Genetics and Animal breeding deck 2 Flashcards
1
Q
In horses gestation lasts for approximately
A
approximately 340 days
2
Q
in cattle gestation lasts for approximately
A
280 days
3
Q
in sheep gestation lasts for approximately
A
150 days
4
Q
in swine gestation lasts for approximately
A
about 114 days
3-3-3 rule
3 months, 3 weeks, 3 days
5
Q
The length of incubation of a chicken egg
A
21 days
6
Q
Embryogenesis lasts for in cattle
A
5 weeks
7
Q
Embryogenesis lasts for in sheep
A
4 weeks
8
Q
in swine Embryogenesis lasts for
A
3 weeks
9
Q
Define embryogenesis
A
this period is characterized by intensive differentiation of cells and the development of primitive organs
this stage comes after conception
10
Q
Define organogenesis
A
stage of gestation for rapid development and extensive relative growth, whereas the absolute growth remains small.
basis for organs and associated systems are formed in addition to cartilaginous skeleton and nervous system
11
Q
Define the prenatal period
A
the longest stage of gestation after organogenesis-stage and lasts till the birth.
32 weeks in cattle,
5 in sheep and
11 in swine.
12
Q
Define absolute growth
A
is the increase in body mass or size in a given time period
measured by weighing
13
Q
Define relative growth
A
describes growth intensity
Shows the ratio between absolute growth (A) and the initial mass, given in percent.
14
Q
absolute growth is denoted?
A
A
15
Q
relative growth is denoted?
A
K and in percentage
16
Q
What is the regression coefficient
A
(b) describes the relationship between traits Y and X
17
Q
how is regression coefficient denoted
A
b (y/x)
18
Q
how is regression coefficient calculated
A
is calculated in two ways: regression of trait Y on trait X, or regression of trait X on trait Y.
e.g. between body weight as y, and age as x
how many units the value (y) of trait Y will change if the value (x) of trait X will change by one unit.
b = (y kg / x days)
19
Q
Define biocoenosis.
A
An association of populations living together in a habitat is called a biocoenosis.
20
Q
define open population
A
Individuals of an open population may mate with individuals of other populations that have a significantly different genotype.
21
Q
define population size
A
is defined as the number of individuals present in a population.
22
Q
A random sample is what
A
is a sample of a population that is chosen randomly without bias. Processes that are non-predetermined under certain circumstances. It is stochastic.
23
Q
What is the probability of an event?
A
The expected frequency of the event A is called the probability of the event that is written p(A).
24
Q
What does genotype frequency indicate?
A
Genotype frequency indicates the genetic structure of a population and the prevalence or number of different genotypes in the population.
25
What does gene or allele frequency indicate?
The frequency or prevalence of the different genes/alleles existing in the different genotypes of a population. Allele frequency can always be calculated from genotype frequency.
26
What conditions must a population meet for Hardy-Weinberg's law to apply?
1) individuals mate randomly
2) individuals with all genotypes are of identical fertility
3) there is no selection
4) no mutations
5) there is no gene flow between populations
6) there is no gene drift
7) the number of individuals in a population is infinitely large
27
Emigration refers to?
individuals removed from a population.
28
Immigration refers to?
new individuals being introduced into an open population.
29
The impact of migration (in or out) on the genetic balance of the population...?
may change the gene and genotype frequencies of the initial population.
30
The impact of migration (in or out) on the genetic balance of the population...?
may change the gene and genotype frequencies of the initial population.
31
What is the formula for calculating effective population size.
Ne = (4Nββ’ Nβ) : ( Nβ+ Nβ)
32
the probability of the event can be written as the formula..?
0 < p (A) < 1
33
What does inbreeding coefficient (Fx) tell you
measures the proportion of the loci which was heterozygous in the base population, which probably has become homozygous due to inbreeding.
34
what is passive inbreeding
Inbreeding may occur in a small population where a very small number of animals increases the opportunity for loci in the offspring to become homozygous.
35
define outbreeding
Outbreeding is a general term applied to any breeding system in which animals mated are less closely related than the average of population from which they come.
36
What does the phenotypic value of an individual depend on?
is due to its genotype or genotypic value (Gi) in conjunction with environmental factors (E).
