EFFECT OF VARIOUS EXTENDERS AND TAURINE ON SURVIVAL OF STALLION SPERMCOOLED TO 5-DEGREES-C

Stallion semen was diluted in five different extenders (dimitro-poulus onze (Dimitro's), Kenney's modified tryode (Kenney's), modified INRA8 2 (INRA82), egg yolk-citrate-taurine (Citrate) and EZ-Mixin) and evalu ated for motility after cooling and storage at 5 degrees C for 0, 24, 48, 72 and 96 h. EZ-Mixin extender was used as control while 70 and 10 0 mM of taurine were added to Dimitro's, Kenney's and INRA82 to study its effect under conditions of storage at 5 degrees C and varying proc essing modifications. Motility in INRA82 was 57.0, 58.4, 61.1, and 56. 1% after 24, 48, 72 and 96 h, respectively and was higher (P<0.05) tha n in other extenders after 48, 72, and 96 h. Motility decreased over t ime in Dimitro's (P<0.05) and Kenney's (P<0.01). Motility in INRA82 an d EZ-Mixin decreased (P<0.05) after 24 h and then remained unchanged u ntil 96 h. In taurine (70 mM) containing extender Citrate, motility de creased throughout storage. Motility in INRA82 and Kenney's with tauri ne decreased (P<0.05 and P<0.01, respectively) after 48 h, and then re mained stable until 96 h only in INRA82 with taurine. Motility in INRA 82 with taurine was higher (P<0.05) than in Citrate throughout incubat ion, whereas motility in INRA82 with taurine was higher than in EZ-Mix in and Kenney's with taurine after 24 and 48 h, respectively. Motility in INRA82 and Kenney's with taurine improved (P<0.05) when osmotic pr essure was increased with taurine (100 mM) but not when osmotic pressu re was increased with Na+ and KC salts. Motility was always higher (P< 0.01) in taurine (70 mM or 100 mM) containing extenders than in non-ta urine extenders, Dimitro's, INRA82, and Kenney's, when sperm were incu bated for 24 h at 5 degrees C in these extenders, then washed and incu bated at 39 degrees C in Sp-TALP for 12 or 24 h. In conclusion 1) INRA 82 was a better extender than the other extenders tested. 2) inclusion of taurine (100 mM) in INRA82 and Kenney's improved sperm survival un til 96 and 48 h, respectively, and 3) sperm preincubation for 24 h in taurine containing extenders resulted in better sperm survival when wa shed and stored in Sp-TALP for further 12 or 24 h.