SUMMER STRESS MANAGEMENT IN LIVESTOCK

Team Pashudhan Praharee

June 25, 2021

589

SUMMER STRESS MANAGEMENT IN LIVESTOCK

Aravindkumar K.

B.V.Sc. & A.H. Student,Rajiv Gandhi Institute of Veterinary Education and Research, Puducherry – 605009

Email ID- divas291099@gmail.com

Abstract:

https://www.pashudhanpraharee.com/traditional-treatment-of-heat-stress-during-summer-in-dairy-animals/

Heat stress is of greatest concern in livestock animals and birds. The animals can tolerate the heat up to a certain degree, but if the temperature is beyond its tolerating point it may lead to heat stress in animals and birds. In dairy animals it is found that there is a reduction in energy utilization of about 30% due to heat stress, which may vary with species. So, certain managemental practices or strategies are required to reduce the effect of heat stress on the animal’s health such as disease outbreaks and to reduce the economic loss such as decreased production during summer. A good management practice has its effect on the animal heath, production and reproduction in the positive side.

Key words: Heat stress, Livestock, Temperature,Management,Health

Introduction:

Summer stress or heat stress refers to the undesired changes that occur in animals due to extremely hot humid or hot dry weather. Heat Shock Proteins many also be produced when the temperature is very high. The thermoregulatory ability of the animals to dissipate heat is suppressed due to the high temperature and so it leads to summer stress or heat stress. The heat stress can be measured accurately by using the heat index(Temperature + Humidity) than using the temperature alone. Severe heat stress may lead to increased body temperature, decreased feed intake with increased water intake, increased heart rate, and various health complications depending on the species of the animal. Animals with dark skin colour are more prone to heat stress whereas animals with light skin colour are more prone to skin burns. Fat animals are more affected. Polled (disbudded) animals are more prone to heat stress than horned animals. Young animals are more prone than the adult animals to heat stress. Immuno compromised or animals with poor nutritional status are more prone to heat stress. Though some animals have the ability to tolerate such situations by panting, sweating, and various heat dissipating methods, human intervention is required at times of extremely high temperature. The management practice varies for different animals depending upon the nature of the animal’s anatomy and physiology. The feed also should be altered during the summer season; an additional amount of protein in feed is needed for animals as their intake during hot weather is reduced. If the animal is left unchecked then it may lead to decreased milk yield in dairy animals, decreased egg production in poultry, course wool production in sheep, low quality meat in pigs and many other complications. The indirect effects of heat stress in animals are ruminal acidosis with decreased bicarbonate level, reduced weight gain, causes early embryonic death, the fat content of milk is reduced. The animals under stress are prone to tick infection and haemoprotozoal diseases. In extreme cases viral and bacterial diseases may occur because the animal’s natural immunity is reduced due to the heat stress, this combined with dehydration, heat stroke, fever and muscle tremors may lead to the death of the animal. The housing, feeding pattern, and bedding of the animal should be properly checked at times of summer. The management practices of dairy animals, sheep, goat, pig, poultry and horse are of discussed below.

Management of Dairy animals during summer

The indigenous breeds of cattle are more thermo-tolerant than the crossbredcattle and exotic breeds of cattle. Buffaloes are more prone to heat stress because of their black skin, this dark skin absorbs more radiation from the sun and due to lesser sweat glands (has only 1/6^th of that present in cattle), buffaloes are less heat tolerant. When the temperature crosses the Upper critical temperature, the animal’s body cannot maintain homeostasis through thermoregulatory processes. This combined with increased body heat production leads to heat stroke. The Upper Critical Temperature for Exotic breeds and crossbreds it is 24-26°C, for Zebu it is 33°C, for Buffaloes it is 36°C.

Signs of heat stress in dairy animals include:

Animal moves towards shady areas.
It prefers to stand alone.
It has rapid but shallow breath, increased body temperature (106 – 108°F), and unusual salivation.
Often the animal has Open-mouth panting.

Management aspect:

Providing natural or artificial shade: Tree shades are most effective. If tree shade is not available then, a thatched roof made of paddy straw with a height of 9 feet can be provided. Nets that have 20% perforation can also be used.

ii. Feeding strategy: Water should be provided ad libitum throughout the day. Feeding or grazing of animals should be done during early morning or late evenings. Since the feed intake will be reduced, a high density ration that can provide the same nutrient even if the animals consumes less. Potassium rich mineral mixture is preferred to meet the increased demand of minerals.

Housing strategy: Heavy duty fans can be installed to provide ventilation. During hot dry weather, fogging of water around the animal using mister with mini pumps at least thrice an hour can be adopted to reduce the heat stress. Water can also be sprinkled around the animal for a period of 1-5 minutes with an interval of 30 minutes. In case of buffaloes, wallowing pond can be provided to reduce the heat stress.

Management of Sheep and goat during summer

Heat stress is well tolerated by sheep and goats when compared to other animals. Sheep are less tolerant to heat stress when compared to goats. Heat stress is more common in dark coloured animals. In light-coloured animals sun burns are common. It is found that sheep with one inch fleece are less prone to heat stress than sheep with less wool because wool dissipates heat. The heat stress tolerance is less in Angora goats when compared to other breeds of sheep and goats. High temperatures (32.2ºC) affect fertility.

