Pregnancy, Parturition, and Dystocia

ANSC 410

parturition

giving birth

dystocia

difficult birth often requiring human intervention

fertilization

egg and sperm joining

natural fertilization

semen deposited in vagina or uterus 

• ruminants — vagina

• horse/pig — uterus

artificial fertilization

semen deposited in uterus

embryo

fertilized egg before implantation into the uterus

fetus

embryo after implantation into the uterus

abortion

expulsion of the fetus after organ formation

stillborn

full term fetus that is born dead

early embryonic death

death of the embryo before implantation in the uterus

theriogenology

study of reproduction

ovariohysterectomy

surgical sterilization procedure in the female by removing the ovaries and uterus; “spay” in dogs/cats

castration

surgical sterilization procedure in males by removing the testicles; “neuter” in dogs/cats

what is the ideal age of first breeding for heifers?

breed at 18 months

1st calving 28-30 months

60% estimated mature weight (golden rule)

what is a cow’s gestation length?

283 days

zygote

fertilized egg

immediately after fertilization

day 1-3

oviduct

embryo

beings to move from oviduct to uterus

fertilized egg before implantation in the uterus

day 4 - till implantation

blastomere

(in oviduct) 5 days after conception

morula

(in oviduct) 8-16 days after conception

blastocyst

in uterus

fetus

fertilized egg after implantation in the uterus

lives off mothers body

the fetus forms what?

the placenta

placenta is also known as…

afterbirth

what is the placenta attached to?

the uterus

what is the placenta important for?

• O2 and CO2 exchange

• for protection and nutrition for fetus

what are the 3 layers of the placental membrane? from outermost to innermost

• chorion

• allantois

• amnion

what layer of the placenta becomes the umbilical cord?

allantois

what are the 3 types of placenta in domestic animals?

• zonary - dogs/cats

• diffuse - horses/pigs

• cotyledonary - ruminants

caruncles on ruminant uterus attach to cotyledons of the placenta to form ____________

placentomes

caruncles

glandular structures on the uterus where implantation occurs

placentome

junction of placenta and uterus

umbilical cord

carries blood to and from the fetus

umbilical vein

carries oxygenated blood to the fetus from the mother

umbilical artery

carries deoxygenated blood from the fetus to the mother

proper hay and forage is essential for _____ _________

fetal development

greater than ____% of fetal growth occurs during the last trimester

75%

ways to diagnose pregnancy

• rectal palpation

• ultrasound

• blood tests

• visual signs

fetal membrane slip

occurs when chorioallantoic membrane slips easily between your fingers

detected around day 35

what is the earliest sign of pregnancy in cattle?

fetal membrane slip

retracting the uterus

gently pulling the uterus into the pelvic canal so that the entire uterus can be examined during rectal palpation

open

means pregnancy has not been detected

what are the golden rules of rectal pregnancy exam?

1. You must examine the entire tract before declaring the cow open.  

2. You must find one of the positive signs of pregnancy before you call a cow pregnant.

3. Pregnancy examination must always be the first step in your examination. If you are not sure, recheck the cow...maybe in a few minutes, maybe tomorrow.

4. The only positive signs of pregnancy in the cow are fetus, cotyledons/caruncles, amniotic vesicle, and fetal membrane slip
   

what are some visual signs of pregnancy?

• Observe for missed heat cycles

• Gradual swelling in abdomen

• Gradual mammary gland development

• “Springing” in cattle

• flanks appear hollow

what is “springing”?

• late stages of pregnancy

• vulva enlarges

• milk production in udder

• pelvic muscles and tail relax

• discharge from vulva

list the correct terms for parturition in different domestic animals.

cow - calving

pig - farrowing

goat - kidding

sheep - lambing

chickens - laying/hatching

what are factors that affect gestation length?

• age of mother

• species

• breed

• nutrition received by fetus

(true/false) horses have longer gestation periods than cows

true

what triggers parturition?

• hormones

• fetus

• mother

if the mother senses danger or is nervous from human intervention, parturition may be ___________

delayed

what hormone is responsible for maintaining pregnancy?

progesterone

progesterone will begin to ________ before parturition

decrease

what hormone relaxes the pelvic muscles and dilates the cervix?

relaxin

relaxin is produced from the …

uterus

what hormone is responsible for uterine contraction of milk-let down?

oxytocin

estrogen will ______ as parturition nears

increase

what hormone cause the CL to regress?

prastaglandin

prostaglandin ________ with partuition

increases

fetal cortisol

increases and initiates parturition

describe the 3 stages of labor

• Stage 1

  • Cervical Dilation

  • Uterine Contractions

  • Lasts 12-14 hours

• Stage 2 

  • Active labor and delivery

  • Water breaks

  • Pushing/straining

  • Usually around 2-4 hours

  • Observe the female closely during this time

  • Consistent, active pushing should produce a baby within 30 mins -1 hour

• Stage 3

  • Expulsion of placenta

  • Involution of the uterus

what is shrinking of the uterus?

uterine involution

what hormone is released with nursing?

oxytocin

uniparous

(single fetus) 1 ovum produced/cycle

cow, horse

multiparous 

(multiple/litter of fetuses) multiple ova produced per cycle

dog, cat, pig, sheep, goat

colostrum

the first milk produced by the mother

what does colostrum contain?

rich antibodies that are important for sustaining life for the first few weeks after birth

in dystocia, there may need to by human intervention. what will the veterinarian reach their arm into to help?

vaginal cavity, cervix, and sometimes the uterus

factors that cause high mortality rates

• Dystocia

• Mismothering behavior

• Failure of passive transfer

• Exposure to the elements

• Poor lactation

• Unable to latch on the teats

• Predators

word for no milk production

Agalactia