Method for hand-feeding mouse pups with nursing bottles

The purpose of this study was to establish a hand-feeding method for the mouse by using nursing bottles. Five different-sized nipples were tested. The largest nipple used for pups from 12 to 15 days of age was 5.5 mm in diameter and 10 mm long, with a tip of 1.5 mm in diameter. The size of the nipple was much larger than that of the mothers, and bloating due to air accumulation was observed in the artificially-reared pups. To prevent bloat, the nipple size was increased, and a piece of sponge was stuffed in the nipple. Among the 30 pups fed from 1 day of age, 26 were weaned and 4 died. Three pups died due to aspiration of milk into the lung, and the remaining one died due to bloating. The development of nursing bottles with nipples may be potentially useful for the studies of nutrition, behavior, immunology, psychology, and toxicology.