Animal breeding course

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Lecturer: Abdirahman Awsamire (MSc.) Faculty of Animal Science
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UNIERSITY OF HARGEISA
COLLEGE OF AGRICULTURE, VETERINARY AND ANIMAL SCEINCE
Faculty of Animal science
Program Faculty Animal Science
Courses Title Animal breeding
Pre-requisites Animal genetics
Instructor Abdirahman Awsamire (MSc.)
Course
Description
The scope of this course includes Historical development and modern concepts of
animal breeding. Breeds of livestock and major traits in farm animals; Genetic
parameters: heritability, repeatability, and correlation among traits. Categories of
relationships; Principles and methods of selection (Selection based on records of
individuals, progeny, pedigree, collateral relatives and combination of records
simple selection indices). Mating systems in farm animals; Recording and
standardization of herd records; Breeding programs in the tropics and their results;
Development of new breeds; Principle of nucleus breeding program; Conservation
of farm animal genetic resources:
Course
objective
At the end of the course, the student will be able to:
Describe the historical development and modern concept of animal breeding
Identify and characterize the different breeds of livestock breeds
Understand how to estimate genetic parameters
Describe the categories of relationship and evaluate coefficients of
relationship and inbreeding

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Understand the principles of nucleus breeding program
Identify methods of animal genetic conservation
Understand the principles, types and methods of selection
Describe the nature, opportunities and threats of animal breeding in the
tropics

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ANIMAL BEERING COURSE
1. INTRODUCTION
Animal breeding is the application of principle of Genetics and Physiology of Reproduction for
improvement of the animals. Improvement is betterment of the characters both qualitative and
quantitative over those of the ancestors, over that of the average of family.
Animal breed: breed is group of livestock (animals) with in the species of common origin. They
have certain distinguishing characters not found in members of other group in the same species.
These characters are transmitted to successive generation.
Breeder: Breeder is one who planned and determined the type of mating. For practical purpose
breeder of an animal is a person who owned the dam of that animal at the time of breeding (horse
race course term).
Task of animal breeder: The task of animal breeder is to speed up and control every process of
improvement. A progressive breeder should bring about new combination of genes which are best
suited to his purpose than the existing combinations. Hence he has to learn.
1. Probable genetic make up of his animals through
a. Animals individualities
b. Parentage
c. Performance of their close relatives
2. Combining the favourable characters by
a) Selection
b) Breeding
History of Animal Breeding
Exact date as to when animal breeding was practised is not available from history. The evidences
gathered from the archaeological excavations indicate that the Mediterranean countries (Egypt,
Rome Greece) initiated the animal breeding. Egypt and Arabs are known for the horse breeding.
Arabs in 12th
century considered that dam was important in breeding and not aware of importance of
the sire. At about the same time in Denmark and Holland the cattle breeding was practised by
providing better environment such as feed. In U.K; the royal families in 14th
century considered
performance of horses for selection and breeding. The Earls and Dukes took interest in cattle
breeding and imported the cattle from Denmark and Holland. Until the 18th
century there was no
planned or systematic animal breeding. During industrial revolution in England (1760) the people
started migration from villages to cities. This created a heavy demanded for milk and meat. Robert

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Bake well (1725-1790) an English man is generally acknowledged as great pioneer in Animal
Breeding and father of Animal Breeding.
Bake wells contributions and methods:
1. He had definite ideas, such as beef cattle should be low set, blocky, and quick maturing.
2. He gave more importance to sires by selecting best animals.
3. He started a systematic progeny testing of sires. He lent the good sires to other breeders for
given fee and also insisted that the progeny of the sire should be rared under similar conditions. He
used those males which gave the best progeny in his farm.
4. While breeding best to best he practised inbreeding which led to development of true breeding
stock.
5. He also kept the records of individuals.
In 18th
century pure breeding was preferred and people wanted information on pure bred animals. To
supply authenticated information one Mr. George Coat in 1822 opened the Herd Book for Short
Horn cattle. It was followed by opening of Herd books for most of the breeds by middle of 19th
century. The first association of farmers for milk recording was formed in Denmark and followed by
all other milk producing countries.
Modern History of Animal Breeding
BREEDING ANIMALS
AGRISCIENCE AND TECHNOLOGY
TERMS USED IN BREEDING ANIMALS
BREED: Breed is made up of animals of the same species that share common traits.
BLOODLINES: Bloodlines are groups within breeds; tend to have one common
ancestor.
PUREBRED: Animals registered in a breed or eligible for registry.
INHERIT TRAITS OF ANIMALS
COLOR
MILK CAPACITY
HORNS
SIZE
TYPE

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OFFSPRING THAT HAVE TRAITS GENETICALLY DIFFERENT FROM THEIR PARENTS ARE
KNOWN AS MUTANTS.
BREEDS OF CATTLE
ANGUS: Originated in Scotland. Black, polled and have a smooth coat of hair.
BRAHMAN: Originated in United States. Light gray to nearly black, loose skin and
large humps over the shoulder; tolerant of heat and insects.
BRANGUS: Developed by crossing Brahman and Angus cattle. Solid black and polled.
CATTLE BREEDS CONT.
CHAROLAIS: Originated in France. White to a light straw color; large breed, most are
naturally horned.
CHIANINA: Originated in Italy. White except for the switch of the tail, which is
black; skin has a black pigment. Largest beef breed.
HEREFORD: Originated in England. White face and red bodies. A horned breed.
CATTLE BREEDS CONT.
POLLED HEREFORD: Developed in the United States. White face and red bodies;
polled.
LIMOUSIN: Originated in France. Most are red but may be light yellow or black.
They usually have horns.
SANTA GERTRUDIS: Developed by the King Ranch in Texas. Cherry red, usually
horned and have loose hide. Crosses of the Shorthorn and Brahman breeds.
BEEF BREEDS CONT.
SHORTHORN: Originated in England. Red and white, with a red-white mix (roan),
have horns except for the Polled Shorthorn breed.
SIMMENTAL: Originated in Switzerland. Faces are white/light straw and their
bodies are red to dark red.

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DAIRY CATTLE BREEDS
AYRSHIRE: Originated in Scotland. Red, mahogany, brown or white in color.
Rank third in milk production (11,700 lbs. per year with 4.0 % milk fat).
BROWN SWISS: Originated in Switzerland. May be any shade of fawn with white
markings. Rank fourth in milk production (10,600 lbs. per year with 5% milk fat).
DAIRY BREEDS CONT.
GUERNSEY: Originated off the coast of France. May be any shade of fawn with
white markings; horns turn outward and toward the front. Tied for fourth in milk
production (10,600 lbs. per year with 5% milk fat).
HOLSTEIN: Originated in the Netherlands. Black and white color patterns. Rank
first in milk production (14,500 lbs. per year with 3.5% milk fat).
DAIRY BREEDS CONT.
JERSEY: Originated on the Isle of Jersey. Color range from cream to almost black.
Ranks fifth in milk production (10,000 lbs. per year with 5.4% milk fat). Smallest of
the dairy breeds.
SWINE BREEDS
AMERICAN LANDRACE: White breed with ears drooped over the eyes. Produce
large litters of pigs.
BERKSHIRE: Black with six white points: each foot, some white on the face and a
white tail switch; erect ears.
CHESTER WHITE: White breed; popular in the northern parts of the United States.
=

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SHEEP BREEDS
FINE WOOL SHEEP - Rambouillet, American Merino, Delaine Merino and Debouillet.
MEDIUM WOOL SHEEP - Cheviot, Dorset, Finnish Landrace, Hampshire, Shropshire,
Southdown and Suffolk.
LONG WOOL SHEEP - Cotswold, Leicester, Lincoln and Romney.
SHEEP BREEDS CONT.
CROSSBRED WOOL SHEEP - Columbia, Panama and South dale.
GOAT BREEDS
MOHAIR AND CASHMERE - Angora; most of these are grown in Texas and other
southwestern states.
DAIRY GOATS - LaMancha, Nubian, Saanen and Toggenburg.
POULTRY
Poultry includes chickens, duck and turkey. Other poultry animals include quail,
guinea, ostrich and emu.
Most common breeds of chickens are White Leghorn, White Rock, Rhode Island Red,
Barred Rock and New Hampshire.
Chickens are selected for one of two uses: eggs and meat.
AQUACULTURE
Term used to describe the farming of fish.
Examples include: catfish, trout, tilapia, hybrid striped bass, shrimp, oyster, crawfish,
red fish, snails, crabs, alligators and frogs.

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KINDS OF BREEDING SYSTEMS
STRAIGHTBREEDING: Mating of animals of the same breed.
Different approaches of straight breeding include purebred breeding (mating purebred
animals), outcrossing (mating animals of the same breed but of different families in
the breed) and inbreeding (mating animals of the same breed with closely related
animals).
BREEDING SYSTEMS CONT.
CROSSBREEDING: Involves mating animals of different breeds.
Used to improve the quality of the products yielded by the offspring.
Used to produce calves with more meat, no horns or to accomplish other specific
genetic purpose.
PUREBRED PRODUCTION SYSTEM
Used to produce purebred animals that will be used for meat, milk or other purposes.
May compete in shows.
Raise both male and female animals.
Must keep accurate records.
MEAT-ANIMAL PRODUCTION SYSTEM
COW-CALF PRODUCTION - Involves keeping cows to produce calves that are
used for meat.
Calves are weaned at about 500 lbs.

