METHODS OF KEEPING RECORDS 



527 



identification number of the male and kind of male, and date when he is removed. 

 In some systems two cards are used, a mating card and a litter card (see figure 74C, D, 

 and E). 



When inbred strains are being maintained (brother x sister) it is unnecessary to 

 provide an individual card for the male since all data for the female is applicable to 

 the male and neither he nor she will have any other mate during their lifetime. If a male 

 is to be used in genetic experiments, it is advisable to have a pedigree card for the male, 

 so that one can easily obtain any information needed about him, no matter what 

 pen he may be occupying at the time. The reverse side of the pedigree card now in 

 use at this laboratory has been designed to allow space for comments on gross findings 

 when animals are autopsied (figure 74F). 



Fig. 74C. A PEDIGREE CARD USED IN MANY GENETIC EXPERIMENTS. 



Across the top in order is found the female number, her genotype, numbers of her 

 parents, and the cage number. On the blank line across is recorded the strain or stock 

 and the generation and birth date. In the first column appears the number and genotype 

 of the sire of each litter, next is his relationship to the female, the date of mating, date of 

 birth of litter, size of litter minus number dead, the ledger number, fate of the litter, and 

 finally, a space for remarks about the litter. The male card (not shown) is similar to the 

 female card but does not include information about the litters. Death date is recorded in 

 the lower right-hand corner of the card. 



