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Animal Reproduction and Genetics. Terminology. Objective: Define terminology related to reproductive management and breeding systems including castration, colustrum, estrus, gestation, lactation and parturition. . Terminology. Castration Removing the testicles of the male to prevent breeding

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Animal Reproduction and Genetics

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  • Objective:
    • Define terminology related to reproductive management and breeding systems including castration, colustrum, estrus, gestation, lactation and parturition.
  • Castration
    • Removing the testicles of the male to prevent breeding
  • Colustrum
    • First milk
  • Gestation
    • Time an animal is pregnant
  • Estrus
    • When a female is receptive to be bred
  • Lactation
    • Period of time that milk is secreted by the mammary glands
  • Parturition
    • Than act of giving birth
breeding systems
Breeding Systems
  • Objective
    • Discuss crossbreeding, grading-up, inbreeding, linebreeding, and purebreeding
breeding systems6
Breeding Systems
  • Pure Breeding
    • Registered male and female animals
    • Angus X Angus


breeding systems7
Breeding Systems
  • Cross Breeding
    • Mating a male and female of different breeds
    • Angus X Charolais = Crossbreed


breeding systems8
Breeding Systems
  • Inbreeding
    • Mating closely related animals
    • Brother X Sister
    • Son X Mother
    • Father X Daughter
breeding systems9
Breeding Systems
  • Linebreeding
    • Breeding more distant relatives than inbreeding
    • Cousin X Cousin
breeding systems10
Breeding Systems
  • Grading-Up
    • Mating purebred male (sires) to unregistered or corssbred females (dams)
    • Yorkshire bore X Yorkshire/Hampshire sow
    • Hybrid Vigor
      • Superior traits from crossbreeding
      • Offspring are better than parents
the female reproductive system

The Female Reproductive System

Objective: Identify the parts of the female reproductive system of livestock

female reproductive system
Female Reproductive System
  • Ovary - the ovary is comparable to the male testicle and is the site of gamete production.
    • A bovine animal has 20,000 potential eggs per ovary, while a human female has 400,000 potential eggs per ovary.
    • Ova are fully developed at puberty and are not continuously produced as in the male.
    • All species contain two functional ovaries except for the hen which has only a left functioning ovary.
female reproductive system15
Female Reproductive System

The ovaries have three major functions:

  • Gamete production
  • Secrete estrogen (hormone)
    • absence of muscle development
    • development of mammary glands
    • development of reproductive systems and external genitalia
    • fat deposition on hips and stomach (source of energy)
    • triggering of heat
  • Form the corpus luteum
female reproductive system16
Female Reproductive System
  • Infundibulum - the funnel shaped portion of the fallopian tube near the ovary that catches the ovulated egg.
  • Fallopian Tubes (or Oviducts) - pair of small tubes leading from the ovaries to the horns of the uterus (5 - 6 inches).
    • Fertilization occurs in the oviduct.
    • Egg travels from ovary to uterine horn in 3 - 4 days.
female reproductive system18
Female Reproductive System
  • Uterine Horn - The anterior, divided end of the uterus in the cow, ewe, and mare. Sow has only 2 horns, no body, woman has no horns, only body.
female reproductive system20
Female Reproductive System

Uterus - Muscular sac connecting fallopian tubes and cervix

1. Sustains the sperm and aids in its transport 2. Supports embryo and fetus during gestation

3. Expels fetus at parturition

female reproductive system21
Female Reproductive System
  • Cervix
    • Area between the uterus and vagina
    • Normally closed
    • Opens at estrus and parturition
    • (2 -3 inches)
female reproductive system22
Female Reproductive System
    • Vagina - the female organ of copulation

1. admits penis

2. receives semen (except in sow)

3. passageway for fetus at parturition

  • Bladder - storage organ for urine
  • Vulva - extended genitalia; opening for both urinary and genital tracts
reproductive functions female
Reproductive Functions (Female)

Steps in the female reproductive process:

1. Ovulation

  • Produce gamete (ova or ovum)
  • Release of egg(s)
  • Infundibulum pushes the ovum into the fallopian tube
reproductive functions female26
Reproductive Functions (Female)

