Abstract
Environment is surroundings of a living organism consisting of natural forces, living things that facilitate circumstances for the progress and improvement along with risk and impairment.
Environmental physiology facilitates the understanding of the interrelationship between the environmental factors and animal. The environmental factors that influence animals’ performance are ambient temperature (Ta), relative humidity (RH), radiation, precipitation, atmospheric pressure and wind velocity. Homeothermic animals sustain a consistent inner body temperature (Tc) by adjusting the heat produced or increased by metabolism and heat loss to the environment. Thermoregulation is accomplished by physiological, morphological and behavioural mechanisms. Chronic heat stress compromises the animal production. Therefore, animals combat the heat load and reduce its adverse impact on production, reproduction through physiological process. When the animal experiences the heat stress, it stimulates sensible and insensible heat loss through conduction, convection, radiation and evaporation. The energy demand increases during winter to maintain the Tc by shivering or non-shivering thermogenesis. The body temperature regulates chemical reactions in the body, with an increase in temperature accelerating such reactions and a decrease in temperature slowing them down. Further, heat stress associated physiological responses of animals activate endocrine, autonomic and central nervous systems along with redistribution of blood flow. The different systems act in a coordination in relation to the level of stress so as to maintain the homeostasis by stimulating physiological mechanisms to reduce the adverse impacts. The stress controlling systems differ between entities in association with their past exposure, physiological status, genetic predisposition, the extent and severity of stress.G. Krishnan (K) ∙ V.
SejianCentre for Climate Resilient Animal Adaptation Studies, ICAR- National Institute of Animal Nutrition and Physiology, Bangalore, Karnataka, India
M. V. Silpa
Institute of Animal Breeding and Genetics, Justus-Liebig-Universitat Gieβen, Gieβen, Germany
© The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2023
P. K. Das et al. (eds.), Textbook of Veterinary Physiology, https://doi.org/10.1007/978-981-19-9410-4_28
Graphical Abstract
Homeothermic animals maintain their body temperature relatively constant with narrow range. The decrease in body temperature stimulates the hypothalamus and initiates the shivering and non-shivering thermogenesis to enhance heat increment. Similarly, the increase in body temperature also activates the hypothalamus to enhance heat dissipation mechanisms to reduce the core body temperature to its normal range
Keywords
Animal ∙ Environment ∙ Heat and cold stress ∙ Thermoregulation ∙ Adaptation
Learning Objectives •
• The chapter aims to understand all important definitions and terms pertaining to environmental physiology of farm • animals.
The chapter highlights the various cardinal weather variables which could influence animal responses to its environment.
The chapter elaborates the different effects of heat stress on the productive response in farm animals.
The chapter defines the thermoneutral zone for animals and its significance.
The chapter describes the thermoregulatory mechanisms of domestic animals.
The chapter also provides details on various indices to evaluate heat stress response in farm animals.
• The chapter also highlights in brief the different approaches to maintain livestock productivity during heat stress.
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