1. Gestation and Parturition

2. Gestation Length of PREGNANCY.
Begins with FERTILIZATION and ends with PARTURITION (BIRTH).
All animals have DIFFERENT gestation lengths. Usually the LARGER the animal, the LONGER the gestation length.

3. Gestation period Length -Cattle
Range days
Average 283 days

4. Gestation period Length - Sheep
Range days
Average 148 days

5. Gestation period Length - Swine
Range days
Average 115 days

6. Gestation period Length - Horses
Range days
Average 336 days

7. Gestation period Length - Rabbit
Range days
Average 30 days

8. Gestation period Length - Goat
Range days
Average 149 days

9. Gestation period Length - Chicken
Range days
Average 21 days

10. Gestation period length
The length of gestation is GENETICALLY determined, but other factors cause it to VARY, such as:
a. Maternal Factors -- age of the dam (mother)
b. Fetal Factors -- litter size, sex of fetus

11. Gestation period length
The length of gestation is GENETICALLY determined, but other factors cause it to VARY, such as:
c. Genetic Factors -- species, breed, fetal genotype
d. Environmental Factors -- nutrition, temperature, season

12. Gestation period length
Knowledge of the length of gestation period is important to the producer because:
a. it helps to regulate production cycles
b. it helps in the planning of the breeding program
c. it helps to predict the date of birth

13. Abortion -
EXPULSION of the fetus before the time of PARTURITION.

14. Causes for abortions: 1. Infections
a. Bacteria and Fungi (ex., Brucellosis [Bangs], Vibriosis)
b. Viral (ex., Bovine Virus Diarrhea [BVD])
c. Protozoans (ex., Trichomoniasis)

15. Causes for abortions: 2. Genetic Abortions
a. Occur when the fetus is malformed
b. Dam's body usually rejects the malformed fetus for reasons unknown.

16. Causes for abortions: 3. Injury related abortions
a. Rare because fetus is well protected
b. Prevent injuries caused by kicking, bumping, or squeezing

17. Causes for abortions: 4. Nutrition Examples: - Poisonous Plants
- Ration too low in required nutrients

18. Development 3 periods of development from pregnancy to birth
- Ovum Period
- Embryonic Period
- Fetal Period

19. Ovum Period ( Days 0 to 15 in cattle)
1. Fertilization - the union of the egg and sperm nuclei – takes place in fallopian tube

20. Ovum Period
2. Cell Division- after the cell has been fertilized it begins to divide (Mitosis) 1 becomes 2 becomes 4 becomes 8, 16, 32, 64, . . .

21. Stages during the ovum period
Zygote – 2 to 8 cells

22. Stages during the ovum period
A. Zygote – 2 to 8 cells
B. Morula – spherical mass of cells (outer layer and central core)

23. Stages during the ovum period
A. Zygote – 2 to 8 cells
B. Morula – spherical mass of cells (outer layer and central core)
C. Blastula -- mass of cells with a hollow cavity

24. Embryo Period (Days 16 to 45 in cattle)
3. Implantation - the new embryo becomes implanted in the uterine horn where it will be nourished and develop.

25. Abnormal implantation
Ovarian: Young seldom survive to full term
Tubal: Young occasionally survive to birth
Abdominal: Young do not survive to full term

26. Embryo Period
4. Differentiation - cells become organized into specific structures

27. Three layers of development tissue:
a. Ectoderm - the outside layer that becomes the skin and nervous system
b. Mesoderm - the middle layer that becomes the bones and muscles
c. Endoderm- the inside layer that becomes the lungs and digestive system

29. Embryo Period
5. Completion of all major ORGAN systems.

30. Embryo Period
6. Looks like the ORGANISM.

31. Fetal Period (Days 46 to 283 in cattle)
7. Placentation - MEMBRANES develop to provide the FETUS with NUTRITION.
Each embryo usually has their own set of membranes (Twins in cattle have common membranes and common blood supply [Freemartin])

32. Placental Structures:
Amnion – inner most layer that forms a sac around the embryo/fetus. (Amniotic Sac)
Filled with amniotic fluid that protects young from shock and adhesion

33. Placental Structures:
Allantois – middle layer that also forms a sac
Filled with allantoic fluid that accumulates waste from the developing fetus
Chorion – outer layer that attaches to the uterus

34. Types of placental attachment
Cotyledon – contacts made only at certain points in the uterus
Also known as “buttons”
Cows and Ewes
Ewe
Cow

35. Types of placental attachment
Diffuse – contact is made over most of the uterus
Mares, sows, humans

36. Placental Structures
Umbilical Cord - long FLEXIBLE tube attached to the placenta where FOOD, OXYGEN, and WASTES are exchanged between the MOTHER and the baby.

37. Placental Barrier
Placenta prevents large molecules from passing from mother to young.
Viruses are small enough to penetrate as are certain other chemicals.

39. Fetal Period
8. Growth and Development - the fetus GROWS and organs continue to DEVELOP so that the animal can LIVE on its OWN.

