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Cohort-to-Aim Planner.

Map grant aims to animal cohorts, identify sharing opportunities, and generate a breeding schedule. Quantify 3Rs reduction from cohort overlap.

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Validated2026-04-08
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Colony Parameters

Aim 1

Required fields
  • Aim 1: name is required.
  • Aim 1: sample size must be at least 1.
  • Aim 1: start date must be YYYY-MM-DD format.

When to use

  • Multi-aim grant applications (R01, P01, U-series) with overlapping animal needs
  • IACUC protocols requiring 3Rs justification for cohort sharing
  • Breeding colony planning across multiple concurrent studies
  • Timeline planning for when to set up breeding pairs

Do not use for

  • Single-aim studies with one cohort (use Colony Expansion Forecaster instead)
  • Studies not requiring age-matched cohorts
  • Non-rodent species with different breeding parameters

Pearl

List all aims first, even if they seem independent — the planner often finds overlap you would not spot manually.

Pearl

For transgenic crosses, set genotype yield to the expected Mendelian ratio (e.g., 0.25 for homozygous from het ×\times het). This correctly inflates the litter count.

Pitfall

Do not assume longitudinal animals can always be reused — check that the first study does not alter the animals in ways that confound the second (e.g., drug exposure, surgery).

Pitfall

Narrow age windows (e.g., exactly 8 weeks) reduce sharing opportunities. If your protocol allows 8–10 weeks, use the full range.

1

Method

For each aim: compute birth date window = [start_date − max_age ×\times 7d, start_date − min_age ×\times 7d]. Split "both" sex aims into male + female sub-aims. Group by {genotype, sex}. Within each group, merge aims whose birth windows intersect into shared cohorts. For sequential longitudinal→any pairs, compute reusable animals. Breeding: pair_setup = birth_date − gestation; weaning = birth + weaning_age; ready = weaning + genotyping. Litters = ceil(animals / (litter_size ×\times genotype_yield ×\times 0.5)).

2

Validated

Last validated 2026-04-08. Calculations are designed for planning and documentation support; verify procurement decisions against manufacturer specifications or institutional SOPs.

3

How to cite

How to Cite

ConductScience Cohort-to-Aim Planner (v1.22.0). ConductScience. https://conductscience.com/tools/cohort-to-aim-planner

Russell, W.M.S. & Burch, R.L. (1959). The Principles of Humane Experimental Technique. Methuen.

Optimizing Animal Use Across Multiple Grant Aims

Multi-aim grants (R01, P01, U-series) often require overlapping animal resources that can be consolidated:

Cohort overlap principle: If two aims need the same genotype, sex, and similar age, breeding a single larger cohort is more efficient than two independent cohorts. The breeding colony produces animals in litters — coordinating birth timing across aims maximizes the use of each litter.
Sequential reuse: When a longitudinal aim finishes before another aim starts, the surviving animals can transfer to the new aim. This directly reduces total animal numbers and is a strong 3Rs (Reduction) argument for IACUC and NIH reviewers.
Breeding lead time: Mouse gestation is ~21 days, weaning at ~21 days, genotyping takes ~7 days. From pair setup to experiment-ready animals is approximately 7–10 weeks plus the target age. Planning backwards from each aim's start date determines when breeding pairs must be set up.
Practical considerations: Aims requiring different sexes from the same genotype naturally share a breeding cohort — males go to one aim, females to another. This is often the largest source of "free" reduction in multi-aim grants.

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Next steps

App

ConductColony

Auto-assign weanlings to aims as they hit age windows. ConductColony tracks real-time census against your cohort plan and alerts when breeding pairs need to be set up.

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