Abstract

Bali bull has great potential to be developed as a national meat source in Indonesia which can address con-cerns of meat importation. Bali bull farming only requires small holding system, has high fertility and low calf mortality as its advantages and is a growing enterprise by way of artificial insemination (AI) with se-men collected from phenotypically superior bull sires. However, efficient means of preserving Bali bull semen quality using diluents still requires exploration at a national level. The purpose of this study was to determine which of the selected diluents will best preserve the quality of local Bali bull semen over a period of five days at 4 °C. Andromed® and egg yolk-tris diluents were compared in preserving quality of semen collected from seven-year old bulls with 70% minimum motility. Spermatozoa motility, viability, and ab-normality were observed and compared. This research used factorial complete randomized design with two factors in which each factor has 2 levels and 5 levels with three-times treatment. Results of the study showed Bali bull spermatozoa demonstrated 51.66% motility, 59.13% viability, and only 22.68% abnormal-ity until day five in egg yolk-tris diluent. In comparison, Andromed® diluent demonstrated 23.33% motil-ity, 45.59% viability, and 23.15% abnormality under similar conditions. To conclude, egg yolk-tris is a superior diluent when compared to Andromed® in preserving local Bali bull semen quality by better main-taining spermatozoa motility, viability and lower percentages of abnormalities when stored for five days at 4 °C. This data provides useful information for bull farmers, in particular Bali bull farmers in Indonesia in the practice of AI to consider carefully the choice of diluent relative to storage time and temperature in im-proving cattle farming practices for increased meat productivity in the region.