Calculate total animals to request per aim by compounding breeding yield, weaning survival, genotyping yield, and experimental attrition. Includes best/expected/worst case sensitivity analysis.
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Do not use for
A 25% genotyping yield means you need 4× as many animals as your experimental N just to get the right genotype. For complex crosses (double-conditional knockouts at 6.25%), you need 16×. This is the single factor that most inflates animal numbers — plan your breeding strategy to maximize genotyping yield.
IACUCs are much more likely to approve large animal numbers if you show the per-aim breakdown with each yield factor justified. "We need 500 mice" gets questioned. "We need 500 mice because we need 40 homozygous knockouts from a het×het cross at 25% yield with 85% breeding success" gets approved.
If your colony's actual breeding yield is 0.70 (not the textbook 0.85), use 0.70. IACUCs prefer evidence-based estimates. After your first year, compare actual vs estimated yields and adjust for renewals.
For each aim: animals_required = ceil(experimental_N / (breeding_yield weaning_survival genotyping_yield experimental_survival) buffer_factor). Sensitivity analysis perturbs each yield by +5% (best) and -10% (worst), clamped to [0.01, 1.0]. Results are summed across aims and grouped by species. All computation is client-side.
Last validated 2026-04-07. Calculations are designed for planning and documentation support; verify procurement decisions against manufacturer specifications or institutional SOPs.
ConductScience IACUC Animal Use Budget Estimator (v1.12.0). ConductScience, Inc. 2026. Available at: https://conductscience.com/tools/iacuc-budget-estimator
National Research Council. Guide for the Care and Use of Laboratory Animals. 8th ed. Washington, DC: National Academies Press; 2011.
Festing MFW, Altman DG. Guidelines for the Design and Statistical Analysis of Experiments Using Laboratory Animals. ILAR Journal. 2002;43(4):244-258.
The fraction of pups born alive from each mating. For mice, typical values are 0.80–0.90. Factors that reduce breeding yield: advanced maternal age, inbred strain subfertility, mutant alleles affecting fertility, first-time breeders.
The fraction of live-born pups that survive to weaning (typically P21). Values of 0.90–0.98 are normal for standard mouse strains. Lower for fragile mutants, immunodeficient lines, or strains with pup cannibalism.
The fraction of weaned animals with the desired genotype. This is driven by Mendelian genetics: 50% for heterozygous wild-type, 25% for het het targeting homozygous, 6.25% for double-het crosses. This is usually the biggest multiplier in the budget.
The fraction of genotype-confirmed animals that complete the experimental protocol. Typically 0.85–0.95. Lower for surgical models, chronic disease models, or studies with high-mortality endpoints.
A safety margin (typically 1.1–1.2×) that accounts for unexpected losses not captured by the yield factors above. The buffer is the first thing the IACUC will question if your total animal number seems high.
ConductColony compares your budgeted animal numbers to actual use in real time, alerts you when a protocol is approaching its limit, and auto-generates amendment requests when needed.
Open app EquipmentDesign the breeding scheme to produce the genotyped animals your budget requires.
Browse EquipmentGenerate the Reduction justification that explains your animal number calculation.
Browse EquipmentConvert your animal budget into per-diem housing costs for the grant application.
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