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METHODS OF INSEMINATING LIVESTOCK
NATURAL INSEMINATINATION - Involves using animals to mate in pastures or
pen breeding.
ARTIFICIAL INSEMINATION - Involves collecting semen from a male and
depositing it in the reproductive tract of the female.
ADVANTAGES OF USING AI
AI allows the use of semen from superior males that are owned by another party.
AI makes it possible for a male to breed many more females than could be done
naturally.
* Semen can be stored for a week at 41F or for several months frozen at -320F (liquid
nitrogen).
IMPORTANT INFORMATION IN BREEDING ANIMALS
SPECIES AGE/BREED GESTATION
COW 14 MONTHS 283 DAYS
SOW 12 MONTHS 114 DAYS
EWE 17 MONTHS 148 DAYS
DOE 18 MONTHS 151 DAYS
MARE 2-3 YEARS 336 DAYS

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ESTRUS SYNCHRONIZATION
Involves using hormones to get several females to come in heat at the same time.
Used when using advanced breeding procedures such as superovulation (getting the
female to produce a number of eggs at one time) and embryo transfer.
PREGNANCY TESTING
BLOOD TEST
URINE TEST
RECTAL PALPATION (MOST COMMON METHOD USED)
“BUMPING”
SIGNS OF PREGNANT FEMALES GOING INTO LABOR
ENLARGED UDDER
SWELLING OF THE VULVA
HOLLOWNESS IN FRONT OF THE PIN BONES
NERVOUSNESS
GOING AWAY FROM THE HERD
GIVING BIRTH
Most animals give birth without assistance.
Calves should be born within one hour after labor begins.
Calves are normally delivered with the head between the two front legs.
Cow may need assistance if calf is in a different position.
AFTER THE BIRTH
It is very important that the calf gets the first milk known as “colostrum”.
Colostrum is high in antibodies and other substances that help the new animal survive.

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Animal should expel the placenta 3-6 hours after giving birth.
1.1. Breeding of Dairy Cattle
1.1.1. Selection Methods of Dairy Animals
This selection is based on information available on the ancestors like
parents, grandparents and great grandparents. The contribution beyond
three generations is not much to be considered in pedigree selection.
Pedigree selection enabled selection at an early age, and selection of
males which do not express the traits like milk production through they
transmit the genes for the traits.
Individual Selection:
Selection is based on the individuals own milk vein, teats, pelvic cavity
and udder. This is ideal for characters with high heritability. Where as in
dairy cattle most of the economic traits have low to moderate
heritability.
Family Selection:
Where families are selected or rejected as units according to the
phenotypic value of the family. The families may be full sibs or half
sibs.~ The method is useful when the character for which selection is
made has‟ low heritability. Two modifications of family selection
applicable to dairy; cattle are sib selection and progeny testing.

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Sib Selection:
This is a type of a selection where in the selected individuals do not
contribute to the family means. This applies to selection of males which
do not express the characters and selection of females at an early age.
Progeny Testing
The criteria of selection is the mean value of an individual‟s progeny,
which comes close to the breeding value. The value of an individual is
judged by the mean value of its progeny known as breeding value. It is
equal to the sum of average effects of genes;, the individual carries.‟
Progeny testing prolongs the generation interval. As the bull had to wait
its progeny test result before „its use, but it is more than made up by the
increase in accuracy of selection. A higher intensity of selection is also
possible by employing Artificial insemination with pedigree semen.
Culling of Dairy Animals:
Culling is elimination or weeding out of undesirable animals from the
herd for reasons of uneconomic, poor production, or very poor
reproductive ability, with sterility problems and breeding, irregularities,
very poor conditions, stunted growth, suffering from incurable illness, or
disease animals found to be positive for serious infectious diseases like
Tuberculosis, Johns disease, Brucellosis, lost one or more quarters and
teats of the under due to chronic mastitis resulting in marked reduction
in milk production. Undesirable breed characters present in young
animals.
When the herd is a pure bred herd leading to disqualifications family
lines, exhibiting heritable characters like supernumerary teats, loose
horns in cows of certain breeds. Disable animals due to injury or loss of

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organ, extreme lameness leading to unmaintainable conditions, unhealed
fractured animals etc., come under the animal proposed or culling. The
culled animals carry lower values and a separate list is made for such
called animals and it is known as culling list.
When the culling cows for poor production, the entire lactation yield is
considered and preferably first two lactations are observed and if the
lactional yield is less than what is expected from the breed or herd, the
animal is included in the culling list.Very old animals are culled, as their
maintainance will be uneconomical. Male animals or other animals
surplus in the farm or not useful in the farm and they are culled. Calves
born much below the normal birth weight are included in the culling.
Yearlings animals male or females, stunted much below their normal
body weight, bad confirmation are culled.
Valuation and culling is done on the farms every year at least once in
year. In some farms culling is done twice a year however doing it once a
year is must.

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1.1.2. System of Breeding
Breeding is defined as the crossing of the male and the female parents to
get the off spring for the characters desired. The main breeding methods
are
1) In breeding 2) Out Breeding
Inbreeding:
Inbreeding is the mating of closely related individuals, whose
relationship is more than the average relationship of the population. The
example is the individual having one or more common ancestors or
relatives. The measures of inbreeding is the coefficient of inbreeding. In
breeding may be mild, or close inbreeding and line breeding.
Close Inbreeding:
In this type is inbreeding mating is made between very closely related
individuals such as full brothers are crossed with full sisters, or
offspring‟s are crossed with parents.
Advantage of Inbreeding:
i. Undesirable recessive genes may be discovered and eliminated by
further testing in this line.
ii. The progeny are more uniform than and breed progeny. It
increases homozygosis and decreases genetic variance.
iii. Breaking down of population into different inbreed lines.

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Disadvantages:
i. The progeny becomes more susceptible to diseases.
ii. Breeding problems and reproductive failure usually increases.
iii. It is difficult to find out the stereo breeding at which it should be
discontinued, in order to avoid the bad effects of the system.
iv. It depresses‟ vitality in early life than in later life.
v. A small breeder stands a good chance of gain by doing too much in
breeding. A rule to follow is never to inbreed more than 12 % and
then only in exceptional cases.
vi. In breeding appears to have little value in dairy cattle breeding
programs, because of its numerous detrimental effects.
Line Breeding:
It is repeated back crossing to one outstanding ancestor, so that its
contribution to the progeny is more. In this type of breeding mating are
made to concentrate, the inheritance of desired characters of some
favored individuals.
i. It brings about the uniformity of the required type.
ii. The dangers involves in case in breeding can be reduced.
The breeder will select the animal for its pedigree giving due
consideration for the individual merit. This may result in very little
benefit in new generation, in some case having the benefit.

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Outbreeding:
It is the opposite of inbreeding. Mating unrelated animals is known as
out breeding. It is divided into six classes as detailed below;
1. Pure breeding
2. Line Crossing (Crossing of inbreed lines)
3. Out Crossing
4. Cross Breeding
5. Grading up
6. Species Hybridization
Pure Breeding:
It is mating of male and female belonging to the same breed. Pure
breeding is a sort of out breeding. The examples of pure breeding are
Jersey Cow -x Jersey Bull
The outstanding advantage of pure breeding is for production of bulls for
breeding purpose only pure breeding is to be followed in almost all the
breeds except in case of inter-se-mating. It avoids mating of closely
related individuals.
Cross Breeding:
It is mating of animals of different breeds. Cross breeding is followed
for breeding animals for milk production and meat production. Zebu
breeds of cows and nondescript cows are crossed with exotic breeds like
Holstein Fresian, Brown Swiss and Jersey bulls or their semen, to
enhance the milk production potential of the progeny.

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Advantage:
1. The desirable characters of the exotic parent are transmitted to the
progeny which the indigenous parent does not have.
2. In India Cross-breeding and cows is done by using the exotic bulls
and the progeny inherit the desirable characters of the parent like
high milk yield early maturity, higher birth weight of calves, better
growth rates, better reproductive efficiency and indigenous parents
characters like, heat tolerance, disease ability to resistance
3. In pairs the way to evolve new breeds with desirable characters.
4. Hybrid vigor is made use. Of in the progeny
5. Results are seen more quickly in characters like milk yield in the
cross bred progeny.
Disadvantages:
1. The breeding merit of cross breed animals may be slightly reduced.
2. Cross breeding requires maintenance of two or more pure breeds in
order to product the cross breeds.
• Dairy Cattle Production and Management Part

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Chapter 3: Breeding Programs
The aim of animal breeding is to genetically improve populations of livestock so
that they produce more efficiently under the expected future production
circumstances. Genetic improvement is achieved by selecting the best individuals
of the current generation and using them as parents of the next generation. To
select the best animals one needs to define explicitly what is meant with "best".
This means that it is necessary to specify the direction in which we want to change
the population. Defining the breeding goal is the first step when designing a
breeding program. It is useless to design a breeding program if there is no idea of
the desired genetic change.
NB. A breeding program is the organized structure that is put into place to
genetically improve livestock populations.
Successful genetic improvement requires breeding programs to have (at least)
the following components:
 A system to record data on selection candidates. Without data on selection
candidates it is impossible to identify the best individuals.
 Methods and tools to estimate the genetic merit (breeding value) of selection
candidates. This step is called the "breeding value estimation".
 A system to select the animals that become parents of the next generation, and
mate them to produce the next generation.
 A structure to disseminate the genetic improvement of the breeding program
into the production population. In most cases, the breeding population and the
production population are (partly) separated. Since the aim is to improve
livestock production, genetic improvement created in the breeding population
should be disseminated into the production population.

