Mammary gland growth and milk ejection in the agile wallaby, Macropus agilis, displaying concurrent asynchronous lactation

Abstract

Summary. Lactation was initiated and confined to the mammary gland to which the neonate attached at birth, and continued for about 360 days. The lactating gland continued to grow for over 200 days, increasing 7- to 10-fold in size between Days 50 and 250. The young at these times weighed approximately 35 and 2500 g respectively. The young left the pouch permanently at 200–220 days, although they continued to suck intermittently for a further 160 days. Twenty-six days after evacuation of the pouch a second young was born and this attached to one of the three unused nipples. Thereby a second lactation developed in parallel to the previous one, but over 200 days in arrears. ..