Sweating rates of cattle in the field and their reaction to diurnal and seasonal changes

Abstract

Twenty-six replicate observations of sweating rate were made on six Hereford x Shorthorn and six Brahman x Shorthorn steers in the field at different times of day and different seasons. Sweating rates were lower in Brahman cross than in Hereford x Shorthorn steers under mild conditions, but higher under stressful conditions. Brahman cross steers increased sweating rate at lower skin and rectal temperatures. Maximum sweating rates were significantly lower in winter than in summer. This is ascribed to an association between sweating function and other aspects of skin function which undergo seasonal changes. Under cool conditions, either there was no consistent difference between animals in sweating rate as in the Brahman cross steers, or the less heat-tolerant animals with higher body temperatures and thicker coat type showed the higher sweating rates. Under challenging conditions of heat, between-animal differences in sweating capacity were revealed and, in the British steers, animals with higher sweating rates then had lower body temperatures. Furthermore, animals with sleek coats showed a higher sweating capacity despite lower thermal stimulus to the skin. The environmental conditions under which sweating capacity is challenged, when differences between animals become important as a component of heat tolerance, depend upon genotype, season, and duration of heat stress.

Relationship Between Cyclic Changes in the Hair Follicle and Sweat Gland Size in Cattle

“…Earlier observations by Dowling (1958) that sleek coats are associated with a higher sweating capacity have been confirmed by Schleger and Turner (1965) who were able to show that this relationship· holds between breeds, between animals within breeds, and between seasons. This investigation is an attempt to explain this ... Division of Animal Genetics, CSIRO, Cattle Research Laboratory, Rockhampton, Qld.…”

“…The association between follicle phase and gland size which has been described offers a partial explanation for the association of coat characters with differences in sweat gland size and activity between breeds, between strains, between animals within breeds, between different body regions, and between seasons (Dowling 1958;McLean 1963;Schleger and Turner 1965). The fuller explanation almost certainly lies in a more general association between follicle activity and gland activity, of which this morphological association is one facet.…”

Perda de calor por evaporação cutânea associada às características morfológicas do pelame de cabras leiteiras criadas em ambiente tropical

“…A média geral obtida neste trabalho para a perda de calor por evaporação cutânea ( Tabela 1) Schleger & Turner (1965), no qual são retirados todos os pêlos dos animais no local da medição, observando-se que a evaporação que se processa no interior da massa de pêlos é menos intensa que a evaporação da superfície cutânea exposta, em termos de calor, eliminado (Kerslake, 1972). Além disso, a taxa de sudação encontrada por Schleger & Turner (1965) somente foi avaliada próximo ao pescoço, embora a secreção de suor não seja homogênea em toda a superfície corporal (McLean, 1963ab).…”

“…Além disso, a taxa de sudação encontrada por Schleger & Turner (1965) somente foi avaliada próximo ao pescoço, embora a secreção de suor não seja homogênea em toda a superfície corporal (McLean, 1963ab).…”

Advances in Stress Physiology and Bioenergetics of Farm Animals: An Overview

“…The ability of farm animal to maintain body temperature depends on their capacity of thermoregulation based on the balance of heat gain and heat loss through: conduction, convection, radiation, and evaporation (Kadzere et al, 2002). Bos indicus cattle, with their higher sweat gland density, tend to have higher sweating rate (Schleger and Turner 1965). The sweat glands of Bos indicus are baggy-shaped, higher in volume (Pan, 1963), and closer to the skin surface (Nay and Hayman 1956) than those of Bos taurus.…”