1. For: ADVS 1110 Introduction to Animal Science
ANIMAL REPRODUCTION
For:
ADVS 1110
Introduction to Animal Science

2. Farm Animal Reproduction is About a Full Understanding of the Roles and Missions of:

3. Farm Animal Reproduction – Major Topics:
General Reproduction
Hormones & Endocrinology
Female Reproduction
Male Reproduction
Conception
Pregnancy & Parturition
Artificial Insemination
Embryo Transfer

7. Reproduction - Hormones
Hormones are chemical mediators produced by the endocrine glands that regulate the function of target organs in another part of the body.

8. ‘Negative Feed-Back’ Mechanism Between the Target Hormone and the Parent Secretory Units

9. Reproduction - Hormones
Endocrine Feedback with CL Present.

10. Reproduction - Hormones
Reproductive Hormones are Produced by the:
Pineal Gland (photoperiod)
Seasonal Breeders
Hypothalmus
Pituitary Gland
Ovaries
Testes
Placenta

11. Reproduction - Hormones
Hormones regulate all of the critical steps in successful reproduction in both sexes, including:
Puberty
Ovulation
Transport of Sperm and Ova

12. Reproduction - Hormones
In the female reproductive tract hormones regulate:
Maintenance of Pregnancy
Parturition

13. Reproduction - Hormones
In the male, hormones regulate:
Puberty
Sperm Production
Development and Maintenance of Accessory Sex Glands
Secondary Sex Characteristics
Libido

14. Reproduction - Hormones
Glands & Hormones Affecting Reproductive Processes – Summary:
Gland Secreting Hormone
Name of Hormone
Function of Hormone
Anterior Pituitary
FSH (follicle stimulating hormone)
1. Initiates follicular growth (oogenesis)
2. Influence spermatogenesis
3.Synthetic products (Ovagen, Folltropin)
LH (luteinizing hormone)
1. Stimulates growth of tissues in gonads which secrete hormones
2. Acts with FSH to cause ovulation.
3. Causes corpus luteum formation

15. Reproduction - Hormones
Glands & Hormones Affecting Reproductive Processes – Summary:
Gland Secreting Hormone
Name of Hormone
Function of Hormone
Anterior Pituitary
Prolactin
1. Ovary: maintains functional capacity of the corpus luteum
2. Mammary gland: stimulates formation of milk in alveoli
3. Causes broodiness in birds

16. Reproduction - Hormones
Glands & Hormones Affecting Reproductive Processes – Summary:
Gland Secreting Hormone
Name of Hormone
Function of Hormone
Posterior Pituitary
Oxytocin
1. Uterus: stimulates contraction (birth, avian egg laying)
2. Mammary gland: initiates let-down of milk into ducts and cisterns

17. Reproduction - Hormones
Glands & Hormones Affecting Reproductive Processes – Summary:
Gland Secreting Hormone
Name of Hormone
Function of Hormone
Ovary (Follicle)
Estrogen
1. Stimulates growth of accessory reproductive organs and secondary sex characteristics
2. Induces estrus (heat)
3. Mammary gland: stimulates development of the duct system

18. Reproduction - Hormones
Glands & Hormones Affecting Reproductive Processes – Summary:
Gland Secreting Hormone
Name of Hormone
Function of Hormone
Ovary (Corpus Luteum)
Placenta
Progesterone
1. Inhibits release of FSH & LH
2. Prepares uterus for implantation
3. Maintains pregnancy
4. Mammary gland: develops alveolar system
5.Synthetic product (CIDR and Regumate)

19. Reproduction - Hormones
Glands & Hormones Affecting Reproductive Processes – Summary:
Gland Secreting Hormone
Name of Hormone
Function of Hormone
Cervix
Relaxin
1. Relaxes pubic bones and cervix (birth)
Testes
Androgen
(Testerone)
1. Stimulates sexual desire
2. Stimulates growth of accessory reproductive organs and secondary sex characteristics

20. Reproduction - Hormones
Glands & Hormones Affecting Reproductive Processes – Summary:
Gland Secreting Hormone
Name of Hormone
Function of Hormone
Hypothalmus
Gonadotrophin-Releasing Hormone (GnRH)
Causes release of FSH and LH from anterior pituitary
Synthetic products (Cystorelin, Fertagyl, Factrel, OvaCyst)
Uterus
Prostaglandin F2 alpha
Causes regression of corpus luteum in sheep, cattle and swine
Synthetic products (Lutalyse, ProstaMate, Estrumate, In-Synch, estroPLAN)

22. The Reproductive Cycle of Farm Animals

23. Farm Animal: Female Reproduction

24. Reproduction - Female
Successful livestock production depends upon obtaining the optimum number of viable offspring per year from each producing female:

25. Reproduction - Female Beef & Dairy Cattle
Giving birth to one offspring per pregnancy
Efficient reproduction means obtaining a calf each year from as many cows as possible.

26. Reproduction - Female Sheep & Goats:
Obtaining more than one lambing/kidding per year, if possible, or
At least two lambs/kids per ewe per year.

27. Reproduction - Female Swine: Two litters per year,
Having at least 8-9 piglets weaned per farrowing

28. Reproduction - Female Poultry (laying hens):
The highest number of eggs per hen per year,
Or minimally 285 eggs per year.

