The effects of climate change on livestock production
Introduction
The agricultural sectors in developing and developed countries consider livestock as a major contributor to the agricultural GDP. On the global platform, there is growing demand for animal products, and this implies that it will be important for livestock sector to expand to ensure that it meets the growing demands. Despite this need, the existing reality is that livestock is susceptible to the detrimental effects of extreme weather conditions. This implies that seasonal fluctuations and climatic extremes in herbage quality and quantity can affect the well-being of livestock, which may result in a decline in livestock reproduction and production efficiency. This research attempts to project the effects of climate change on livestock production.
On the global platform, climate change threatens the sustainability of livestock systems. Consequently, Sejian et al. (2015) argue that the mitigation of and adaptation to the detrimental effects of extreme climates can be critical in combating the effects of climatic change on livestock. The predictive models on the impact of climate change suggest that its impact on livestock performance will be necessitated by its ability to manifest itself as rapid changes in climate in the short term or over the decades in the form of subtle changes. Since climate change is largely associated with increased global temperatures, existing climate model project that by 2100 the average global temperature will be 5.5 °C warmer than in 2000. The major climatic difficulty that faces livestock is weather extreme, which is characterized by droughts, floods, and intense heat waves. These events will not only result in production losses but also in increased livestock deaths (Gaughan and Cawsell-Smith, 2015). From an evolutionary perspective, it is notable that animal can adapt to some aspects of extreme weather conditions such as hot climates. However, the response mechanism that these animals initiate to enhance their survival may have detrimental effects on their survival.
Direct and indirect effect of climate change on livestock
A major impact of climate change on livestock production emanates from heat stress. The heat stress phenomenon can present a major financial burden for livestock farmers because it results in among other factors a decrease in meat production, declining animal health, reproduction efficiency, milk production and milk component. The implication is that an increase in the average air temperature as predicted by the existing climate change models could have a significant and direct effect on animal performance.
Majority of the production losses that animal farmers experience arise from the indirect effects of climate change. In most cases, these effects are associated with unavailability or reduction of water and feed resources. Potentially climate change affects the quality of forage, the reliability and quality of forage production and the quantity of water needed for forage production. If the predictions by climate change model are accurate, then it is possible to assert that in the coming decades the gradual increasing air temperatures will continue affecting crop and forage plants (Sejian, 2013). This is because factors such as elevated carbon dioxide level and the alterations in precipitation patterns will result in fluctuating water availability, which will affect the forage quality, quantity, and production. Climate change also has an adverse effect on species composition, productivity, and quality with the potential impact on the ecological roles of grasslands (Giridhar and Samireddypalle, 2015). The wide fluctuations in rainfall distribution, especially in growing seasons in different parts of the world, imply an adverse effect on forage production. The possible emerging phenomenon that is already evident from the effect of climate change, it is possible that livestock production will face negative challenges considering that patterns such as longer dry period and droughts will be responsible for the reduction of groundwater recharge and reduction in river flow. These factors will have an ultimate effect on the availability of sufficient and clean water for agricultural purposes. Deprivation of clean water will affect the physiological homeostasis in animals, which can potentially result in a loss in body weight, decreases resistance to diseases and low reproduction rates (Naqvi et al., 2015). The resulting phenomenon implies the need for more research on issues of water resource vulnerability to climate change. Such initiatives will support the development of adaptive strategies in the agricultural sector. Furthermore, such ingenuities will assess the ramifications and mitigating strategies for emerging livestock diseases such as vector-borne diseases, which arise as an effect of climate change.
Climate change and the impact of multi-stressors on livestock production
Livestock reared in the tropic are often subjected to multiple stressors at a time. These stresses can have an effect on animal production, immune status, and reproduction. According to Sejian et al. (2010), existing studies on the effect of stressors on animal production have only investigated one stressor at a time because of the technical difficulties in the management, analysis, and interpretation of a balanced multifactorial experiment. When the prevailing climatic conditions result in the subjection of livestock to nutritional and heat stress at the same time, it is likely that such exposure will have a negative effect on their growth, reproduction, and performance. The implication is that when animals are subjected to multiple stressors arising from environmental conditions, their performance and productivity is negatively affected because the biological functions necessary for maintenance and adaption in such situations may be relatively severe (Sejian et al., 2013).
