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Nutrition and growth of suckling black bears (Ursus americanus) during their mothers' winter fast

  • Olav T. Oftedal (a1), Gary L. Alt (a2), Elsie M. Widdowson (a3) and Michael R. Jakubasz (a1)
Abstract

In black bears the last 6–8 weeks of gestation and the first 10–12 weeks of lactation occur in winter while the mother is in a dormant state, and reportedly does not eat, drink, urinate or defaecate. Measurements were made of the body composition and organ weights of cubs, of the composition of milk, and of milk intake (by dilution of 2H2O), in the first 3 months after birth. Additional milk samples were collected until 10 months postpartum. Bear cubs were small at birth, only 3·7 g/kg maternal weight, and chemically immature, as indicated by the high concentration of water (840 g/kg) in their bodies. Organ weights at birth were similar to those of puppies. In the first month after birth cubs gained 22 g/d or 0·23 g/g milk consumed; the milk was high in fat (220 g/kg) and low in water (670 g/kg). About 30% of the ingested energy and 51% of the ingested N were retained in the body. Over the entire 12-week period bear cubs required about 11 kg milk, containing (kg) water 7, fat 2·5, protein 0·8 and total sugar 0·25, to achieve a 2·5 kg weight gain. The birth of immature young and the production of high-fat, low-carbohydrate milk seem to be maternal adaptations to limit the utilization of glucogenic substrates during a long fast. Isotope recycling indicates that mothers may also recover most of the water (and perhaps much of the N) exported in milk by ingesting the excreta of the cubs. Lactation represents another aspect of the profound metabolic economy of the fasting bear in its winter den.

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G. L. Alt (1983). Timing of parturition of black bears (Ursus americanus) in northeastern Pennsylvania. Journal of Mammalogy 64, 305307.

P. Baverstock & B. Green (1975). Water recycling in lactation. Science 187, 657 658.

G. F. Cahill (1976). Starvation in man. Clinics in Endocrinology and Metabolism 5, 397415.

H. M. Cunningham & G. J. Brisson (1957). The endogenous urinary and metabolic fecal nitrogen excretion of newborn dairy calves. Canadian Journal of Animal Science 37, 152156.

J. S. Davies , E. M. Widdowson & R. A. McCance (1964). The intake of milk and the retention of its constituents while the newborn rabbit doubles its weight. British Journal of Nutrition 18, 385392.

H. Dove & M. Freer (1979). The accuracy of tritiated water turnover rate as an estimate of milk intake in lambs. Australian Journal of Agricultural Research 30, 725739.

M. Dubois , K. A. Gilles , J. K. Hamilton , P. A. Rebers & F. Smith (1956). Colorimetric method for determination of sugars and related substances. Analytical Chemistry 28, 350356.

R. A. Hall & E. M. Widdowson (1979). Response of the organs of rabbits to feeding during the first days after birth. Biology of the Neonate 35, 131139.

M. Hamosh (1979). A review. Fat digestion in the newborn: Role of lingual lipase and preduodenal digestion. Pediatric Research 13, 615622.

W. C. Heird , S. M. Schwartz & I. H. Hansen (1984). Colostrum-induced enteric mucosal growth in beagle puppies. Pediatric Research 18, 512515.

E. C. Hellgren , M. R. Vaughan , R. L. Kirkpatrick & P. F. Scanlon (1990). Serial changes in metabolic correlates of hibernation in female black bears. Journal of Mammalogy 71, 291 300.

R. J. Hock & A. M. Larson (1966). Composition of black bear milk. Journal of Mammalogy 47, 539540.

D. F. Holleman , R. G. White & J. R. Luick (1975). New isotope methods for estimating milk intake and yield. Journal of Dairy Science 58, 1814 1821.

S. J. Iverson , C. L. Kirk , M. Hamosh & J. Newsome (1991). Milk lipid digestion in the neonatal dog: the combined action of gastric and bile salt stimulated lipases. Biochimica et Biophysica Acta 1083, 109119.

