Seminal vesicles were collected from 60 heads of Bulls which butchered in slaughter house (RPH) Yogyakarta. The aims of this study are knowing the relationship between body weight, age, fluids volume and concentration of prostaglandin F 2 α (PGF 2 α) in seminal vesicle of beef cattle. Those seminal vesicles were gathered from bulls which recorded its body weight and age then measured its seminal vesicles for weight, fluids volume and PGF2α levels. The PGF 2 α level was measured by Enzyme-Linked Immunosorbent Assay. Statistical analysis was performed using one way -analysis of varian, regression and correlation with P<0.05. Body weight of bulls showed positive correlation with the weight of seminal vesicle and its fluids volume. However, PGF 2 α levels were not correlated with the body weight of cattle. Weight of seminal vesicles also exhibited positive correlation with volume of vesicle fluids but no correlation with PGF 2 α levels. Based on the age of bulls, there were no correlation with the weight of seminal vesicles, seminal fluids volume and PGF 2 α levels. Those result indicated that the weight and fluids volume were affected by the body weight of bulls altough the PGF 2 α levels have a standard of development which seems affected by other factors such as concentration of androgen hormone.Keywords : cattle, body weight, age, seminal vesicle, PGF 2 α Abstrak Vesikula seminalis dikoleksi dari 60 ekor sapi yang dipotong di Rumah Potong Hewan Yogyakarta. Tujuan dari penelitian ini adalah mengetahui hubungan antara berat badan, umur, volume cairan dan konsentrasi prostaglandin F 2 α (PGF 2 α) dari vesikula seminalis sapi potong. Tingkat konsentrasi PGF 2 α diukur menggunakan Enzyme-Linked Immunosorbent Assay (ELISA) kit. Analisa statistik dilakukan menggunakan one way ANOVA, regresi dan korelasi dengan P<0.05. Berat badan sapi menunjukkan korelasi positif terhadap berat vesikula seminalis dan volume cairan yang dihasilkan. Konsentrasi PGF 2 α tidak berkorelasi terhadap berat sapi. Berat vesikula seminalis memiliki korelasi positif terhadap volume vesikula seminalis tetapi tidak berkorelasi dengan konsentrasi PGF 2 α. Berdasarkan pada umur sapi, parameter tersebut tidak berkorelasi dengan berat vesikula seminalis, volume cairan seminalis dan konsentrasi PGF 2 α. Hasil tersebut mengindikasikan bahwa tingkat konsentrasi PGF 2 α memiliki standar perkembangan tersendiri yang kemungkinan dipengaruhi oleh faktor lain seperti konsentrasi hormon androgen.Kata kunci: sapi potong, berat badan, umur, vesikula seminalis, PGF 2 α JSV 35 (1), Juni 2017