Calculator Colony Breeding

Demand per week: The number of animals required to be obtained with the set confidence.

Confidence level: Likelihood of successfully obtaining the required number of animals. This is usually set to 0.8 (80%) or 0.9 (90%).

Standard deviation of productivity: The week to week change in productivity is used to calculate the standard deviation of productivity. The standard deviation is preset to 3 according to Festing 1989.

Productivity: This parameter is calculated as number of weaned pups per female per week. While reference numbers exist for common strains, it is best extracted from own breeding data. Productivity is also referred to as colony index (CI) or productivity efficiency index (PEI). Cave: Some authors have used the term productivity to indicate the accumulated number of offspring of a female/group of females

Shelf life: The shelf life indicates the age span that the animals collected for further purposes are allowed to have. It essentially indicates for how long animals are collected before an e.g., experimental cohort is removed.

Other parameters that should be considered:

Mendelian success probability: Percentage of offspring of the desired genotype determined by e.g., the Punnett square. Examples of online Punnett square calculators are Punnett 1 and Punnett 2. If the likelihood of obtaining your required genotype is e.g., 025, increase demand in this colony calculator by factor of 4. 

Sex: If you are interested in only one of the sexes, double the demand in the calculator. If the sex ratio of a particular cross is deviating from the 50% norm, adjust accordingly.

Actual productivity parameters

According to Festing 1987

Festing 1987: Festing, M. F. W. in UFAW Handbook on the Care and Management of Laboratory Animals (ed. Pool, T. B.)18–34 (Longman Scientific & Technical, 1987).