author(s)
Muhammad Ameen Jamal, Arslan Mahmood Ahmad, Muhammad Tahir, Shahzad Munir, Abdul Sattar, Aamir Ghafoor and Amjad Riaz

abstract
The study was conducted to investigate the superovulatory response in aged female mice by adjusting gonadotropin dose at Department of Theriogenology, UVAS, Lahore, Pakistan from December 2013 to May 2014. Female BALB/c mice of different ages (4-6 weeks vs 7-9 weeks) were injected with five different concentration of eCG (0, 2.5, 5, 7.5 and 10 IU) and embryonic recovery and quality was evaluated. The embryonic recovery, was significantly high in both age groups (37.00±6.54 vs 10.20±0.96; 30.60±5.26 vs 9.40±0.92) 26.00±4.46 vs 8.60±1.32) at 7.5 IU as compared to control. In 4-6 weeks old mice, the embryonic recovery and grade I embryos at low dose (2.5 IU; 16.00±1.30 and 8.60±1.32) were comparable with high dose (5.0 IU; 17.20±3.55 and 7.20±1.11) in 7-9 weeks. This revealed injecting high dose to old females mice can improve superovulatory response considering factor of age can be nullified by adjusting the gonadotropins dose.