Fetal growth rate and determination of weaning time for adoption of kittens in free-roaming cats.
The aims of the present study were to determine the weaning time for adoption of kittens, and to evaluate the fetal growth rate during pregnant in free-roaming cats. This study was conducted on three pregnant free-roaming cats (one feral cat and two stray cats). Radiography and ultrasonography were performed on the feral cat and on one of the stray cats. In the feral cat, fetal head diameter was measured once during pregnancy to determine the cesarean section (C-sec) time. In the stray cat, serial fetal head diameter was measured from capture to parturition. The body weight of the feral cat's kittens was measured from 4 weeks postpartum because of their wildness. That of the stray cats' kittens was measured immediately after birth. In the feral cat, scheduled C-sec was performed at predicted parturition day by measurement of head diameter, and six healthy kittens were delivered. The stray cats had five and six kittens by natural delivery, respectively. In the body weight gain of feral and stray cat's kittens, two female kittens of the feral cat lost weight rapidly after they were separated from their mother, so they were returned to their mother for 1 more week. After that, the female kittens grew up without difficulty. Body weight gain of the ten kittens born to the two stray cats consistently increased, by approximately 14 g every day, until they were adopted. The body weight of kittens born by natural delivery was on average 77.5 g greater than that of kittens born by C-sec. However, the gap decreased with time. During the stray cat's pregnancy, fetal head diameter increased by 0.042 cm every day. Maximum head size before parturition was 2.43 cm. These results indicate that the weaning time for adoption of kittens was 5-week-old postpartum.