41. Parturition -the act of giving birth

42. Signs of birth in cattle
1. Swollen udder
2. Fluid in udder changes from watery to thick, milky colostrum
3. Muscles around tailhead shrink

43. Signs of birth in cattle
4. Noticeable enlargement and swelling of the vulva
5. Cow is nervous, uneasy, anorexic

44. Signs of birth in cattle
6. Muscular contractions start
7. Look for young
8. Makes a nest or seeks out an isolated area

45. Signs of birth in sheep
1. 10 days prior, ewe teats become firm and full of milk
2. Vulva swollen
3. Cervical seal passes as thick creamy mucus
4. Ewe becomes nervous (switches from laying to standing)

46. Signs of birth in horses
weeks prior, udder swells
days prior, muscles shrink and abdomen drops
days prior, teats fill with milk
hours prior, “wax” appears on nipples (“waxing”)

47. Signs of birth in pigs
1. About 3 days prior, sow will spend most of time sleeping and feeding
2. As labor draws nearer, sow begins “nest building”

48. Signs of birth in pigs
3. Will clean and dry birth site (will chew long grass or straw to provide bedding)
4. Vulva enlarges
hours before farrowing, milk fills the teats

49. Stages of Parturition (Labor)
Stage 1 - Preparatory Stage
Stage 2 - Expulsion of fetus
Stage 3 - Expulsion of the placenta
Stage 4 - Period of Rest

50. Preparatory Stage
1. Restlessness of animal due to minor contractions
2. Dilation of the cervix
3. Cervix expands allowing uterus and vagina to become a continuous canal

51. Expulsion of the fetus
1. Increased contraction (abdominal pressing marks)
2. Straining followed by a few minutes of rest
3. Fetus enclosed in amnion, propelled through birth canal and appears at vulva

52. Expulsion of the fetus
4. In cows & ewes, fetus is expelled while still attached to the fetal membranes, so the fetus has oxygen even if birth is prolonged
5. In swine & horses, placental connections are broken. 2nd stage must be rapid

53. Expulsion of placenta (afterbirth)
1. Caused by uterine contractions
2. Placenta should be expelled within 12 hours following parturition

54. Expulsion of placenta (afterbirth)
(calving problems, abortion, twins, etc., may cause it to be retained)
3. Used to remove retained placenta by hand, now we treat it with antibiotics.

55. Stage 4
Period of Rest

56. Proper Presentation
Most common is forelegs first with nose resting on the forelegs (anterior)
Piglets may be born anteriorly or posteriorly
Mild labor pains usually start several hours before actual birth

57. Proper Presentation
First water bag will appear on the outside increasing in size until it ruptures due to its own weight
Immediately after the first bag, the amniotic bladder (second water bag) follows, containing the fetus

58. Proper Presentation
Presentation of fetus after straining on the cows part
If presentation is normal and within 1-2 hours after the first signs of calving, then no assistance is necessary

60. Dystocia
Difficulty during parturition

61. Fetal Dystocia problems
Over sized fetus
Multiple births
Breech presentation
Deviations in normal presentation

62. Maternal dystocia problems
Narrowing of the birth canal due to fractures of the pelvis
Twisted uterus reducing size of birth canal
Cervix fails to dilate
Absence of uterine contractions
Caused by large litter size or exhaustion due to fetal dystocia

63. Should I lend assistance?
What is the due date?
How long has the animal been trying to give birth?
Has the animal given birth before?

64. Should I lend assistance?
Have some offspring already been delivered?
Has anyone attempted to assist yet?
Should I assist or call vet?

65. Pulling a calf OB Chains Soft cotton rope
Mechanical calf-puller (wench)
Dead calves cut into pieces with cables and then removed
C-section (Cesarean section)

66. Calf and Lamb Delivery Problems
Calf or Lamb in the Wrong Position and method of correction

67. Breech

68. Method of Correction Calf or lamb pushed forward
Rear legs pulled into birth canal

69. Leg Back

70. Method of Correction Calf or lamb pushed forward
Folded foot brought forward

71. Upside Down and Backward

72. Method of Correction Caused by twisting of uterus Difficult to correct
Try to turn calf
Bring rear legs out first

73. Backward with rear legs extended

74. Method of Correction
Often requires no assistance

75. Head back

76. Method of Correction Calf or lamb pushed forward
Head pulled around in line with the birth canal

77. Dog Sitting Position

78. Method of Correction
Rear legs pushed back
Birth proceeds as normal

79. Behavior after giving birth
Postpartum Behavior
Behavior after giving birth

80. Postpartum Behavior in Mares
Following birth the mare often lies exhausted for minutes
Mares do not eat the afterbirth, but will groom their foals

81. Postpartum Behavior in Cows
The cow will lick the uterine discharge from herself
Rest for a period, then lick the fetal membranes and fluids from her calf
Will eat the placenta, bedding and fluids

82. Postpartum Behavior in Ewes
May chew and eat parts of the fetal membranes but not the entire afterbirth
Recognition of ewes by lambs is important
will reject their young if taken away immediately and then returned (30 min)

83. Postpartum Behavior in Sows
Pay little attention to young until after the last one is born
Will eat all or part of afterbirth
Will call her litter to suck by making repeated short grunts

84. Postpartum Behavior in Sows
Will emit loud barking grunts if an intruder disturbs the nest
Rarely licks or grooms young but will position them to eat
Nervous sows may cannibalize their young or crush them

85. Care of the newborn calf
Apply tincture of iodine on the navel cord to prevent infection.

86. Care of the newborn calf
A vigorous calf will attempt to stand in about 15 minutes and will nurse within minutes
Human assistance is sometimes necessary to get a calf to begin nursing
Clean newborn animals to get them dry.
Remove all mucus and foreign matter from the mouth and nasal passage

87. Care of the newborn pig
Use guard rails in the farrowing crate to keep baby pigs away from the sow to prevent being crushed