Animals are subjected to multiple stressors as a result of the changing climate. From bushfire and flood, heat, and increased disease. Veterinarians play a key role in ensuring the welfare of livestock.
Dr Tanya Stephens BVSc MSc IAWEL MANZCVS (Animal Welfare) FRCVS
Four years ago the WHO declared climate change to be the greatest threat to global health in the 21st century. Worldwide, climate change impacts on agriculture and livestock production with a risk to food security and animal welfare (FAO 2017) Under a ‘business as usual’ emission scenario it has been estimated that around 90% of the world’s population, most of whom live in the most sensitive and least developed countries, could be exposed to losses of food production (Lauric et al 2019). Even in Australia which is self sufficient in food production, climate change effects its ability to produce food (daff.ent.sirsidnix.net.au, Hughes et al 2015).
Australia’s climate is historically highly variable with lower mean rainfall and higher rainfall variability, however climate change has led to rising temperatures and more frequent intense and adverse weather events (BOM and CSIRO 2018, IPPC 2014) such as heatwaves (Perkins et al 2012) bush fires (Williams et al 2001) and droughts (Karoly et al 2003). Just recently the official Government enquiry into the 2019/2020 bushfires in Australia stated that climate change played a role. (Final report October 2020)
Although Australia is one of the most fire prone countries on earth and bushfires form part of the natural cycle of its landscape, the 2019/2020 bushfires were different as a result of prolonged drought, higher than usual temperatures and two large scale climate phenomena, an extreme positive Indian Ocean Dipole (IOD) and the Southern Annular Mode. Whilst the IOD is a natural phenomenon and extreme IOD events are rare, human induced climate change is modifying the behaviour of these climate modes. Over the past century more frequent positive IODs have led to the worst droughts in southeastern Australia (Ummenhofer et al 2009)
Drought is endemic in Australia, the world’s driest inhabited continent, however the most recent drought affected 100% of NSW and 67.4% of Queensland with drought the most severe on record. Rainfall in NSW and Queensland was more than one tenth below the previous record low of 1902 and average rainfall in SE Australia has been falling since 1990 (BOM and CSIRO 2018) This drying trend is the largest sustained change in climate since records began and is linked to global warming (Cai and Cowan 2013). 2019 was the hottest and driest year on record in Australia with the temperature 1.88 degrees above average and above average temperatures have become the new normal (BoM 2019)
Climate change has meant long term changes to Australia’s climate and predictions can no longer assume that weather conditions would return to a longer term average. Projected agricultural output has dropped by as much as 25% in some parts of Australia at only 1 degree of global warming. (ABARES 2020). On account of climate change hot days will become more frequent and hotter (very high confidence) and the time in drought is projected to increase over Southern Australia (high confidence) (BoM and CSIRO 2018)
Climate change with higher temperatures and extreme adverse weather events impacts on livestock welfare. The scale of the impact is not fully understood as there is a lack of peer reviewed literature regarding present and future risks. Some of these risks such as the catastrophic bushfires of 2019/2020 are so new that the impacts on animal welfare are yet to be determined.
Worldwide climate change is affecting farmers, food production and animal welfare. Across Africa, for example, as a result of changes to temperature, rainfall patterns and lower food sources pastoralists and livestock farmers have experienced increased animal mortality rates, decreased animal productivity, lower herd sizes and new animal diseases (Lenis Saweda 2019)
LIVESTOCK PRODUCTION IN AUSTRALIA
Australia’s livestock industry is a valuable commodity which significantly contributes to the economy. Cattle and sheep production lead the way and are predominantly free range on Australia ‘s rangeland areas. Figures from 2019 show there are over 20 million cattle and over 60 million sheep (down from 170 million in the 70’s) As well as over 100 million poultry and much smaller numbers of pigs. (daff.ent.siridynix.net.au). The gross value of livestock and livestock products are $13 billion for cattle and calves, $4 billion for sheep and lambs, $1 billion for pigs and $10 billion for livestock products such as wool, milk and eggs. Australia is self-sufficient in food and dependent on food exports worth $2 billion for meat and $448 million for dairy per annum. (ABARES 2020)
CLIMATE CHANGE HAS IMPACTS ON LIVESTOCK PRODUCTION
It has been evident for some time that agriculture in Australia has been impacted by climate change and whilst farmers are used to climate variability, climate change has presented some novel challenges. Climate change has already depressed farm profits with the value of farm produce in Australia falling to $58 billion from $63.8 billion two years ago (ABARES 2020)
The response of farmers to climate change is variable depending on the size and nature of the farm with small farms most at risk and cropping farms at more risk than beef farms. Livestock farmers can mitigate some of these risks by holding stocks of grain and hay, reducing livestock herd size and diversification but small farms, which are less profitable, are more likely to suffer than large holdings. (ABARES 2019)
Animal welfare is defined as ‘the physical and mental state of an animal in relation to the conditions in which it lives and dies. An animal experiences good welfare if the animal is healthy, comfortable, well nourished, safe, is not suffering from unpleasant states such as pain, fear and distress and is able to express behaviours that are important for its physical and mental state’. (OIE)
Moving beyond the Five Freedoms it is now well recognised that an animal should have the right to have ‘a life worth living’ (FAWC 2019). Further to this the Five Domains Model of animal welfare (Mellor 2017) considers the physical and functional well being of the animal as well as giving the animal the opportunity to experience positive emotions in all areas: Nutrition, health, environment, behaviour and interactions with humans’.
