Simplified Method to Measure Mouse Fertility

Estimating breeding performance from mouse mating trials has focused on lifetime mating trials, which are too slow and costly for characterizing the many novel genetic mouse lines produced in fertility research, an underpinning of reproductive pathophysiology research. This study introduces the fertility index, defined as the slope of the regression of cumulative number of pups produced by a female over elapsed time in a monogamous mating trial. By using a robust resampling technique, the Theil-Sen estimator (widely available in free or niche statistical software), to estimate the fertility index, the present study of 410 mating trials of mice from 7 genotypes lasting a median of 10 litters shows that it is possible to estimate the fertility index reliably over as few as 4 litters.