Climate change is a global threat to livestock sector to so many species and ecosystem in different parts of the world. Climate change, heat stress, and nutritional stress are the major intriguing factors responsible for reduced fertility in farm animals in tropical countries. Heat and nutritional stresses affect the reproductive performance by decreasing the expression of estrous behavior, altering ovarian follicular development and hormonal profiles, compromising oocyte competence, and inhibiting embryonic development in livestock. Climate is changed by greenhouse gases that released into atmosphere through man-made activities. Livestock contribute 18% of the production of greenhouse gases itself and causes climate change including heat stress, which has direct and indirect impact on fertility of the animals as well as reduce milk production. Adaptation to climate change and lowering its negative effect by alteration of animal micro-environment using different essential technologies are the main mitigation strategies to recover heat stress damage in this respect.
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Livestock production is cover almost 45% of earth’s land and one of the dominant lands use for business purpose; however, after use the land become variably different depending upon the environmental condition, and unsuitable for other purposes (Baumgard et al, 2012). Developing country like India, agriculture is an integral part of livestock and most of the people depends on that with various reason of economical support (Das, 2017). The world population is increased approximately 1 billion inhabitants during the past 12 years and make the count till 7.6 billion in 2017 according to the United Nations. However, these population growths are slower than last 10 years (1.24% and 1.10% respectively, per year) and predict that it will increase 8.6 billion in 2030 and 9.8 billion in 2050. This population growth and demand of people to get the income and to maintain the economic balance give rise to the demand for livestock products in developing countries (UN, 2017).
In the 21st century, there is huge increase in the demand of animal products that also expected in the next decade. The food and water are one of the primary needs for human. At the same time the increased population due to their miscellaneous activities causes local and global climate changes (i.e., global warming), leading to the major alteration of the livestock production. Although the adverse effect of global warming is not being same everywhere but it is accepted that it relatively affects the livestock and other crop production. In general, hot environment or rather heat stress is related with different factors like growth, quality and quantity of meat and milk production, quality of egg and its weight etc., which are the indirect indicators of reproductive performance, metabolic and health status, and immune response of an animal (Nardone et al, 2010). In the contrary, all over worlds, at some points global warming has positive effect at forecast: it shows the more productivity at the mid and high latitude as An increased temperature of 1-3°C. Also as a need of warm temperature in these areas, frost, heat waves or heavy rainfall decrease the advantage of hot temperature and a lowering of temperature also negatively affects the crop and other cereal production at lower latitude (Thornton et al, 2007). This high temperature between 2–3°C in any country for prolong time is sufficient to cause climate change of the country and simultaneously increases stressful condition to the dairy animal; and as a result of which animal shows reduced growth, meat and milk production. The global population is increased so rapidly that the demand of milk and meat is increasing day by day. The developing county like India stands at a second largest producer in cattle after Brazil (13% of world population), largest number of buffaloes (56% of world population) in the world (FAO, 2014), which is also a source of revenue; hence any impact of climate change on these livestock poses a serious threat to the country’s economy.
Developed countries are also not an exception in this regard. For example, USA has been reported the economic loss of 2.4 billion USD due to change in climate, and mainly heat stress give so many opportunities to other factors that cumulatively restricted the growth of livestock. This is also related with several diseases that affect the livestock production directly via restriction on vectors, environmental habitants, and disease causing agents (Stem et al, 1989). The developing countries mainly face this negative effect of climate change where population growth, food need and security, and other socioeconomic factors suffers from this vulnerable impact (Bishaw et al, 2013). As a result of this some important live hood factors like agriculture activity, average health due to food resources, water quality and other global warming affected factors like shrinking glaciers, river floods, disease prevalence, erratic weathers and disrupt ecosystem leads the whole country of natural hazards and disasters (Younas et al, 2012) that have an impact on global livestock sector.