ABSTRACT This research was conducted to investigate the effect of various concentrations of lactose supplementation in Tris extender for maintaining the quality of Etawa crossbreed goat epididymal spermatozoa stored at 3-5 C. Semen in the control group was diluted with a tris extender containing 20% egg yolk without lactose. Semen in the test groups was diluted with a tris extender containing 20% egg yolk and added with 0.3% (0.3 g per 100 mL extender) and 0.6% lactose for group TL1 and TL2, respectively. Parameters evaluated of the fresh epididymal spermatozoa were motility, concentration, percentage of live, and abnormality of spermatozoa, while for dilutedspermatozoa were motility and percentage of live spermatozoa. Spermatozoa observation was conducted until it reaches 40% motility. The results showed that the mean percentage of motility, live sperm, concentration, and abnormality of epididymal spermatozoa were 70%; 81%; 3,220x106 cells/mL; and 4.30%, respectively in all group. After dilution, the percentage of motility and live spermatozoa were also 70% and 81.00±1.58%, respectively in all groups. The decreasing of spermatozoa motility was observed on day 4 of storage, in which percentage of spermatozoa motility in control group (40.00±0.00%) was significantly lower (P<0.05) than those in TL1 (44.00±2.24%) and TL2 (45.00±0.00%) groups. Percentage of live spermatozoa in control (63.20±2.68%) was not significantly different (P>0.05) than TL1 (65.40±1.95%) and TL2 (65.60±1.95%). In conclusion, the supplementation of lactose into Tris extender could maintain the epididymal spermatozoa of Etawa crossbreed for 3 days of storage at 3-5 C. ____________________________________________________________________________________________________________________ Key words: epididymal spermatozoa, Etawa crossbreed, lactose, preservation ABSTRAK Penelitian ini bertujuan mengetahui pengaruh penambahan laktosa pada berbagai konsentrasi dalam pengencer Tris kuning telur terhadap kualitas spermatozoa kauda epididimis kambing peranakan etawa (PE) yang disimpan pada suhu 3-5 o C. Pengencer Tris kuning telur digunakan sebagai kontrol (K), perlakuan pengencer Tris kuning telur + 0,3% laktosa (TL1), dan pengencer Tris kuning telur + 0,6% laktosa (TL2). Pengamatan spermatozoa asal epididimis meliputi persentase motilitas, konsentrasi, persentase hidup spermatozoa, dan abnormalitas. Pengamatan spermatozoa setelah pengenceran meliputi pengamatan persentase motilitas dan hidup/mati. Pengamatan dilakukan sampai motilitas spermatozoa mencapai batas minimum 40%. Hasil penelitian menunjukkan motilitas; persentase hidup; abnormalitas; dan konsentrasi spermatozoa masing-masing adalah 70%; 81%; 4,30%; dan 3.220 x 106 sel/ml. Setelah pengenceran, persentase motilitas dan hidup spermatozoa pada K, TL1, dan TL2 adalah sama yakni 70% dan 81±1,58%. Penurunan motilitas terjadi pada hari ke-4, pada K1; TL1; dan TL2 masing-masing adalah 40,00±0,00; 44,00±2,24; dan 45,00±0,00% (P<0,05). Persentase hidup spermatozoa pada K; TL1; dan TL2 masingmasing adalah 63,20±2,68; 65,40±1,95; dan 65,60±1,95% (P>0,05). Disimpulkan bahwa laktosa mampu mempertahankan kualitas spermatozoa epididimis kambing PE yang disimpan selama tiga hari pada suhu 3-5°C. _______________________________________________________________________________________