Reproduction and Postnatal Growth of Microtus fortis fortis under Artif icial Feeding Conditions
HU Zhongjun WANG Yong GUO Cong ZHANGMeiwen
2003, 23(1):
58-65.
Asbtract
(
)
PDF (182KB)
(
)
Related Articles |
Metrics
Preliminary studies on the reproduction and postnatal growth of Microtus fortis fortis were carried out under laboratory feeding conditions. The animals could be bred all year round with mean litter size , gestation period , mean breeding intervals , and the ratio of females to males of 3.8 ±1.5 , 20 - 21 days , 39.3 ±26.4 days , and 1.48 , respectively. New-born pups could erect their ears completely 3 days after birth ; lower and upper front teeth begin to emerge at day 4 and day 5 , respectively ; open their eyes at day 7 - 8 ; could be weaned at day 20 ; and could be sexually matured at around day 55. All three sigmoidal growth models , i.e. , logistic , Gompertz and Von Bertalanffy equations , are fitted well with growth data of body weight , body length , tail length , and hind foot length from birth up to the age of 120 days. In this studies , Von Bertalanffy equation was chosen for the growth of body weight , body length , and tail length , and logistic equation was selected for the growth of hind foot length. The growth of Microtus fortis fortis could be divided into four stages : infancy phase , from birth to 10 day old ; juvenile phase , from 11 to 20 days old ; subadult phase , from 21 to 55 days old ; and adult phrase , over 56 days old. In addition , we compared preliminarily the differences of growth and development , and reproduction characteristics between of M. f. fortis and of M. f. calamorum.