Pregnancy and lactation

Name female behavioral signs of estrus

1. increased activity

2. vocalization

3. mounting

4. Lordosis (mating posture)

5. tail flagging

• estrus occurs 24+ hours before ovulation

What is copulation?

the act of breeding

Intromission is?

insertion of the penis into vagina

• followed by thrust and ejaculation

What is the main mission for sperm?

travel from vagina to oviducts with the help of

• retrograde transport

• phagocytosis

• transport to oviduct post 5 min. after ejaculation

What assistances for spermatozoa get? 4

Oxytocin→ posterior pituitary = induce myometrial contractions

Estrogen → primes repro tract for sperm

Prostaglandins → increase sperm motility

Cilia → oviducts carry sperm

The sperm has to undergo what?

The sperm has to undergo further maturation in the females

Capacitation?

changes that occur to the sperm that make them fertile

Acrosome reaction?

release of enzymes from acrosome

• allows attachment of the zona pellucida (cover of oocyte) of ovum

The 4 stages of fertilization?

1. sperm binds to the zona pellucida

2. acrosome reaction

3. sperm binds and fuses to oocyte membrane

4. sperm delivers genetic material into cytoplasm

What happens to the oocyte once the sperm delivers genetic material to the cytoplasm?

The oocyte undergoes cortical reaction

• release enzymatic granules

• prevents polyspermy, more than one sperm in egg

What is a ootid?

male and female pronucleus are visible in single cell

What is syngamy?

fusion of male and female pronuclei

• forms diploid chromosome number

embryonic developmental stages leading up to implantation

1. Zygote → single cell fertilized ovum

2. Cleavage → rapid mitosis after formation of zygote

3. Morula → > 8 cell embryo. develop hollow cavity

4. Blastocyst → embryo implant into uterus , half becomes fetus other half becomes placenta

How long does blastocyst stay in oviduct during implantation?

lasts 4-5 days, implants in uterine endometrium

Implantation known as “maternal recognition of pregnancy”

Why must Luteolysis be prevented?

Luteolysis= breakdown corpus luteum if no pregnancy

Because animal is pregnant, it can not happen because it is the breakage of corpus luteum

What is the function of the placenta?

• nutrient and waste exchange

• endocrine

attaches to lining of uterus

umbilical cord attaches fetus to placenta

• fetal and maternal blood do not mix

3 placental membranes

1. Amnion→ layer around the fetus, the amniotic cavity is the space

2. Allantois → layer around amnion, allantoic cavity

3. Chorion→ attaches uterine lining, link to fetus by umbilical cord

histological types of placentas in order of invasiveness (4)

1. Epitheliochorial : sow and mare

2. Syndesmochorial : ruminants

3. Endotheliochorial

4. Hemochorial : primates and rodents

Components of umbilical cord?

• umbilical arteries → deoxygenated waste-products

• umbilical vein → nutrient and O2 blood

• Urachus → fetal urine away from bladder to allantoic sac

the four types of placental attachment

1. Diffuse: pigs, horse, camelids

2. Cotyledonary: ruminants

3. Zonary: dogs and cats

4. Discoid: primates, rabbits, rodents

In which type of placental attachment does the placenta get retained?

Common in cotyledonary more dangerous

What is gestation and type of trimester?

Gestation= fertilization to delivery

1st trim.: embryo

2nd: fetus

3rd: fetal growth stage

Gestation lengths for different animals?

Cats and dogs → 2 months

Horse: 11 months

Pigs → 3 months 3 wks and 3 days

Cattle→ 9 months

What is parturition and what hormones trigger it?

active birth

• release of ACTH, fetal cortisol, estrogen, and PGF2a and oxytocin

3 stages of labor?

1. Stage 1→ uterine contractions= cervix dilates

2. Stage 2→ rupture of water bags= delivery of newborn

3. stage 3 → delivery of placenta

What is the function of mammary glands?

produce colostrum and milk

• present in males and females

• hormones initiate the function

Teats

quantity?

location?

number of openings?

• varies, horses= 2, swine= 14

• inguinal (cattle) to entire ventrum (cats,dogs, pigs)

• 1 per teat in cattle, sheep, goats but 20 per teat in dogs

What is lactation and what are two present hormones?

process of milk production

1. prolactin→ primary hormone of milk production

2. oxytocin→ hormone of milk ejection

What is the basic unit of milk secretion?

Alveoli

Milk let-down vs. milk production

Milk production: creation of milk in alveoli by prolactin

• more prolactin= more milk produced

Milk let-down: release of milk thru ducts by oxytocin causing myoepithelial cells contraction

Colostrum is produced…

It is produced in the first 2-3 days “first milk”

Passive immunity?

absorbed through gut of newborn

• failure passive transfer = insufficient intake