AN SCI 101 Midterm 2

Cow (Puberty, Cycle, Estrous, Gestation)

1 year

21 days

10 hours

282 days

Sheep (Puberty, Cycle, Estrous, Gestation)

7 months

17 days

24 hours

150 days

Pig(Puberty, Cycle, Estrous, Gestation)

4 months

21 dyas

48 hours

114 days

Horse(Puberty, Cycle, Estrous, Gestation)

18 months

22 days

48-200 hours

337 days

Goats(Puberty, Cycle, Estrous, Gestation)

4-8 months

21 days

42 hours

151 days

Cat (Puberty, Cycle, Estrous, Gestation)

4-18 months

18 days

6-7 days

63 days

Ovary (Primary Sex Organ)

Functions:

Hormonal- estrogen, progesterone

Female Gamete- oocyte

Ewe Bicornuate

smaller uterine horns

Cow Bicornuate

1 vagina

1 cervix

1 uterine body

2 uterine horns

sow

1 vagina

1 cervix

1 uterine body

2 uterine horns(large)

Mare Bicornuate

1 vagina

1 cervix

1 uterine body (large body)

2 uterine horns(small horns)

Opossum Duplex

2 vaginas

2 uterine horns

2 cervixes

Rabbit/Mouse Duplex

1 vagina

2 uterine horns

2 cervixes

Broad Ligament

Connective tissue sheet which supports and suspends the reproductive tract

Follicle

produces estrogen and oocyte

Corpus Luteum

produces progesterone

Oviduct Functions

Gamete Transport(sperm, oocyte)

supports early embryo development

transport of embryo to uterus

Uterus Functions

Muscle Contractions(transport sperm, expel fetus and placenta)

Absorption and phagocytosis

Partially prepares sperm for fertilization(capacitation)

Provides environment for embryo and fetal growth

Hormone production(prostaglandin F2a production)

Cervix Functions

Transport of sperm

Barrier of sperm(species dependent)

Reservoir for sperm

Blocking bacterial invasion during pregnancy

Birth canal

Vagina Functions

Copulatory organ

Glands secrete lubrication

Birth canal

Glands secrete pheromones

External Genitalia Functions

Labia- closes entrance to vagina

Clitoris-female sensory organ

Polyestrus

multiple periods of estrus (heat) and can conceive repeatedly throughout her life or during a specific breeding season

queen, cow, sow

Seasonly Polyestrus

goes into heat (estrus) multiple times during a specific part of the year, rather than continuously year-round or just once

sheep, horse

Monoestrus

only goes through heat once a year

dog, wolf, bear

Progesterone

Produced by Corpus Luteum (Placenta)

Action: maintain pregnancy, block estrus/GnRH, relax smooth muscle

spikes at end of estrus

Estrogen

Produced by Follicle (Placenta)

Action: Induces GnRH surge, induces estrus, contracts smooth muscle

peaks immediately after progesterone drops

GnRH

produced in hypothalamus

action:LH surge

LH(luteinizing hormone)

Produced in the anterior pituitary gland

action: causes ovulation, starts at the onset of estrus, causes estrogen to decrease(ends estrus)

Signs of estrus

increase in activity, standing to be mounted increases, mucous discharge increases

Prostaglandin F2a

Produced in the non-pregnant uterus

action: regresses the corpus luteum

Phases of Estrous Cycle

Follicular Phase

Luteal Phase

Stages:

-Proestrus

-estrus

-metestrus

-diestrus

Testicles(testes)

primary sex organ

sperm & testosterone production

Vas Deferens

sperm transport

Epididymis

sperm maturation & storage

Scrotum

protection and thermoregulation

Bull testis (Weight, % of body wt, Orientation)

300+

.03

vertical

Ram Testis (Weight, % of body wt, Orientation)

250

.3

vertical

Boar Testis (Weight, % of body wt, Orientation)

350

.2

oblique

Stallion Testis (Weight, % of body wt, Orientation)

