STRESS MANAGEMENT IN POULTRY

There are different types of stressors, namely:

Climatic stress (heat stress and cold stress) Managemental stress (excess light, wet litter and poor ventilation) Nutritional stress (excess salt and low nutrients) Physiological stress(rapid growth, sexual maturity) Physical stress (catching, injection, immobilization and transportation) Social stress (overcrowding, poor body weight) Psychological stress (fear and harsh caretakers)

Among all these types of stressors, environmental stress adversely affects the production performance of commercial poultry.

The thermoneutral zone for laying hens is 55°F to 75°F and is typically higher for

younger, still-growing birds. Temperatures that fall below the thermoneutral zone would be characterized as “cold stress” conditions, while temperatures that exceed the thermoneutral zone would be referred to as “heat stress” conditions.Laying hens require four- to ten-percent less energy in the summer months than during winter because they don’t have to use as many calories to maintain proper body

temperature.

MANAGEMENT OF CHICKS DURING SUMMER

Summer season causes number of deleterious effects on broilers and layers which ultimately reduces profitability. Summer stress a serious concern for poultry producers as it directly leads to financial losses by impaired poultry performance.

 EFFECT OF HEATMost important effect of heat stress is decrease in body resistance and more susceptibility to E.coli and CRD etc. In summer outbreaks of gout may be seen in broilers and layers. In heat stressed birds blood flow increases to upper respiratory tract, skin and abdominal muscles for relieving heat, however, blood flow to intestinal tract is decreased. As a result there is reduction in appetite leading to lower feed intake. Concurrently water intake is

increased resulting in fluid contents in intestinal tract. This further cause’s diarrhea that results in loss of electrolytes needed to maintain acid base balance.CLINICAL SIGNS OR SYMPTOMSThe following clinical signs will be observed in heat stressed birds:

Panting/rapid respiration More intake of water Reduced appetite. Reduction of egg production Poor egg shell quality

THE EFFECT OF HEAT STRESS ON EGG SHELL QUALITYHeat-stressed laying flocks often lay eggs with thinner, weaker eggshells because of an acid/base disturbance occurring in the blood as a result of panting (hyperventilation, gular reflex). As birds hyperventilate to lose body heat, there is excessive loss of CO2 gas from their lungs and blood. Lower CO2 in blood causes blood pH to elevate or become more alkaline. This condition is called respiratory alkalosis. The higher blood pH reduces the activity of the enzyme carbonic anhydrase, resulting in reduced calcium and carbonate ions transferred from blood to the shell gland (uterus). Increasing the amount of calcium in the diet will not correct this problem. Another contributing factor to thin eggshells is reduced intake of calcium as feed consumption drops, and an increased loss of phosphorus

Less body weight gain in broilers Reduced feed efficiency Increase in body temperature Death

POST MORTEM LESIONS Dehydrated carcass Mucoid exudates in mouth and nostrils Pale/cyanotic combs Pale breast muscles Congestion of liver, spleen, kidney and

lungs. Fluid contents in intestines. Rapid decomposition of carcass

STEPS TO COMBAT HEAT STRESS

The aim of adopting measures to combat heat stress is not only to keep birds alive but also to get production out of them to achieve targeted figures i.e. number of egg from layers and a better body weight at particular age with specific FCR in broilers.

Following steps will help to combat heat stress in birds:

Housing Management Water Management Feed Management General Management

HOUSING MANAGEMENT Orient the long axis of poultry house in an east-west direction to minimize solar heating

and direct access to sunlight. Poultry houses in tropics should have good roof insulation (if possible with false roof to

reduce the conduction of heat) with support of foggers and cooler systems. In open sided houses, width of house will be a limiting factor so keep the optimum width

(24-32 ft) based on temperature, humidity and wind velocity, type of house and nature of bird for effective cross ventilation.

Increased air movement over the birds by cooler fans/exhaust to produce a wind chill effect which will cool birds even without drop in the house temperature.

