Animal Reproduction Animal Science II Estrus Cycle Time of day when a female will accept a...

Animal Reproduction

Animal Science II

Estrus Cycle

• Time of day when a female will accept a ____________ for ________________

• Length– ______ day cycle

• Cow- _________________ hours• Sow- __________ days

• Best indicator is when the animal stands to be _________________

Ovulation

• Release of the _______ from the _____________

• Number of young born is an indicator of _________ released– Sows: _____ to ______– Cow: _________

• Split eggs produce _________, triplets, etc.

Methods of Reproduction

• ___________________• Artificial Insemination (_____)• _______________ Transfer• ____________ using Nuclear Transfer

Artificial Insemination

• Steps– Insert hand into the _____________ and

grasp ___________– Insert insemination _________– Deposit bull ___________ from the

middle of the ______________ to just into the _____________.

Artificial Insemination

Bovine Reproductive Tract Diagram

Artificial Insemination

Sow Reproductive Tract Diagram

Artificial Insemination

Artificial Insemination

Artificial Insemination

Artificial Insemination

• Advantages– Wider variety of superior _________

used– Increase number of _________ that can

be bread to a superior ________– Reduces _______________– Don’t have to keep a _________ on the

___________

Artificial Insemination

Artificial Insemination

• Disadvantages– Requires a ____________ inseminator– Requires more ____________ and herd

_______________

Embryo Transfer

• Procedures– ________________ donor– AI– Flush ______________ (catheter)– ___________ and ____________ embryos– Store in liquid ______________– Transfer to ____________– Diagnose pregnancy ____ to ____ months

later

Embryo Transfer

• Advantage– __________ of the female (dam) can be

passed on ____________ than natural breeding

Cloning

• Using Nuclear Transfer• Procedures

– __________ (same as embryo transfer)– ___________– Remove _____________ materials from

recipient oocytes– ____________ is removed through

microsurgery

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

Cloning

• Advantages– Increase herd __________________– Increase herd ________________– Produce genetically identical animals

Parturition Process

• Increased ______________ causes uterus muscles to contract

• Water bag appears and ____________

• The __________ water bag appears with the ____________

Parturition Process

• Normal Presentation• Front ___________ first• ______________• ______________ and shoulders• _____________• Rear ___________• Rear ___________ last

• Any presentation not in order could cause ___________ of the baby and/or mother

Parturition Process

• Several hours later the ________________ and other membranes (_______________) are expelled– A retained placenta is

_________________

Animal Genetics

• Genotype– kinds of ____________ pairs the

animal has

Dominant Genes

• Genes in a pair that hides or _______________ the effect of the other gene in the pair

• Indicated by _____________________ letters

• P=___________

Recessive Genes

• Genes that are ______________ or covered by the dominant gene in the pair

• Indicated by _____________________ letters

• p = _____________

Homozygous

• Homozygous gene pair carries two genes for the ______________ trait– PP = polled and polled.

Heterozygous

• Heterozygous gene pairs carries two ____________ genes that affect a trait– Pp = polled, horned

Sex Determination

• Half the sperm carries an ___ chromosome and one half carries a __ chromosome

• All the _____ carry an ___ chromosome– Male offspring in mammals

• ____

– Females• ____

• In ___________ the chromosome configuration is opposite of mammals

Sex-Linked Characteristics

• Some traits are carried on only the __ chromosome and some on only the ___ chromosome– Traits on the ____ chromosome are transmitted only

from fathers to sons

• Certain genes are expressed in only one ______ although they are carried by both _______– ________ production– _______ laying– rooster tail feathers

• Sex-linked traits are often ___________ and are covered by ______________ genes

Incomplete Dominance

• Takes place when _____ gene does not completely _______ the effect of other gene

• The offspring has a __________ of the two traits– Roan color is a mixture of red and

white

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

Crossover

• Chromosomes cross over one another and _________ to form new ______________ with different combinations of genes

Crossover

Mutation

• A new ______ appears• Did NOT ________ in the genetics of

either parent

Punnett Square

• Used to __________ the results of crossing animals– Male __________ are shown

across the ______– __________ gametes are

shown down the _______ side

Punnett Square

P= Polledp= hornedExample:• Two polled cattle

that are homozygous for the polled trait

P P

P PP PP

P PP PPPol

led

Dam

Polled Sire

Punnett Square

N= Normal sizen= DwarfismExample:• Normal size in

cattle is dominant to dwarfism

N N

N NN NN

n Nn NnD

am

Sire

Punnett Square

N= Normal sizen= DwarfismExample:• What if both

parents are carriers for a trait or disorder?

N n

N NN Nn

n Nn nn

Dam

Sire

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