37
Correlation coefficient demonstrates
the degree to which a trait changes, if the other trait either increases or decreases.
38
what is rP
Phenotypic correlation (rP)
correlation coefficient which is calculated between phenotypic traits
39
what is rG
Genetic correlation (rG)
correlation coefficient which is calculated between phenotypic traits of RELATIVES (not to be confused with rP)
40
correlation coefficient range is?
from -1 to +1
41
what is regression analysis
involves identifying the change in the numerical value of one trait if the numerical value of the other trait will change by one unit.
42
Which traits are taken into account in estimation of breeding value of animals?
```
Performance data (e.g. milk yield)
Exterior traits
Growth and development rate
Fertility
Health
```
43
Sources of information for the estimation of breeding value.
based on the data of the animal itself and the relatives
Multiple sources of information increases the accuracy of breeding value estimation.
44
What is a fixed reference base in reference to breeding values
using the BLUP method to compile data for reference.
45
what is absolute breeding value (BV)
is the breeding value that has been calculated based on the fixed reference base (BLUP)
46
What is a moving reference base
a reference baseline that is constantly updated to suit modern data
made from one or several successive contemporary groups of individuals (bulls) all of whom have received their first relevant value estimates.
47
what is (RBV)
relative breeding value for an individual is calculated based on the average breeding values of the reference bulls and the standard deviation from those values
48
Which organization deals with the international evaluation of bulls?
An organization called INTERBULL, located in Uppsala, Sweden. Internationally carries out genetic evaluation of dairy bulls
49
Concept of selection:
Selection is a process of deciding which animals are allowed to become parents of the next generation, and which ones with undesired properties will be culled.
50
Tandem selection focuses on
one trait until a desired level is reached (several generations), then another trait will be in focus
51
selection according to the type of unit refers to what types of "units"
Individual selection
Group selection
Mass selection
52
Individual selection method?
Genetic value of every individual entering the breeding program will be assessed for every
criterion (fitness is determined entirely by individual trait value).
53
Group selection method?
Selection between groups, where the group with certain characteristic features is the unit of
selection.
The selection criterion is the trait that is characteristic of a certain group of animals, whereas the value of this trait surpasses the value of the same trait of another group.
54
Mass selection method?
A larger group of animals is selected in a population according to phenotypic traits that correspond to the breeding objectives.
55
selection can be based on what 3 sources of information
animal's own phenotype
the phenotypes of relatives
combined selection
56
Definition for pair mating of farm animals:
Pair mating is a breeding technique that uses systematic selection of males and females for generating offspring with desired characteristics.
57
what is Individual pair mating
parental pairs are selected from among animals of high breeding value to produce offspring of exceptional value
58
what is Mass pair mating
female animals are mated with males that are included in the herd, whereas the males are not related with the females and are of higher breeding value.
59
Homogeneous pair mating is
Mating of similar animals characterized by coancestry, common body conformation and similar performance characteristics.
The objective of this method is to produce offspring that is both phenotypically and genotypically similar to their parents.
60
Heterogeneous pair mating is
characterized by a larger genetic and phenotypic difference between the breeding pair.
61
Genealogical line refers to
comprises all genetically similar descendants of the initial purebred sire.
62
State 2 "regularities" that have been found to be true in regard to growth and development.
1) Organs that grow slowly during the embryogenesis, grow quicker in the postnatal period and vice versa.
2) Malnutrition or disease inhibits the growth of rapidly growing organs and bones the most.
63
Outcrossing is
the mating of unrelated animals within a breed. They belong to different lines.
64
Family selection is a term used to describe
Purposeful mating of the progeny of an outstanding female ancestor that is aimed at
maintaining the properties of the thoroughbred dams is referred to as family selection.
65
The purposes of outcrossing
to improve an existing line
to obtain new lines
to obtain animals that have intermediate features
66
Crossbreeding is
the mating of animals of two or more different breeds.
67
Main objective of crossbreeding is
to obtain economic benefit from heterosis.
68
3 Crossbreeding uses:
for commercial production
for formation of new breeds
for improvement of existing breeds
69
Crossbreeding for commercial production means
that animals of one breed are mated
with those of another breed (or breeds) with superior growth and carcass attributes, and all progeny are sold for slaughter.