Minimum welfare standards for farm animals have been described (FAWC 2009) but there is an ethical obligation to provide positive welfare.
Using this Five Domains framework the animal welfare risks of climate change can be seen across the physical/functional domains of nutrition, environment, health and behaviour and the affective experience domain. As a result of climate change the animal may suffer from hunger, thirst, malnutrition, starvation, pain, injury, bushfire smoke, exhaustion or combinations of these stressors.
CLIMATE CHANGE, ANIMAL WELFARE and MULTIPLE STRESSORS
Predicting the effect of climate change on livestock welfare can be difficult because of the interrelationships between the animal, it’s surroundings and the impact of humans. (Caughan et al 2015) Indirect effects on animal welfare come from the effects of climate change on soil fertility, water availability and spread of diseases that affect the ability of livestock producers to care for their animals (Nardone et al 2010, Henry et al 2012). Livestock are at increased risk of hunger and starvation because of the effects of climate change on pasture growth (Harle et al 2007)
Animals are subjected to multiple stressors as a result of climate change. Heat combined with bushfires for example. Studies on sheep have identified that they can effectively cope with a single stressor but when exposed to more than one stressor this has a negative impact on growth and reproduction. Animals simply can’t cope with multiple stressors (Sejian et al 2012) and whilst there are a number of studies on the effect of multiple stressors in small ruminants there are few for large ruminants (Lees 2019)
Rising temperatures and adverse weather events such as drought, bushfires and floods also have an impact on human health and wellbeing with farmers having to make tough decisions that impact on the welfare of their animals (Dairy Australia 22/8/19). This is an important consideration in assessing animal welfare in livestock as it is well known that human behaviour and stockmanship is important in providing good welfare outcomes for animals (Hemsworth 2007)
Transport is a regular part of livestock management and is a known risk to animal welfare (Broom 2003) Increasing temperatures impact on animal welfare during transportation especially as livestock are deprived of food and water when transported by road (Fisher et al 2009) this may add to the impacts of heat stress (Silanikove 2000). Live export in hot conditions is also known to impact on animal welfare and can cause mass mortalities (Caulfield 2014)
The 2019/2020 bushfires affected a significant number of livestock. An estimated 100,000 sheep, beef and dairy cattle perished as a result of the bushfires in NSW and VIctoria (ABC News 1/07/20). Commodity analyst firm Mecado 2020 (mecardo.com.au) estimated the fires in NSW and Victoria affected 8.6 millions sheep and 2.3 million cattle which accounts for 12% of the National flock of sheep and 9% of the National herd of cattle.
Whilst cattle are common victims of fires in Australia, they are generally less affected than sheep because of their height and speed (agric.wa.gov.au). But they can be severely burnt if trapped. Farmers in NSW lost between 10,000 and 20,000 animals, including 6,000 dairy cows on the South Coast of NSW where more than 30 dairy farms were affected. Generators were burnt which prevented milking, feed sheds and pastures were destroyed. An estimated total 56,000 livestock have perished including 32,000 sheep on Kangaroo Island. (ABC news 5/1/20)
Rising temperatures due to global warming means animals are exposed to warmer and more humid weather. In southern Australia the average number of consecutive days of heat stress has increased from two days per heat stress event from 1960 to 1999 to four days from 2000 to 2008 (Nidumolu 2014). Whilst cattle and other livestock businesses may be able to adapt to an increasing global temperature, the main concern is the ability of livestock to cope with climate extremes such as heat waves.