2. Estrus (heat, estrous period)

  • Period of time when a female will accept a male in copulation
  • The female must stand (standing heat) to be mounted before the reproductive process can begin
reproductive functions female27
Reproductive Functions (Female)

3. Gestation

  • Fertilization to parturition
  • Develop embryo in uterus

4. Parturition

  • Expel fully developed young at birth

5. Lactation

  • Milk production
ovulation rates
Ovulation Rates

Ovulation Rates by Species

Cow- 1 egg per estrus

Ewe- 1 to 3 eggs per estrus

Sow- 10 to 20 eggs per estrus

Mare- 1 egg per estrus

Hen- Approx. 28 eggs per month

reproductive terminology
Reproductive Terminology
  • Species Act Offspring
  • Cows calving calf
  • Ewes lambing lamb
  • Sows farrowing pig
  • Hens hatching chick
  • Mares foaling foal
  • Goats kidding kid
reproductive functions female31
Reproductive Functions (Female)

Gestation and Lactation Periods:

Species Gestation Period Lactation(Milking)

Cow 275 - 285 days beef 180 - 270 days dairy 305 - 365 days

Ewe 115 - 142 days 60 - 90 - 120 days

Sow 112 - 115 days 21 - 42 days

Mare 330 - 345 days 90 - 150 days

Woman 270 days ? years

reproductive functions female32
Reproductive Functions (Female)

Estrous period length by species:

Cow 12 - 18 hours

Ewe 24 - 36 hours

Sow 48 - 72 hours

Mare 90 - 170 hours

Hens & Women none

reproductive functions of the female
Reproductive Functions of the Female

Estrous cycle - time from one heat period (or menstrual cycle) to the next.

Length of estrous cycle by species:

Cow 19 - 21 days

Ewe 16 - 17 days

Sow 19 - 21 days

Mare 21 - 24 days

Woman 28 days

Hen none

the male reproductive tract

The Male Reproductive Tract

Objective: Identify the parts of the male reproductive system of livestock and poultry

male reproductive tract36
Male Reproductive Tract
  • Scrotum - external sac that holds testicles outside of the body to keep sperm at 4-5oF cooler than the body temperature
  • Testicles - the primary male organs of reproduction
    • to produce sperm
    • to secrete testosterone
male reproductive tract37
Male Reproductive Tract
  • Epididymis - Long coiled tube that is a path for sperm
    • Provide passageway for sperm out of the seminiferous tubules
    • Storage for sperm
    • Fluid secretion to nourish sperm
    • Place for sperm maturation
male reproductive tract38
Male Reproductive Tract
  • Vas Deferens - slender tube from epididymis to urethra which moves sperm to the urethra at ejaculation
  • Urethra - long tube from bladder to penis; passageway for urine and sperm out of the body
male reproductive tract39
Male Reproductive Tract
  • Penis - male organ of copulation which conveys semen and urine out of the body
  • Penis retractor muscle - allows extension and retraction of the penis; sigmoid flexure extends in copulation
male reproductive tract40
Male Reproductive Tract

Accessory Glands:

  • Seminal vesicles- add fructose and citric acid to nourish the sperm
  • Prostate Gland - located at the neck of the bladder
    • cleans the urethra prior to and during ejaculation
    • provides minerals for sperm
    • provides the medium for sperm transport
    • provides the characteristic odor of semen
male reproductive tract41
Male Reproductive Tract
  • Cowper’s gland
    • Also called the Bulbourethral gland
    • Paired organs
    • cleans the urethra prior to semen passage
reproduction in poultry

Reproduction in Poultry

Objective: Specify how the reproductive system for poultry functions

reproduction in poultry46
Reproduction in Poultry

The poultry oviduct has five parts:

1) Vagina

  • Holds the egg until laid

2) Uterus

  • Secretes the shell

3) Isthmus

  • Adds the two shell membranes

4) Magnum

  • Secretes the albumen

5) Infundibulum

  • Where fertilization takes place
reproduction in poultry49
Reproduction in Poultry
  • Major difference:
    • Embryo of livestock develop inside the female’s body while the embryo of poultry develops inside the egg.
  • Poultry only have the left ovary and oviduct when mature
  • The yoke is the ovum
  • Chicken Incubation
    • 21 days
poultry reproduction
Poultry Reproduction

