Extreme heat causes significant stress for all animals. There are a few simple guidelines you can follow to reduce the impacts of high temperatures on animals.
The provision of a plentiful supply of clean, cool water and shade is essential.
Water troughs or containers should be large enough and designed in such a way that all animals have easy access. The number of watering points and/or water flow should be increased if a large number of animals are kept together.
Troughs or containers should be firmly fixed so they cannot overturn. They should be kept clean and should be designed and maintained to prevent injuries. Large concrete troughs help keep drinking water cool. Water pipes should be of sufficient diameter with sufficient pressure to cope with periods of peak demand. Unless you are around to continually check water containers then water should be provided through automatic or reticulated systems rather than in containers that may be emptied or tipped over by thirsty animals.
Location of water should be familiar to animals before days of extreme heat. Animals should not have to walk too far for water. If putting livestock into a new paddock, especially where pasture is high, ensure they are familiarised with watering points as the height of pasture may prevent them from seeing the water sites (especially young or small stock).
Animals need to be provided with shelter during extended periods of extreme temperatures. Shelter is especially important for very young or old animals or animals that are in poor condition or sick.
Animals which are tethered or confined and cannot move themselves to shelter should be located in a position where they will have access to shade and water during the heat of the day. Kennels, aviaries, rabbit hutches, cat runs and the like should have an area in the shade for the whole day.
The best type of shelter during extreme heat protects the animals from the sun and allows for the cooling effect of wind. The following is a list of shelter alternatives:
- Constructed shelters - using materials such as shade cloth, corrugated iron or timber. Aluminium or galvanised steel are ideal roofs for shelters, kennels, and chicken coops as these materials are very good at reflecting the radiative rays of the sun.
- Trees with large canopies can be planted individually in fields. Trees have a cooling effect due to absorption of heat by the leaves.
- Naturally undulating paddocks and gullies.
- Shelterbelts – thick hedges of trees often fenced off from stock, shelter belts can provide good protection from sun, but should be thinned evenly to allow wind flow and planted in an east-west direction to provide shade during the hottest part of the day.
- Forestry blocks can provide temporary shelter from extreme heat.
- Pets and small animals should be moved to cool areas of the house or shed
During extreme heat conditions wind flow is important for keeping animals cool, so this should be considered when deciding type and location of shelter.
If insufficient shelter is provided for large groups of livestock there is the risk of animals crowding together under shelter resulting in smothering. It is important that shelter is available to all animals at the same time. It is preferable that shelter includes sufficient room for all animals to be able to lie down, as this assists with cooling.
It may be necessary to divide the number of animals into smaller groups. Group mentality may mean that even when animals have access to several smaller areas of shelter they will tend to camp together crowding under one source and around water.
Outdoor poultry houses (for example free range set ups or backyards) should be positioned in an area that is shaded from the sun and has good airflow. Insulate the east and west walls if necessary. Use wide overhangs at the eaves and solid end walls. In addition, an angled roof will reflect more heat at the hottest time of the day if the face of the slope is not directly facing the sun. The construction and positioning of nest boxes should be such that they avoid becoming heat traps.
Holding and processing areas for livestock should have shaded areas available. Use of water sprinklers can be useful to cool some species (i.e. pigs, cattle).
It is recommended not to handle animals in extreme heat unless absolutely necessary. If necessary, make sure it is done as early or late in the day as possible when temperatures are lower.
Research has shown that movement or handling of cattle during hot weather can increase their body temperature by 0.5 to 3.5 °C. Increased body temperature or heat stress will cause production losses in livestock and impact on their ability to maintain normal function. Moving animals during cooler hours can decrease the impact of high temperatures on production performance. For example, a delay in milking by an hour or more in the evenings can result in an increase in production of up to 1.5 litres/day/cow.
Transport of animals should be planned so that climatic extremes likely to compromise the animals' welfare are avoided. If transport is absolutely necessary, the journey plan should minimise the effects of hot weather on the animals; pre-determine your route, mark out a map with places of shade and perhaps water availability (such as rest stops).
Animals should only be transported during the cooler hours of the day. If it is necessary to stop, park the vehicle in the shade and at right angles to the wind direction to improve wind flow between animals during hot weather. Duration of stops should be kept to a minimum to avoid the build up of heat while the vehicle is stationary.
Stocking densities should be reduced to 85% of capacity to ensure good air flow between animals, and drivers should have contingency plans in place for adverse weather events.
Animals at high risk of heat stress include:
- young animals
- dark coloured animals
- animals that have been sick or have a previous history of respiratory disease.
Heat stress tolerances can also vary between and within a species, for example:
- pigs become heat stressed at a lower temperature level and are very prone to sunburn
- sheep that are newly shorn are at risk of sunburn
- high producing dairy cows are more effected by extreme heat than lower producing cows
- lactating cattle are more susceptible than dry cows because of the additional metabolic heat generated during lactation
- beef cattle with black hair suffer more from direct solar radiation than those with lighter hair, although those with pink skin are at risk of sunburn
- Holsteins are less tolerant than Jersey cows
- British breeds of sheep and cattle are less tolerant than merino or tropical beef breeds
- heavy cattle over 450 kg are more susceptible than lighter ones
- cattle, alpacas and llamas are more prone to heat stress than sheep and goats.
These types of animals should be watched more closely for signs of heat stress during days of high temperature.
Identifying heat stress
There are many signs of heat stress that you can look for in your animals. Some general signs include:
- increased respiration rate
- increased water intake
- loss of appetite
- increased salivation
- in severe cases may become unconscious.
You should ensure you are well informed on the heat stress signs of any species you own and watch closely during days of extreme heat.
Treating heat stress
If your animals are showing signs of heat stress the following actions can be taken to cool them down:
- move them to the shade immediately, preferably somewhere with a breeze. If animals are too stressed to move, pick them up and move them or provide shade where they are
- offer plenty of cool clean water, but encourage them to drink small amounts oftenspray them with cool water, especially on the legs and feet, or stand them in water. Use sprinklers or hoses for cattle, pigs and horses. Lay wet towels over them. Dogs and cats can be placed in buckets/troughs of cool water. Poultry should not be wet down unless there is a breeze to aid the cooling process
- increase air movement around them. This can be done with fans, ventilation, or wind movement
- decrease stocking rates to allow animals room to lie down
- if the animal shows no sign of improvement contact your local veterinarian for assistance.
While heat stress can have significant impacts on production and animal welfare, by making some minor management changes and taking a little extra care of your animals during periods of extreme hot weather, the effects of heat stress can be substantially reduced.
© State Government of Victoria 1996-2014