Abstract :
[en] This work aimed to investigate the association between productive and reproductive traits of the dairy Sicilo Sarde ewes. After edits, a database containing 5,935 lactation records collected during 6 successive years in 8 dairy flocks in the North of Tunisia was used. Total milked milk in the milking-only period. (IMM) was retained as productive trait. The interval from the start of the mating period to the subsequent lambing (ML) and the status ofpregnancy (SP) was designed as reproductive traits. Sicilo-Sarde ewes had an average TMM of 60.93 L (+-44.12) milked during 132.8 days (+-46.6) after a suckling period of 1004 days (+-24.9). Average IML was 165.7 d. In a first step, the major factors influencing milk production and reproductive traits were determined. The significant sources of variation identified for TMM were: flock, month of lambing, year of lambing, parity, suckling length, litter size and milking-only length. Flock x month of mating, parity, year of mating and litter size were identified as significant factors of variation for IML. While, flock x month of mating, parity and year of mating were identified as significant sources of variation for PS. In a second step, variance components were estimated using a 3-traits threshold mixed model which combined SP as categorical trait and TMM and IML as continuous traits. Repeatability estimates were 0.21 (+-0.03) for TMM, 0.09 (+-0.02) for IML and 0.10 (+-0.05) for SP Moreover, TMM and IML were found to be favorably associated for the interval from the start of mating to the subsequent lambing (-0.45). This antagonism was largely explained by environmental factors specially flock x year of lambing effect (-0.45 +- 0.18) but unfavorably associated for the animal effect (0.20+-0.09)