Shed design and construction should not allow direct sunlight on birds. Thatching of roof with paddy straw or sugar cane leaves will reduce temperature inside the

shed. The roof should be painted with white wash to reflect light. Shades from tall trees and plantation around the sheds can reduce the radiant heat. The

plantation of trees should be such that trees will be leafy during summer and bald during winter.

Roof overhangs should be sufficient (3-5 ft) to protect the birds from strong sunrays. WATER MANAGEMENTPractically water is the most important criteria of these four managemental factors during summer. In summer water consumption is 3-4 times more. Even a slight shortfall of water can lead to heat stroke and mortality. Normally feed and water consumption ratio is 1:2 but when temperature shoots beyond 95oF, this ratio may increase up to 1:4 or more.

Points to be taken into consideration:

Supply of plenty of clean and cool water (60-70oF) must be ensured during summer months.

Use good quality sanitizers in water to control infections through water. For day old chicks provide cool water and electrolytes on their arrival to farm before

offering feed to avoid dehydration after transportation. Cover water tanks with wet gunny bags to avoid direct exposure to sun. Increase number of waterers by 25%. Increase frequency of watering. In case of nipple drinkers, insulate nipple pipe with wet gunny cloth. Provide electrolyte (1-2 gm/liter) in water during hot hours.

Addition of 0.25% of salt to drinking water increases water consumption. Adjust the amounts of medications and volumes of water used for water vaccination to

reflect the increase water consumption of the flock during hot weather. Do not withhold drinking water from the flock when vaccine is provided through drinking

water. Use good quality sanitizers in water to control infections through water. For day old chicks provide cool water and electrolytes on their arrival to farm before

offering feed to avoid dehydration after transportation. Cover water tanks with wet gunny bags to avoid direct exposure to sun heat. Increase frequency of watering. Keeping water below 25°C will help maintain higher water intakes and therefore

encourage higherfeed intake. Water temperature above 30°C will negatively impact water intake and have furthernegative impact on feed intake.FEED MANAGEMENT

During summer consumption of feed by birds is reduced considerably leading to reduced body weight, egg production and shell quality.

Increase the frequency of feeding. Do not offer feed during day time in broilers. Certain changes in feed formulations are necessary. Increase nutrient density of feed to compensate for depressed feed intake. Energy of feed should be reduced. Similarly 20-30% extra vitamins and trace minerals should be added to feed. Available phosphorus content of feed should be increased. Vitamin C is necessary to maintain integrity of blood vessels. Supplementation of vitamin

C @ 200-500 gm /ton feed will be beneficial. Vitamin E @ 50 gm /ton feed will also be beneficial. Pelleted feeding is beneficial where low energy fiber diets are used Add soda-bicarbonate @ 0.1% for improvement of shell quality. Since hot humid climate favors growth of moulds/fungi in feed, so constant use of anti-

fungal is recommended. The diet should be balanced with limiting amino-acids, methionine and lysine which will give

better results. Increase the calcium level from 3-3.5% in layer diet.

* Inclusion of vitamin A 8000 IU and vitamin E 250mg /kg diet for better performance and combat heat stress.When formulating the diet for hot weather conditions, there are several things to consider:• Formulate diets using highly digestible materials, particularly protein sources. Metabolism of

excess protein is particularly heat-loading on the bird and exacerbates the ionic misbalance.Formulate to digestible amino acid targets and do not apply a high crude protein minimum in theformula. Synthetic amino acids can reduce crude protein in the diet without limiting amino acidlevels.• Increasing the proportion of energy contribution from highly digestible lipid, rather than starches or proteins, will reduce the body heat production resulting from digestion. This is known as heatincrement and is lowest with the digestion of dietary fat.• The phosphorous requirement increases during heat stress due to increased urinary excretion.Increases of up to 5% should be appropriate under heat stress conditions.• The ratio of chloride to sodium in the diet should be between 1:1 and 1.1:1 in hot weather conditions, with a target dietary electrolyte balance (molar equivalence of Na+ + K+ – Cl-) of about250 mEq/kg. Due to elevated electrolyte loss in hot weather, higher sodium levels may be required(0.02–0.03% more than in non-heat stress conditions). Care should also be given that water is notproviding a significant level of chloride to the birds.• Organic zinc may improve shell quality by assisting the activity of the carbonic anhydrase enzyme, as zinc is a key mineral element of this critical enzyme.• Organic copper may also be helpful, by reducing the negative antagonism between inorganiccopper and zinc sources during digestion.• Do not use nicarbazin (anticoccidial drug) during hot weather, as it can increase heat stress induced mortality.•providing them with a feed that has been fortified with probiotics and prebiotics. When fed together, probiotics and prebiotics work to support the growth of beneficial bacteria in the digestive tract of the bird, which in turn can reduce the population of pathogenic bacteria through competitive exclusion. Feeding probiotics and prebiotics to birds not only aids in the prevention of bacterial infections in the digestive tract, but can also improve production performance and immunity. This is an especially important thing to consider during the stress of the summer months.

