ENVIRONMENTAL PHYSIOLOGY

Subject:

Agricultural Science

Class:

SSS 1

Term:

Third Term / 3rd Term

Week:

Week 9

Topic:

ENVIRONMENTAL PHYSIOLOGY

Previous Knowledge: The pupils have previous knowledge of

   PROCESSES OF EGG FORMATION IN POULTRY

that was taught in their previous lesson.

Behavioural  Objectives : At the end of the lesson, learners will be able to

• Define environmental Physiology
• State the effects of changes in climate on growth, milk production and egg production
• Mention the ways to control rainfall and wind.

Instructional Materials 

• Wall charts
• Online Resource
• Textbooks
• Laptop
• Wikipedia

Methods of Teaching 

• Role modelling
• Questions and Answers
• Explanation
• Discussion
• Recitation
• Imitation
• Story Telling
• Dramatization

WEEK NINE 

ENVIRONMENTAL PHYSIOLOGY

CONTENT   

• Definition
• Effect of changes in climate on growth, milk production and egg production
• Mention two air-borne diseases that affect farm animals.

Environmental physiology refers to the effects of the environment on the growth and performance of farm animals. It is the study of the environment in relation to the response of farm animals. The effects could be high or low in nature. Moderation is the target for optimum growth and performance.

CLIMATE

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

RAINFALL

1. High rainfall increases pests like tsetse. High rainfall causes chilling of young ones
2. High rainfall does favor rearing of dairy animals
3. Extremes of rainfall do not favor growth of grasses for foods

CONTROL OF RAINFALL

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

WIND

1. Wind aids the spread of air-borne diseases e.g. tuberculosis; and death eventually
2. Moderate wind velocity promotes good ventilation.
3. Scare animals producing 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 reduce spermatogenesis and libido in males
3. High temperature causes heat stress and reduced activity.
4. It may result in death of animals; in adult animals e.g birds, young animal e.g chicks and production animals e.g layers
5. It increase water intake in hot weather and reduces water intake in cold weather.
6. It is necessary for incubation of eggs
7. It lowers  yield e.g. lower egg production
8. It affects  product storage  period under high climatic condition
9. High temperature affects the young ones e.g. hatching of egg is reduced.

CONTROL OF HEAT AND TEMPERATURE

1. Introduce fans or air conditioners to animal house.
2. Provide enough windows or opening for ventilation
3. Cover windows with cloth materials to conserve heat
4. Provide vents at the roof tops;
5. Use poor conductors of heat for roofing/ sun reflecting sheets or paint roof with reflecting color 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 body and thus increases their water intake
4. High humidity encourages the spread of diseases
5. High humidity causes feeds to go moldy
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 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 they are 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 includes

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

A favorable climate 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 animal house
3. Used building materials that are poor conductors of heat
4. Painting walls of animal house white to reflect sun rays
5. Construct farm houses east west direction
6. Use mesh in place of 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 favors growth of pathogens, 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, hatch ability, feed intake, and decrease in quantity of egg produced. Light length increases feeding time for birds which may not translate into extra yield.

The topic is presented step by step

Step 1: The class teacher revises the old topic

Step 2: The class teacher introduces the new topic

Step 3: The class teacher allows the pupils to give their own contributions and gives room for pupils” participation

Class Teacher and Pupils Activities. Interaction or Participation 

This involves class teacher and pupils’ interaction, conversation, imitation or modeling through discussion, play method or just by recitation or asking and answering questions that are related to the topic that has just been taught.

EVALUATION QUESTIONS

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 air-borne diseases that affect farm animals.
4. Write short notes on the effect of changes in the following on physiological processes in farm animals a) Temperature b)Relative Humidity c) Light
5. State the ways to control rainfall and wind.

Conclusion : 

The class teacher concludes the lesson by giving the pupils some notes on the topic that has just been taught. He goes round to mark and he does the necessary corrections.