The composition of hooded seal ( Cystophora cristata ) milk: an adaptation for postnatal fattening

• Published in: Canadian Journal of Zoology
• Main Authors: Oftedal, Olav T., Boness, Daryl J., Bowen, W. Don
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1988
• Subjects: Animal Science and Zoology; Ecology, Evolution, Behavior and Systematics; Cystophora cristata; hooded seal
• Online Access: http://dx.doi.org/10.1139/z88-047; http://www.nrcresearchpress.com/doi/pdf/10.1139/z88-047

We obtained milk from 22 hooded seals on pack ice off the southeast coast of Labrador. Milk composition was not affected by degree of mammary evacuation or method of milk collection (drug immobilization vs. postmortem collection). Lactation stage exerted relatively little influence on milk composition over the course of the 4-day lactation period, but colostrum was higher in crude protein content. At mid to late lactation (2 – 4 days postpartum), hooded seal milk contains the highest dry matter (70%), fat (61%), and gross energy (5.9 kcal/g) contents that have been reported for any mammalian milk. This high fat content may be essential to achievement of the extremely rapid rate of fat deposition (about 4 kg/d) by suckling pups. The relatively low protein content (4.9%) at mid to late lactation is consistent with the small proportion of postnatal weight gain that is lean body mass. The proportion of milk energy contributed by protein is the lowest known for any mammal.