment. This study evaluated key reproductive traits in a long-term crossbreeding program involving indigenous Red Maasai sheep, exotic Dorper sheep, and their crosses (50% and 75% Dorper) under semi-arid conditions in Kenya. Traits analysed included age at first lambing (AFL), lambing interval (LI) and litter birth and weaning weights. All traits were significantly influenced by breed, season of birth, parity and sex. Heritability estimates for AFL and LI were close to zero, indicating strong environmental control, while moderate and significant heritabilities were observed for litter weight traits. Pure Red Maasai sheep exhibited the best overall reproductive performance and the highest genetic gains across traits, outperforming Dorper sheep. Among crossbreds, the 50% Dorper–50% Red Maasai cross (F1) showed better performance compared with the 75% Dorper cross. Negative genetic correlations between lambing interval and litter weights suggest that reducing lambing interval will positively influence litter weights. Phenotypic trends demonstrated sensitivity of AFL to rainfall variability, implying environmental influence. Overall, the results highlight the importance of management with indirect selection using litter weights to improve reproductive performance of the sheep while conserving Red Maasai and optimising crossbreeding strategies with the Dorper. Information © The Authors 2026