GENERAL MANAGEMENT Litter preferably fresh litter of 2 inches thickness with racking or stirring of litter 2-3 times

a day during cool hours is recommended. 10% extra floor space should be provided in summer. Overcrowding of birds should be avoided. Shifting, transportation, de-beaking and vaccination should be done during night or cool

hours of the day. Birds severely heat stressed may be dipped in cold water for 2-3 minutes keeping their neck

and head above water level. Provide proper cross ventilation. Fans (pedestal, ceiling or exhaust) may be fitted in sheds. Use foggers in the shed which could reduce the shed temperature up to 5-10oC depending

upon quality. Use of paint ,white lime etc practically reduces the shed temperature up to 2oC Use side curtain in shed which should be sprinkled with water. Provide 3 exhaust fans on one side and pad cooling on other side (200ft) which completely

seals the shed sides and brings down temperature below 8oC. Use sprinklers on the top or inside shed.

Surround the house with tall trees. Thatched roof is suitable for hot areas.

The house should be situated away from other buildings in order to facilitate free movement of air.Height of roof is ordinarily 2.6 to 3.3 m from foundation to the roof line to provide maximum ventilation.

Provide 1meter overhang to cut the direct sun and rain into the house.LIGHTING PROGRAMS FOR HEAT-STRESSED FLOCKS• Adjust the lighting program to provide more morning light hours (and fewer afternoon light hours)to encourage feed consumption during the cooler period of the day.• Use a midnight feeding of 1–2 hours to provide an additional feeding during the cool of the night to encourage feed intake during hot weather. • In extreme heat stress, lower the intensity of light during the hottest time of the day to reduce bird activity.• Intermittent lighting programs have also been used successfully in heat stress conditions to encourage feed intake..

MANAGEMENT OF POULTRY DURING WINTERWinter season has great effect on poultry production by lowering the temperature of surrounding. During winter when temperature goes down below 55o F, various problems like reduction in egg production, reduction in water intake, reduction in fertility and hatchability etc occurs. Therefore, the management of poultry during winter is an important concern for poultry farmer. Following points should be considered to get better production from poultry during winter season:1. Orientation of house 2. Ventilation 3.Litter management 4.Feed management 5.Water management ORIENTATION OF HOUSE

Poultry house should be designed in such a way to provide all the comfort required by birds during winter. Orientation of a building with respect to wind and sun consequently influence temperature, and light on different external surfaces. In winter the arc of the sun’s visible path is shortened, an east west alignment of a rectangular house provides a maximum gain of solar energy in winter. House should be designed in a way that maximum sun light enters the shed during day time. Birds should be protected from chilled winds, for this gunny bags should be hanged at the places from where the cold air enters. These gunny bags should be hanged down as soon as sunlight goes in the evening till the arrival of sunlight next morning.