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6.1. The breeding goal
The breeding goal, or breeding objective, is the starting point of animal breeding.
Broadly speaking, the breeding goal is the direction in which we want to improve
the population. The choice of the breeding goal affects the structure of breeding
programs. Broiler (chicken for meat) breeding programs for example differ from
layer (chicken for egg production) breeding programs because improvement of egg
production requires another breeding program than improvement of meat
production.
The breeding goal has a number of characteristics.
1. The breeding goal is a combination of traits. It specifies the relative
importance of each trait. In principle, all traits of importance should be included in
the breeding goal. Thus the breeding goal only depends on the importance of a
trait, not on its genetic parameters. An important trait of low heritability should be
included in the breeding goal, whereas unimportant traits should be left out,
irrespective of their heritability.
2. The breeding goal should aim at the future. Animal breeding is a long-term
activity. It takes a long time before genetic improvement due to selection is
expressed in the production population.
3. From an operational point of view, the breeding goal should ideally
summarize all traits in a single criterion. A single criterion to express the
quality of selection candidates is convenient because animal breeders can
simply rank their selection candidates on this value and select the highest-
ranking individuals. A breeding goal expressed as a single value can be
obtained by weighting all traits by an (economic) factor, so that the breeding
goal is a sum of breeding values weighted by their (economic) value.

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Questions should be raised in developing breeding programs are like:
 what market the breeding goal is aimed at;
 whether the breeding goal should be based on the competitive position of the
breeding company or on an economic model of the production herds
 Existence of political or market circumstances such as production quota that
affect the breeding goal.
In Western countries, breeding goals primarily include economically important
traits such as milk yield, meat production and egg production. In addition, breeds
are often specialized for a single purpose; dairy breeds are kept for milk
production and beef breeds for meat production, layers for egg production, broilers
for meat production. In developing countries however, the situation is quite
different, because livestock is often kept for auto-consumption and not to produce
for a particular market.
==========================Message==========================
NB. The breeding goal specifies which traits should to be improved, in which
direction and the relative emphasis given to each trait.
=============================================================
In animal breeding, there are two common approaches to define breeding goals.
The first approach is to express breeding goals as a weighted sum of economic
values and breeding values. In this approach, economic weighting factors of traits
(economic values) are based on an economic model of the production system. The
second approach is to express the breeding goal as a set of desired gains for each
trait. The desired genetic gain for each trait is based on marketing and commercial
considerations of breeding companies. In many cases, desired gains are based on
maximizing the market share of the breeding company in the time frame.
Breeding goals based on economic models of the production system:

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When breeding goals are based on an economic model of the production system,
the economic value for each trait is determined by modeling the effect of that trait
on the profit of a production herd.
NB. Breeding goals can be expressed in terms of economic values, which
express the increase in profit due to a single unit improvement of a trait, or as
desired genetic gains.
6.3. Design and evaluation of breeding programs
Design of breeding programs: The structure of breeding programs depends on
both the species and the breeding goal. The optimum design of a breeding program
will differ between species with large reproductive capacity and species with small
reproductive capacity, between breeding programs that aim to improve production
or reproduction traits, and low heritable traits versus high heritable traits. The
question whether the breeding goal traits have high or low heritability is
important. In the case of high heritability, (pure line) selection is an adequate tool
to genetically improve the population. When breeding goal traits have low
heritability, it will be more difficult to improve them by means of selection, and
crossbreeding may be a solution.
For traits where selection is the best option, the next question is whether breeding
goal traits are favorably correlated. If breeding goal traits show a strong but
unfavorable correlation, then it will be difficult to improve them within a single
population. In that case, the development of separate sire and dam lines may be a
solution. When separate sire and dam lines are the best option, then the final step is
to choose or develop separate lines and to optimize selection within those lines. On
the other hand, if breeding goal traits are favorably correlated then they can be
improved within a single breeding population by means of index selection.
The final step is then to optimize the breeding scheme, which involves questions
related to the size of the population and the data recording strategy.

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Judging the quality of breeding programs
Choosing the best breeding scheme among a number of alternatives requires
yardsticks to measure the quality of breeding schemes. Such yardsticks can be
developed only when there is a well-defined breeding goal.
Given that the breeding goal is clearly defined, there are three criteria that
summarize the quality of a breeding program.
These are:
1. Selection response for the breeding goal.
2. Maintenance of genetic diversity as measured by the rate of inbreeding.
3. Costs of the breeding program.
1. Selection response for the breeding goal traits is the revenue of a breeding
program, whereas loss of genetic diversity and financial costs are the expenses of
a breeding program. Selection response, loss of genetic diversity and financial
costs are expressed in different units. The problem therefore is to combine them
into a single criterion for the quality of a breeding program.
A comparison of breeding schemes based on selection response and the rate of
inbreeding can be done as follows. To avoid long-term loss of genetic diversity an
upper limit can be set to the rate of inbreeding.
Next, alternative breeding schemes can be judged by comparing their selection
response at the same rate of inbreeding. The scheme with the highest selection
response at the same rate of inbreeding (e.g. 1%/generation) is the best scheme.

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Evaluation of breeding programs:
Once a breeding program is operational it is essential to routinely evaluate the
results. Evaluation may consist of comparing realized genetic improvement and
rates of inbreeding with values expected when designing the breeding program.
When there are clear differences between expected and realized selection response
and inbreeding, then one needs to find the causes of those discrepancies and if
possible improve the breeding program.
Reasons that breeding programs do not yield the expected genetic improvement
are:
a) the use of inappropriate models for breeding value estimation, for example
when the models do not include systematic environmental effects that are
present in the data;
b) overestimation of the genetic parameters (e.g. h2
) resulting in biased EBVs
and overprediction of the expected response;
c) preferential treatment among selection candidates resulting in selection of
individuals that received good treatment" instead of genetically superior
individuals, and
d) unexpected correlated response in other traits.
==================================Message==================
================
The quality of alternative breeding schemes can be judged by comparing
selection response, rate of inbreeding and costs of the alternatives.
2. BREEDS OF LIVESTOCK AND THEIR MAJOR TRAITS
General characteristics of Somalia Livestock
A. Diversity in livestock types:
Ethiopia has a diversified topographic and climatic condition. Within this
diversity, various livestock breeds or types have evolved; however, there

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are no detailed studies on the identity of each type and their genetic
potentials.
Classification of Ethiopian Livestock:
I) Cattle: generally classified in to four main groups
1. Humpless: Brachyceros sheko (mitzan, Goda) Bench Zone: Hamitic long
horn-Kuri (Kouri)
2. Zebu cattle: Arsi, Borana, Barca, Jijiga small zebu,
Harar short horned, Jem Jem black, Bale highland zebu and various small
short horned types.
3. Sanga: Abigar, Danakil (Afar, Adal, Raya-Keriyu), Raya-Azebo(Oromo-
Azebo)
4. Intermediate sanga-Zebu cattle: Arado, Fogera, Horro and Jiddu.
General characteristics of Zebu cattle:
Hump: Differ in size depending on breed, age, sex, fatness.Function of
hump is not well known in all the breeds. Body: Body is usually narrow
with sloping rump. Legs: are usually long to keep the distance between the
body and ground more so as to avoid heat of the ground. Heat tolerance:
Because of low basal metabolic rate, low growth rate, less yield they
generate less of internal heat. They have more capacity to dissipate heat by
conduction and evaporation. They have short sleek coat, high surface area
to body mass ratio and high number of sweat glands. Tick resistance: They
are partially resistant to ticks and they have the ability to repel the flies by
movement of their skin. Nutritional requirement: They have low nutritional
requirement because of small size, low basal metabolic rate. They are
highly efficient in digestion of low level of feeding (low quality feed).
When there is shortage of feed and bad living condition smaller animals are
superior to larger animals. Productivity: Late maturity, longer inter calving

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period, shorter lactation length, poor yield and failure let down milk with
out calf. However milk contains higher percentage of fat and solid-not-fat.

