FARM ANIMAL HUSBANDRY (CONTINUED) ENOTE

WEEK FIVE

SUBJECT: AGRIC SCIENCE

CLASS: GRADE 8

TERM: SECOND

TOPIC: FARM ANIMAL HUSBANDRY

REQUIREMENTS IN ANIMAL HUSBANDRY IN RELATION E.G. CATTLE, SHEEP, GOATS, PIGS’ RABBITS AND POULTRY:  The capacity of an animal to produce differs between species, breeds and strains as a result of genetic factors. However, a complex of inter-related factors in the animal husbandry will influence the animal’s ability to utilize that capacity for growth, development and production.

Progress in breeding and feeding for further increase in production and efficiency can be limited by environmental factors. Research into these factors has therefore been increasing in recent years, especially in countries having intensive animal production. Disease causing organisms in animal husbandry, are transmitted through air, water, feed, insect vector.

Animal housing design is mainly concerned with the physical environment, in particular climatic and mechanical factors, but all should also be considered in order to create a good layout, where healthy, high yielding animals can be provided with correct feeding, can be easily handled and can produce without stress or suffering physical harm.

Heat Regulation: All domestic livestock are homo-therms; that is, they maintain relatively constant internal body temperatures, usually within a 1 to 2⁰C range. Normal body temperatures of some domestic animals and humans are given in the table below;

Animals	Temperature0C
	Average	Range
Dairy cow	38.0	38.0-39.3
Beef cow	38.3	36.7-39.1
Pig	39.2	38.7-39.8
Sheep	39.1	38.3-39.9
Goat		38.7-40.7
Horse	37.9	37.2-38.2
Chicken	41.7	40.6-43.0
Humans	37.0

The body temperature of most domestic animals is considerably higher than the environmental temperature to which they are exposed most of the time. They maintain their body temperatures by balancing internal heat production and heat loss to the environment. The hypothalamus gland acts as a body thermostat by stimulating mechanisms to counteract either high or low ambient temperatures. For example, increased conversion of feed to that energy is used to counteract low ambient temperatures, while for example increased respiration (rate and volume) and blood circulation in the skin counteracts high ambient temperatures.

Most animals reduce their level of activity in a hot environment and for example, pigs lie clustered in a heap at low temperatures, while they lied spread out with extended limbs at high temperatures. Sometimes they require wallow to control their body temperatures. This will suggest increased space requirement for pigs held in a warm, tropical climate. The body can tolerate short periods of heat stress, but if the ambient temperature exceeds the body temperature for an extended period, it may prove fatal.

Temperature: The over-riding environmental factor affecting the physiological functions of domestic animals is temperature. For most farm animals a mean daily temperature in the range 10 to 20 ⁰C is referred to as the “comfort zone”. In this range the animal’s heat exchange can be regulated solely by physical means such as constriction and dilation of blood vessels in the skin, ruffling up the fur or feathers and regulation of the evaporation from lungs and skin.

Humidity: Poultry do not have sweat glands, so all evaporative heat loss must originate from the respiratory tract. Other livestock species have varying abilities to sweat and in descending order they are as follows: Horse, donkey, cattle, buffalo, goat, sheep and pig.

In a hot-dry climate evaporation is rapid, but in a hot humid climate the ability of the air to absorb additional moisture is limited and the inadequate cooling may result in heat stress.

Too low humidity in the air will cause irritation of the mucous membranes, while too high humidity may promote growth of fungus infections. High humidity may also contribute to decay in structures. If possible keep the relative humidity in the range of 40 to 80%.

Radiation: The heat load on a grazing animal can be considerably increased by direct solar radiation and radiation reflected from clouds or the ground. A white hair coat will absorb less radiant energy than a dark, but the heat penetrates deeper in a white, loose coat. Air movements will dispel the heat and reduce the differences. Furthermore, solar radiation may adversely affect the animal’s skin in particular breeds having unpigmented skin. Heat gain by radiation can effectively reduced by the provision of a shaded area.  It must, however, be sufficiently large to allow space between the animals so that the heat loss by other means is not reduced. Grass covered ground in the surroundings of the shade will reflect less radiation than bare soil.

Air Movement: Air movement will assist in heat loss by evaporation and by conduction/ convection as long as the air temperature is lower than the skin temperature. When the air temperature approach the skin temperature  rapid air movements are experienced as comfortable, but at low temperatures it will lead to excessive cooling of unprotected skin areas. In addition air movements are required to remove noxious and toxic gases and to supply the animal with fresh air for breathing. A wind velocity of 0.2m/s is generally regarded as a minimum requirement, but it can be increased to 1.0m/s, when the temperature is nearing the upper critical, or more when it goes beyond that. 

Precipitation: Heavy rain may penetrate the fur of an animal and decrease its insulation value. A strong wind can in such circumstances lead to excessive cooling. However, a naturally greasy hair coat will resist water penetration and with the provision of a shelter for the animals the problem may be avoided altogether.

ASSIGNMENT

OBJECTIVE:

1. Which of the following animals requires wallows to control its body temperature? A. Donkey B. Goat C. Pig D. Rabbit E. Sheep

2. Disease causing organisms in animal husbandry, are transmitted through the following means EXCEPT A. air B. direct contact C. feed D. insect vector E. water  

3. Which of the following operation should be carried out to prevent diseases in farm animals A. Branding B. Castration C. Culling D. Insemination E. Vaccination

4. Career can be developed in agriculture in the following fields EXCEPT A. drilling B. engineering C. fishery D. forestry E. research

5. Which of the following signs may NOT indicate a condition of ill-health in farm animals? A. Change in body temperature B. Increase breathing rate C. Increased water intake D. Loss of appetite E. Weight loss

6. The following are management systems of preventing diseases in a farm animal EXCEPT A. castration B. nutrition C. quarantine D. sanitation E. vaccination

THEORY:

1. List six requirements in farm animal husbandry.