Document Detail

Limits to milk flow and energy allocation during lactation of the hispid cotton rat (Sigmodon hispidus).
MedLine Citation:
PMID:  9634178     Owner:  NLM     Status:  MEDLINE    
Energy allocation for maternal maintenance and milk production was examined in lactating hispid cotton rats (Sigmodon hispidus) supporting three to seven offspring at 10 degrees or 24 degrees C. Lactating mothers obtained most of their energy from dietary intake (ca. 90%), and the remainder was withdrawn from maternal stores. There was no indication that a central limit to maternal energy assimilation constrained lactational performance. Maternal energy assimilation increased with a larger litter size (a higher production cost) and a decline in ambient temperature (a higher thermoregulatory cost) during lactation, without reaching an apparent limit. Further, there was no evidence of competitive energy allocation, which might occur if maternal energy assimilation were limited. Hence, increases in maternal thermoregulatory expenditure during lactation did not decrease the energy allocation for milk production. Lactating mothers had a capacity to increase milk production. Nonetheless, the milk flow did not fully satisfy the energy requirements of dependent offspring in larger litters or at the lower ambient temperature (growth rates of offspring declined in both cases). Local physiological constraints and behavioral effects appear to limit maternal allocation during lactation. Constraints to allocation may be favored by selection because they reduce maternal risk or reproductive cost.
G L Rogowitz
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Physiological zoology     Volume:  71     ISSN:  0031-935X     ISO Abbreviation:  Physiol. Zool.     Publication Date:    1998 May-Jun
Date Detail:
Created Date:  1998-08-07     Completed Date:  1998-08-07     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0401142     Medline TA:  Physiol Zool     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  312-20     Citation Subset:  IM    
Department of Biology, Indiana University, Bloomington 47404, USA.
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MeSH Terms
Body Temperature Regulation
Body Weight
Energy Metabolism*
Lactation / physiology*
Litter Size
Maternal Behavior
Milk / secretion*
Regression Analysis
Sigmodontinae / physiology*

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