The impacts of climate change on the livestock industry
The livestock industry is likely to be impacted greatly by the effects of climate change. Some climate forecasters predict that NSW will experience increasing average temperatures and humidity in the future, and more hot spells. A 'hot spell' means three or more consecutive days where temperatures are above 40°C.
Scientists use a kind of scale, called the temperature-humidity index (THI), to measure heat stress on cattle, and this can also measure how productive the cattle are. When cattle are under heat stress, farmers can expect their stock to have:
- reduced grazing time (because animals might be seeking shade);
- reduced feed intake;
- increase in body temperature;
- increased sweating and panting;
- weight loss.
Find out more about the temperature-humidity index at http://www.coolcows.com.au/go-on-alert/thi.htm.
Intensive livestock
Holstein-Friesian cow and calf
In dairy cows, heat stress reduces the amount of milk produced, reduces milk fat and protein content, and decreases reproduction rates.1
High-producing dairy cows are the most susceptible to increases in the THI. Heat stress days where THI > 80 lead to a substantial effect on reproduction of dairy cows, particularly of the Holstein-Friesian breed.
A change in average temperatures over the hot dry period and a change in the number of 'extreme' days2 will both likely lead to changes in dairy production.
Shelter from the sun provided for cattle at a feedlot
Beef cattle in feedlots subject to heat stress can experience reduced health and a reduction in growth, influencing the amount of beef product sent to market.
Other intensive livestock animals such as chickens and pigs are also susceptible to heat stress. Some responses include:
- a reduced feed intake
- reduced laying performance (chickens)
- reduced fertility levels
- decreased activity
- in the worst cases, increased mortality.
Intensive pig and poultry industries rely heavily on cereal grains such as wheat and barley as their principal feed type. Climate changes will have the potential to affect the extensive grains industry, which will put pressure on the pig and poultry industries.
Climate changes will have the potential to affect the extensive grains industry, which will put pressure on the pig and poultry industries.
The pig and poultry industries are usually located in the cropping regions so that transport costs for both the raw materials such as feed, and the product, are minimised. If cropping locations need to change because of altering weather systems, or because the price of grain climbs, then the location of pig and poultry enterprises and the profitability and hence product price for the consumer will most likely be affected.
The availability of water will also affect the pig industry if demand for water increases, due to the need to provide more in-shed cooling to maintain the appropriate temperature conditions.
Pastures and crops
The livestock industry will also be affected by impacts of climate change on pastures and crops, which provide the feed source for this industry. Read more about the impacts on pasture and crop productivity.
Weeds, pests and diseases
Climate change may make worse the impacts of weeds, pests and diseases, through increasing occurrences and changes in their geographic distribution.
1Jones, RN & Hennessy, KJ 2000, Climate change impacts in the Hunter Valley: a risk assessment of heat stress affecting dairy cattle, CSIRO Atmospheric Research, Aspendale, Victoria, Australia.
2Howden, SM, Hall, WB & Bruget, D 1999b, ‘Heat stress and beef cattle in Australian rangelands: recent trends and climate change’, in D Eldridge & D Freudenberger (eds), People and rangelands: building the future: proceedings of VI International Rangelands Congress, Townsville, 6th International Rangelands Congress.