Gestation and Parturition

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.

Gestation period Length -Cattle Range 274-294 days Average 283 days

Gestation period Length - Sheep Range 144-152 days Average 148 days

Gestation period Length - Swine Range 110-118 days Average 115 days

Gestation period Length - Horses Range 310-370 days Average 336 days

Gestation period Length - Rabbit Range 30-31 days Average 30 days

Gestation period Length - Goat Range 144-154 days Average 149 days

Gestation period Length - Chicken Range 19-22 days Average 21 days

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

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

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

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

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

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.

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

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

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

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

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, . . .

Stages during the ovum period Zygote – 2 to 8 cells

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

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

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.

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

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

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

Embryo Period 5. Completion of all major ORGAN systems.

Embryo Period 6. Looks like the ORGANISM.

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])

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

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

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

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

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

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

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

Parturition -the act of giving birth

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

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

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

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)

Signs of birth in horses 1. 2-6 weeks prior, udder swells 2. 7-10 days prior, muscles shrink and abdomen drops 3. 4-6 days prior, teats fill with milk 4. 12-24 hours prior, “wax” appears on nipples (“waxing”)

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”

Signs of birth in pigs 3. Will clean and dry birth site (will chew long grass or straw to provide bedding) 4. Vulva enlarges 5. 10-18 hours before farrowing, milk fills the teats

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

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

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

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

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

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.

Stage 4 Period of Rest

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

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

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

Dystocia Difficulty during parturition

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

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

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?

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

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)

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

Breech

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

Leg Back

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

Upside Down and Backward

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

Backward with rear legs extended

Method of Correction Often requires no assistance

Head back

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

Dog Sitting Position

Method of Correction Rear legs pushed back Birth proceeds as normal

Behavior after giving birth Postpartum Behavior Behavior after giving birth

Postpartum Behavior in Mares Following birth the mare often lies exhausted for 20-30 minutes Mares do not eat the afterbirth, but will groom their foals

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

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)

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

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

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

Care of the newborn calf A vigorous calf will attempt to stand in about 15 minutes and will nurse within 30-60 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

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