Genetic analyses of early-expressed reproduction traits of Boran and their crosses with Holstein Friesian and Jersey in Central Highlands of Ethiopia.

The study was conducted to assess early-expressed reproductive traits of Boran cattle and their crosses with Jersey and Holstein Friesian (HF). The traits studied were age at first services (AFS), number of services for first conception, age at first calving (AFC), first dry period (FDP), first calving interval (FCI), and first service period (FSP). Genetic group and period of birth/calving had a significant (p < 0.05) effect on reproductive traits. The Boran cattle were inferior to HF or Jersey crosses. First crosses (F 1) for Jersey and Boran (50 % Jersey: 50 % Boran) showed a significantly (p < 0.05) younger AFS (by 7.25 months) and AFC (by 10.75 months), had shorter FCI (by 63.27 days), FDP (by 61.13 days), and FSP (by 60.3 days), and needed less (by 0.35) numbers of services per first conception as compared to the Boran cattle. The F 1 for Jersey and Boran (50 % Jersey: 50 % Boran) crosses showed better performance than the F 1 for HF and Boran (50 % HF: 50 % Boran). Heritability values for AFS and AFC were the highest and were estimated at 0.51 ± 0.10 and 0.49 ± 0.13, respectively, and lowest heritability was recorded for FDP (0.02 ± 020) and FSP (0.10 ± 0.29). The genetic correlation was highest (0.10 ± 0.20) between AFS and AFC and was lowest (-0.01 ± 0.66) between FCI and FSP. The breed additive for Jersey was only significant (p < 0.01) for AFS and AFC. The crossing of HF with Boran cattle has desirably reduced 9.16 ± 2.88 months in AFS; the corresponding reduction in AFS was 3.49 ± 3.59 months by crossing with Jersey. The performance comparisons and genetic and crossbreeding parameters indicated that crossbreeding of Boran with HF or Jersey can improve reproductive performance.