IMPORTANT TIPS FOR SUMMER STRESS MANAGEMENT IN LIVESTOCK

IMPORTANT TIPS FOR SUMMER STRESS MANAGEMENT IN LIVESTOCK

Dr. Shivika Chouksey

(Post Graduate Student)

Department of Veterinary Gynaecology and Obstetrics,

College of Veterinary Science and Animal Husbandry, NDVSU, Jabalpur (M.P.)

shivichouksey23@gmail.com – 7024056144

 

ABSTRACT-

Livestock plays an important role in the global economy. Climate change effects are not only limited to crop production, but also affect livestock production, for example reduced milk yields and milk quality, reduced meat production and reduced fertility. Furthermore, multiple stressors are a common phenomenon in many environments, and are likely to increase due to climate change. Among these stresses, summer stress appears to be the major factor which negatively influences livestock production. Livestock responds to the changing environments by altering their phenotypic and physiological characters.  to sustain livestock production in an environment challenged by climate change, the animals must be genetically suitable and have the ability to survive in diversified environments. An imbalance between metabolic heat production inside the animal body and its dissipation to the surroundings results to heat stress (HS) under high air temperature and humid climates (summer season). The foremost reaction of animals under thermal weather is increases in respiration rate, rectal temperature and heart rate. It directly affects feed intake thereby, reduces growth rate, milk yield, reproductive performance, and even death in extreme cases. Summer stress suppresses the immune and endocrine system thereby enhances susceptibility of an animal to various diseases. Hence, sustainable dairy farming remains a vast challenge in these changing climatic conditions globally.

https://www.pashudhanpraharee.com/summer-stress-management-in-livestock/

INTRODUCTION-

Climate change is the natural condition, while summer means the heat stress occur from March to June. Summer stress is the environmental conditions were increased climatic temperature and cause stress to livestock. This inducing thermoregulatory changes in cattle, buffaloes, sheep, goat, dog and horses. Summer / Heat stress in animals is associated the imbalance in heat production and dissipation in the body of the animals, more heat is produced or absorbed but less heat is dissipated from body. Heat Stress has harmful impact on production, reproduction, metabolism and immune status of animal. Semen quality of exotic cattle is also affected by heat stress. Similarly, fertility decreases during highly warm months due to heat stress. Humidity plays significant role in heat stress. Cattle and buffalo are most susceptible animal for summer stress.

 

India is first in milk production in the world production, with 78 million metric tons of milk from 57 million cows and 39 million buffaloes. Summer stress can reduce milk production upto 50%. Summer stress in livestock occurs when the heat load of an animal is greater than its capacity to lose heat. High air temperature, humidity, solar radiation and low air movement contribute to increased risk of summer stress. Though indigenous breeds of cattle are more thermotolerant then crossbred and exotic breeds of cattle are highly sensitive to summer stress. The thermoneutral zone (TNZ) of dairy animals ranges from 16°C to 25°C, within which they maintained a physiological body temperature of 38.4-39.1°C (Yousef et al, 1986). Animals experience heat stress when the body temperature is above the optimum range defined for normal activity because the total heat produced is greater than the heat dissipation capability (Bernabucci et al., 2010). In India, the summer temperature goes beyond 45 °C which is 18 °C above the upper critical temperature of dairy cattle. When the temperature exceeds 270 even with low humidity, the temperature is above the comfort zone for the high producing dairy cows.

 

Armstrong (1994) reported following responses in animals during heat stress.

(a) Reduced feed intake

(b) Increase water intake

(c) Change in the metabolic rate / maintenance requirement.

(d) Increased evaporative loss

(e) Changes in blood hormones concentrations.

(f) Increase body temperature.

 

 

There are several factors, which influence the severity of heat stress. These include

􀂙 Environmental condition

􀂙 Level of production & feed consumed

􀂙 Stage of lactation

􀂙 Cooling management.