In your notes, define the following poultry reproductive terms and tell how they differ from livestock we have studied so far:

  • Ovary
  • Magnum
  • Isthmus
  • Uterus
  • Vagina
  • Papilla
  • Testicles
  • Cloaca
  • Vent

Follow the Lecture


Build a crossword puzzle containing 12 reproductive terms from your class notes. Have another student complete and sign your crossword puzzle. The assignment as well as your other assignment from the handout is due at the end of class.

animal reproduction and genetics52

Animal Reproduction and Genetics

Objective: Describe the cell and process involved in cell division including how genes affect the transmission of characteristics

animal cell
Animal Cell
  • The body is made up of millions of tiny cells
  • Most of the cell is made up of protoplasm
  • Cell parts:
    • Nucleus
    • Cytoplasm
    • Cell membrane
animal cell54



Cell Membrane

Animal Cell
cell division
Cell Division
  • Mitosis
    • Increases total number of cells
    • Results in animal growth
    • Chromosomes pairs are duplicated
  • Meiosis
    • Produces gametes
    • Only have one-half the chromosomes of normal cells
  • When the sperm from a male reaches the egg from a female
  • Two cells join to form a complete cell
  • Pairs of chromosomes are formed again
  • Many different combinations of traits are formed
Rod shaped bodies

Made of protein

Found in the cell nucleus

Exist in pairs except for gamete cells

The number of chromosome pairs differ for various animals

Cattle 30

Swine 19

Horses 33

Chickens 6

Humans 23

  • Located on chromosomes
  • Thousands found in each animal
  • Control inherited characteristics
    • Carcass traits
    • Growth rate
    • Feed efficiency
  • Two types of inherited traits
    • Dominant
    • Recessive
  • Read pages 186
    • Livestock and Poultry Production textbook
  • Complete problems 1-9
  • Write the question and provide a short answer in complete sentences.
  • Dominant gene
    • Hides the effect of another gene
    • Polled condition in cattle is dominant
    • The gene is represented by a capital letter
  • Recessive
    • Gene that is hidden by another
    • The gene is represented by a lower case letter


The dominant gene is written- P

The recessive gene is written-p

P= Polled

p= horned

homozygous and heterozygous
Homozygous and Heterozygous
  • Homozygous gene pair
    • Carries two genes for a trait
    • Polled cow might carry the gene PP
  • Heterozygous
    • Carries two different genes that affect a trait
    • Polled cows might carry a recessive gene with the dominant Pp
predicting genotype
Predicting Genotype
  • Genotype-kind of gene pairs possessed
  • Phenotype- the physical appearance of an animal
  • Punnett squares are used to predict genotypes and phenotypes of animals
punnett square
Punnett Square

P= Polled

p= horned


  • Two polled cattle that are homozygous for the polled trait

Polled Dam

Polled Sire

punnett square66
Punnett Square

N= Normal size

n= Dwarfism


  • Normal size in cattle is dominant to dwarfism

Normal Dam

Sire Carrier

punnett square67
Punnett Square

N= Normal size

n= Dwarfism


  • What if both parents are carriers for a trait or disorder?

Normal Dam

Sire Carrier

Result: one out of every four births could result in a dwarf animal (1:2:1)


Complete a Punnett Square for two animals that are heterozygous for two traits:

  • Polled=P
  • Black= B

(Alternatives are horned and red)





  • A Punnett Square for two animals that are heterozygous for two traits:
  • Polled=P
  • Black= B
  • (Alternatives are horned and red)




  • Objective:
    • Discuss hertability estimates for beef and swine
  • Estimated the likelihood of a trait being passes on from the parent to the offspring
    • Low heritability
      • slow herd improvement
    • High heritability
      • faster improvement
  • Swine rates are usually lower than cattle
  • Heritiability for carcass traits are higher than reproductive traits
  • Estimates vary from 0 to 70%

Heritability Estimates

Birth weight 40%

Weaning Weight 25-30%

Yearling Weight 60%

Fertility 10%

Tenderness 60%

heritability review
Heritability Review
  • Herd improvement
    • slow for low heritability
    • faster for high heritability
  • Estimates are higher for:
    • beef compared to swine
    • carcass traits compared to repro