70
define a breed
a specific group of farm animals with definable and identifiable external characteristics that enable it to be separated by visual appraisal from other similarly defined groups
71
explain Crossbreeding for improvement of existing breeds
when a breed needs to be upgraded and improved, and when the use of pure breeding is too time-consuming.
the "grade" breed is usually chosen from among a similar breed type.
A female is mated with a sire of another breed for just one generation then progeny is crossed back with the initial breed, so the influence of the 'foreign' breed gradually declines.
72
what is grading up breeding
is cross breeding to upgrade a local purebred breed and create a new breed.
73
what is Composite crossbreeding
developing a new breed composed of two or more pre-existing breeds.
74
Crossing inbred lines for commercial production:
Crossing of inbred lines occurs when the lines are of different breeds.
The majority of loci are homozygous. Crossing of two lines of this kind will ensure heterozygosity in most of the loci.
75
Crossing of inbred lines of the same breed is referred to as
hybridization.
76
define breeding programme
is an organization or system in which information on performance of potential breeding animals is gathered and used to estimate breeding values, and superior animals are selected and used to breed the next generation.
77
The purposes of hybridization are:
production of commercial animals
improvement of existing breeds
formation of new breeds.
78
Main/basic purpose of using Artificial insemination (AI)
Enables getting more descendants from one sire. / Enables more efficient use of semen.
79
What breeding value related factors increase with the use of AI?
```
selection differential (SD),
selection intensity (i) of the sires increases.
Generation interval (L) increases.
```
80
Semen can be stored deep-frozen at what temp. and for what purpose
-196βC
for long-term storage and transport.
81
What is ET
Embryo transfer is a biotechnological method used to maximize reproductive efficiency
of a highly genetic valued female (donor) by increasing the number of offspring during lifetime.
82
Purposes of ET
Mostly applied to produce the top sires.
Allows for rapid transition from one breed to another.
Enables the storage of the genes of endangered breeds.
83
Short history of ET
ET was first performed by Walter Heape at the University of Cambridge, England, in 1890.
84
5 Basic steps in ET
1. induce multiple ovulation in donor
2. embryos flushed from donor 1 week after insemination
3. Embryos separated from flush media and examined.
4. synchronize estrus of donor and recipient.
5. Transfer embryo into recipient.
85
Growth is
the increase of the mass and size of tissues and organs.
86
Parameters to evaluate breeding programmes,
* average accuracy of selection
* realized selection intensities
* realized generation intervals
The increase in efficiency of production is the final parameter for the evaluation of a breeding program
87
Absolute growth is
the increase in the body mass or size in a given time period (e.g. year, month, day, etc). The mass of the body is measured by weighing.
88
How do you calculate absolute growth?
We get the absolute growth or increment (A) if we minus the initial weight (W0) from the final weight (Wt).
89
what is π«F
the unit measurement of endangered status and given as a percentage
its used for this purpose BECAUSE it is also the 'drift in inbreeding coefficient'
90
Daily gain is calculated how
absolute growth / time period (days) x 1000 = given in grams
91
Preservation of genetic resources is
a process, which ensures the preservation of genetic diversity with a known or potential value in order to ensure availability for exploitation by present and future generations..
92
The importance of genetic resources conservation?
Valuable genetic material may disappear due to the low knowledge about the local endangered breeds.
Conservation of genetic resources makes it possible for mankind to ensure against prospective changes and unforeseeable events.
93
In principle an animalβs constitution may be divided into two parts:
1) External body conformation is the exterior of the animals that can be directly
seen, measured or valued.
2) Internal body conformation deals with the interior; organs etc.
94
Constitution types of farm animals by P.N. KULESHOV.
1. Compact or strong
2. Delicate
3. Bulky
4. Coarse
95
Constitution types of farm animals by J.U. DUERST.
1. Respiratory type
2. Digestive type
3. Combined type
96
Concept of body condition scoring.
Body condition shows how well the body is supplied with reserves. An animal body condition can be assessed by visual inspection or by palpation.
Body condition score of cows is a 9-point scoring system.