􀂙 Exercise requirements

􀂙 Breed and Body color

SYMPTOMS OF SUMMER STRESS-

• Rapid and weak pulse
• Elevation in heart rate, rectal temperature
• Shallow and rapid breathing
• Unconscious, dizziness, dry body condition
• Skin become dull, shrunken eye, unusual salivation
• Animals may fall down suddenly due to dehydration
• Animal moves to shade
• Water intake enhanced while feed intake reduced
• Increased respiration rate or Panting is first sign of heat stress (>70/min). It impairs the acid base balance as well as calcium homeostasis, this leads to increased incidence of hypocalcemia and milk fever (Pejman and Habib., 2012).
• Increased maintenance energy requirement through various mechanisms animal tries to dissipate the excess heat and maintain body temperature. Due to this the maintenance energy requirement may increase by 20-30% in animals under heat stress. This decreases the energy available for production functions.
• Decreased milk production.
• Dry matter intake decreases, depending on the severity of heat stress may be reduced by 8-12% or more, because decreased blood flow to the rumen and intestines, to avoid increased heat production from feed digestion, increased water intakes that fill the stomach (Saini and Chandrahas, 2013).
• Decreased reproductive performances elevated temperature impairs the follicle and embryo development. Redistribution of blood flow from the viscera to the periphery during heat stress, leads to reduced perfusion of placental vascular bed, retarded foetal growth (Alejandro et al., 2014).

MANAGEMENT OF SUMMER STRESS-

Practices and nutritional correction under managemental practices, emphasis should be given on proper water supply, proper animal housing to reduce or to manage heat stress. These are –

1. Proper animal housing

The cow sheds in Indian conditions should be designed to reduce the heat load because heat stress cause more damage to animals compared to winter. The temprature above 30 °C result in drop in milk production and breeding efficiency. Theoretically speaking, the best type of animal shelter is a one where the microenvironment temperature remains within 15 to 25°C and humidity level around 10-12 mm Hg. Shades of trees provides an ideal protection from radiant heat, but do not fit because of other reasons. Principles for creating an optimum microenvironment within an around the sheds are directed to reduce heat gain and promote heat losses from structure of animal’s house by radiation & condition. The point needs to be considered are :

(i) Orientation

Shed with its long axis running East – West provides a cooler environment than one with a North-south orientation (Kelly et al, 1950). In the East- West oriented shelters animals get more opportunity for radiation exchange with cooler north sky. Thus, this orientation favours heat loss from animal body to environment both by radiation and conduction

(ii) Shelter design

Open type of sheds has advantage over closed type shed. Mean temperature and minimum temperature in close shed was significantly higher than those of open type shed. The close type shed significantly contributed to higher ambient temperature during both hot dry and hot humid months i.e., from April to September.

(iii) Width and size of shelter

Slightly more shaded area than the minimum recommended floor space required for different species of livestock should be provided in hot dry climate. Floor space requirement for calf is 1.5 to 2 m2, adult male 7.0 m2 and for adult female is 4.0-5.0 m2. Optimum width of the shelter is 5.0-6.0 m. although wide shelter results in lower ground temperature underneath it and thus the amount of radiation from ground to animal body is reduced.

(iv) Height of shelter

Minimum roof height should be 10.0 feet to reduce heat load. The height of shelter in hot climate should be between 3.0 – 5.0 m. A height less than 3.0 m interferes with proper ventilation resulting into reduced convective heat loss from animals.

(v) Shape and type of roof

The shape of the roof can be either flat, slopped or “A” shaped. “A” shaped roof is definitely better than a flat roof in hot climate. One side of “A” shaped roof saves the other half form direct solar radiation by casting its shadow. This helps in cutting down heat gain from roof.

(vi) Roofing material

It may be Hay or Straw, Galvanised steel, Plywood and several types of plastics are the roofing material. On a typical summer day differences in radiant heat load under shades covered with straw and galvanized iron or plastics were of the order of 163 Kcal/hour/ m2 of animal surface. A 4-6-inch-thick hay thatch does not receive much heat from the upper surface by conduction. The surface convective co-efficient of the hay, because of its uneven surface is also high. Hay thatch is more suitable for hot dry climate than hot humid climate (need for frequent removal of thatch is limiting factor).

(vii) Ventilation

Proper ventilation at ridge level keeps two or three walls open.