Climate change can have negative effects on livestock production because animals exposed to heat stress increase water intake while reducing feed intake. These can be considered as major changes in the endocrine status which result in increased maintenance needs and a reduction in performance levels (Gaughan and Cawsell-Smith, 2015). Environmental stressors can be major contributors to a reduction in average daily gain, body weight and the body conditions of animals, which can be major contributors to reduced milk quality and milk, yield (Sejian, 2013). There is a consensus that when exposed to different environmental stressors, it is the high production animals that will face most of the adverse effects considering that their adaptation to prolonged stressors may be characterized by lower production levels and production losses to the agricultural sector.
Climate change can also have a major effect on livestock reproduction. This is based on the understanding that thermal stress affects the reproduction process. Among dairy cows, conception rates may drop by about 25% in the summer considering that when they are subjected to heat stress cows experience the reduced expression of oestrus because of limited secretion of oestradiol in the luteinizing hormone environment. Additional reproduction inefficiencies that result from heat stress include changes in embryonic development and ovarian function. These changes are facilitated by the reduction in the competence of the oocyte that is positioned for fertilization (Naqvi et al., 2012). When the growth of oocyte in cows is compromised by heat stress, the animals experience an alteration an alteration in the functioning of the hormones responsible for different functions in the reproductive system. According to Sejian (2013), additional effect includes the impairment of the embryonic development process, which can be cited as a contributing factor to the increase in embryonic mortality rates in livestock. Existing evidence indicates that when animals are exposed to heat stress during pregnancy, they are most likely to experience slow growth of the fetus and in some cases the loss of foetus.
Climate change can also affect livestock adaptation depending on the adversity of the effects. When subjected to factors such as heat stress animals often initiate adaptive and compensatory mechanism, which are critical in maintaining their body temperatures within the psychological limits. These mechanisms facilitate the re-establishment of hemostasis and homeothermy which may be critical for their survival, but they also result in reduced productivity potential (Gaughan, 2015). Heat stress facilitates the development of relative changes in different physiological responses, which include rectal temperature, pulse rate, and respiration rate. Among animals living in relatively hot climates, it is possible to assert that their adaptive mechanism has made it possible to develop genes that have been effective in protecting their cells from increased environmental temperatures. It is during stressful events necessitated by climate change that genetically superior animals can be identified for coping with stress. Such process can be effective in facilitating the creation of therapeutic drugs and treatments targeting affected genes to improve the survival rates of genetically inferior animals (Collier et al., 2012).
Rainfall and temperature variations can be categorized as the major climatic variables that affect disease outbreaks in livestock. Warner and wetter weather conditions provide an environment that increases the risk and occurrence of livestock diseases considering that some of the species that act as disease vectors such as ticks and biting flies have the likelihood of surviving year round. The movement of livestock diseases into new areas such as Rift Valley fever in Europe indicates the possibility of certain parasitic diseases is becoming more prevalent and spreading out of their geographical range when rainfall increases (Sejian, 2013). The outbreak of livestock diseases such as foot and mouth diseases can affect a large number of livestock hence contributing to further degradation of the environment and the health of the surrounding community of livestock.
Conclusion
Evidence from existing studies indicates that when livestock are subjected to climate change factors such as heat stress, there are most likely to experience a substantial reduction in their performance. Such reduction affects their productivity hence inflicting major economic losses on livestock farmers. Technological development has provided innovative measures that can be used in the identification of the genetic factors that contribute to the increased possibility of survival for animals when they are faced with adverse climatic conditions. However, these developments are still ineffective because the effects of climate change are relatively gradual and the adversity of their effects increase every decade. Despite this assertion, systematic information from impact assessment of the effect of climate change on livestock production can be valuable in facilitating the development of appropriate mitigation and adaptation strategies for sustainable livestock production as the climatic scenarios changes. Livestock is an important source of livelihoods, and this implies that it will be necessary to develop sustainable solutions for maintaining the industry by gaining profitability and decreasing environmental pollutants.
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