Signs of heat stress in sheep and goat include:

Dry matter intake is reduced but water intake is increased.
Animal shows staggering behaviour.
Animal seeks for shade.
Respiratory rate of the animal is increased.

Management aspect:

Shearing of the animal: Shearing is not generally done in sheep and goats, but if the temperature and humidity is elevated, the lambs are sheared to improve their growth during summer.
Providing adequate water: Sheep and goat must be provided with plenty of fresh and cool water in order to prevent heat stress. On an average a goat or sheep needs 4 to 8 litres of water per day. The water requirement of young and lactating females are more than that of the adults. Sheep drinks more water than goats are adaptation to heat stress. Another adaptation of sheep to heat stress is that they produce concentrated urine.

Providing adequate shade: Shade can be provided either by tress or low cost alternatives. Simple shade structures can be constructed using fabrics and metal sheets.

Management of pig during summer

Pigs are more sensitive to heat stress. At high temperature the possible outcomes are decreased growth rate, decreased fertility, decreased ovulation and delayed oestrus, more embryonic deaths. If they are not taken care at this stage, the death rates are high in pigs. External stress such as loud noise to make the pig move fast, overcrowding of pigs should be avoided. Keeping pigs in large groups and moving them makes them excited leading to heat stress.

Signs of heat stress in pigs include:

Pig shows Stiffness
Pig has increased body temperature and heart rate.
Pig has muscle tremors.
Blotchy skin and vocalization (squealing) are most common.

Management aspect:

Provide Proper ventilation: Fans, Spray cooling system, Cool cell pads are to be installed. Periodic inspection of the equipments so as to prevent the reduction in ventilation rate.
Provide adequate water: Fresh and clean water should be provided ad-libitum throughout the day. A nursery pig can drink up to 1 gallon (4 litres) per day and a finisher can drink up to 5 gallons (19 litres).

Prevent overcrowding: Overcrowding results in excitation of the pigs which results in heat stress in a faster rate. During the nursing stage, the piglets need 1.7 to 2.5 square feet per pig and a fully grown pig needs 5 square feet initially and it ends with 8 square feet depending upon the weight of the pig.

Care during transport of the animal: The pigs must be wet before transporting on hot days. The vehicle must provide maximum ventilation and proper bedding must be provided using wet sand and wet wood shavings.

Management of poultry during summer

The effects of heat are severe in case of poultry leading to high health and economic losses. In case of turkeys and broilers, high temperature can lead to decrease in the growth rate and reduced feed conversion ratio. In case of laying birds, there is a decrease in egg production; even if eggs are produced it may be having less weight and poor shell quality. The poor quality of egg shell may be due to decreased feed intake, panting of the birds that result in alkaline blood (carries less calcium). At a temperature of 21-27^oC, turkeys, layers and broilers are not affected. If the temperature rises above this then it affects the intake of feed and production. In general high temperature (32^oC) can cause mortality in case of poultry. At high temperatures the water intake is increased, due to which wet droppings occur leading to secondary infections. To lose heat birds increase their respiration rate and thus panting occurs. In general Poultry does not sweat like animals they, dissipateheat to maintain their body temperature through 5 natural processes namely: Water evaporation, convection, conduction, convection, excretion, and radiation. Older birds are more prone to heat stress due to more production of internal temperature and more feathers which makes it difficult for them to lose heat.

Management aspect:

There are 2 important areas to manage heat stress in poultry, they are

Altering the management and feeding practice
Reducing the number of birds exposed to the effect of heat by effective construction of the housing.

Feed management: Increasing the feed ratio density because the birds consume less due to high temperature. Feeding the birds during the day time during which the feed consumption is more. Providing fresh water source is essential

Construction of the building: The building site, place, roof overhang and the design of the equipments have effects on heat management. So it must be constructed in such a way that air movement is well ventilated. The roof surface can be painted with metallic zinc paint or aluminium roofs can be installed for under insulated buildings. Fans can be installed and all these should be routinely maintained. Different types of ventilation can be adopted for cooling such as:

Evaporative cooling with power ventilation
Tunnel ventilation
Forced ventilation
Natural ventilation

Management of horse during summer:

Horses are affected by heat stress to a larger extent. Higher temperature, high humidity poor ventilation, and dehydration increase the risk of heat related diseases in horses.

Signs of heat stress in horse include:

Increased heart rate (more than 50 beats per minute)
Increased respiration rate ( more than 20 breaths per minute)
High rectal temperature (more than 38°C)
Skin becomes dry and hot

Management aspect:

Provide adequate water: Fresh water is needed to help the animal stay hydrated. A horse working at a temperature more than 70°C will drink double the amount of water when compared to a normal working horse.
Providing proper shade: Horse requires shade both in their barn in the pasture. Shade in pasture lands can be either from trees.

Providing fans: Barns can be installed with agricultural fans so as to prevent barn fires.

Providing proper electrolytes: Extra electrolytes should be provided to horses. They are found in hay and pastures. They can also be added in the feed. Sodium chloride and potassium chloride are the two main components that can be added in the feed of the horse.

Conclusion:

The heat management in animals and birds is an essential need for animals. This is because, the productivity, reproduction, and growth of the animal is challenged by the high temperature during summer. Implementing a good management practice can protect the animals from summer stress and can minimize the dangerous effects of heat stress on the animal’s health.

Reference:

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