(viii) Colour of roof and walls

It should be white outside and coloured inside Reflectivity of white colour is around 75%. The reflectivity of the underneath surface should be less at it determines the quantity of incidental energy from the ground which will be reflected back down to the animals. Painting of side walls white from outside reduces the surface temperature of the walls inside by 12 to 22 °C in comparison to unpainted walls at air temperature of the walls inside by 12 to 22 °C in comparison to unpainted walls at air temperature above 37 °C. Water troughs should be kept under shade ensuring 24 hours water availability.

 

 

2. Feeding and nutritional management

Points to be consider while feeding animals during ot weather, as feeding frequency, (extra feeding) time of feeding, (cooler time of a day, adequate feeding space and plenty of cool water. Modification in ration can help to minimize the drop in milk production, decreasing forage to concentrate ratio, result in more digestible rations. Feeding buffers such as sodium bicarbonate and magnesium oxide allow higher concentrate rations and can help in low fat milk syndrome also. Hot weather increases the need of certain minerals. Do not overfeed highly degradable protein during hot weather it should be 18% or less. Supplemental fat can be added in ration to increase energy in take. Also avoid feeding excess fat, over feeding causes problem with rumen function supplementing extra vitamins during summer has no added advantage.

3. Animal cooling system

Rise in ambient temperature activates sweat glands to produce sweat. Each gram of sweat evaporated from skin utilises 590 calories from skin surface (Latent heat of evaporation of water). This process of evaporation causes cooling of skin. A part form sweating animals increase their respiration rate. (Induced evaporation of moisture from mouth/ lungs). Breathing of animals at a much faster rate to combat heat stress leads to panting. To reduce the metabolic heat load, animals reject feed and fodder.

• Wallowing tanks

Swine, as well as water buffaloes, are naturally wallowing animals and allows for them have been shown to improve performance (Dasilva, 2004). cooling during 5-10 min after exiting the pond. But access to streams and farm ponds has been associated with a number of infectious disease and some toxicity to dairy cattle.

• Fans

High velocity blast fans are to be mounted on sidewalls can help in reducing thermal stress on animals and body temperature. Cows reared under electric fan produced 1.2 kg/d more milk during the early lactation (Suriyasathaporn et al., 2006). The fan system in the holding pen should be capable of moving 1,000 cubic feet of air per minute per cow (cfm/cow). The total ventilation rate is based on the maximum number of cows in the holding pen. Most 30- and 36-inch fans will move between 10,000 and 12,000 cfm per fan, so install one fan per 10 cows or 150 square feet of holding pen area (Murphy et al., 2002).

• Sprinklers

Sprinkler cooling is a process whereby water droplets are applied to wet the cow’s hair coat to the skin, and fans are used to force dry the cow. Sprinkling does not attempt to cool air as in the case of fogging and misting but instead uses large water droplet size to wet the hair coat to skin. Cooling is accomplished as water evaporates from hair and skin. In combination with forced air, sprinkling increases the loss of body heat over that possible by sweating alone (Nagpal et al., 2005). It is found that cooling using fans and sprinklers improved DM intake by 7 to 9%, milk yield by 8.6 to 15.8%, reduced rectal temperature by 0.8-1.0°C.

• Misters

This system does not work well in humid environments, because the mist droplets are too large to evaporate before they reach the floor and the bed or feed becomes wet. In mist system, the fine mist particles stay suspended in the air and evaporate before being deposited on the ground, thus cooling the surrounding air; some small droplets may be deposited on the hair coat of cattle (Nagpal et al., 2005).

• Foggers

Foggers disperse very fine droplets of water which quickly evaporate and cool the surrounding air, while raising the relative humidity. A ring of fog nozzles is attached to the exhaust side of the fan and then the cooled air is blown down over the.

 

• Desert coolers

Most effective during dry hot conditions.

• Air conditioners

Though it is very effective the cost associated with this facilitates makes this system are rare today.