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II) Sheep: Ethiopian sheep types are classified into 3 main groups,
based on hair type and tail or rump type.
Classification Breed Geographic distribution
Hairy thin
tailed
Bonga, Horro Kefa, Wollega
Fat tailed Menz, Arsi Bale,
Tukur
North-Shewa, Arsi and Bale, Wello
Fat rumped Black head Somali,
Adal
Hararghie, Somali, Afar Sidamo, Bale,
Wello, Shewa
III) Goats:
Using various characteristics such as size, color, horn etc. the following
classification is done.
Breed Geographic distribution
Oromo – Sidamo Southern Shewa and Northern Sidamo
Arsi – Bale (Gishe) Highlands of Bale and Harargie
Somalli Ogaden, Mudugh,
Borana
Ogaden and Elkere (Somali)
Adal (Afar, Danakil) North rift valley in wello and Afar
Bati South west wello, Western Ethiopia
Dinka Southern Ethiopia
Southern Abyssinian Wello Mule

27
IV) Camel: There is no classification work, but they are one humped
(Dromedaries)
V) Horse: Classified in to two, 1. Oromo Horse, 2. Dongola
VI) Donkey: classified into four: Jima donkey, Abyssinian donkey,
Ogaden donkey and Sennar donkey
VII) Mule: Two groups: Sennar mule and Wello Mule
VIII) Chicken: No detailed classification work
Livestock in Ethiopia are generally poor for most of the economic traits
e.g. Milk, meat, power Production egg etc. Livestock do have multi-
purpose use
Cattle - Draft power, milk, meat, hide, manure
Sheep – Hair, meat, skin and milk in some area
Goat – Meat, milk, skin,
Horse – Draft power (ploughing and pack) and transport
Donkey – Draft power as pack and transport
Mule - Draft power as pack and transport
Camel – For milk, meat and pack and transport
Poultry – Egg and meat

28
Ethiopian cattle
Group Zebu Sanga Intermediate
Example –
Breed
Related types
BORAN
Somali Boran, Tana
land Boran, Kenya
Boran
DANAKIL
Adal
Cattle of Jibuti
ARADO
Tigre, Wellega,
Borica
Bileri
Origin habitat Borana
(province of Ethiopia)
Ethiopia (South east)
(long horned sanga)
Low land and semidesert of
Eritrea.
Rared by Afar and Danakil
tribes.
North –east Amhara
of Ethiopia.
Functional traits
Birth wt
Weaning wt
Mature wt
25 kg.M : 23 kg F
170 kg
318 –680 kg. M. 250-
450 kg F
-- --
-- --
250-375 kg.M 200-300 kg.F
----
-----
----
Dressing % 54-75% V. high -- --- ------
Milk yield
Fat
L.L
454-1814 kg
4.1-6.8%
139-303 days
200-300 kg
6.8%
160-225 d.
---
---
----

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The following points of comparison bring out the chief differences between
Bos taurus and B. indicus cattle:
European (B. Taurus)
cattle
Zebu (B. indicus) cattle
1. No hump 1. Hump present in thoracic or cervico-thoracic
region.
2 . Rounded ears, held at right
angle to the head.
Long drooping ears, pointed rather than
rounded
3. Head short and wide. Long and comparatively narrow head.
4. Skin held tightly to body.
Dewlap, umbilical fold and
brisket small.
Skin very lose, often falling away from body
in folds
Dewlap, umbilical fold and brisket
extensively developed.
5. Skin relatively thick, (7-8mm) Skin relatively thin, average thickness 5-6
mm.
6. Large amount of
subcutaneous fat especially in
mature animals.
Relatively small amounts of subcutaneous fat
at all stages.
7. Back line straight or relatively
straight.
Back line high at shoulders, low behind
hump, high over pin bones, sloping down
markedly over tailbud
8. Hip bones wide and
outstanding
Hip bones narrow and angular.

30
Certain of the above differences have probably been reduced as a results of
artificial selection, particularly animal breeding by man, since the species
was domesticated. Thus, items 7, 10, 16 and 19 have probably been
modified, to a greater or lesser extent, by man. Certain of the features noted
are of little or no significance with respect to productive performance or the
adaptation of the species to its environment. However, the majority of the
factors listed are of great importance in one or other of these respects.
3. VARIATIONS AND ESTIMATION OF GENETIC PARAMETERS
Genetic and Environmental variation
The variation is raw material on which a breeder works to produce
genetically superior animal. The variation noticed in any matric
(quantitative) trait arise from two sources
Genetic variation: Variation because of particular combination of genes.
The genetic variation noticed among animals is transmitted to next
generation and any improvement made is permanent important. The genetic
variation is caused by Number of loci involved. Exact number of gene loci
involved for any quantitative trait is not known. Even if you take one locus
possible type of gametes and genotype of progeny is enormous. The
recombination of genes due to crossing over leads to several types of
gametes. e.g.(with one locus)

31
5.1. Current Situation of Somalia Animal Genetic Resources (AnGR)
Somalia Farm Animal Genetic Resources are mostly underutilized biological
resources
Farm Animal Genetic Resources of Somalia:
In Ethiopia, classification of farm AnGRs into breeds is far from complete.
Classification studies have been conducted on most of the cattle and goat breeds
that exist in the country. However, research is at its rudimentary stage for the other
species, particularly chickens. Therefore, the list of breeds presented below should
be viewed from this perspective. The most common farm animals of the country
can be categorized into mammalian, avian and honeybee species. Cattle, sheep,
goats, camels, donkeys, horses and mules are the major farm animals that lie under
the mammalian category
Populations Types/ subtypes
/breeds?
44.32 million Cattle---------------25 types or sub-types
23.62 million Sheep------------------13 types or sub-types
23.32 million Goats-----------------15 types or sub-types
6.06 million equines------------------- (4donkey, 2horse, 2mule)
2.31 million Camels---------------------4 types or sub-types
42 million chickens--------------------------5 types or sub-types

32
Cattle breeds
Indigenous breeds: major cattle breeds identified so far are Arsi, Begayit,
Ogaden, Borena, Goffa, Arado, Nuer, Gurage, Jidu, Karayu/Afar, Harar, Horro,
Smada, Fogera, Mursi, Raya-Azebo, Adwa, Jem-Jem, Sheko, Ambo, Jijiga,
Bale,Hammer, Medenece and Abergelle.
Medenece and Abergelle are recently reported by the Tigray Regional Bureau of
Agriculture and Natural Resources Development to exist in that part of the country.
Since there has not been any exhaustive identification and characterization work, it
is possible that new breeds are to be described yet. Out of 25 indigenous cattle
breeds, the Borena, Horro, Fogera, Karayu, Arsi and
Nuer are the widely used breeds.
Sheep breeds
Indigenous sheep breeds: Fourteen Ethiopian sheep populations are traditionally
recognized as sheep breeds. Microsatellite DNA-based analysis revealed that some
breeds could not be separated at the genetic level, resulting in six genetically
distinct breed groups. In Table 5.1 breeds and breed groups are listed.

33
Table 5.1. Traditional breeds, breed groups, ecology of Ethiopian/somalia sheep
Exotic sheep breeds: Exotic sheep breeds introduced for their wool and mutton
production are Awassi, Hampshire, Blue-de-main, Merino, Romney, Corriedale
and Dorper. Crossbreeding of the Menz breed with the five exotic breeds, namely:
Awassi, Hampshire, Bleu-de-Main, Romney and Dorper are being used for
development and research activities.
Goat breeds
Indigenous goat breeds: Major goat breeds existing in the country are Begayit,
Ille, Afar, Hararghe Highland, Arsi-Bale, Short-eared Somali, Woyito-Guji, Long-
eared Somali, Central Highland, Abergelle, Western Highland, Widar, Western
Lowlands, Maefur and Keffa. Moreover, Felata, Arab, Gumuz, Agew and have
been recently reported.
Equine breeds
Donkey breeds that exist in the country are the Jimma, Abyssinian, Ogaden and
Sinnar. Major breeds of horses that have so far been well recognized are the
Oromo and Dongola. In Ethiopia, crossing of Asses with mares to produce mules
dates back to centuries. Except for two well known, namely: Sinnar and Wollo
Mule breeds, there are no other well-defined hybrids in the country.

34
In Mekele University,Tigray region, phenotypic characterization of local donkeys
has been carried out. However, such activities have to be complemented with
proper genetic characterization in order to classify the donkey types found in the
region or elsewhere.
Camel breeds
Attempt to classify Ethiopian camels has not been satisfactory so far. Wilson
(1984) has classified and described major camel breeds in the country as the Afar,
Borena, Anfi and Somali/Ogaden breeds.
Poultry breeds
Indigenous chicken breeds: Based on geographical locations, indigenous chicken
breeds identified so far are Horro, Jarso, Tililli, Tepi and Cheffe breeds that are
found in the central highland areas. The naked-neck breed found in northern,
northwestern, western and southern lowland areas of the country.
Exotic chicken breeds: Several layer, broiler and dual-purpose exotic chicken
breeds introduced into the country are being used for food and agriculture. Rhode
Island Red (RIR), White Leghorn, Lawman Brown, Cobb-500, Fayoumi, Bovans
Brown, Arob Acre and Bubcocks are reared by small and large-scale commercial
producers in urban and peri-urban areas. Besides, RIR and White Leghorns as well
as their crosses with indigenous chicken are used by rural smallholders for egg and
meat production.
Honeybees
It is estimated that Ethiopia has about 10 million honeybee colonies. Species of
honeybees identified so far are Apis melifera adansol, Apis melifera lementica,
Apis melifera monticola, Apis melifera litorea and Apis melifera abyssinica.
5.2.1. PHENOTYPICAL CHARACTERIZATION
Phenotypic characterization of AnGR is the process of identifying distinct breed
populations and describing their external and production characteristics in a given

35
environment and under given management, taking into account the social and
economic factors that affect them. The information provided by characterization
studies is essential for planning the management of AnGR at local, national,
regional and global levels. Characterisation of livestock breeds has been based on
description of morphological characters such as horns, ears, coat colour, body size
and production and reproductive traits. Since livestock breeds in developing
countries have not been subjected to selection for specific traits, considerable
phenotypic variation is observed within and among populations with regard to size,
horn and ear types and coat colour. Furthermore, most productive traits are
polygenetically inherited and are influenced by environment effects, sometimes
with a genotype x environment interaction. This leads to some inconsistencies in
the classification of the various populations into breeds or strains. Therefore,
reliance on phenotypic characters as the basis for characterisation of breeds for
sustainable utilization and conservation may be misleading.
5.2.2. MOLECULAR GENETICS CHARACTERISATION
DNA marker data provide useful information on the origins, relationships, genetic
diversity and gene pool development of domestic animal breeds. The data help to
identify those breeds that are genetically distinct. Genetically differentiated breeds
can carry genes and gene combinations of economic and scientific importance and
which determine an animal's capacity to adapt to particular environments.
Molecular genetic characterisation is factual and precise. It is in this sphere that
molecular biotechnology has an important role to play. Genetic characterisation of
livestock species involves estimation of the genetic uniqueness of the breeds or
strains and their evolutionary relationships. This can provide information on
which of the populations represent homogenous breeds or strains and which are
different.
Such knowledge will enable decision-making regarding the choice of breeds or
strains for conservation.