VENTILATIONDuring winter season it is necessary to keep the hose draft free but with plenty of ventilation. Birds release a lot of moisture in their breath and droppings which adversely affects their health, if there is restricted ventilation it causes ammonia build up in the air which causes respiratory problems. So, they need plenty of fresh air circulating around the house. For the purpose sliding windows are useful as they can be opened during day and closed during night. There should also be arrangement of exhaust fans to remove impure air. LITTER MANAGEMENTPrior to chick being placed in house, the surface of floor should be covered with a bedding material called litter. It gives comfort to the birds. A good quality litter serves as an insulator in maintaining uniform temperature, also absorbs moisture and promotes drying. It dilutes faecal material thus reducing contact between birds and manure. It also insulates the chicks from the cooling effects of the ground and provides protection cushion between bird and floor. Around 6 inches of litter is needed in houses during winter. The litter gives warmth to the birds during winter. If litter management is proper, it will be felt quite warm when taken in hand.FEED MANAGEMENT

Poultry uses food for two main purposes i.e., as an energy source to maintain body temperature and to carry on normal physiological activities and as building material for development of bones, flesh, feather, egg etc.

The variation in feed consumption is smaller for each degree Fahrenheit change in temperature when the weather is cold than when it is hot. Low temperature causes more feed intake and higher oxygen demand. Therefore, when the weather gets colder, it is essential to give the chicken plenty of food as they require extra energy for maintaining body temperature.

When bird eat more feed, along with energy, other nutrients are also consumed more which are actually not needed and they become a waste. To avoid this wastage during winter energy rich sources like oil/fat should be added to the diet or level of other nutrients may be reduced keeping the energy at same level

In winter number of feeders should be increased as compared to summer. Feed should be available to the bird whole of the day. It has been experimentally

proved that for proper growth of broiler during summer, diet containing 23% protein and 3100 Kcal ME/kg diet is needed. While in winter 3400 Kcal/kg ME and 23% protein is needed.

  WATER MANAGEMENT

SPRINKLER ARRANGEMENTAdvantages :

• Reduces high temperature to prevent heat stress and mortality.

• Reduces heat stress condition, that eliminates negative impact of heat stresson egg size, shell quality and number of eggs produced.

• Reduces temperature by 6° to 7° F or more.

During winter season birds take less water so far maintenance of water in the body, it is necessary to give continuous supply of fresh water which can be taken by the bird.

Water must be fresh and clean. If water is cold enough, then it should be given to chicken after adding hot water to it, so that the water comes to normal temperature.

In ice falling areas, blockage of pipe is a big problem due to freezing of water during winter season. When temperature goes below 0°C routine inspection of pipe line should be done to avoid blockage of water.

Many of vaccines/ medicine/ antis tress vitamins are given to poultry through water. As water consumption of bird is reduced during winter season. Therefore, care should be taken that waterers are removed few hours prior to water medication and medicine/vaccine is given in less amount of water so that birds can consume total water and each bird get benefit of medicine/vaccine or other supplements.VACCINATION CONSIDERATIONS DURING HEAT STRESS• Adjust the amount of medications and volumes of water used for water vaccination to reflect the increased water consumption of the flock during hot weather.• Water vaccinations during hot weather should ideally be administered within one hour.• Use caution when spray vaccinating during hot weather. Newcastle and bronchitis vaccine reactions can occur in birds hyperventilating because of heat stress.• Use caution when water vaccinating a flock during hot weather. Do not withhold drinking water from the flocks during hot weather. It is best to water vaccinate flocks just after the lights come on in the morning.• Postpone vaccinations during periods of heat stress whenever possible. Heat-stressed birds have decreased immune function and may not respond as well to vaccination.• Live vaccines are subject to accelerated deterioration when exposed to high heat. Maintain the refrigeration of live vaccines until the vaccines are administered. Bronchitis and AE vaccines are particularly heat-sensitive and titers can be lost rapidly.

EVAPORATIVE COOLING IN POULTRY SHED

FOGGER SYSTEMThe damages of extreme heat can be devastating. Heat stress causes extreme discomfort to the birds and high temperatures can limit bird growth. Evaporative cooling is a very effective way to reduce heat stress and can drop the temperature inside the poultry house by 7 to 8 degrees Celsius.

FOGGER SYSTEMThe damages of extreme heat can be devastating. Heat stress causes extreme discomfort to the birds and high temperatures can limit bird growth. Evaporative cooling is a very effective way to reduce heat stress and can drop the temperature inside the poultry house by 7 to 8 degrees Celsius.