Swiss Webster


Swiss Webster Outbred Mouse Model

  • Model #
  • Genotype
  • Nomenclature
  • SW-F
  • SW-M
  • Extensively used for decades as an all-purpose stock for research and drug safety testing
  • Often used as recipient mother in transgenic labs due to its superior nurturing ability
  • Swiss Webster females (SW-F) are also ideal pseudopregnant recipients for embryo transfers of black and agouti mouse lines
  • Now available at the Germ-free health profile in addition to Restricted Flora and Murine Pathogen Free health profiles.


Taconic received the Swiss Webster outbred model from the Rockefeller Institute through Rockland Farms, Inc. in 1940. The mice have been maintained as a closed colony since 1951. The mice were derived by caesarean from randomly chosen breeders and reintroduced into a Barrier Nucleus Expansion Colony in 1965-1969. The mice were derived by caesarean in 1983 from randomly chosen breeders from all Taconic's barrier units.


Taconic's outbred colony is known to carry the recessive mutation, Pde6brd1

Coat Color Loci:






Terms of Sale and Use for Swiss Webster

Germ Free Swiss Webster are sold subject to Taconic's Terms and Conditions for the Sale for Products and the following terms of use:

  • For-profit purchasers may not breed Germ Free Swiss Webster except to obtain embryos or fetuses for research use.
  • Non-profit purchasers may breed Germ Free Swiss Webster for use in projects at purchaser's institution and on behalf of non-profit researchers only.
  • Germ Free Swiss Webster, progeny and materials derived from them will not be distributed to third parties.
Murine Pathogen Free™ and Excluded Flora Swiss Webster mice are sold subject to Taconic's Terms and Conditions for the Sale for Products.
For some applications, weight may be critical. For orders where weight is critical, please place orders by weight, not by age. Taconic can accept orders by weight for this model. A minimum 3 gram span is required. All weights are weights at time of packing. Mice and rats can lose weight in transit. Orders for specific weight spans will be assessed a nominal fee. More detail on weight order policies is available.

n= 500 per sex at MPF, and RF health standards from all global colonies. Data collected 2013-15.
High and Low represent mean +/- 1.5 standard deviations.
Based on sample size the charts above represents ~75% of the population.
All growth curves represent animals housed in our barriers, at our standard density and fed NIH31-M diet. Variations at customer facilities will alter expected growth curves.
Growth charts are provided only as a guide, if a specific weight criteria is needed please order animals by weight.

Customize this chart by clicking the legend elements, then explore download options by hovering your cursor over the down arrow to the right of the chart title.
Average litter size: 11
Groups of virgin females at 8 weeks of age were mated with male retired breeders. Vaginal plugs were observed on days 1-4 following set up. The incidence rate of vaginal plug observations were:

Day 1 6.9%
Day 2 8.3%
Day 3 26.2%
Day 4 4.8%

The percentage of females found with plugs that were not, in fact, pregnant was less than 10%.

An analysis was made of 200 timed pregnant females to determine the length of gestation (plug observation date = day 1). The results are as follows:

Day 18 2.5%
Day 19 29.0%
Day 20 50.0%
Day 21 11.5%
Day 22 6.0%
Day 23 1.5%
Eight timed pregnant females were housed individually. The body weight of each pup in each litter was recorded and the average weight per pup calculated:

Pre-Weanling Body Weights in Grams

# Pups in Litter 8 10 11 13
# of Litters Observed 1 2 2 3
Days of Age
1 1.63 1.50 1.55 1.36
2 1.77 1.60 1.70 1.46
5 3.30 2.71 3.04 2.40
8 5.36 4.21 4.62 3.75
10 6.52 5.30 5.61 4.77
12 7.51 6.07 6.21 5.55
15 8.75 7.10 7.23 6.31
17 9.16 7.49 7.32 6.63
19 9.95 8.39 8.28 7.06
21 12.27 10.30 10.23 9.95