36
Chapter 5: Breeding Programs
The aim of animal breeding is to genetically improve populations of livestock so
that they produce more efficiently under the expected future production
circumstances. Genetic improvement is achieved by selecting the best individuals
of the current generation and using them as parents of the next generation. To
select the best animals one needs to define explicitly what is meant with "best".
This means that it is necessary to specify the direction in which we want to change
the population. Defining the breeding goal is the first step when designing a
breeding program. It is useless to design a breeding program if there is no idea of
the desired genetic change.
NB. A breeding program is the organized structure that is put into place to
genetically improve livestock populations.
Successful genetic improvement requires breeding programs to have (at least) the
following components:
 A system to record data on selection candidates. Without data on selection
candidates it is impossible to identify the best individuals.
 Methods and tools to estimate the genetic merit (breeding value) of selection
candidates. This step is called the "breeding value estimation".
 A system to select the animals that become parents of the next generation, and
mate them to produce the next generation.
 A structure to disseminate the genetic improvement of the breeding program
into the production population. In most cases, the breeding population and the
production population are (partly) separated. Since the aim is to improve
livestock production, genetic improvement created in the breeding population
should be disseminated into the production population.
6.1. The breeding goal

37
The breeding goal, or breeding objective, is the starting point of animal breeding.
Broadly speaking, the breeding goal is the direction in which we want to improve
the population. The choice of the breeding goal affects the structure of breeding
programs. Broiler (chicken for meat) breeding programs for example differ from
layer (chicken for egg production) breeding programs because improvement of egg
production requires another breeding program than improvement of meat
production.
The breeding goal has a number of characteristics.
1. The breeding goal is a combination of traits. It specifies the relative
importance of each trait. In principle, all traits of importance should be included in
the breeding goal. Thus the breeding goal only depends on the importance of a
trait, not on its genetic parameters. An important trait of low heritability should be
included in the breeding goal, whereas unimportant traits should be left out,
irrespective of their heritability.
2. The breeding goal should aim at the future. Animal breeding is a long-term
activity. It takes a long time before genetic improvement due to selection is
expressed in the production population.
3. From an operational point of view, the breeding goal should ideally summarize
all traits in a single criterion. A single criterion to express the quality of
selection candidates is convenient because animal breeders can simply rank
their selection candidates on this value and select the highest-ranking
individuals. A breeding goal expressed as a single value can be obtained by
weighting all traits by an (economic) factor, so that the breeding goal is a sum
of breeding values weighted by their (economic) value.
Questions should be raised in developing breeding programs are like:
 what market the breeding goal is aimed at;
 whether the breeding goal should be based on the competitive position of the
breeding company or on an economic model of the production herds
 Existence of political or market circumstances such as production quota that
affect the breeding goal.

38
In Western countries, breeding goals primarily include economically important
traits such as milk yield, meat production and egg production. In addition, breeds
are often specialized for a single purpose; dairy breeds are kept for milk
production and beef breeds for meat production, layers for egg production, broilers
for meat production. In developing countries however, the situation is quite
different, because livestock is often kept for auto-consumption and not to produce
for a particular market.
========================Message==========================
NB. The breeding goal specifies which traits should to be improved, in which
direction and the relative emphasis given to each trait.
==========================================================
In animal breeding, there are two common approaches to define breeding goals.
The first approach is to express breeding goals as a weighted sum of economic
values and breeding values. In this approach, economic weighting factors of traits
(economic values) are based on an economic model of the production system. The
second approach is to express the breeding goal as a set of desired gains for each
trait. The desired genetic gain for each trait is based on marketing and commercial
considerations of breeding companies. In many cases, desired gains are based on
maximizing the market share of the breeding company in the time frame.
Breeding goals based on economic models of the production system:
When breeding goals are based on an economic model of the production system,
the economic value for each trait is determined by modeling the effect of that trait
on the profit of a production herd. The breeding goal (H) is expressed as a
weighted sum of true breeding values and economic values,
NB. Breeding goals can be expressed in terms of economic values, which
express the increase in due to a single unit improvement of a trait, or as desired
genetic gains.
6.2. Components of breeding programs
1.Data recording and collection: Estimation of breeding values requires
phenotypic data on selection candidates. Thus a system has to be set up to

39
routinely record data on selection candidates. The way data is collected depends
on the species and the traits in the breeding goal. Dairy cattle breeding schemes
therefore have a system to record data on daughters of test bulls. Milk yield of
those daughters is recorded on common dairy herds, meaning that farmers are
involved in the data recording. In beef cattle breeding, growth performance of
bulls can be recorded on the selection candidates themselves, meaning that
progeny testing is not necessary. In beef cattle breeding, data collection therefore
takes place at testing stations where the performance of selection candidates is
recorded.
2.Selection and mating: Selection and mating takes place after breeding values are
estimated. Selection refers to the process of choosing parents to produce the next
generation, whereas mating refers to the pairing of selected individuals. Thus
selection precedes mating. The selection process determines the genetic
improvement of the population over time, whereas the mating process determines
how maternal and paternally derived alleles are combined within individuals.
3. Dissemination of genetic progress: In most species, the breeding and
production population are distinct. Genetic progress is created in the breeding
population, but the final aim is to improve livestock production in the entire
population. Thus genetic improvement created in the breeding population has to
be disseminated into the production population. In dairy cattle, the breeding and
production populations are not strictly separated. Superior cows from the
production population can enter the breeding population, meaning that they are
selected as bull dams. Genetic progress created in the breeding program is
transferred to the dairy farms by the sale of semen of progeny tested bulls to the
farmers. The sale of semen is the primary source of income for dairy cattle
breeding companies.
=======================Message========================
A breeding program has the following components: i) a data recording
system, ii) methods and tools for breeding value estimation, iii) a selection
and mating
4. INBREEDING AND RELATIONSHIP

40
All the living beings are interrelated. The relationship between any two
individuals is due to procession of some common genes they have because
of immediate or remote ancestor in their decadency or lineage or heritance.
It is the brood sense of relationship. But for practical purpose any two
individuals are said to be related if they have one or more ancestors in
common at least in first six generations. After six generation because of
halving of remote ancestor‟s hereditary materials two individuals would
have little genetic relationship.
The relationship is categorized into three groups
(a) Direct relationship
(b) Indirect or collateral relationship
(c) Combination of direct and indirect relationship
Direct relationship: If occurs between individual and its ancestor or
between individual and descendant. It arises when out of two individuals
one is direct ancestor (parent) other is descendant (progeny). The
relationship between the parent and offspring is 50 percent or 0.50 because
one half of the offspring‟s genes are obtained from one of the parent i.e.
50% of parental and offspring‟s genes are same. The parent offspring
relationship is the simplest one.
Indirect or collateral relationship: This kind of relationship exists when
relatives are not directly related to each other or descendant in lineage
because they are not ancestors or descendants of one another. However
they have one or more ancestors in common. e.g. Full sibs, half sibs,
cousions etc where in both the individuals, receive common genes from
their ancestors..
Combination of direct and collateral relation ship
This type of relationship is seen when an outstanding individual is mated to
is descendant and also to its collateral relatives. If the ancestor appears in

41
pedigree more than once relationship between the individual and ancestor
in question is always greater than if ancestor had come only once in lineage
or pedigree of an individual
Measurement of inbreeding
Inbreeding (mating of related animals) has many effects on genotype and
phenotype. Inbreeding increases the homozygocity and it decreases the
heterozygocity. All the good and bad phenotypic effects are because of this
increased homozygocity or loss of heteroyzyocity. Therefore it is important
to measure amount of inbreeding of an individual or herd. The term
inbreeding coefficient (F) is used for this purpose which measures the
increased homozygocity. Homozygocity, a likeness of two genes may by
state (chance). They are two randomly drawn genes from population and by
chance they are alike. It is known as identical by state. Two genes of an
individual may be alike by descent. It is because of mating of relatives.
Alikness arise from replication of same genes from common ancestor. It is
known as identical by descent. Thus inbreeding coefficient is probability
that two alleles at a locus in an individual are identical by descent. It is
measure of decrease in proportion of heterozygous genes over what was
present before inbreeding is practiced. It is always a measure relative to
some starting point, some generation back for which F is considered as
zero, It two individuals have no common ancestor in past six generation.
5. METHODS OF GENETIC IMPROVEMENT
Selection
In random mating in large population, in absence of selection, mutation,
migration the gene frequency remains constant. Hence we assume that each
individual of the population contribute equal number of gametes to the
population. Each individual will contribute to next generation in proportion