S. J. Iverson & O. T. Oftedal (1992). Fatty acid composition of black bear (Ursus americanus) milk during and after the period of winter dormancy. Lipids 27, 940943.

K. T. Jagusch & R. M. Mitchell (1971). Utilization of the metabolizable energy of ewe's milk by the lamb. New Zealand Journal of Agricultural Research 14, 434441.

R. Jenness , A. W. Erickson & J. J. Craighead (1972). Some comparative aspects of milk from four species of bears. Journal of Mammalogy 53, 3447.

D. M. Joubert (1956). A study of pre-natal growth and development in the sheep. Journal of Agricultural Science, Cambridge 47, 382428.

R. A. McCance & E. M. Widdowson (1955). The size and function of the spleen in young puppies. Journal of Physiology 129, 636638.

M. J. Manners & M. R. McCrea (1963). Changes in the chemical composition of piglets during the 1st month of life. British Journal of Nutrition 17, 495513.

J. R. Marier & M. Boulet (1959). Direct analysis of lactose in milk and serum. Journal of Dairy Science 42, 13901391.

V. C. Mason (1984). Metabolism of nitrogenous compounds in the large gut. Proceedings of the Nutrition Society 43,4553.

R. K. Maxwell , J. Thorkelson , L. L. Rogers & R. B. Brander (1988). The field energetics of winter-dormant black bear (Ursus americanus) in northeastern Minnesota. Canadian Journal of Zoology 66, 20952103.

M. Messer & B. Green (1979). Milk carbohydrates of marsupials. II. Quantitative and qualitative changes in milk carbohydrates during lactation in the Tammar wallaby (Macropus eugenii). Australian Journal of Biological Sciences 32, 519531.

O. T. Oftedal , W. D. Bowen , E. M. Widdowson & D. J. Boness (1989). Effects of suckling and the postsuckling fast on weights of the body and internal organs of harp and hooded seal pups. Biology of the Neonate 56, 283300.

O. T. Oftedal & J. L. Gittleman (1989). Patterns of energy output during reproduction in carnivores. In Carnivore Behavior, Ecology and Evolution, pp. 355378 [ J. L. Gittleman , editor]. Ithaca, New York: Cornell University Press.

O. T. Oftedal , S. J. Iverson & D. J. Boness (1987). Milk and energy intakes of suckling California sea lion Zaophus californianus pups in relation to sex, growth, and predicted maintenance requirements. Physiological Zoology 60, 560575.

D. R. Perrin (1958). The calorific value of milk of different species. Journal of Dairy Research 25, 215220.

M. A. Ramsay & R. L. Dunbrack (1986). Physiological constraints on life history phenomena: the example of small bear cubs at birth. American Naturalist 127, 735743.

C. T. Robbins , N. Podbielancik , S. Roberta , D. L. Wilson & E. D. Mould (1981). Growth and nutrient consumption of elk calves compared to other ungulate species. Journal of Wildlife Management 45, 172186.

H. Sheng & R. A. Huggins (1971 a). Direct and indirect measurement of total body water in the growing beagle. Proceedings of the Society for Experimental Biology and Medicine 137, 10931099.

C. M. Spray & E. M. Widdowson (1950). The effect of growth and development on the composition of mammals. British Journal of Nutrition 4, 332353.

E. M. Widdowson , V. E. Colombo & C. A. Artavanis (1976). Changes in the organs of pigs in response to feeding for the first 24 h after birth. 11. The digestive tract. Biology of the Neonate 28, 272281.

E. M. Widdowson & C. M. Spray (1951). Chemical development in utero. Archives of Disease in Childhood 26, 205214.

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British Journal of Nutrition
  • ISSN: 0007-1145
  • EISSN: 1475-2662
  • URL: /core/journals/british-journal-of-nutrition
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