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Change in body weight of mothers and neonates and in milk composition during denning period in captive Japanese black bears (Ursus thibetanus japonicus)

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Title: Change in body weight of mothers and neonates and in milk composition during denning period in captive Japanese black bears (Ursus thibetanus japonicus)
Authors: Iibuchi, Ruriko Browse this author
Nakano, Noriko Browse this author
Nakamura, Tadashi Browse this author
Urashima, Tadasu Browse this author
Shimozuru, Michito Browse this author
Murase, Tetsuma Browse this author
Tsubota, Toshio Browse this author
Keywords: Japanese black bear
neonatal growth
milk composition
Issue Date: May-2009
Publisher: The Graduate School of Veterinary Medicine, Hokkaido University
Journal Title: Japanese Journal of Veterinary Research
Volume: 57
Issue: 1
Start Page: 13
End Page: 22
Abstract: Japanese black bears, Ursus thibetanus japonicus, have been classified as a vulnerable species so that data on reproduction are needed to maintain and/or extend their population. They are known to have a peculiar style of reproduction, giving birth to their neonates and raising them during denning, a period of complete fasting. In this study, we investigated the metabolic rate and milk composition of mother bears raising neonates, and the changes in body weight of the neonates under captive conditions. Seven female bears kept in dens were weighed once a month, and the amount of energy they used was calculated. From birth, cubs were also weighed and their growth rate was determined. In addition, the milk composition was analyzed to investigate its characteristics. As a result, it was found that mother bears used 34% more energy than did solitary females. There was no significant difference in the energy used for nursing whether they had single or twin cubs. On the other hand, the body weight gain of single cubs was significantly higher than that of twin cubs, suggesting that the growth of the cubs was highly affected by the suppression of mother's energy consumption during the fasting period. The milk had high fat and low sugar concentrations. This indicates that mother bears used the fat accumulated prior to denning for their main energy source when raising cubs. Considering all results together, Japanese black bears showed remarkable efficiency in the use of energy for reproduction during the fasting period.
Type: bulletin (article)
Appears in Collections:Japanese Journal of Veterinary Research > Volume 57, Number 1

Submitter: 獣医学部図書室

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