Koala milk composition changes significantly as the joey ages. Koala Milk Replacer Late Lactation is specially formulated for older young, when joeys are emerging or fully-emerged and are starting to consume eucalypt leaves. At this stage joeys require a high energy (fat) milk, with elevated levels of protein for growth and low carbohydrate for the onset of weaning.
There is considerable geographical and sexual variation in koala size, but joeys can be aged reasonably accurately based on head length. Refer to the Wombaroo Koala Growth Chart for age estimation guidelines. Body weight is not a good indicator of age because this can vary greatly with regional variation, body condition and level of dehydration.
Success in hand-rearing pouch-bound koalas greatly improves if they receive Impact Colostrum Supplement within a week of coming into care. However Impact may also be of benefit to older out-of pouch joeys with a compromised immune system. Refer to 'Directions for Marsupials' under the Impact feeding guidelines. Note that at about 180-210 days of age young koalas should ideally be provided with 'pap' from an adult animal to assist the transition onto eucalypt leaves.
Making up Milk
To make 100mL of milk: Mix 32g of powder (4 scoops) with 75ml of warm water.
To make 750mL of milk: Mix 240g of powder with 550ml of warm water.
Add about half of the water to the powder first and mix to a paste. Then make up with remaining water and mix thoroughly. Water is preboiled to ensure that it is sterilised. If the water is too hot it can cause the milk to curdle. If it is too cold then it will be difficult to disperse the powder. Wombaroo contains elevated protein and fat levels, so the milk needs to be well mixed to prevent it from separating out. An electric whisk can be used for mixing larger quantities. Milk can be stored in the fridge for a day or can be frozen for up to 2 weeks. It may be useful to store frozen milk in small portions (eg ice cube trays), so that the required daily feed volumes can be easily thawed out. Once thawed out, discard any unused milk, and wash feeding utensils thoroughly.
Warm milk to about 30°C and feed using a bottle and teat. A Wombaroo LD or FM teat is recommended for smaller and larger koalas respectively. Feed around four times a day, reducing this to twice a day by full pouch emergence, when sufficient leaf is being consumed. Reduce this to once a day as increasing amounts of leaf is consumed. If the young is showing signs of dehydration (eg during hot weather), give extra drinks of water between feeds. Joeys can dehydrate rapidly if not maintained under optimum husbandry conditions. Water should always be available ad lib and can be sprayed onto leaves. Joeys should also have access to fresh eucalypt leaves of species that they would normally consume in the wild. Consult your veterinarian or experienced carer for further information about husbandry and feeding of koalas.
Regional differences present considerable variation in koala growth rate. Refer to the Wombaroo Koala Growth Chart for typical growth rates of smaller northern animals compared to larger southern animals. Weigh joeys regularly to verify weight gains and determine the volume of milk to feed. Overfeeding milk can cause diarrhoea so feed the suggested volumes in our tables.
Leaf should be offered from 6 months (180 days) of age. From about 10 months (300 days), if eating sufficient leaf and gaining weight, milk volume can be reduced until fully weaned at 1 year of age. At this stage about 10% body weight in leaves should be consumed per day.