Day of mating

Normally, the day of mating will be considered day 0 post conception (p.c.), some laboratories call it day 1 p.c., which is possible, but care must be taken for days of treatment or sacrifice, which are normally based on day 0 and have to be adjusted accordingly in case of a deviation from this rule. 

Mature (10-13 weeks old) premiparous females are obtained from the breeder on the day of mating (see Note 6). The day of mating is defined as gestation day 0 (GDO). 

The animal supplier should be located as close as possible to the testing laboratory so that the mated females can be delivered on the day of mating with as little stress induced by the transport as possible. 

The day of mating is confirmed by the presence of a vaginal plug or sperm in a vaginal smear or and is defined as day 0 of gestation. Females are separated from the males once copulation has... 

Four-week-old C57B1/6 females are super-ovulated with pregnant mare serum 2 d prior to mating and with human chorionic gonadotropin hormone on the day of mating with C57B1/6 males. 

In random-bred Charles River strain albino mice, thalidomide 1000 mg/kg/day given from the first day of mating failed to produce gross malformations of the offspring (170). 

These components would normally be evaluated in a rodent species (preferably rats) and, in addition, embryo-fetal development would be evaluated in a second species, typically the rabbit. The most probable option in the ICH guideline is the case where three rodent studies would be conducted that separately addressed each of the components listed above. These study designs are described below. The day of insemination or detection of evidence of mating is considered Day 0 of gestation and the day of birth is considered postpartum and postnatal Day 0. Figure 8.1 presents line charts for the ICH Stage-Study Designs. 

Groups of male and female CFW Swiss mice were given diets containing 5 ppm endrin for 120 days beginning 30 days before mating (Good and Ware 1969). There were deaths among one-third of the... 

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