Investigation on Selecting of long time Boar semen extender

Four boar semen extenders were designed(T1,T2,T3,T4)to select long time boar semen extender using EDTA extender as the control,which was quite popular in swine artificial insemination in Sichuan Province.By means of inspecting sperm activity with microscope day in day at room temperature(16～28℃),two extenders(T2,T3)were confirmed to be able to preserve sperm activity above 0 5 for five days,and one extender(T4)to be able to preserve sperm activity above 0 5 for six days.In order to check its preserving effect,sixty eight sows/gilts were mated with diluted semen preserved by T4 for six days.The pregnant rate was 86 8%.In order to better guide the usage of extender more effectively,the changes in pH of the four extenders(still using EDTA as the control)were measured during the first 90 minutes after preparation.Though boar semen extenders do not have the same pattern of pH change across the time,they took almost the same time(60 minutes)to reach balanced pH.Thus it was suggested that the semen should not be mixed with extender until a stable pH was reached.In general,a liquid boar smen extender should be prepared 60 minutes prior to mixing with raw semen.