The aim of study was evaluation of reproductive utilization of chinchilla females on the oldest Polish chinchilla farm in Grywałd. Analysis covers 629 females of different color variety utilized reproductively from 1973 till 1993 and included such information as: 1) length of female reproductive utilization; 2) number and size of litter and; 3) juvenile death at delivery and weaning. Average length of female reproductive utilization was 2.26 years with mean 3.22 litters. The most females were utilized only 1 year (42%) and these females delivered only one litter (38%). Females lined twice (61.58%) or delivered only 1 litter during the served year (28.18%). The most frequent females delivered 2 (41%) or 1 youngness (39%); mean litter size during 21 years was 1.85 offspring included females in 58%. On the farm it was easy recognized existence of two periods of increased sexual activity. This seasonal character was observed also in offspring deaths.

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