Outbred N:Gp (NIH General-purpose) Swiss mice, established at the National Institutes of Health, Bethesda, Maryland, USA in 1935. In 1966 two strains (HSFS/N and HSFR/N) were selected for sensitivity and resistance, respectively, to the action of Histamine after treatment with Bordetella pertussis vaccination. In the early 1970’s, a group of mice at the eighth inbred generation of HSFS/N were found to carry the Fv-1b, allele for sensitivity to the B strain of Friend leukaemia virus. Homozygous mice were then inbred as strain FVB, without further selection for histamine sensitivity (Taketo et al, 1991).
In 1994 to Harlan Laboratories through acquisition of Central Institute for Laboratory Animal Breeding, Hannover, Germany. Harlan became Envigo in 2015.
Han® is a registered trademark of Envigo.
|Over 10 weeks, add per week||3.90||USD|
|Female with litter||287.70||USD|
|Over 10 weeks, add per week||3.50||USD|
Envigo uses well-established techniques to successfully produce time mated rats, mice, hamsters, and rabbits. We use an Impedence Meter for determining the stage of estrus in rats prior to breeding. Time mated rats and mice are determined by observation of a vaginal plug. Plug date is considered to be day zero (0) of gestation.
Due to the natural variation in the length of gestation, the exact day of parturition cannot be guaranteed. In addition, Envigo cannot guarantee the minimum number of offspring per litter.
Please be aware that late-term pregnant animals may deliver their litter prematurely while in transit, and depending on the circumstances involved, requests for credit or replacement of these animals may be declined at our sole discretion.
If problems regarding gestational age or pregnancy are encountered, customers should immediately contact Envigo’s Customer Service Department and provide detailed information regarding the animals involved.
|Expected Pregnancy Rate|
|Stock or Strain||Timed mated <13 days gestation (at shipping)||Timed mated ≥ 13 days gestation and over (at shipping)||Untimed pregnant ≥ 13 days gestation (at shipping)|
* Plug guarantee only; no guaranteed pregnancy. Plug date = Day 0.
** Untimed pregnant rodents will be selected from our breeding colonies on the basis of palpation or visual confirmation. A variation of three to four days gestation can be expected. Therefore Envigo cannot be held responsible for actual gestation and/or exact day of littering.
To avoid charges, cancellations for timed mated animals must be received one week prior to mating date.