Animal Improvement II

Back to: AGRICULTURAL SCIENCE SS3

 

Welcome to class! 

In today’s class, we will be talking more about animal improvement. Enjoy the class!

Animal Improvement II

Breeding:

Breeding involves the development of animals by transferring inherited qualities from parents to offspring. This achieved through mating.

Types of breeding

1. In-breeding: this involves the mating of more closely related animals than the average of the population from which they come e.g. the mating of father to daughter, son to mother or brother to sister.
2. Line-breeding: It is closely related or similar to in-breeding. It involves the mating of not too closely related animals e.g. mating between cousins.
3. Crossbreeding: This is the mating of proven quality animals from different breeds. It may lead to an increase in hybrid vigour e.g. the cross between muturu (resistance to trypanosomiasis) and white Fulani (less resistant to disease) to produce a hybrid which combines two good qualities of two breeds.
4. Outbreeding: This is the mating of unrelated individual animals within the same breed.

Outbreeding is the opposite of inbreeding. It produces offspring with greater vigour and productivity.

Advantages of breeding

1. The crossing or mating of superior animals from two different breeds produce an offspring that is superior to the average of either parent. This is called hybrid vigour or heterosis (cross-breeding)
2. Offspring grows more rapidly and is more economical to the rear (cross-breeding).
3. It results in the production of pure breeds or pure lines (in-breeding).
4. It helps to concentrate and preserve specific qualities in an animal (in-breeding).
5. Offsprings produced can withstand variations within the environment (cross-breeding)

Disadvantages of breeding

1. It may result in inbreeding depression, i.e. a reduction in vigour performance (in-breeding).
2. It can also result in a drop in products such as milk, egg, slow growth rate, loss of fertility (in-breeding).
3. It may also result in poor resistance to diseases (in-breeding).

Evaluation

1. Define selection as a method of animal improvement.
2. State three advantages and three disadvantages of selection.
3. Briefly explain the types of selection.

General evaluation

1. What is animal improvement?
2. State five aims of animal improvement.
3. Define selection as a method of animal improvement.
4. State three advantages and three disadvantages of selection.
5. Briefly explain the types of selection.
6. State four factors to consider while carrying out artificial insemination.

Reading assignment

Essential Agricultural Science by O.A. Iwena, pages 378-381

Theory

1. (a) What is animal improvement?         (b) State five aims of animal improvement. (WASSCE 2013 question 8a and b).

2. Write short notes on the four types of artificial selection.
3. Write a short note on the following system of breeding a. In-breeding     b. Linebreeding
4. Crossbreeding (WASSCE 2000 question 8a).
5. State four objectives of animal improvement programmes in West Africa. (WASSCE 2012 question 8c).

 

In our next class, we will be talking about Artificial Insemination.  We hope you enjoyed the class.

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