42
of frequency of genotype in current generation. Since there is no change of
gene frequency no change of phenotypic properties is expected.
But the nature or men do not allow each individuals to contribute equally to
the gamete pool. Nature allows most successful genotype to multiple and
men allow most useful genotype to multiply. Therefore certain individuals
are preferred to others in production of next generation. Thus selection is
choosing of parents of next generation either by nature or by men. It is
designation of parents of next generation. The process of differential
reproduction among the individuals of different genotype is known as
selection.
Selection
Natural selection Men made selection
(Artificial selection)
The natural selection depends up on the genetic differences among the
individuals in fitness characters such as disease resistance. Libido, mating
behaviors, anatomical and physiological superiority. It is the survival of the
fittest. Only strong and these adapted to environment survive and produce
large number of offspring‟s.
In artificial selection breeder determines which animal to reproduce, which
will be retained for replacement, how long they will be allowed to remain
in population.
Both natural and artificial selection do occur simultaneously in a
population. They may influence the same or different traits same or in
opposite direction. Selection is practiced by nature or men at any stage of

43
life. Some are not allowed to born some are born and die before they
reproduce, some are culled because of their bad pedigree, some are culled
after their own performance and some are culled after knowing their
progeny performance.
Objective of selection
1. To improve the overall productivity which includes utility, survivability
etc
Principles of selection
1. Variation is basis of selection.
2. Selection is effective when the traits selected are heterozygous.
3. When a race / breed / herd becomes homozygous for certain trait selection
no longer improve it.
4. Selection should be based on hereditary variation and not on environmental
variation.
5. Selection does not create any new genes.
6. Selection increases the frequency of desirable genes.
Selection will be effective and meaning full if systematic recording is
practiced. But even without the knowledge of Genetics selection was
highly effective. The difference between the performance of breeds of
present day and primitive type of animals is the best of example of effect of
selection.
Type of selection
Directional selection: The breeder select the individuals to be the parents
of next generation whose phenotype are more nearly approach a maximum
(milk yield) or minimum (back fat thickness in pigs) for some trait. Other
individuals with poorer phenotype are not allowed reproduce. If the trait is
heritable than the part of phenotypic superiority of selected parents will be

44
passed on to the next generation. Next generation will be above the
population average. The favorable genes frequency will be increased.
Therefore the effect of directional selection based on phenotype variation is
due to genotype. It will increase the gene frequency of favorable genes and
decrease the gene frequency of undesirable genes. Directional selection is
practiced utilizing the records of ancestors, individual, progeny, collateral
relatives.
Factors affecting the selection progress
Many physical, biological and management factors affect the selection
progress.
1. Ability of the breeder: Progress of selection depends upon the ability
breeder to select the superior breeding stock. He should have a definite goal
(objective) in his mind and should not change it often. He should have
accurate records for comparison.
The popular type of this year may not have the same favor in coming years.
So the selection progress can be slowed down. Hence should have a plan
well in advance for the future trends and need of the people
2. Foundation stock: Selection will be ineffective if the foundation stock
is poor. If the genes which are desirable are not found in the foundation
stock or are very rare then the selection will be powerless. In that case
the desirable genes have to be introduced from outside (out breeding)
3. Level of performance: If the population performance is uniform the
difference between the selected and rest will be less. Similarly the selection
becomes ineffective if the herd average for that trait is very high. Then it
will be difficult to find animals that exceeds the herd average. This occurs

45
due to long time selection and decrease in genetic variability. By
outbreeding (introducing new genes) and changing the environment
variation can once again brought about for further selection.
4. Number of traits considered for selection: Simultaneous selection for
large number of traits reduce the selection intensity for any one trait. Only
those traits which are economically important should be considered. Less
important traits such as color, shape of the ear, shape of horn etc which
have no influence on the performance should not be taken for consideration
during the selection.
5. Heritability of the trait: The qualitative traits are more heritable than
the quantitative traits. If the heritability of coat colour is one (100%) this
character is completely inherited from parent to offspring. If the h2 of the
trait is high selection progress will also be high because a large portion of
selection difference is due to heredity and not due to environment. Any
difference in environment can not be transmitted to next generation.
6. Selection differential: Larger the selection differential more will be the
selection progress.
7. Length of time selection is practiced: Improvement of performance traits
in large animals is slow and takes long period of selection. Further progress
in single generation is likely to be masked by environmental effect. It takes
few generation to note the real progress.
8. Generation interval: By reducing the generation interval one can increase
the selection progress.
9. Genetic correlation among the traits selected: While selecting for two
traits at time if improvement in one traits brings about the improvement in
another also the total progress will be more. e.g. Rate of gain and efficiency
of gain. If the two traits are negatively correlated than the total progress
will be less or nil.

46
e.g. Milk production and draft capacity.
Concept of Breeding value and transmitting ability
Suppose in beef cattle herd selection is based on the yearling weight
Herd average 200 kg
Selected bulls yearling wt 250 kg
Selection differential 250 – 200
= 50 kg
Heretability of yearling wt 0.50
Genetic gain 50 x 0.50
= 25 kg
Average of the progeny of 200 +25
this bull = 225
Aids to selection
There are several sources of information available to increase the selection
accuracy or probable breeding value of the individual. Some information is
from individuals own performance some are from their relatives
Individual selection (mass selection)
Selection is based on the performance of individual itself. The phenotype
of individual is the sole criterion for estimating his genotype (Genetic
merit). This is also most commonly used basis for selection in livestock. It
is effective when the heritability of the trait is high, indicating that the trait
is greatly affected by additive gene action. High h2 estimate also suggest
that phenotype strongly reflects (correlated with) genotype. Further the

47
individuals that are superior for particular trait should also poses desirable
genes for that trait and should transmit these genes to their offsprings. But
one should provide standard environment to distinguish between the
genetic and environmental effects.
Advantages:
.1.Simple since the characteristics such as milk yield, growth rate, fleece wt
etc can be directly evaluated from the individual itself.
2. Selection can be made even without the knowledge of the pedigree.
3. Less time consuming compared to progeny testing.
4. All the animals can be evaluated, whereas in progeny testing only
limited number of animals can be evaluated.
5. Can be used as preliminary selection before progeny testing.
Disadvantages
1 Many of the economically important traits are sex limited and hence
expressed only in one these sex. (Female). Therefore selection of males
cannot be based on their own performance for the traits (milk yield egg
yield)

48
2 .Records of milk yield, egg yield etc are available only after the sexual
maturity. Therefore selection has to be postponed till such time.
3. Slaughter traits such as carcass quality, dressing percentage etc can be
assessed only after
Slaughter of the animal. Therefore it is of no help in selecting for these
traits.
4. In case of traits which have low h2 individual merit is a poor indicator of
the genotype.
Therefore the improvement from individual selection will be less for such
traits. If the superiority of performance of an individual is due to
heterozygosity it will not be transmitted to the offspring.
Methods of selection
1. Tandem method:
Selection is practiced for only one trait at a time until satisfactory
improvement is done in this trait. Then the second trait is considered for the
selection and so on. If there is a positive correlation between the first trait
selected and any other trait both will improve. If there is negative
correlation, progress in one trait is affected by a decrease in other and will
nullify the effect e. g milk yield and fat percentage, Heat tolerance and milk
yield.
Disadvantages.
Least efficient method
More effort and time consuming
Negative correlation between several economic traits will nullify the
improvement

49
2. Independent culling method
Selection is practical for two or more trait at a time. For each trait a
minimum standard is set. Animal should meet standard for selection.
Failure to meet the set standard for any one trait will disqualify the animal.
e. g
Character Birth wt AFC Milk yield fat %
Min. standard 30 kg 30 m 2000 kg 5 %
This has been usually used in past for type and confirmation traits (color,
size, horn) in show cattle regard less of economic value
Advantage
1. Selection for more than two traits at a time will bring about simultaneous
improvement.
2. Animal can be culled at an early age for failure to meet the minimum
standard thus reduce The cost maintenance.
Disadvantages
1. An animal is culled for failure to meet the minimum standard set for one
trait although it is superior in other traits. (4.5 % fat 3000 kg milk).
2. Animal may culled at an early age for its failure to meet the minimum
standard without giving chance to reveal superiority in later stage of its life.
(i e a female calf weighing 24 kg will be discarded. Without giving chance
for future i.e production.
Selection index method (Total score card method)
In this method value (marks or score) is separately determined for each of
the trait selected for and these values of each trait selected is added to give