It is well known that hot weather is associated with reduced reproductive and feed conversion efficiency (St Pierre 2003, Lees 2019, Sejian et al 2015), has a negative effect on animal performance, health and well-being (Brown-Brandl 2005, Collier et al 1982) reduces milk yield (Ravagnola and Misztal 2000) and associated with painful lameness (Polsky and von Keyserlingk 2017)
Heat stress is particularly challenging to the viability of livestock production as it may affect livestock health and welfare by causing metabolic disruptions, oxidative stress and immune suppression causing infections and death. Indirect effects are linked to effects on feedstuffs, drinking water and diseases (Lacetera 2019). Mass deaths are known to occur with high temperatures (Lacetera 2019, Fey 2015). Heat waves particularly affect cattle in feed lots with deaths recorded in Australia and the USA. For example, in Feb 1991 4000 cattle died in Queensland during a heat wave (Gaughan 2002)
Rapidly growing livestock are at particular risk of heat stress (Polsky 2017) as are those unable to thermoregulate, such as hatching poultry and piglets and those with a narrow thermal neutral zone such as dairy cattle (Das et al 2016). High temperatures cause heat stress, life threatening heat stroke and other disturbances (Lacetera 2019) All animals have a thermal neutral zone (Rojas-Downing 2017) above which the animal will suffer a range of negative affective states such as fear and distress.(Lacetera 2019) Supplementary feeding of concentrates as may occur with heat and drought can make heat stress worse as elevated protein digestion increases body temperature (Polsky and von Keyserlingk 2017))
Intensively farmed animals kept indoors such as pigs and poultry are dependent on good systems to ensure a stable comfortable environment. However, these can fail especially in times of extreme heat and can lead to extreme mortality and morbidity. High environmental temperatures are among the most important environmental stressors for poultry production and climate change has increased the prevalence and intensity of heat stress in poultry production areas worldwide (Lara 2013)
Drought significantly affects animal health and welfare through thirst, hunger and starvation. Weak stock are prone to physical accidents such as falling in dams, can ingest large quantities of sand and dirt, poisonous plants or excessive amounts of indigestible roughage. Drought also predisposes livestock to infectious and parasitic diseases because of lowered immunity as the result of poor nutrition and crowding.
The drought which affected large areas of NSW and Queensland in 2019 and 2020 led to a fall in the gross value of Agricultural produce with increasing numbers of cattle and calves slaughtered because of destocking. Through 2018-2019 the number of cattle and calves slaughtered increased by 10% while the number of sheep slaughtered increased by 15% (abs.gov.au)
The national sheep flock is expected to collapse to its smallest size since 1904 and the cattle herd has fallen to 23.5 because of the drought (ABARES 2019). It is estimated that it will take years to rebuild Australia’s livestock numbers.
Whilst dairy cows mostly graze on pasture, they also feed on forage crops and bought in feeds such as hay and grain. Up to 25% of Australia’s milk is produced from the grain included in the diet of dairy cows. Drought can affect the ability of farmers to grow feed, afford bought in feed and deplete water water supply causing thirst. (ABARES 2018).
Climate change increased the risk of heavy rainfall and flooding that hit North Queensland in 2019 and led to the death of an estimated 625,000 cattle which were already under stress from drought. (Cowan et al 2019)
INCREASED INCIDENCE OF DISEASE
Climate change is predicted to affect livestock health and welfare because of increasing temperatures and change in rainfall patterns giving rise to increasing incidence of diseases, shifting geographical ranges and risks of zoonotic diseases ( Campbell et al 2015)
Climate change is associated with an increased risk of parasitic and vector borne diseases and feed contamination (Lacetera 2019). The incidence of fly strike which impacts on sheep welfare increases as temperatures rise (Wall and Ellse 2011)
Kangaroos are not classified as livestock however, they are an important food source and an animal which has been commercially harvested in Australia for many years. They have a role to play in food security as a good source of low methane emitting sustainable protein as well as a suggested solution to mitigate the effects of climate change by replacing some traditional livestock. (Stephens 2018, Wilson 2019, McLeod and Hacker 2019). Numbers of large macropods have markedly increased since white settlement and are subject to a ‘boom and bust’cycle as a result of climatic conditions. Climate change affects the health and welfare of kangaroos because of increasing adverse events and an estimated six million kangaroos died between 2016-2018 in western NSW because of the drought. (The Land 20/2/20)
It has been suggested bees should be classified as livestock (British Bee Association )as they play an essential role in food security. For example, lucerne, an important livestock feed depends on bees for pollination. Drought and bushfires and now Covid 19 have affected bee health and welfare. The drought which affected the majority of Eastern Australia over the last few years and then the 2019/2020 bushfires destroyed 15.6 million hectares of native forest and ruined more than 12,000 hives (Clarke 2020)
MITIGATING THE EFFECTS OF CLIMATE CHANGE ON LIVESTOCK WELFARE
The lessons learnt from previous adverse weather events and effects of heat waves have led to the livestock industry in Australia producing various plans and guidelines. Dairy Australia has a Dairy Farm Fire Plan (dairyaustralia.com.au). Provision of shade and water is increasingly of critical importance in a warming climate to prevent negative animal welfare outcomes. Dairy cattle will seek shade and increase water intake as temperatures rise (Polsky 2017) It is well known that provision of shade alleviates heat stress in dairy cattle (Buffington et al 1981).