29. Reproduction - Female
For high reproductive efficiency, farm animals should:
Reach puberty at an early age.
Possess high levels of fertility and/or fecundity.
Raise a high proportion of their offspring.

30. Reproduction - Female
CURRENT ESTIMATES OF REPRODUCTIVE EFFICIENCY IN FARM ANIMALS
ANIMAL
STANDARD OF PERFORMANCE*
ESTIMATE OF CURRENT PERFORMANCE
ATTAINABLE PERFORMANCE
Dairy Cattle
Calving Interval
months
12-13 months
Beef Cattle
Calf Crop/Cow/Year
75-82%
90%+
Sheep
Lambs Weaned/Ewe/Year
1.01
3.0+
Swine
Pigs Marketed/Sow/Year
13.5
20+
Chickens
Eggs Laid/Year
235
285+
Turkeys 97
130+
*Commonly used standards of reproductive performance.

31. Reproduction - Female GESTATION LENGTH AND NUMBER OF OFFSPRING BORN:
Gestation Length in Days
Usual Number of Offspring Born
Cow (cattle)
283 1
Ewe (sheep)
150
1 – 3
Mare (horse)
346
Sow (swine)
115
6 – 14
Doe (goat)
2 – 3
Doe (rabbit) 31
4 – 8
Jill (mink) 50 4
Queen (cat) 52
Bitch (dog) 60 7

32. Reproduction - Female
Anatomy: Cow Tract Side View

33. Reproduction - Female

34. Reproduction - Female
Anatomy: Cow Reproductive Tract.

35. Reproduction - Female
Cow Reproductive Tract

36. Reproduction - Female
Reproductive Tracts of Ewe, Sow & Mare:

37. Reproduction - Female
Anatomy: Side view of the sow reproductive tract.

38. Reproduction - Female
Anatomy: Side View of the Sow Reproductive Tract:
Ovary
Follicles
Oviduct
Body of Uterus
Cervix
Os Cervix & Fornix
Vagina
Sub-urethral Diverticulum
Bladder

39. Reproduction - Female

40. Reproduction - Female
Gilt Reproductive Tract

41. Reproduction - Female
Anatomy: Ewe Tract

42. Reproduction - Female
Anatomy: Mare Reproductive Tract

43. Reproduction - Female
Anatomy: Mare Reproductive Tract

44. Reproduction - Female
Anatomy: Avian (hen) Reproductive Tract

45. Reproduction - Female

46. Reproduction - Female
Avian Reproductive Tract:

47. Reproduction - Female
Avian Reproductive Tract:

48. Reproduction - Female
Avian Reproductive Tract:

49. Reproduction - Female
Avian Reproductive Tract:

50. Reproduction - Female
Ovary Diagram: Not all present at once

51. Reproduction - Female
Ovary - Cow
Ovary - Sow

52. Reproduction - Female Estrous Cycle = Anestrus + Estrus
Seasonally Polyestrous:
Ewe
Doe
Mare
Polyestrous:
Cow
Sow

53. Reproduction - Female

54. Reproduction - Female
Endocrine Control of Female Mammalian Reproductive Cycle:

55. Reproduction - Endocrinology

56. Reproduction - Female
Hormonal Control of the Estrous Cycle

57. Reproduction - Female
Ovary Through Estrous Cycle:

58. Reproduction - Female
Estrous Cycle:

59. Cow: Rise & decline of reproductive hormones during a typical 21-day estrous cycle

60. Reproduction - Hormones

61. Reproduction - Hormones

62. Reproduction - Female
Cow in Estrus (Heat).

63. Reproduction - Female
Ewe in Estrus (Heat):

64. Reproduction - Female
Sow in Estrus (Heat):

65. Reproduction - Female
Mare in Estrus (Heat):

66. Length of Estrous Cycle; Duration of Heat; and Time of Ovulation
Species
Average Days in Cycle
Duration of Heat (hr)
Time of Ovulation
Suggested Time of Mating
Cow 21
12–18
12–15 hr after estrus
4–8 hr before end of estrus
Sow
48–72
18–40 hr after start of estrus
24 hr after start of estrus
Ewe 17
24–36
18–26 hr after start of estrus
12–18 hr after start of estrus
Doe
34–39
9–19 hr after start of estrus
Mare 22
4–8
(days)
24-48 hrs prior to end of estrus
Alternate days during estrus

67. Characteristics of Estrus & Estrous Cycles of Farm Animals
Trait
Dairy Cattle
Beef Cattle
Sheep
Goats
Swine
Horses
Average age at puberty, males (days)
275
( )
300
( )
150
( )
( )
200
( )
455
( )
Average age at puberty, females (days)
330
( )
390
( )
( )
180
( )
210
( )
540
Estrous cycle type
Polyestrous
Seasonal Polyestrous
Average length of estrous cycle (days) 21
(17-24) 17
(14-19)
(18-23)
(19-23) 22
(18-24)
Average length of estrus (hrs) 15
(12-20) 20
(12-30) 30
(18-40) 34
(26-42) 56
(40-70)
7 days
(2-11 days)
Time of ovulation after onset of estrus
28 hr
30 hr
24 hr
36 hr
40 hr
5 days
Usual no. of follicles ovulated 1
1-6
1-4
13-22