Effect of grouped raising method on reproductive performance of MLAC:ICR mice in controlled condition at National Institute for Control of Vaccines and Biologicals

The descriptive study was conducted on 132 Mlac: ICR dams and 924 pups raised at the National Institute for Control of Vaccine and Biologicals from June to December 2020 to evaluate the effect of grouping method on reproductive efficiency of Mlac:ICR mice. The study results revealed that there was no difference (p>0.05) in the physical scores of dams at weaning among grouped (3 litters/cage) compare to individual rearing dams (1litter/cage). The pups’ weight gain of grouped litters was higher compared to control litter. The mean weight/pup at 7, 14, and 20 days (weaning) of the control group was 5.94 gr, 8.97 gr, and 12.33 gram, respectively. The average weight of the litter group’s pup at the same measured time point was 6.51 gr, 9.7 gr, and 13.25 gram, respectively. The difference in body weight at all three-time points between two groups of mice was statistically significant (p<0.05). The results suggested that group 3 litter/cage did not affect the physical parameters of the dams and elevate reproductive performance in terms of weight gain of the pups and the number of survived offspring at weaning.