50
a total score for all the traits. The animals with higher total score are
selected.
The value for each of the traits defendants upon
a) Relative economic value of the trait
All the traits selected are not equally important and carry equal marks
b) Heritability of the traits. Higher the h2 more the value
c) Genetic correlation with other important trait
Advantages
1. One of the advantage of this method is even though animal is slightly
deficient in one trait and if it superior in other trait it will be saved.
2. The efficiency of this index selection is more than that of independent
culling level and efficiency decreases as more traits are involved. If the „n‟
is number of traits then an index is n times as efficient as independent
culling level
Disadvantages
1. Construction of selection index under is highly complex
2. The genetic parameters (heritability, correlation) and economic values
are not constant for all the populations and in all the time and depends on
many factors thus lead to revise the index.
Selection based on progeny performance (progeny testing)
It is the estimation of breeding value or genetic worth of an individual from
the study of the performance of its offsprings. It is being increasingly used
as an aid in estimating the genetic worth of an individual. The idea of
progeny testing is not new. About 2000 years ago it was advocated by

51
Varro of Rome. Robert Bakewell used the outstanding sires after knowing
the performance of their progeny in 18th century. the dams.
Principle: The principle underling the progeny testing comes from the
sampling nature of the inheritance where each offspring receives a sample
half of the gene from its parent. Each additional offspring receive another
independent sample from same source.
Selection based on collateral relatives:
Collateral relatives are those individuals who are not directly related either
as ancestor or progeny.
e. g full sibs, half sibs
They do not contribute any gene to their relatives. But they have certain
common genes which they have received from their common ancestors.
Thus average performance of collateral relatives gives an indication of
genetic makeup of an individual. More closely collateral relatives are
related to the individual more accurate is the estimation of its genetic
worth. Therefore selection based on the information of full sibs is more
accurate than that of half sibs.
Advantages of selection based on collateral relatives:
A. For sex limited traits
Selection of bulls based on milk production of his half sibs, full sibs.
B. For slaughter traits (carcass traits)
Slaughtering the half sibs / full sibs to evaluate the carcass quality
c. Less time consuming compared to progeny testing
d.Less generation interval compared to progeny testing

52
e. Useful for traits of low h2
Though less accurate than progeny testing the generation interval is less in
selection based on collateral relatives. Therefore it may be almost equal to
progeny testing in genetic improvement obtained.
Family Selection
In livestock selection, family can be classified into three types.
1. Sire family;
These are the offspring of one sire out of different dams, may be born in
same year or born over number of years.
2. Dams family: These are the offspring‟s of one dam out of different sires
may be born in same year or in different years.
In case of cattle and sheep superovulation of dam and Invitro fertilization
by sperms of different sires. Can give this type of family.
3. Sire and dam family
These are the offspring‟s by one sire and one dam. These offspring can be
obtained by in same year or in different years.
Therefore family is usually made up of full sibs or half sibs. The families of
remote relationship being of little practical importance. Full sibs‟ family
selection is practiced when reproduction rate is high (pigs, poultry) and half
sib family selection when reproductive rate is low (cattle, sheep). However
in poultry the sire family selection is more efficient than the dam family
selection when h2 is near about zero and less than 0.10. Since h2 of egg
production is approximately 0.10, sire family selection is usually practiced
for improving the egg production.

53
Mating systems
The mating systems govern the breeding plans that are aimed to harness the
favorable gene combinations to maximise the net profit to the farmers.
Generally mating systems are executed immediately ofter successful
selection of suitable parental genotype to produce progeny of the next
generations. Therefore mating system is one of the ways open to the
breeder for
a) Changing the genetic constitution of progeny generation over
population.
b) Improvement of the performance of progeny generation over base
population.
General objectives of mating systems
 To produce the future progeny of good genotype to make further profit.
 To bring together the desirable gene combination after selection
 To bring the genetic uniformity
 To enhance the relationship
 To Ancash the effect of heterozygosity
 To overcome the hereditary defects
 To form a base for synthesis of strain / line / breed.
Effects of mating systems:
 Alter the gene frequency (Hardy Weinberg equilibrium is altered.)
 Cause genetic uniformity / purity / and therefore increase the pre potency
 Cause the heterozygosity (heterosis)

54
Broad classification of mating system
Based on genetic relation ship
Random mating Nonrandom mating
Inbreeding Out breeding
Random mating: It is system of mating in which individual of one sex is
equally likely to mate any other individual of opposite sex in a given
population. It is also called as “Panmixie”
Nonrandom mating: It is also known as “Selective mating” in which case,
the selected male is mated with selected female.
Out breeding: It mating of genetically less closely related individuals than
average of the population. It is known as out breeding.
Inbreeding
Mating of closely related individuals compared to average of the
population is known as inbreeding. Inbred individual carry more of
identical genes by descent.

55
Objective
 To increase the relationship to an outstanding sire or dam.
 To increase Homozygocity
Genetic purity
Uniformity
 To eliminate the recessive undesired alleles
 To form distinct lines/strains/family or seed stock from highly
heterozygous population
 To increase the prepotency (ability to produce its on type) due to increased
homozygocity.
Disadvantages
 Too many progeny have to be
 slow increase of homozygocity
Discarded because homozygocity of recessive genes.
 Progeny become susceptible
 to disease, reproductive problem,

56
Chapter 7: Selection and Genetic Change
The previous chapters have introduced basic animal breeding theory and have
shown how one can estimate the genetic merit (breeding value) of individuals. This
and the following chapter will show us how that information can be used to
genetically improve livestock populations and how one can quantify the
expected genetic improvement. The animal breeder has two tools to genetically
improve his populations: selection and mating.
7.1. Selection
In animal breeding, the aim is to genetically improve livestock populations by
exploiting genetic differences among individuals. Genetic improvement is
achieved by selecting individuals that are genetically superior to the rest of the
population. The term "selection" refers to the process of choosing parents to
produce the next generation. The challenge for the animal breeder is to select
genetically superior parents to produce the next generation of offspring, so
that only the alleles of those individuals will be passed on to the next generation.
Similarly, to prevent alleles from genetically inferior individuals from being
passed on to future generations, they should be avoided as parents. In addition,
one may decide to produce many offspring of the very best individuals and fewer
offspring of sub-optimal individuals. In that case, the very best individuals will
contribute more alleles to the next generation than the sub-top individuals. Thus
the process of selection determines which alleles are passed on to future
generations and therefore determines the genetic composition of the population in
the future. It is important not to confuse selection with mating. Selection refers to
the choice of parents, whereas mating refers to the "making of pairs" among the
parents that are already selected. Thus selection precedes mating.
Selection does not create new genes, but increases the proportion of favourable
genes in the population. The gains are accumulated when we continue to select the
best animals in each generation. A continuous, long-lasting genetic improvement
in traits included in the breeding goal is thus achieved.

57
There are two kinds of selection, natural selection and artificial selection.
Natural selection is the process of survival and reproduction in natural populations.
In populations in the wild, the individuals that fit best to the environmental
conditions produce the most offspring. As a consequence, those individuals
contribute the most alleles to the next generation. Natural selection therefore
favours a combination of viability and reproductive ability, i.e. fitness traits.
The selection done under human control to obtain genetic improvement of traits in
domestic animals is called artificial selection. Fitness traits, such as fertility and
disease resistance are usually included in this selection, but large emphasis is given
also to many other traits, such as production traits, productivity, product quality,
performance traits and longevity. Selections of the cows with the highest milk
production or of the fastest growing chickens are typical examples of artificial
selection.
Selection can be performed both between and within populations (e.g. breeds).
To screen animal populations and thereafter use those that have characteristics in
line with a desired breeding goal can be a way to get results quickly, assuming the
populations can be compared properly. For continuous and long-lasting effects,
however, it is necessary to conduct selection within populations. This is what is
normally meant by selection for genetic improvement.

58
Figure 7. 1. Illustration of how selection effects are accumulated and
maintained.
From the above figure we can see that:
 Using selected animals from the base population as parents results in an
increased genetic level of the animals in the next generation (see the column
for generation 1).
 The selection effect obtained through selection in generation 0 is maintained
also in later generations (see the row for selection effects from generation 0).
 Selecting superior parents also in subsequent generations further raises the
genetic level of each generation.
 The selection effects from each generation are accumulated. Thus, the
genetic level of animals in generation 5 is built up by selection effects from
all previous generations (see the column for generation 5).
 The genetic trend per generation is illustrated through the line.
The driving force for genetic improvement is of course the genetic superiority
achieved by the selection of parents, but also other factors, such as generation
intervals and differentiated use of selected breeding animals, have an impact. One
should also remember that additive genetic variation is a prerequisite for any
selection effort to be successful. The animals in the population must be genetically
different with regard to a specific trait. Otherwise it will not be possible to select
individuals that are better than others!
7.1.1. Selection strategies
The traits we want to improve in a population are defined in the breeding goal. A
few of the goal traits might be influenced by simply one or a few alleles, which
means that the true genotype often can be determined (e.g. through a DNA test)
and it is then easy to select the desired genotypes. The majority of goal traits,
however, are quantitative in nature, i.e. influenced both by genes at many loci
and by environment. These traits are often normally distributed. Selection is then
commonly based on predicted breeding values, which in turn are based on

59
phenotypic values and knowledge of heritability, genetic correlations, genetic
relationships, economic weights, etc.
Selection
Directional selection is the most common type of selection. It means that an
extreme fraction of the individuals are selected. If a high value for a trait is
desirable, then we select the animals with the highest values, e.g. those with high
growth rate, milk yield or performance score. If a low value is desirable, then we
select animals in the opposite fraction of the normal distribution, i.e. the animals
having low values, e.g. for back-fat thickness, disease incidence or time to run a
race.
Stabilizing selection means that we select a middle fraction of the animals and
avoid selecting the extremes. In this type of selection it is the optimum values that
are desirable. Examples could be birth weight and quality traits, such as meat
tenderness. It is possible also that in species with large variation in litter size one
wants to avoid selecting animals giving very small or very big litters.
Selection within a population is usually applied in several stages; this is
sometimes called stepwise selection.
 The first selection event might be based entirely on pedigree information
(usually the average of the parents‟ breeding values).
 The next events might occur when information is available on animals
themselves, and maybe also on sibs; one selection round on traits expressed
fairly early in the animals‟ lives, e.g. growth rate,
 Another round on traits expressed later, e.g. fertility or performance.
 A fourth selection round might occur when in addition to previous
information there are also progeny results at hand.
There might also be one step for selection of elite animals as parents to the next
generation of males to be used in artificial insemination. The best animals in
each round of selection are retained to the next selection event, while the ones
that are not selected might be culled, or they might be used as production
animals, or even as parents to non-elite breeding animals.

