ENVIRONMENTAL PHYSIOLOGY

Environmental physiology refers to the effects of the environment on the growth and performance of farm animals.

It is the study of the environment regarding the response of farm animals. The effects could be high or low. Moderation is the target for optimum growth and performance.

CLIMATE

Climate refers to the atmospheric conditions of a place over some time. It is marked by rainfall, wind, temperature, humidity, sunlight, etc.

RAINFALL

1. High rainfall increases pests like tsetse flies and diseases
2. High rainfall causes chilling of young ones
3. High rainfall does favour rthe earing of dairy animals
4. Extremes of rainfall do not favourthe growth of grasses for food

CONTROL OF RAINFALL

1. Shelter
2. Rain break
3. Drainage channels
4. Building orientation

 

WIND

1. Wind aids the spread of airborne diseases, e.g. tuberculosis, and death eventually
2. Moderate wind velocity promotes good ventilation.
3. Scared animals produce an undesirable level of growth hormones.

 

CONTROL OF WIND

1. Shelter
2. Wind break
3. Openings
4. Building orientation

 

TEMPERATURE

1. High temperature causes a reduction in food intake; low temperature encourages more feed intake
2. High  temperature reduces spermatogenesis and libido in males
3. High temperature causes heat stress and reduced activity.
4. It may result in the death of animals; in adult animals, e.g birds, young animals, e.g chicks and production animals, e.g layers
5. It increases water intake in hot weather and reduces water intake in cold weather.
6. It is necessary for the incubation of eggs
7. It lowers  yield, e.g. lower egg production
8. It affects the product storage  period under high climatic conditions
9. High temperature affects the young ones, e.g. hatching of eggs is reduced.

 

CONTROL OF HEAT AND TEMPERATURE

1. Introduce fans or air conditioners to the animal house.
2. Provide enough windows or openings for ventilation
3. Cover windows with cloth materials to conserve heat
4. Provide vents at the rooftops.
5. Use poor conductors of heat for roofing/ sun reflecting sheets, or paint the roof with a reflecting colour, e.g. white. Pens should also have ceiling boards under the roof
6. Use room heaters or lanterns to warm building when it is cold

 

RELATIVE HUMIDITY

1. It is very important in physiological processes, e.g. incubation.
2. High humidity compounds stress.
3. Low humidity induces rapid water loss from animal’s body and thus increases their water intake
4. High humidity encourages the spread of diseases
5. High humidity causes feeds to go mouldy
6. Causes chilling of young ones

 

CONTROL OF HUMIDITY

1. Fixing humidifiers or open trays filled with water to increase humidity
2. Allowing free ventilation when the humidity is high
3. Avoidance of spilling of water to reduce humidity or dampness e.g. in poultry house

 

LIGHT

1. Controls egg laying in hens
2. Duration of lightning controls time spent at feeding, which regulates growth and the rate of feathering, furring.
3. Direct light of high intensity causes stress to the eyes
4. Bright light makes the animals active, e.g. birds
5. Light makes objects visible to animals’ eyes

 

CONTROL OF LIGHT

1. In short daylight, provide extra illumination
2. There should be openings to promote lighting, e.g. use of wire meshing and glass as reasonable parts of building construction.
3. Cover up windows with a dark cloth to reduce light intensity.

 

EFFECT OF CHANGES IN CLIMATE ON GROWTH

The effect of climate on growth could be economically positive or negative to the farmer in that if the climate is extreme (excessively hot or cold), animals will not eat well and thus not grow well or each more and still not grow well. Other instances include

1. Wind aids the spread of disease
2. High rainfall causes more incidence and multiplication of the Tsetse fly and another pest
3. High humidity favours mould growth in pens and also in feed, which could cause diseases

 

A favourable climate, ceteris paribus, should give room for farmers to make optimum gain from their enterprise. To this end, farmers ought to keep things in check, such as

1. Installing fans and air conditioners
2. Plan for good ventilation when constructing an animal house
3. Used building materials that are poor conductors of heat
4. Painting the walls of the animal house white to reflect the sun’s rays
5. Construct farm houses in east-west direction
6. Use mesh in place of a brick wall at some heights
7. Install humidifiers or open trays filled with water to increase or reduce humidity.

And try to control all they can to ensure their investment do not go to waste.

 

EFFECT OF CHANGES IN CLIMATE ON MILK PRODUCTION

Excess sunlight brings about heat stress, high humidity favoursthe growth of pathogens, and milk will spoil at a temperature higher than 37°C. All these causes reduction in milk yield

 

EFFECT OF CHANGES IN CLIMATE ON EGG PRODUCTION

High temperature reduces shelf life for eggs, hatchability, feed intake, and decreases in quantity of eggs produced. Light length increases feeding time for birds, which may not translate into extra yield.

 

EVALUATION

1. What is environmental physiology?
2. Write short notes on the effect of changes in rainfall and wind on growth in farm animals.
3. State two airborne diseases that affect farm animals.

 

GENERAL EVALUATION

1. Write short notes on the effect of changes in the following on physiological processes in farm animals a) Temperature b)Relative Humidity c) Light
2. State the ways to control rainfall and wind.

 

WEEKEND ASSIGNMENT

1. The instrument used to measure the relative humidity is A. thermometer B. anemometer C. hygrometer D. hydrometer

1. Which of the climate factors is likely to have the greatest effect on animal production in Nigeria? A. temperature B. air movement, C. rainfall D. pressure
2. The factors that can predispose animals to diseases include the following, except A. poor housing,g B. malnutrition, C. immunity, D. physical injuries
3. The effects of high environmental temperature on dairy cows include the following, except A. fever B. high feed intake C. high water intake D. low milk production
4. The equatorial rain forest belt is not usually used for cattle production because of the A. low relative humidity B. absence of  natural grasslands C. incidence of Tsetse flies D. dense vegetation

 

THEORY

1. Discuss briefly A. rainfall, B. light C. temperature about poultry production.
2. Write a short note on the effect of temperature on brooding of chicks.

 

See also

REPRODUCTION IN FARM ANIMALS

REPRODUCTION IN FARM ANIMALS

RESPIRATORY SYSTEM

ANATOMY AND PHYSIOLOGY OF FARM ANIMALS

FARM MECHANIZATION