97
According to their body conditions animals can be divided into the following stages:
```
Working condition
Breeding condition
Exhibition condition
Fatstock condition
Pathological condition
```
98
Livestock temperature assessment is based on?
the balance and unbalance of excitation and inhibition and their mobility
(i.e. the rapidity of the shift from excitation to inhibition and vice versa).
99
name 4 temperament types for livestock assessment
Sanguine type
Phlegmatic type
Choleric type
Melancholic type
100
define a breed
a specific group of farm animals with definable and identifiable external characteristics that enable it to be separated by visual appraisal from other
similarly defined groups
101
breeds can be classified using what 3 different systems
on the basis of their performance traits
dependent on productivity
On the basis of development
102
Breeds classified on the basis of their performance traits as follows:
1. milk performance;
2. meat performance;
3. egg performance;
4. wool performance etc
103
Classification of breeds dependent on productivity:
one-purpose breeds β one performance trait
dual purpose breeds β two performance traits
universal breeds β three or more performance traits
104
Classification of breeds on the basis of development:
1. Primitive β breeds of local importance, not significantly changed by breeding
2. Transition breeds β breeds under development
3. Formal breeds β breeds developed by people. They have specific characteristics and are suitable for autonomous breeding.
105
Development stages of breeds
I-IV
106
define breeding programme
is an organization or system in which information on performance of
potential breeding animals is gathered and used to estimate breeding values, and superior animals are selected and used to breed the next generation.
107
Designing comprehensive breeding programs involves a how many steps.
Step 1. Describe the production system
Step 2. Formulate the objective
Step 3. Choose a breeding system and breeds.
Step 4. Estimate selection parameters and economic values.
Step 5. Design an animal evaluation system.
Step 6. Develop selection criteria.
Step 7. Design matings for selected animals.
Step 8. Design a system for expansion β dissemination β of genetic superiority.
108
Factors determining the structure of breeding program
Reproduction capacity
Social infrastructure
Genetic parameters
109
what are nucleus animals
The animals for the production of the next generation of breeding animals
In dairy cattle this refers to bull sires and bull dams.
110
In basic animal breeding courses, four selection paths were distinguished:
sires to breed sires (SS),
sires to breed dams (SD),
dams to breed sires (DS) and
dams to breed dams (DD)
111
Selection path for dairy cattle
The traditional structure is often called 'a progeny testing scheme'.
112
There are what 3 variants for progeny testing schemes after test inseminations:
Variant A - Scandinavian system
Variant B β waiting bulls system
Variant C β young bulls system
113
MOET nucleus scheme
Reproduction capacity of females in the nucleus can largely be increased using multiple ovulation embryo transfer (MOET).
114
An open nucleus scheme
nucleus animals are owned by the breeding organization, but superior females in the base population can enter the nucleus.
115
A closed nucleus scheme
nucleus animals are selected only from nucleus herds.
116
Selection path for pigs and poultry,
A main characteristic is the use of crossbreeding, and as a consequence, different levels in the structure. The structure is often called 'a pyramidal structure'.
117
3 Parameters to evaluate breeding programmes,
* average accuracy of selection
* realized selection intensities
* realized generation intervals
118
The concept of the conservation of animal genetic resources:
The diversity of animal genetic resources is the main source to guarantee the desired selection results in the future.
Production animal breeds are not threatened by extinction but they are threatened by decreased genetic diversity.
119
Factors contributing to the changes in the genetic diversity;
* similar production systems
* good keeping and feeding conditions
* existence of animal recording
* intensive selection
* AI and ET, well-developed IT
* similar systems and technologies in many regions, therefore there is no need to adapt the animals to the requirements of a certain region or state
* consumer and market demands and advertising
120
Conservation of genetic resources refers to
human activities which ensure that genetic material used would meet the demands of the present generation
and the potential of these resources should be increased in such a way that it would satisfy the needs of the next generation as well.
121
The importance of genetic resources conservation?
Valuable genetic material may disappear due to the low knowledge about the local endangered breeds.
Conservation of genetic resources makes it possible for mankind to ensure against prospective changes and unforeseeable events.
122
Ex-situ conservation of genetic material is
AI and ET
123
In-situ conservation of genetic material is
closed herds, nature parks, farm parks, etc.