60
Measuring and keeping records of important traits, and also predicting breeding
values without bias and with a high precision, is fundamental for a functioning
selection program. The accuracy by which we are able to rank the individuals
determines the success of a selection among them.
7.1.2. Selection schemes
Various schemes are adopted for the selection of the best animals into breeding herd. In
the simplest methods, animals can be selected on the basis of:
a) their own performance records (individual selection or mass selection),
b) progeny records (progeny testing)
c) their family mean (family selection) or pedigree selection).
Literally all of these methods of selection use the available information about each
animal‟s breeding value in order to determine the genetic worth of the animals through
development of an index of merit.
a) Performance Testing
Performance testing is basically selection of genetically superior animals on the basis of
their own records of economically important performance traits. In this method, animals
are tested either on-station or on-farm. In each case, performance data for the traits
under consideration are recorded and analysed to estimate the breeding values for the
animals. If selection is based solely on the basis of the animal‟s phenotypic values, it is
also referred to as individual selection. There are some conditions that must be met for
maximum response to be attained from this scheme: -
 The production traits must be accurately measured and correct records of performance
maintained. Inaccurate measurements, just like inaccurate records, result in misleading
predicted breeding values resulting in poor performing animals being selected for
breeding. This will impact negatively on overall productivity and performance of the
farm when the cost of maintaining a wrongly selected animal
 The breeder must ensure that the animals being considered for selection are from the
same contemporary groups that had equal provisions in terms of age, sex, management
including feeding, treatment, vaccinations

61
 All predictable fixed effects (environmental factors) should be pre-adjusted for before
genetic evaluation of the animals is carried out.
If all the above conditions are met, performance testing provides the simplest selection
scheme and apparently gives the most rapid response to selection
However, this scheme has its own
Disadvantages: -
 Some traits are sex-limited being expressed only in one sex. As such, performance
testing cannot be conducted in both sexes and this has a tendency to limit the progress
of genetic improvement
 Some traits can only be measured very late in life when the animal is approaching the
end of its economic value. In beef cattle breeding, some traits like carcass quality are
measured after slaughter and thus such records cannot be utilized in performance
testing
 This scheme is of little significance for traits of low heritability, because of the very
low genetic progress realized from selection on its basis.
b) Progeny Testing
This is a form of family selection that is widely used in animal breeding. This method is
based on the principle that the mean performance of a progeny group should give a
reliable indication of the estimate of the breeding value (EBV) of one or other of its
parents, since each offspring receives a random sample of genes from both parents (half
of them from each parent). As such the selection criterion with this system is the mean
value of an individual‟s progeny. Progeny testing estimates the breeding value of one
parent, on the basis of performance of its progeny. Dams are not usually progeny-tested
because of the limited number of offspring that they produce in their lifetime.
Procedure for progeny testing
 Potential parents are mated to a random sample of dams within a herd;
 The resultant offspring (progeny) are measured for performance on the traits
under consideration;

62
 On the basis of the progeny group average, and after weighting for the different
number of progeny per parent, the breeding parents are selected from the group
potential parents.
 Selected parents are mated to produce a second batch of progeny which become
the next group of parent to be progeny tested.
Limitations of progeny testing
 There is a lengthened generation interval since the selection of the parents cannot
be carried out until the progeny have been measured.
 There is possibility of generations overlapping and this further complicates the
evaluation of the parents.
 There is a possibility of ambiguity since the progeny will be tested just when the
parents are being tested. There is a real possibility of using both as parents.
c) Pedigree selection
The pedigree of an animal is a record of all the ancestors, recent and remote that are
related to the animal under consideration. In this respect, knowledge of the genealogy of
the animal alone may be of limited use in pedigree selection but rather, the productivity
of all these ancestors to the individual animal. Pedigree selection therefore estimates the
breeding value of an animal on the basis of production performance of its ancestors. If the
performance of an individual animal is known with precision, it may not be wise to carry
out pedigree selection but rather individual selection.
Pedigree selection is only useful when: -
 Progeny performance data are not available;
 The animals to be selected are so young such that their individual merit cannot be
ascertained with any degree of certainty;
 Selection is being made for animals with comparable individual merit.
Pedigree selection has several advantages including that it is: -
 Relatively less expensive to carry out since it uses only records.
 Useful for initial selection of those traits that are expressed in one sex only.
 Selection can be carried out early in the life of the animal to be selected.
The disadvantages of pedigree selection include: -
 It puts undue emphasis on relatives, particularly remote relatives, resulting in a
reduction in the intensity of individual selection.

63
 It is biased towards progeny of favoured parents having been selected previously
7.1.3. Multiple trait selection methods
The goal of multi-trait selection is to increase the net merit of the population.
Thus, one important factor in designing multi-trait selection schemes is the relative
economic value of a unit genetic gain in each trait included in the selection
program. The most effective way to account for differences in the economic worth
of each trait is to weight each trait by its economic value so that each component
breeding value in the aggregate breeding value is improved in proportion to the
economic gain expected.
There are three recognized approaches to multi-trait selection, although many
operational selection programs combine parts of more than one method to achieve
various breeding goals. The three selection methods are:
a) the tandem selection procedure
b) independent culling method
c) the index selection procedure,
a) TandemSelection
This method of selection involves selection for each trait singly, but is
sequence. Selection is first carried out for the most important trait, based on
economic value of genetic gain and predicted genetic gain, for a given number of
generations. Once the goals for the first trait have been achieved, selection effort is
targeted to the next most important trait, and carried out for specified number of
generations. The process can continue indefinitely, for any number of traits. Often
in practice, the tandem method is superimposed on top of the other two methods of
selection to provide long-term flexibility in changing traits targeted for selection

64
as market conditions change. As is true for all three methods of selection, tandem
selection has advantages and disadvantages.
Advantages of Tandem Selection:
It is the simplest of the three methods and requires the least amount of detailed
information. Prediction of selection response is simple since response for each trait
in sequence can be predicted using the simple equation for truncation selection on
a single trait. In addition, the method can take advantage of favorable genetic
correlations with other traits, allowing correlated genetic gain in secondary traits to
offset the cost of selection.
Frequently, the tandem method is applied when a population is first placed
under domestication or a new breed is under initial development. Under such
conditions, little genetic information is available for traits because of the newness
of the population so the simplest approach is to choose a single trait with high
economic value to initiate the program. As more information is acquired regarding
additive genetic variances and phenotypic and genetic correlations, the program
can be modified to address other important traits.
Disadvantages of Tandem Selection:
It is difficult to set a goal representing the desired end point for selection on each
trait in the sequence. Tandem selection can have a major negative impact on net
merit of the population if unfavorable genetic correlations exist between the trait
under selection and any other trait important to net merit.
b) Independent culling level
This method is used in multiple trait selection. The implementation of this method
based on setting a minimum level of performance for each trait included in the
selection program. The selection procedure is simple truncation selection for each

65
of the traits based on the culling level specified for each trait. The culling levels are
said to be independent because once the culling levels are established for each trait
selection proceeds on each trait without reference to the performance of individual
animal may exhibit for other traits. Culling is a procedure used to remove under-
performing animals from a production herd so culling decisions is based on some
estimate of producing ability.
Example: Consider a program for the selection of heifer replacements for a beef
cattle population, designed to increase yearling weight but to keep birth weight
below at maximum accepted level. Selection for yearling weight may be desirable
because increased weight would reflect rapid growth rate and would increase the
number of heifers that could be bred for the first time at one year of age without
impairing their long-term reproductive performance. On the other hand, controlling
or reducing birth weight would reduce parturition problems in the herd.
Advantages of independent culling method
 relatively easy to apply because the procedural rules are very direct; determine the
culling levels and select all individuals meeting or exceeding the culling levels.
 The method can be very effective for qualitative characters such as coat color,
general body conformation or physical soundness.
 The method is also convenient when selection can be carried out in steps over the
life time of the animal.
 This approach allows flexibility in determining the importance of the various traits
to net merit by adjusting the selected proportions to achieve the desired final result
(based on economic values and predicted selection response).
Disadvantages of independent culling method
There only two difficulties in applying the independent culling levels method of
selection.
 It is difficult to establish culling levels that truly reflect the economic value and
expected selection response.

66
 Preventing arbitrary modifications to the culling levels, because of short-term
changes in market conditions or the attitude of the breeder.

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