Impact of climate change on the dairy industry in temperate zones: Predications on the overall negative impact and on the positive role of dairy goats in adaptation to earth warming

The environment within which domesticated livestock production, agricultural crops and related management practices developed over the past 10,000 years is rapidly changing due to human-induced climate change (CC). Nowadays, even countries located within the temperate zone are affected by changes in global warming. These changes are associated with unprecedented events of extreme high ambient temperature (above 40°C) and seasonal changes. The number of days with temperature humidity index (THI) above a specific comfort threshold (>68) has noticeably increased in recent years in European countries located within the temperate zone. The rate of global warming, including in the temperate zone, is expected to continue to vulnerable in coming years. Agricultural production from crops and livestock, and thus global food security, is already affected by CC and will continue to be influenced by global warming. Thus, these changes will continue to affect the dairy industry directly and indirectly. The most significant indirect effect is expected to result from cruel reduction in worldwide grains (concentrate feedstuffs) production. This change will impose need to tradeoff between the diminished food sources: using higher proportions of grains production for human nutrition, instead of feeding it to livestock. Similar conflict is expected to be relevant in using high-quality forages that can be used as edible food for humans. Heat stress imposed by high ambient temperature in temperate zones, such as in Germany, northern Italy and the US was identified in recent years as a major factor that affect negatively milk production, reproduction, and the health of dairy cows. Heat stress also has shown to increase appreciably cow's mortality in those areas. On the other hand, there is no evidence that dairy goat production in temperate zones is affected so far; though, evidence for such an effect was notice in desert and Mediterranean (e.g., Turkey) countries. The major aim of this critical review is to analyze the literature in order to predict how the current trend in harshening of the impact of climatic changes affect dairy industry and to forecast how CC will affect the dairy cows and goat industry in countries located within the temperate zone? Particularly, the direct effects of heat stress on milk production are emphasized. Among domestic ruminants, goats are the most adapted species to imposed heat stress in terms of production, reproduction and resistance to diseases. The main conclusion that can be made is that uttermost scenarios of climatic change will negatively affect the dairy industry and that the importance of goats to the dairy industry will increase in proportion to the severances of changes in environmental temperature.