Age effect on post freezing sperm viability of Bali cattle (Bos javanicus)

Abstract

Post freezing sperm viability is one of factors which determine artificial insemination success. In the other side, bull's or sire age influences the semen quality through sperm membrane constituent. It is known that freezing process change the sperm membrane during the processing stage. This research aims to know the effect of sire age on post freezing sperm viability of Bali cattle. The samples were collected in Singosari Artificial Insemination Centre, Malang, East Java, Indonesia on September - November 2016. Eight Bali cattle (4 and 7 y.o, 4 heads in each group) were used as semen source. Semen was collected using artificial vagina, 10 times spanning for 5 weeks (2 times per week, interval 3 and 4 days) in a row. The samples were then evaluated at fresh, chill and frozen stage. Fresh semen was diluted in Tris-citrate-egg yolk 20% (v/v) followed with chilling and freezing. Semen qualities were observed as sperm % motility (MOT), % live sperm using eosin-nigrosine staining (EOS) and % sperm membrane integrity using hypoosmotic swelling test (HOS). Variable comparisons between age groups were done using t-test. On the average, 4 y.o bulls showed higher semen quality at fresh, chill and frozen compared to 7 y.o in MOT (68.00±6.39 vs 65.9±7.62; 56.40±3.71 vs 54.33±5.83; 44.25±3.52 vs 40.40±7.06), EOS (72.08±6.63 vs 71.82±7.38; 57.81±3.83 vs 57.41±6.32; 53.16 ±8.41 vs 46.49±9.13) and HOS (60.85±13.91 vs 54.84±13.43; 53.16 ±8.41 vs 46.49±9.13; 44.6±9.39 vs 33.8±10.70) respectively. Statistical analysis results showed that age was significantly (P<0.05) affecting HOS at chill stage and MOT and HOS at frozen. In conclusion, younger Bali cattle (4 y.o) have more viable post freezing sperm compared to the older ones (7 y.o).