ANSC 3180 Lecture Notes - Lecture 18: Thermoregulation, Muskox, Vasoconstriction
24 Apr 2019
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Dee = bmr + activity + thermoregulation + heat increment of feeding. Still air boundary layer insulation is affected by air movement. A layer of still air next to the animal"s skin / cover layer (pelage, pumage) in an environment with little / no air movement. Animal or bird must also be still, resting, sleeping. About 0. 35 cm thick, all species, all body sizes. 0. 35 cm thick layer of still air provides as much as insulation as tissue layer insulation during maximum vasoconstriction. Cover insulation, pelage (hair/fur) / plumage (feathers), and the still air they trap. Some are specialized, insulative air cells in the medulla of the hair shaft, hollow feather shafts. Contour feathers vs down (e. g. eider duck) Numbers determined at birth - skin grows but no increase in number of hair follicles. Differs with species (horse 1290, cow 700, pig 37 hair / cm^2) Differs with breed (marino 5000, lincoln 1400 fibres / cm^2)
