Managing heat stress in dairy cows: Part 1

In the first part of this three-part series, Dr Jan du Preez, managing director of UCK Investments, discusses the contributing effect of global warming on the occurrence of heat stress in dairy cattle.

- Dr Jan du Preez

Heat stress has an obvious negative impact on the immune function and general health of livestock. This is particularly true for dairy cows, as the impact of this is seen throughout the life cycle of a cow, and affects each of her life stages. Heat stress also suppresses the animal’s immune system and undermines her ability to maintain homeostasis, a self-regulating process by which an organism maintains stability while adjusting to conditions that are best for its survival.

CLIMATE CHANGE VS GLOBAL WARMING

Climate change and global warming are terms that may be used interchangeably, but they are not the same phenomenon. It is important to understand the difference:

Global warming is primarily a result of the accumulation of greenhouse gases (GHG) in the earth’s atmosphere, of which carbon dioxide is a major contributing factor. Global warming refers to actual ‘warming’, that is, an increase in the world’s average temperature. Since the beginning of the 20th century, the earth’s average atmospheric temperature has increased by around 0,74°C. In South Africa, the average rate of warming is around 0,16°C every decade. Taking this into consideration, it’s expected that the country’s average temperature will increase by around 8°C over the next century.

Climate change, on the other hand, refers to a change in the distribution of weather patterns over a long period of time. In this regard, it may refer to a change in the average weather conditions of a region, or to the time variation of weather patterns within the context of long-term averages. Some anthropogenic activities have been identified as the leading causes of ongoing climate change, which ultimately leads to global warming.