1. Animal Reproduction and Genetics

2. Terminology Objective:
Define terminology related to reproductive management and breeding systems including castration, colustrum, estrus, gestation, lactation and parturition.

3. Terminology Castration
Removing the testicles of the male to prevent breeding
Colustrum
First milk produced after a mammal gives birth that contains antibodies needed for immunity.
Gestation
Time an animal is pregnant

4. Terminology
Estrus
When a female is receptive to be bred (also called ‘in heat’)
Lactation
Period of time that milk is secreted by the mammary glands
Parturition
The act of giving birth

5. Breeding Systems Objective
Discuss crossbreeding, grading-up, inbreeding, linebreeding, and purebreeding

6. Breeding Systems X Pure Breeding Registered male and female animals
Angus X Angus X

7. Breeding Systems X Cross Breeding
Mating a male and female of different breeds
Angus X Charolais = Crossbreed X

8. Breeding Systems Inbreeding Mating closely related animals
Brother X Sister
Son X Mother
Father X Daughter

9. Breeding Systems Linebreeding
Breeding more distant relatives than inbreeding
Cousin X Cousin

10. Breeding Systems Grading-Up
Mating purebred male (sires) to unregistered or crossbred females (dams)
Yorkshire boar X Yorkshire/Hampshire sow
Hybrid Vigor
Superior traits from crossbreeding
Offspring are better than parents

11. The Female Reproductive System
Objective: Identify the parts of the female reproductive system of livestock

12. Female Tract

13. 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.

14. 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

15. Female Reproductive System
Infundibulum - the funnel shaped portion of the fallopian tube near the ovary that catches the ovulated egg.
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 days.

16. 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

17. Female Reproductive System
Cervix
Area between the uterus and vagina
Normally closed
Opens at estrus and parturition
(2 -3 inches)

18. Female Reproductive System
Vagina - the female organ of copulation
1. admits penis
2. receives semen
3. passageway for fetus at parturition
Vulva - extended genitalia; opening for both urinary and genital tracts

19. 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

20. Reproductive Functions (Female)

21. Reproductive Functions (Female)
Estrus (heat, estrous period)
Period of time when a female will accept a male in copulation

22. Reproductive Functions (Female)
3. Gestation
Fertilization to parturition
Develop embryo in uterus
4. Parturition
Expel fully developed young at birth
5. Lactation
Milk production

23. 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

24. Reproductive Terminology
Species Act Offspring
Cows
Ewes
Sows
Hens hatching chick
Mares
Goats

25. Species Act Offspring
Cows calving calf
Ewes lambing lamb
Sows farrowing pig
Hens hatching chick
Mares foaling foal
Goats kidding kid

26. Reproductive Functions (Female)
Gestation and Lactation Periods:
Species Gestation Period Lactation(Milking)
Cow days beef days dairy days
Ewe days days
Sow days days
Mare days days
Woman days ? years

27. Reproductive Functions (Female)
Estrous period length by species: Cow hours Ewe hours Sow hours Mare hours Hens & Women none

28. 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 days Ewe days Sow days Mare days Woman 28 days Hen none How to AI a Cow

29. The Male Reproductive Tract
Objective: Identify the parts of the male reproductive system of livestock and poultry

30. Male Reproductive Tract

31. 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

32. Male Reproductive Tract
Epididymis - Long coiled tube that is a path for sperm (connected to each testicle)
Provide passageway for sperm out of the seminiferous tubules
Storage for sperm
Place for sperm maturation

33. Male Reproductive Tract
Vas Deferens - slender tube from epididymis to urethra which moves sperm to the urethra
Urethra - long tube from bladder to penis; passageway for urine and sperm out of the body

34. Male Reproductive Tract
Penis - male organ of copulation which conveys semen and urine out of the body, covered by a sheath

35. Male Reproductive Tract
Accessory Glands:
Seminal Vesicles
Function: Produce a fluid that protects and transports sperm.
Description: A gland that opens into urethra.
Prostate Gland
Function: Produces a fluid that is mixed with the seminal fluid.
Description: Gland near the urethra and bladder.

36. Male Reproductive Tract
Cowper’s Gland
Function: Produces a fluid that moves down the urethra ahead of the seminal fluid. It cleans and neutralizes the urethra to protect the sperm.
Description: A gland near the urethra.

