METHODS OF KEEPING RECORDS 



531 



2. When the colony is small and animals are put in and removed at irregular 

 intervals, a file-guide system for the pens is more efficient. 



3. If the system employed involves a pool of unmated females and males, as well 

 as mated pairs and subsequent removal of pregnant females, then the card file could 

 be handled more efficiently if it were divided into sections such as pregnant, mated, 

 and unmated, and the cards were in numerical order within each section. 



Fig. 76. Cage tags. 



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Left. Cage tags may provide much information about the animals housed within. In 

 the colonies of pedigreed expansion stocks, different colors and marks present or absent 

 across the top help insure that strains will not be mixed. The female and male number, 

 their dates of birth and generation are recorded. The N in the lower corner denotes the 

 number of generations removed from the ultimate source in the small colony of foundations 

 stocks. Litters are recorded, crossed off at weaning, and when other types of information 

 such as diarrhea, weights, and so on are recorded, a check mark is placed beside the litter. 

 Mating date is not recorded in these inbred lines because all matings are set up at weaning, 

 25-30 days of age. 



Center. Cage tags in a small colony may provide information similar to that listed 

 above. The order is slightly different, and the columns may be arranged to suit individual 

 needs. The date of mating appears before the female number. 



Right. Cage tags in mutant stocks can provide information usually recorded on the 

 pedigree card, thus eliminating that card from the system. The fate of the litter is recorded 

 here in as much or as little detail as the investigator wishes. 



