Breed Selection, Methods and Selection Factors for SS 1

Selection of Breeds

Performance Objectives

By the end of the lesson, students should be able to:

1. discuss the purpose of breed selection;
2. enumerate the types of breed selection;
3. explain the factors to consider in breed selection;
4. select good breed.

Meaning of Breed and Selection

A breed is a group of domestic animals within a species that possess distinctive, identifiable physical characteristics and performance traits which are consistently passed down to their offspring.

Examples of breeds include the White Fulani in cattle, the Large White in pigs, and the Rhode Island Red in poultry.

Selection is the systematic process of choosing outstanding animals from a herd or flock to become the parents of the next generation, while culling or removing undesirable ones.

Through selection, farmers gradually improve the genetic quality of their livestock over successive generations. This process ensures that only animals with superior traits are allowed to reproduce, thereby increasing the overall productivity and profitability of the farm.

Purpose of Breed Selection

Breed selection is a fundamental practice in animal husbandry. Farmers select specific breeds and individual animals for several critical reasons.

The main purposes of breed selection include:

1. To Increase Productivity: Selecting breeds with high genetic potential ensures maximum output of animal products such as milk, meat, eggs, and wool.
2. To Improve Product Quality: Selection helps in obtaining high-quality products, such as milk with high butterfat content, tender meat, or eggs with strong shells.
3. To Enhance Disease and Pest Resistance: Farmers select breeds that are naturally resistant or tolerant to local diseases and parasites, which reduces treatment costs and mortality rates.
4. To Improve Feed Conversion Efficiency: This ensures that the selected animals can efficiently convert the feed they consume into body weight, milk, or eggs, thereby reducing production costs.
5. To Ensure Adaptation to Local Climate: Selecting breeds that can withstand local environmental conditions, such as high temperatures, humidity, or drought, prevents environmental stress and production drop.
6. To Promote Rapid Growth and Early Maturity: Selecting breeds that grow quickly and reach market weight or reproductive age early increases the turnover rate of the farm.
7. To Eliminate Genetic Defects: Systematic selection allows farmers to identify and cull animals with hereditary abnormalities, such as scrotal hernia, cryptorchidism, or jaw deformities, preventing these traits from being passed to future generations.

Types of Breed Selection

Livestock selection operates through different mechanisms depending on whether nature or human intervention drives the process. There are three primary types of breed selection.

1. Natural Selection

Natural selection is the process where environmental forces determine which animals survive and reproduce. In nature, factors such as climate, disease, predators, and food availability act as selective pressures. Only the fittest animals that are best adapted to these harsh conditions survive to pass on their genes to the next generation. This type of selection occurs without any human intervention and takes a very long time to produce noticeable changes in animal characteristics.

2. Artificial Selection (Selective Breeding)

Artificial selection is the conscious and deliberate choosing of animals by humans to breed for specific desirable traits. Farmers and breeders control the mating process to ensure that animals with superior characteristics, such as high milk yield or rapid growth, produce the next generation. Artificial selection is much faster than natural selection and is the primary tool used to develop modern, highly productive commercial livestock breeds.

Common methods of artificial selection include:

1. Mass Selection: Choosing individual animals based solely on their own physical appearance and performance records, without considering their ancestors or relatives.
2. Pedigree Selection: Selecting animals based on the performance and history of their ancestors or parents.
3. Progeny Testing: Evaluating and selecting breeding animals based on the actual performance of their offspring.

3. Genomic or Marker-Assisted Selection

Genomic or marker-assisted selection is a modern, biotechnology-driven method of selection. It involves analyzing the DNA of livestock in a laboratory to identify specific genetic markers associated with desirable traits, such as disease resistance or high meat quality. This method allows breeders to predict the future performance of an animal at a very early stage, even as a newborn or embryo, without waiting for the animal to grow, mature, and express the trait physically. It significantly increases the speed and accuracy of genetic improvement in livestock farming.

Factors to Consider in Breed Selection

When selecting livestock breeds for a farm, several critical factors must be evaluated to ensure that the chosen animals will perform optimally and yield high returns on investment.

The key factors to consider in breed selection include:

1. Animal’s Performance Record: This refers to the documented history of the animal’s productivity. For breeding stock, farmers examine records of growth rate, daily weight gain, milk yield, egg production, litter size, and weaning weight. Animals with consistently high performance records are preferred.
2. Body Conformation: This is the physical appearance, skeletal structure, and body shape of the animal. The conformation must match the production purpose. For example, a dairy cow should have a wedge-shaped body, a deep barrel, and a well-developed udder with evenly spaced teats. A beef animal should have a blocky, rectangular, and muscular frame.
3. Health Status: Selected animals must be in excellent health. They should show signs of vigor, have bright eyes, a smooth coat, alert ears, and be free from infectious diseases, external parasites, and physical deformities.
4. Adaptability to the Local Environment: The breed must be capable of thriving in the specific climatic conditions of the farm. For example, in Southern Nigeria, N’Dama and Muturu cattle breeds are often selected because of their natural tolerance to trypanosomiasis (sleeping sickness) carried by tsetse flies.
5. Age of the Animal: Young, vigorous animals that are close to or have just reached reproductive maturity are preferred. Extremely old animals have declining reproductive capacity and lower productivity.
6. Temperament or Docility: Animals should be calm, gentle, and easy to handle. Aggressive, wild, or highly nervous animals are difficult to manage, can cause injuries to farm workers, and often perform poorly due to stress.
7. Mothering Ability: For female breeding stock, it is essential to select animals with a history of good maternal instincts, high milk production for their young, and low offspring mortality rates.

How to Select a Good Breed of Livestock

Selecting a good breed requires a systematic, hands-on approach combining visual inspection, record analysis, and physical handling of the animals. This practical procedure ensures that only the best animals are introduced to the farm.

The required materials and resources for this procedure are:

1. A livestock farm or livestock market containing various breeds
2. Animal performance record sheets or digital farm records
3. A measuring tape and weighing scale
4. A clipboard, pen, and selection checklist
5. Protective farm wear (boots, overall, and gloves)

The procedure for selecting a good breed involves the following steps:

1. Define the Production Objective: Determine the primary purpose of the livestock enterprise, such as meat production, milk production, or egg production, to guide the choice of breed.
2. Analyze Farm Records: Request and carefully study the pedigree and performance records of the candidate animals. Look for high growth rates, high fertility rates, and consistent productivity in their lineage.
3. Conduct a Visual Distance Inspection: Observe the animals from a distance while they are moving. Check for alertness, active movement, balanced gait, and general body symmetry. Cull any animal showing lameness, lethargy, or abnormal posture.
4. Perform a Close Physical Examination: Approach the animal safely and inspect its body conformation. Examine the head, eyes, mouth, chest, legs, and reproductive organs. Ensure the jaws align properly, the eyes are clear and bright, and the limbs are strong and straight.
5. Inspect the Reproductive System: For males, ensure both testicles are present, well-developed, and equal in size. For females, inspect the udder or mammary system to ensure it is healthy, free from mastitis, and has the correct number of functional teats.
6. Assess the Temperament: Observe how the animal reacts to human presence and handling. Select animals that are calm and cooperative, and reject those that show excessive fear or aggression.
7. Make the Final Selection and Quarantine: Mark or tag the selected superior animals. Before introducing them to the existing herd or flock, place them in a quarantine pen for at least thirty days to monitor them for any hidden diseases.