title: Plasma prolactin concentrations during lactation, pouch young development and the return to behavioural oestrus in captive koalas (Phascolarctos cinereus).
abstract: Plasma prolactin (PRL) concentrations in captive koalas during lactation were determined by serial blood sampling. PRL concentrations were low (1.3 ± 0.1 ng mL-1; n = 5) during early lactation until pouch young (PY) began to emerge from the pouch (around Day 130) before significantly (P < 0.05) increasing between Day 161 and Day 175 (5.3 ± 1.0 ng mL-1). A significant (P < 0.001) peak in PRL (7.7 ± 0.6 ng mL-1) coincided with maturing young between Day 189 and Day 231. All females failed to exhibit any signs of oestrous behaviour until Day 268.8 ± 8.5 (n = 4), some 102 ± 19 days before PY were weaned following achieving target weights of 2.5-2.7 kg. Throughout lactation, plasma LH concentrations were relatively high (range 4.9-8.7 ng mL-1) and LH responses to exogenous gonadotrophin-releasing hormone were observed in all koalas at all times during lactation.
authors.affiliation: School of Agriculture and Food Science, University of Queensland, Gatton, Qld 4343, Australia.|Corresponding author. Email: kate_068@msn.com.
authors.forename: K
authors.initials: K
authors.lastname: Ballantyne
authors.affiliation: School of Biomedical Sciences, University of Queensland, St Lucia, Qld 4072, Australia.
authors.forename: S T
authors.initials: ST
authors.lastname: Anderson
authors.affiliation: Dreamworld, Dreamworld Parkway, Coomera, Qld 4209, Australia.
authors.forename: A
authors.initials: A
authors.lastname: Mucci
authors.affiliation: Dreamworld, Dreamworld Parkway, Coomera, Qld 4209, Australia.
authors.forename: V
authors.initials: V
authors.lastname: Nicolson
authors.affiliation: School of Agriculture and Food Science, University of Queensland, Gatton, Qld 4343, Australia.
authors.forename: S D
authors.initials: SD
authors.lastname: Johnston
keywords: LH; marsupial