[MARMAM] New paper: The influence of reproductive experience on lactation performance in the grey seal

Shelley Lang shelley.lang at dal.ca
Tue May 24 09:18:55 PDT 2011

Dear MARMAM subscribers: 


The paper below has just been published in PLoS ONE:


Lang, S. L. C., S. J. Iverson, and W. D. Bowen. 2011. The influence of
reproductive experience on milk energy output and lactation performance in
the grey seal (Halichoerus grypus). PLoS ONE 6:e19487.





Abstract: Although evidence from domestic and laboratory species suggests
that reproductive experience plays a critical role in the development of
aspects of lactation performance, whether reproductive experience may have a
significant influence on milk energy transfer to neonates in wild
populations has not been directly investigated. We compared maternal energy
expenditures and pup growth and energy deposition over the course of
lactation between primiparous and fully-grown, multiparous grey seal
(Halichoerus grypus) females to test whether reproductive experience has a
significant influence on lactation performance. Although there was no
difference between primiparous females in milk composition and, thus, milk
energy content at either early or peak lactation primiparous females had a
significantly lower daily milk energy output than multiparous females
indicating a reduced physiological capacity for milk secretion. Primiparous
females appeared to effectively compensate for lower rates of milk
production through an increased nursing effort and, thus, achieved the same
relative rate of milk energy transfer to pups as multiparous females. There
was no difference between primiparous and multiparous females in the
proportion of initial body energy stores mobilized to support the costs of
lactation. Although primiparous females allocated a greater proportion of
energy stores to maternal maintenance versus milk production than
multiparous females, the difference was not sufficient to result in
significant differences in the efficiency of energy transfer to pups. Thus,
despite a lower physiological capacity for milk production, primiparous
females weaned pups of the same relative size and condition as multiparous
females without expending proportionally more energy. Although reproductive
experience does not significantly affect the overall lactation performance
of grey seals, our results suggest that increases in mammary gland capacity
with reproductive experience may play a significant role in the age-related
increases in neonatal growth rates and weaning masses observed in other
free-ranging mammals.



Shelley Lang

Department of Biology

Dalhousie University

Halifax, NS   B3H 4R2


shelley.lang at dal.ca

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