Hi, welcome to this hall on the Effects of Environmental Physiology In Agriculture and the Meaning.
Table Of Contents
- Meaning Of environmental physiology
- Effects of environmental physiology
- Effects of changes in reproduction
- Effects of changes on milk reproduction
- Effects of changes on egg reproduction
Meaning: Environmental physiology can be defined as the effects of the environment on the growth and performance of farm animals. Normal growth and performance are enhanced when climatic factors like temperature, rainfall, wind, relative humidity, sunlight, etc, are moderate. Excess or lack of this factors will definitely have a negative impact on the growth and overall performance on farm animals.
Effects of Environmental Physiology
Effects of changes in climate on Growth: Changes in the climate have some effects on the growth of farm animals. These effects of Environmental physiology on climate includes the following:
1. High temperature of about 39°C leads to proper development of chicks but excess of heat leads the chicks to pant.
2. Extreme of either heat or cold condition is unfavorable and reduces the performance of farm animals.
3. Extreme low temperature leads to retarded growth or even death of chicks.
4. Wind aids the spread of diseases (air borne disease, e.g, tuberculosis) which cause retarded growth or even death of farm animals.
5. High rainfall leads to the multiplication of tsetse flies which transmits tryponosomiasis and such disease reduces the growth or even leads to the death of farm animals.
6. High relative humidity leads to heat stress in farm animals, e.g, cattle, poultry, pig, etc.
7. High relative humidity affect food intake of farm animals.
8. High intensity of radiation affects food intake of farm animals.
9. High humidity in poultry houses causes mouldiness of feeds, thereby leading to low feed intake and retarded growth.
10. Moderate wind velocity promotes good ventilation and this enhances the normal growth of farm animals. Extremes of wind have negative impacts on the growth of animals.
11. Increase in temperature of blood flowing through the brain of birds initiates panting and this in turn leads to water loss through evaporation.
12. In low temperature, mortality in birds increases through hudding or suffocation (asphyxia).
13. At high temperatures also, feather coverage in chicks is poorly developed which may leads to pecking.
14. At high temperature, feed intakes in chicks is reduced, leading to reduced level of growth.
15. At low temperature, there is reduced feed efficiency as more nutrients are needed for body maintenance, leading to poor growth.
EFFECTS OF CHANGES IN CLIMATE ON REPRODUCTION
Changes in climate have some effect on reproduction of farm animals. The effects of Environmental physiology on REPRODUCTION includes:
1. Heat stress, (i.e high temperatures) causes abortion in farm animals.
2. High relative humidity affects the productivity of farm animals.
3. High intensity of radiation causes heat stress in farm animals thus reducing their reproductive capabilities.
4. High temperature leads to low rate of conception or fertilization in farm animals.
5. At high temperature frequency of mating, the quality and quantity of semen in breeder birds decreases.
6. High temperature decreases ovulation in animals.
7. At high temperature, fertility and hatchability in breeder birds decreases.
8. Light control sexual maturity i.e. low light intensity is desirable during rearing of pullets to prevent early sexual maturity.
9. High rainfall and high humidity causes the chilling of Young ones soon after Parturition.
10. High temperature decreases or reduces heat periods in farm animals leading to low reproductive capability.
EFFECTS OF CHANGES IN CLIMATE ON MILK PRODUCTION
Changes in climate have some effects on milk production by farm animals. These effects of Environmental physiology on MILK PRODUCTION includes the following:
1. High relative humidity favours the growth of disease pathogens that can reduce milk production in farm animals.
2. High intensity of radiation from the Sun causes heat stress in animals thus reducing their milk production.
3. High temperature reduces the rate of milk production in farm animals.
4. High temperature and rainfall do not favour the rearing of dairy animals.
5. High rainfall leads to multiplication of tsetse flies which transmit trypanosomiasis in dairy cows; thereby leading to low milk production.
6. Extremes of rainfall do not favour the growth of grasses, leading to low feed intake less milk production by farm animals.
EFFECTS OF CHANGES IN CLIMATE ON EGG PRODUCTION
Changes in climate have some effect on egg production in poultry birds. The effects of Environmental physiology on EGG PRODUCTION includes the following:
1. Temperature
- High temperature causes reduction in feed intake while a low temperature encourages more feed intake.
- It reduces spermatogenesis and libido in males.
- high temperature causes heat stress and reduced activities.
- It increases water intake in hot weather and reduces water intake in cold weather.
- It is necessary for incubation of eggs
- high temperature lowers egg production
- Egg storage period is reduced under high temperature.
- High temperature reduces hatchability of eggs.
CONTROL OF HEAT/TEMPERATURE
- Fans or air conditioner should be introduced.
- Enough Windows or openings for ventilation should be provided.
- vents should be provided at the rooftops.
- windows should be covered with cloth materials to conserve heat.
- Poor conductors of heat should be used as roofings sheets. Sun reflecting sheets can also be used or the roof should be painted with white. Pens should also have ceiling board under the roof.
- Room heaters or lanterns should be used to warm buildings when it’s cold.
- during construction, keep open parts of buildings away from direct solar radiation at (i.e east – west direction).
2. RELATIVE HUMIDITY
- It is very important in incubation of eggs.
- high humidity compounds heat stress.
- low humidity includes rapid water loss from the birds body and thus increases their water intakes.
- high humidity encourages the spread of diseases.
- high humidity causes feed to go mouldy.
Control Of Humidity
- This can be controlled by fixing of humidifiers or open trays filled with water to increase humidity.
- free ventilation should be allowed when the humidity is high.
- spilling of water in poultry houses should be avoided to reduce humidity of dampness.
3. LIGHT
- It controls egg laying in hens.
- duration of lighting controls the time spent at feeding which regulate growth and the rate of feathering.
- direct flight of high intensity causes stress to the eyes.
- bright light makes the birds active.
- light makes object invisible.
Control of Light
- In short day length, extra illumination should be provided.
- A reasonable part of the walls should be made up of wire mesh or glass to promote lighting.
- windows should be covered with dark cloth to reduce light intensity.
Revision Questions
- What is environmental physiology in agriculture?
- What are the effects of changes on milk reproduction?
- What are the effects of changes egg reproduction