37. Male Reproductive Tract

38. Reproduction in Poultry
Objective: Specify how the reproductive system for poultry functions

40. Reproduction in Poultry
Ovary- poultry only have one functioning ovary as compared to livestock animals.
Function: Produces ova and hormones. The yolk of an egg is the ovum.
Description: An attached cluster of yellow, round egg yolks.
Infundibulum
Function: The place where fertilization takes place.
Description: Funnel shaped structure located just below the ovary. It is the start of the oviducts.

41. Reproduction in Poultry
Oviduct- tube like structure that consists of five parts:
Magnum- secretes the thick egg white or albumen.
Isthmus- adds the two shell membranes.
Uterus- secretes the thin white, the shell and the shell pigment.
Vagina- holds the egg until it is laid.

42. Reproduction in Poultry
Cloaca
Function: Location where the papilla of the male bird deposits semen. Egg also passes through this part.
Description: Located between vent and base of oviduct.
Vent
Function: Expel egg, liquid and solid waste.
Description: Outside opening to the poultry reproductive tract.

45. Reproduction in Poultry
The major difference between mammals and poultry reproductive systems is that the embryo of livestock develops inside the female’s body and the poultry embryo develops outside the body. Papilla is the organ in male poultry’s cloaca wall that puts the sperm in the hen’s reproductive tract
Chickens (domestic birds) have only the left ovary and oviduct functional at maturity (produce eggs). The right ovary and oviduct do not function.

46. Reproduction in Poultry
Egg- function is reproduction, but is eaten as food by humans and wild animals.
Domestic chickens lay an egg every hours regardless even if sperm are not present. Commercially sold eggs are not fertilized.
Incubation time for chicken eggs is 21 days.
Turkeys and ducks eggs incubation is 28 days.

47. Animal Reproduction and Genetics
Objective: Describe the cell and process involved in cell division including how genes affect the transmission of characteristics

48. Parts of a cell
Protoplasm- the material or contents inside of a cell.

49. Parts of a cell
Cell Membrane- a thin layer of protein and fat that surrounds the cell. Some substances can pass into the cell and the membrane blocks others materials from entering.
Cell Membrane

50. Parts of a cell
Centrosome- small body where the microtubules are made. The centrosome divides during mitosis.
Centrosome

51. Parts of a cell
Nucleus- gives cell ability to grow, digest food and divide. Contains chromosomes and DNA.
Nucleus

52. Parts of a cell
Cytoplasm- a jellylike substance that gives the cell shape and contains components necessary for cell functions.
Cytoplasm

53. Parts of a cell
Golgi body- located near the nucleus and produces the membrane that surrounds the lyosomes.
Golgi body

54. Parts of a cell
Lyosome- round shaped organelles that contain digestive enzymes that allow for digestion of cell nutrients.
Lysosome

55. Parts of a cell
Mitochondrion- rod-shaped organelles that convert the energy stored in glucose into ATP (adenosine triphosphate).
Mitochondrion

56. Parts of a cell
Nuclear membrane- the membrane that surround the nucleus.
Nuclear membrane

57. Parts of a cell
Nucleolus- organelle found inside the nucleus. Produces ribosomal RNA.
Nucleolus

58. Parts of a cell
Endoplasmic Reticulum- transports materials through the cell.
Rough ER
Smooth ER

59. Parts of a cell
Vacuole- fluid filled membrane that fills with food and waste products inside the cell.
Vacuole

60. Parts of a cell
Ribosome- site of protein synthesis.
Ribosome

61. Cell Division Two types of cell division that we must know: Mitosis
Meiosis
Videos:

62. Mitosis – what is it?
Mitosis is a type of cell division that increases the total number of cells and results in animal growth with the chromosome pairs being duplicated in each new cell.
Results in animal growth.
Animals begin as a single cell.
Chromosomes are duplicated in each new cell as division occurs.

63. Mitosis There are four typical stages in mitosis cell division:
Prophase
Metaphase
Anaphase
Telophase

64. Mitosis – Stage 1
Prophase- the nucleolus disappears and centrioles move to opposite ends of the cell. Fibers begin to form and extend from the centromeres.

