No abstract

Continuous body weight dynamics in supplementally fed free-ranging sika deer (Cervus nippon) during the three consecutive overwinters (from January to April), 1992-1994 were surveyed. Almost all individuals lost weight continuously throughout each winter (adult deer 5 -13%; young deer 3-19%) and several deer lost weight even in April. Weight gain after loss began in the mid-April when ambient temperature increased and when plant growth began. Weight dynamics varied according to sex, age and reproductive status. Adult deer showed significant large weight loss than the young. Young deer lost weight (calves 18 -----11 g/day, yearling and two-year-olds 27 _ 29 g/day) more slowly than the adults (65 +__ 23 g/day). Following this study of over-winter body weight dynamics, it seems that early springs are the most critical periods for the survival of free-ranging sika deer because of their poor nutritional condition.

Age − related body weight changes ， wirlter body weight changes and breeding condition of free − rarlging sika deer and captive sika deer ， which had the same genetic origin and different nutritional conditions ， were surveyed ． The adult male reached around 75 kg in body weight and the adult female reached arOunCl 50 kg ， and they showed an apparent difference of sexual demography ． The captive deer under yearbng good food condition showed large body weight increase until winter of yearling and the free − ranging deer under yearlong poor fQod condition kept large body weight increase until winter of two − years old ． The body weights at birth were not different significantly each other ， but the body weight gains from the birth to the beginning of first winter and the mean birth date were different between free − ranging deer and capttve deer ． The body weight increase and sexual maturation of free − ranging deer delayed about a year compared with those of the captive deer． The winter weight changes also showed different patterns each other ， especially in the case of young deer and pregnant deer． Above results suggest that poor food condition may delay body growth during the period of development and sexual 「「1atu 「ation on sika deer， Key words ：sika deer， body weight change ， stage of development， sexual maturation ， food condition Jpn ． J ． Zoo MliJd ． Med ，2(1)： 59 ． 66， 1997