EFFECTS OF HEAT STRESS

 As a result low in feed intake which ultimately effects the production and reproductive ability of animal. Milk production decreases from 20 to 40 percent and milk fat also decreases.

MEASUREMENT OF HEAT STRESS:

 To measure the combined effect of both heat and humidity, we use temperature humidity index(THI).

FEEDING  STRATEGIES :

Following feeding managemental practices are adopted during heat stress.  

(1)  WATER MANAGEMENT:

1^st step is to give abundant water to animal and it is most important nutrient for animal and provision of water to animal consider as most important.

• Water should be fresh, clean and cool
• Water should not be contaminated
• Water should be cleaned regularly
• Research shows that provision of cool water to animal decreases its body temperature and increases feed intake

 (2) ENERGY:

Increase the energy contents of the feed. Because during heat stress feed intake decreases and as a result decrease in availability of energy to the body. To accomplish body need of energy, contents of energy are increase in the diet. And this can be achieved by

• Adding concentrates to the feed
• Level of concentrates should be optimum(should not increases from 55 to 60 percent).
• It should not be increased from mentioned level otherwise it will be harmful because of reduces in fiber contents in diet
• Above from 55-60 percent causes
• Acidosis
• Depressed milk fat
• Decrease efficiency of other nutrients
• laminitis
• Reducing fiber contents in the feed because it produces heat in the body.

DIETARY  FAT MANAGEMENT:

                 Addition of fat to the diet is also an impotent step to increase the energy contents of the diet. Fat is higher in energy than carbohydrates about 2.5 times more energy present in fat than carbohydrates.

Important guidelines for adding fat into diet

• Fat contents should not be exceeds from 6-8% of dry matter
• Thumb rule for addition of fat into diet
• 1/3 of fat already present in feedstuff
• 1/3 of fat comes from oilseeds
• 1/3 of fat comes from rumen bypass or rumen inert fat
• Don not add starch into diet because it minimizes rumen acidosis.

PROTIEN  MANAGEMENT:

During heat stress feed intake decrease so we have to compensate it by increasing CP contents in the feed.

Following precautions are taken:

• Avoid overfeeding of rumen degradable protein(RDP) because this excess protein must be metabolized which results increase in heat production.
• Portion of rumen un-degradable protein(RUP) can be increased up-to 40%
• RUP is more beneficial than RDP
• Research shows that diet should not contain 18%CP with degradable protein more than 60%

CRUDE FIBER  MANAGEMENT:

Fiber present in diet in necessary for proper functioning of rumen. Digestion of fiber produces more heat than concentrates. So reduce the fiber contents in diet(reduce use of forages) of heat-stressed animal.

• ADF should not be less than 20%
• NDF should not be less than 25%

Certain steps should be taken during feeding of dry fodder

• Chaffing of hay and its mixing with total mixed ration(TMR)
• Silage also should be chop and mix with TMR
• We can use wet grains(brewers grains) and silage to make hay wet
• We can also add water to make the dry feed wet to enhance fedd intake
• MINERAL ELEMENTS  MANAGEMENT:

Mineral elements can be added into diet during the period of heat stress.

BUFFERS MANAGEMENT:

Buffers can be added into diet during period of heat stress.

For example sodium bicarbonate, niacin and yeast can be added into diet.

Buffers should be added in diet which is

• High concentrates
• And low fiber contents

     Advantages:

• It helps in utilization of dry matter
• It also helps in maintaining the milk fat

SUCCULENT FEEDSTUFF  MANAGEMENT:

• Succulent fodder can be used to increase feed intake.
• Succulent fodders are those which have high moisture contents .
• Examples are green forages, silage and wet grains like brewers grains these can be added into the diet to increase feed intake during the period of heat stress.

Precautions:

  Succulent fodder spoil rapidly during hot weather, so    

  succulent fodder should be use as early as possible and   

  should clean the fodder bails and bunks.

Summary:

Good manage-mental practices and feeding strategies can reduces the effect of heat stress as a result production of animals will not effected  and there will be no economical loss. Farmer should be prepare before the start of summer season. Farmer should know that animals suffer from heat stress temperature lower than humans. The temperature suitable for humans may not be suitable for the animals.

 Feeding management includes:

• Kept the animals in the shade and protect animals from direct sunlight.
• Provision of extra cooling to the animals by using fans etc.
• Provision of proper amount of water, protein, energy, minerals in the animal diet.
• Feed the animal early in morning or evening to avoid more heat production
• There should not be shortage of feed in the feed bunk
• Feed Bunk space should be adequate
• Feed bunk should be clean properly
• Provision of total mixed ration is better than provision of feedstuff separately.
• Fodder with high moisture contents should be given to animals this will increase feed intake.
• Add water to dry fodder to increase feed intake
• Feed should be given to animal twice a day to reduce heat production.
• Feed additives can be added to avoid from mould growth as a result decrease in secondary fermentation which ultimately decrease heat production.

Table  

 by: MUHAMMAD ARSLAN (11-948)