65. Mitosis – Stage 2
Metaphase- spindle fibers align the chromosomes along the middle of the cell nucleus.

66. Mitosis – Stage 3
Anaphase- the paired chromosomes separate and move to opposite sides of the cell.

67. Mitosis – Stage 4
Telophase- nuclear membrane forms around the newly divided chromosomes and cell membrane begins to contract.

68. Now to meiosis…..

69. Cell Division Two types of cell division that we must know: Mitosis
Meiosis
Videos:

70. Meiosis
Meiosis is a type of cell division that produces the sex cells or gametes that have ½ the number of chromosomes that body cells have.

71. Meiosis Gamete Formation
One set of chromosomes come from the sperm and one from the ovum.
The zygote that is created during fertilization has chromosomes from each parent. Chromosomes match up with one another based on the genetic information they carry.

72. Meiosis
Sex cell formation of the sperm and ova are also produced through meiosis:
Production of sperm is called spermatogenesis.
Male animals begin producing sperm at sexual maturity.
Spermatocytes divide into spermatids through meiosis.

73. Meiosis
Sex cell formation of the sperm and ova are also produced through meiosis:
Production of an ovum is called oogenesis.
Females also begin releasing ova at sexual maturity.
The oocytes divide and form an ovum. The ovum contains cytoplasm and stored food. It provides nourishment for the zygote and embryo.

74. Fertilization 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

75. Fertilization

76. Meiosis – putting it all back together…

77. Chromosomes 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 32
Chickens 39
Humans 23

78. Genes Located on chromosomes Thousands found in each animal
Control inherited characteristics
Carcass traits
Growth rate
Feed efficiency
Two types of inherited traits
Dominant
Recessive

79. Genes 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

80. Genes
Example: The dominant gene is written- P The recessive gene is written-p P= Polled p= horned

81. 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

82. 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

83. Genotypes Three class genotypes Homozygous Dominant = PP
Homozygous Recessive = pp
Heterozygous = Pp
P = Polled & p = horned
Six possible crosses:
PP x PP, PP x Pp, PP x pp, Pp x Pp, Pp x pp, pp x pp

84. Punnett Square P= Polled p= horned P Example:
Polled Dam
P= Polled
p= horned
Example:
Two polled cattle that are homozygous for the polled trait
Genotypic Ratio: 4PP : 0
Phenotypic Ratio:4 polled animals
Polled Sire
Polled Dam P PP
Polled Sire

85. Punnett Square N= Normal size n= Dwarfism Example:
Normal Dam
N= Normal size
n= Dwarfism
Example:
Normal size in cattle is dominant to dwarfism
Genotypic Ratio:
Phenotypic Ratio:
Sire Carrier
Normal Dam N NN n Nn
Sire Carrier

86. Punnett Square N= Normal size n= Dwarfism Example:
Normal Dam
N= Normal size
n= Dwarfism
Example:
What if both parents are carriers for a trait or disorder?
Genotype:
Phenotype:
Sire Carrier
Normal Dam N n NN Nn nn
Sire Carrier

87. Assignment
Complete a Punnett Square for two animals that are heterozygous for two traits:
Polled=P
Black= B
(Alternatives are horned and red)
Dam
Sire

88. Answer
A Punnett Square for two animals that are heterozygous for two traits:
Polled=P
Black= B
(Alternatives are horned and red)
Dam PB Pb pB pb
PPBB
PPBb
PpBB
PpBb
PPbb
Ppbb
ppBB
ppBb
ppbb
Sire

89. Heritability Objective:
Discuss hertability estimates for beef and swine

90. Heritability
Estimated the likelihood of a trait being passes on from the parent to the offspring
Low heritability
slow herd improvement
High heritability
faster improvement

91. Heritability Swine rates are usually lower than cattle
Heritiability for carcass traits are higher than reproductive traits
Estimates vary from 0 to 70%
Traits with low heritability estimates are improved most through environment, and those traits with high heritability estimates are improved most by selective breeding and environmental improvements.

92. Heritability Estimates
Birth weight 40%
Weaning Weight %
Yearling Weight 60%
Fertility 10%
Tenderness 60%

93. 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