Various State and Territory Government Departments have produced Animal Welfare Guidelines for use in Australia during drought such as the NSW DPI ‘Welfare scoring nutritionally deprived beef cattle, dairy cattle and their crosses 2019’ dpi.nsw.gov.au This scores fat reserves, behaviour and ability to be transported. The WA Dept of Primary Industries and Regional Development (agric.wa.gov.au) has Guidelines for assessing cattle and sheep after a fire to determine if they need to be destroyed or can be kept. Included in the assessment is the availability of food and water, the owner’s ability for ongoing care and outlook for productivity.
The Australian Animal Welfare Standards and Guidelines (animalwelfarestandards.net.au) sets out producers responsibilities and animal’s needs in relation to food and water and risk management in extreme weather.
There is a general lack of research on the impacts of climate change on livestock welfare. We do, however understand the effect of heat on animal welfare and that multiple stressors need to be considered.
Before climate change was recognised as a threat to agriculture, rising demand for animal products for human consumption as a result of a growing population was already seen as having a significant impact on human health, the environment and the lives of farm animals. (Waithes2013, D’Silva 2010, Cribb 2010). Concerns were raised over increasing intensification of livestock production to meet the demand and impacts on animal welfare. It is now more important than ever to consider in any discussion around livestock welfare that ‘production should not be promoted at any cost and livestock production must include the welfare of animals as it is not considered sustainable if an animal’s life is not worth living’ (FAWC 2009).
The FAO’s 2006 ‘Livestock’s Long Shadow, environmental issues and options’, (fao.org) presents an in-depth assessment of the various significant impacts of the world’s livestock sector on the environment. Debates around sustainable livestock production and protein are often highly contentious and controversial. Five main themes that require more research or better communication of existing research have been identified including ways of measuring methane, the role of regenerative farming and soils as a climate solution (Breewood H, Fraanje W and Garnett T 2020).
The interplay between livestock production and climate change is complex. (Lynch 2019, Garnett et al 2017, Garnett 2015). Livestock can play an important role in recycling biomass unsuited for human consumption back into the food system, act as a carbon sink (Gerber et al 2013) and there is emerging research on methane and the impacts of cattle and sheep farming on global temperatures (Allen MR et al 2018). In Australia MLA contend that livestock production will become carbon neutral by 2030 (mla.com)
Importantly, whilst the FAO states that a western diet cannot be sustained for the increasing world population, it asserts that livestock farming is essential to sustainable food production. Livestock in developing countries contribute up to 80% of agricultural GDP and around 600 million rural poor people rely on livestock for their livelihoods. Whilst livestock are especially vital to the economies of developing countries where food insecurity is an endemic concern, livestock have been an integral part of all human progress and even developed societies remain reliant on animals for food and nutrition security.
The FAO released a report ‘Transforming the livestock sector through the Sustainable Development Goals (www.fao.org). The focus has shifted from fostering sustainable livestock per se to enhancing the sectors contribution to the SDG with the aim to do more to end poverty and hunger. Livestock play a key role in improving the lives of millions by providing the world with sufficient and reliable supplies of meat, milk eggs and dairy products; increasing the direct consumption of animal-based food, strengthen the assets of rural households, improving children’s cognitive and physical development, empowering women and close inequality gaps.
To sustain livestock production and ensure food security in a warming world, it is essential to adopt effective mitigation strategies such as optimizing animal productivity (Grossi 2019) and sustainable production methods (Padmakumar V et al 2019). The booming demand for livestock products is taking place almost exclusively in developing countries, the so called ‘livestock revolution’ (Delgado 1999) which may be particularly vulnerable to the impacts of climate change.
On a positive note Meat Livestock Australia contends that sheep, cattle and goat production in Australia will become carbon neutral by 2030 (mla.com). Similarly farmers in the UK say they can be carbon neutral by 2040.
Finally, animal welfare should always be a priority. Veterinarians play a key role in feeding the world and ensuring that livestock production is not promoted at any cost and must include the welfare of animals as it is not considered sustainable if an animal’s life is not worth living.
Dr Tanya Stephens BVSc MSc IAWEL MANZCVS (Animal Welfare) FRCVS
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Written September 2020, updated March 2023