Impact of heat stress on health and performance of dairy animals: A review.

Ramendra Das,Jnyanashree Saikia,Imtiwati Imtiwati,Pranay Bharti,Lalrengpuii Sailo,Nishant Verma,Rakesh Kumar

doi:10.14202/vetworld.2016.260-268

Abstract

Sustainability in livestock production system is largely affected by climate change. An imbalance between metabolic heat production inside the animal body and its dissipation to the surroundings results to heat stress (HS) under high air temperature and humid climates. The foremost reaction of animals under thermal weather is increases in respiration rate, rectal temperature and heart rate. It directly affect feed intake thereby, reduces growth rate, milk yield, reproductive performance, and even death in extreme cases. Dairy breeds are typically more sensitive to HS than meat breeds, and higher producing animals are, furthermore, susceptible since they generates more metabolic heat. HS suppresses the immune and endocrine system thereby enhances susceptibility of an animal to various diseases. Hence, sustainable dairy farming remains a vast challenge in these changing climatic conditions globally.

Highlights

Stress is a reflex reaction of animals in harsh environments and causes unfavorable consequences ranges from discomfort to death
Hsp gene expression under thermal stress changes include: (i) Activation of heat shock transcription factor 1 (HSF1); (ii) increased expression of Hsp genes and decreased expression and synthesis of other proteins; (iii) increased glucose and amino acid oxidation and reduced fatty acid metabolism; (iv) endocrine system activation of the stress response; and (v) immune system activation via extracellular secretion of Hsp. These gene expression changes lead to an altered physiological state referred to as “acclimation,” a process largely controlled by the endocrine system [8]
Extended periods of high air temperature coupled with high relative humidity compromise the ability of dairy animal to dissipate excess body heat which affects feed intake, milk production, and reproductive efficiency and reducing profitability for dairy farmers

Summary

Introduction

Stress is a reflex reaction of animals in harsh environments and causes unfavorable consequences ranges from discomfort to death. As a results body surface temperature, respiration rate (RR), heart rate and rectal temperature (RT) increases which in turn affects feed intake, production and reproductive efficiency of animals.

Results

Conclusion