A heat transfer analysis of animals: Unifying concepts and the application of metabolism chamber data to field ecology

Abstract

Total surface of the animal [equation (Z)]. Effective radiating area of the animal [equation (2)]. Proportionality constant between K. and Kz [equation (27)]. Heat capacitance of the animal [equation (711. Diameter of the bodv of the animal. excluding appendages (Table 2). Total heat lost by evaporation [equation (1411. Evaporative heat loss from the respiratory system [equation (7)]. Evaporative heat loss from the outer surface [equation (5X. Evaporative heat loss from the skin surface of a furred animal [equation (6)]. Efficiency of evaporation at the outer surface of a furred animal [equation (23% Efficiency of evaporation at the outer surface of a naked animal [equation (24)]. Efficiency of evaporation at the skin surface of a furred animal [equation (22)]. Heat transfer coefficient to the ground [equation (711. Convective conductance, free or forced [section 2(B); equation (511. Free convection conductance [section Z(B)]. Forced convection conductance [section 2(8)]. Turbulence intensity in the direction of air flow [equation (25)]. Thermal conductance [equation (l)]. Thermal conductance of fur or leather layer [equation (5)]. Newton's Law dry thermal conductance [equation (1411. Overall thermal conductance [equation (lo)]. Overall thermal conductance under standard conditions [equation (19% Thermal conductance of skin layer [equation (611. Thermal conductance of skin and fur/feather layers [equation (ll)]. Conductivity of fur or feather layer [Table 21. Conductivity of skin layer [Table Z]. Metabolic heat production [equation (7)]. Oxygen consumed by metabolic processes [section 3(A)]. Effective net metabolic heat production [equation (13)]. Effective net metabolic heat production under standard conditions [equation (19)]. Superscript used to note that a parameter applies to a taxidermic model [section 4(~)1. Numerical correction factor used in linearizations [equation (3)]. Time period [equation (26)]. Rate of heat flow [equation (l)]. Absorbed thermal and solar radiation [equation (4)]. Emitted thermal radiation [equation (211. Net rate of heat transfer bv all radiative nrocesses when T, = F,:, if N = 0 [equation A HEAT TRANSFER ANALYSIS OF ANIMALS 341

Temperature regulation and microhabitat choice by free-ranging Galapagos fur seal pups (Arctocephalus galapagoensis)

“…Operative environmental temperature, the effective temperature of the environment as perceived by the animal, was calculated using Bakken's (1976) equation (12): Table 2. Climatic variables at pup height for day and night.…”

“…T, (~ C) air temperature and Tg (~ C) ground temperature were measured and hourly means used (Table 2). R (W/m2.~ radiation transfer coefficient; varying with iP r between 4.0 (20 ~ C), to 4.4 (30 ~ C) and 4.9 (40 ~ C) (Bakken 1976). iPr (~ C): overall surface temperature, hourly values are averages of fur and flipper temperatures (Table 3).…”

Nest insulation: Energy savings to brown lemmings using a winter nest

“…In both cases the rates of heat loss are retarded by added insulation, in the former case behaviorally, and in the latter, morphologically. The magnitude of the change in conductance (40 to 50%) is not surprising since nest walls are several cm thick and in still air the thickness of the insulator is a major determinant of rates of heat flow through it (see Bakken, 1976). …”

Factores climáticos que afectan el desempeño productivo del ganado bovino de carne y leche

“…La producción de calor metabólico es directamente controlada por el sistema nervioso central (Hammel 1968), por el sistema endocrino a través de la modificación del apetito y procesos digestivos, e indirectamente por alteraciones de la actividad de enzimas respiratorias y síntesis de proteína (Yousef 1985). A la fecha existen diversos estudios que intentan predecir el balance térmico del ganado en condiciones de producción comercial (Bakken 1976, McArthur 1987, Loewer 1998 . Sin embargo, la mayoría de los modelos basa sus resultados en una serie de supuestos en torno a variables fisiológicas involucradas en el balance térmico, existiendo en la práctica una gran variabilidad en la respuesta entre animales.…”