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Animal Reproduction

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Animal Reproduction Animal Science II Estrus Cycle Time of day when a female will accept a male for breeding Length 21 day cycle Cow- 16-18 hours Sow- 2 days Best ... – PowerPoint PPT presentation

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Title: Animal Reproduction


1
Animal Reproduction
  • Animal Science II

2
Estrus Cycle
  • Time of day when a female will accept a male for
    breeding
  • Length
  • 21 day cycle
  • Cow- 16-18 hours
  • Sow- 2 days
  • Best indicator is when the animal stand to be
    mounted

3
Ovulation
  • Release of the egg from the ovary
  • Number of young born is an indicator of eggs
    released
  • Sows 10 to 15
  • Cow One
  • Split eggs produce identical twins, triplets, etc.

4
Methods of Reproduction
  • Natural
  • Artificial Insemination (AI)
  • Embryo Transfer
  • Cloning using Nuclear Transfer

5
Artificial Insemination
  • Steps
  • Insert hand into the rectum and grasp cervix
  • Insert insemination rod
  • Deposit bull semen from the middle of the cervix
    to just into the uterus

6
Artificial Insemination
Bovine Reproductive Tract Diagram
7
Artificial Insemination
Sow Reproductive Tract Diagram
8
Artificial Insemination
9
Artificial Insemination
10
Artificial Insemination
11
Artificial Insemination
  • Advantages
  • Wider variety of superior bulls used
  • Increase number of cows that can be bread to a
    superior bull
  • Reduces disease
  • Dont have to keep a bull on the farm

12
Artificial Insemination
13
Artificial Insemination
  • Disadvantages
  • Requires a trained inseminator
  • Requires more time and herd supervision

14
Embryo Transfer
  • Procedures
  • Superovulate donor
  • AI
  • Flush embryos (catheter)
  • Isolate and classify embryos
  • Store in liquid nitrogen
  • Transfer to recipient
  • Diagnose pregnancy 1 to 3 months later

15
Embryo Transfer
  • Advantage
  • Genes of the female (dam) can be passed on faster
    than natural breeding

16
Cloning
  • Using Nuclear Transfer
  • Procedures
  • Flush (same as embryo transfer)
  • Filter
  • Remove genetic materials from recipient oocytes
  • Nuclei is removed through microsurgery

17
Cloning
  • Procedures (continued)
  • The nuclei are separated and each one is
    transferred to an unfertilized egg cell that has
    had its nucleus removed
  • Plugs are placed in sheep for 5 to 6 days
    (develops to the 32 to 64 cell stage)
  • Embryos are placed in surrogate, frozen or used
    to clone more animals

18
Cloning
  • Advantages
  • Increase herd uniformity
  • Increase herd quality
  • Produce genetically identical animals

19
Parturition Process
  • Increased estrogen causes uterus muscles to
    contract
  • Water bag appears and breaks
  • The second water bag appears with the fetus

20
Parturition Process
  • Normal Presentation
  • Front feet first
  • Nose
  • Head and shoulders
  • Hips
  • Rear legs
  • Rear feet last
  • Any presentation not in order could cause death
    of the baby and/or mother

21
Parturition Process
  • Several hours later the placenta and other
    membranes (afterbirth) are expelled
  • A retained placenta is deadly

22
Animal Genetics
  • Genotype
  • kinds of gene pairs the animal has

23
Dominant Genes
  • Genes in a pair that hides or dominates the
    effect of the other gene in the pair
  • Indicated by upper-case letters
  • Ppolled

24
Recessive Genes
  • Genes that are hidden or covered by the dominant
    gene in the pair
  • Indicated by lower-case letters
  • p horned

25
Homozygous
  • Homozygous gene pair carries two genes for the
    same trait
  • PP polled and polled.

26
Heterozygous
  • Heterozygous gene pairs carries two different
    genes that affect a trait
  • Pp polled, horned

27
Sex Determination
  • Half the sperm carries an X chromosome and one
    half carries a Y chromosome
  • All the ova carry an X chromosome
  • Male offspring in mammals
  • XY
  • Females
  • XX
  • In poultry the chromosome configuration is
    opposite of mammals

28
Sex-Linked Characteristics
  • Some traits are carried on only the X chromosome
    and some on only the Y chromosome
  • Traits on the Y chromosome are transmitted only
    from fathers to sons
  • Certain genes are expressed in only one sex
    although they are carried by both sexes
  • milk production
  • egg laying
  • rooster tail feathers
  • Sex-linked traits are often recessive and are
    covered by dominant genes

29
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30
Incomplete Dominance
  • Takes place when one gene does not completely
    hide the effect of other gene
  • The offspring has a mixture of the two traits
  • Roan color is a mixture of red and white

31
Linkage
  • The tendency for certain traits to appear in
    groups in the offspring because the genes for
    those traits are located near each other on the
    chromosome and stay together to pass traits in
    groups

32
Crossover
  • Chromosomes cross over one another and split to
    form new chromosomes with different combinations
    of genes

33
Crossover
34
Mutation
  • A new trait appears
  • Did NOT exist in the genetics of either parent

35
Punnett Square
  • Used to predict the results of crossing animals
  • Male gametes are shown across the top
  • Female gametes are shown down the left side

36
Punnett Square
  • P Polled
  • p horned
  • Example
  • Two polled cattle that are homozygous for the
    polled trait

Polled Sire
Polled Dam
37
Punnett Square
  • N Normal size
  • n Dwarfism
  • Example
  • Normal size in cattle is dominant to dwarfism

Sire
Dam
38
Punnett Square
  • N Normal size
  • n Dwarfism
  • Example
  • What if both parents are carriers for a trait or
    disorder?

Sire
Dam
What is the probability that a Homozygous dwarf
calf is born?
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