4. Zero energy cooling

Cows having access to sheds with evaporated coolers had marked higher breeding efficiency than cows having access to only conventional sheds. The milk production is group maintained under cooled shed was 1.8 kg more per head than in conventionally shaded group. The NDDB, Anand has developed a cooling with an estimated cost of Rs. 5000/- per set suitable for 6-8 milch animals. The results of the same system used for cooling Holstein cows are presented in table. It required a power of Rs. 400/- per summer which comes to about Rs. 50/- per animal which results in increase in milk production of about 1 to 1.5 kg per animal per day.

5. Reproductive Management

There should be provision of thermal comfort to heifers, buffaloes and bulls to improve heat detection efficiency. Observation for estrus thrice in a day and at least once during night hours is needed. Close observation of all non-pregnant buffaloes for cervical mucus discharge and its characteristics is important. Artificial insemination during cooler parts of the day and night can be done. Insemination between mid and late estrus with good quality semen should be done. Repetition of insemination in case of prolonged estrus can be done. Cooler environment must be provided for first 15 days after artificial insemination. Breeding of underweight heifers needs to be avoided.

6. Sufficient water

Availability of water is another important issue when minimizing the effects of summer stress. Water must be clean and easily accessible. Water troughs should be cleaned regularly and placed at multiple locations in the barns, holding pens, travel alleys and feeding area. Cows should have water easily available right after milking.

 

7. First aid Treatment

Immediate veterinary aid should be provided to the suffering animal. The animal should be moved to a cooler place, given bath with cold water or wrapped in wet sheets and provided with fan.

 

CONCLUSION

The summer stress impacts on animal performance and profitability, by lowering feed intake, nutrient utilization and production. Summer season is the most detrimental for production in animals especially reared in tropical and subtropical area. Exotic dairy cows are more prone to environmental stress as they have more heat of metabolism. In tropical region, production of the animals can be maintained through nutritional management during heat stress. These strategies include supplementation of monensin, propylene glycol, niacin, yeast, by pass fat as well as sodium bicarbonate.

Heat stress has become a major concern for dairy producers because of the associated decreases in milk production and large economic losses. However, to ensure high standards of welfare for livestock, a broader approach is needed that includes the importance of considering how heat stress may also cause negative affective states and that heat mitigation strategies should, where possible, consider the natural adaptions of cows to aversive conditions. Gaps in the literature highlight the need for research into the pain, frustration, aggression, and malaise associated with heat stress, specifically increased hunger and thirst in the short term and foot lesions and lameness in the long term.

 

REFRENCES

1. Alejandro, C. I., Abel, V. M., Jaime, O. P. and Pedro, S. A. (2014). Environmental stress effect on animal reproduction. scientific research. 4, 79-84.
2. Bernabucci, U., Lacetera, N., Baumgard, L. H., Rhoads, R. P, Ronchi B, Nardone A. (2010). Metabolic and hormonal acclimation to heat stress in domesticated ruminants. Journal of Animal Science. 
3. Dasilva, R. G. (2004). Weather and Climate and Animal Production. In: Huda S and Flesch J (Ed.), pp1-36.
4. Kelly, C. F., Bond, T. E. and Ittner, N. R. (1950). Thermal design livestock sheds. Agric. Engg., 36, 173- 80.
5. Murphy, J. P., Harner, J., Smith, J. F. and Brouk, M. J. (2002). Reducing Heat stress in the Holding pens. MilkProduction.com.
6. Nagpal, S. K., Pankaj, P. K., Ray, B. and Talaware, M. K. (2005). Shelter Management for dairy (a review). Indian Journal of Animal Science. 75(10): 1199-1214.
7. Saini, A. L. and Chandrahas (2013). Shelter Management in Modern Dairying. Agrotech Publishing Academy, India, 196-207
8. W., Boonyaytra, S., Kreausukon, K., Pinyopummintr, T. and Heuer, C. (2006). Modification of Microclimate to improve milk production in tropical rainforest of Thailand. Asian- Australian Journal of Animal Science. 19: 811-815.
9. Yousef, M. K. (1985). Stress Physiology in Livestock. 1. Boca Raton: CRC Press. pp. 67–73.

https://extension.purdue.edu/article/29261