200

.03

horizontal

Dog Testis (Weight, % of body wt, Orientation)

25

.2

oblique/horizontal

Rabbit Testis (Weight, % of body wt, Orientation)

2.5

.1

vertical

Scrotum Functions

Protective sack

Temp regulation of the testes, tunica dartos muscle will contract and relax, lifting and lowering the testes

Parenchyma

where sperm is produced

houses the seminiferous tubules

mediastinum

connective tissue for support(prevents the tubes from being squeezed)

houses and protects the ducts that transport the sperm that were just produced in the parenchyma

Testicle Anatomy

Seminiferous Tubules(site of spermatogenisis)

Rete Testis(within the mediastinum)

Vas Efferentia(6-12 tubles)

Caput Epididymis

Corpus Epididymis

Cauda Epididymis

Vas Deferens

Spermatic Cord(holds the testes)

Spermatic Cord

Contains vasculature, lymphatic system, and nerves

heat exchanger(pampiniform plexus(counter-current exchange of heat))

houses cremaster muscle(pulls testicles up when contracted)

houses vas deferens(sperm transport)

Semen

Sperm + Seminal Plasma

Fibroelastic Penis

allows the penis to fully retract back into the body(bull, boar)

Muscular/Vascular Penis

no sigmoid flexure(horse, human)

Stressors of Sperm Production

Heat stress

disease of infection

physical trauma to the testis

Oocyte life span

6-12 hours after ovulation

Sperm life span

24-48 hours after ejaculation

Cow Timing of Insemination (Time of Ovulation, Optimal Insemination Time)

29 hours after start of estrus

End of estrus (12 hr after first seen in estrus)

Ewe Timing of Insemination (Time of Ovulation, Optimal Insemination Time)

End of estrus

End of 1st day or start of 2nd day of estrus

Sow Timing of Insemination (Time of Ovulation, Optimal Insemination Time)

End of estrus

End of 1st day or start of 2nd day of estrus

Mare Timing of Insemination (Time of Ovulation, Optimal Insemination Time)

1-2 days before end of estrus

Every other day beginning day 3 of estrus

More Ovulation %

Higher Milk Production

Trophoblast

Forms into the placenta

Inner Cell Mass(ICM)

Forms into the fetus

Maternal Recognition of Pregnancy

embryo signals its presence to the dam and allows pregnancy to be maintained, by preventing luteolysis of the corpus luteum (CL)

Placenta Endocrine Functions

Transient

Progesterone

Estradiol

Placenta Exchanges

Gas

Nutrients

Waste exchange

Placenta Chemical Protection

Immunosuppression

Prevents infiltration by maternal defenses

Filters toxins

Placenta Physical Protection

Shock Absorption

Sheep Placenta Shape

concave shape

Cow Placenta Shape

convex shape

zonary placenta

Villi are concentrated in a single band/zone, carnivores

diffuse placenta

Villi are “diffused” across the entire surface of the placenta, horse/pigs

discoid placenta

Closest contact to maternal blood supply, primates/rodents/humans

multicotyiedonary placenta

spots(like cow spots), ruminants

Genetic Factors Influencing Fetal Growth

Species

Breed

Litter size

Genotype

Environmental Factors Influencing Fetal Growth

Mother

Nutrition

Size, Parity

Placenta

Blood flow

Size

Fetal Hormone Factors Influencing Fetal Growth

Thyroid

Insulin

Growth hormone

Hormonal Changes Near Parturition

Fetal cortisol (stress hormone) increases.

PGF2a increases.

CL begins to die, progesterone decreases, beginning of uterine contractions and parturition

Ewe Artificial Induction with Drugs

Dexamethasone or Lutalyse.

Few issues with retained placenta

Cow Artificial Induction with Drugs

Should not be done before day 269 of gestation.

Drugs: dexamethasone (acts like cortisol) or Lutalyse (PGF)

High chance of retained placenta

Sow Artificial Induction with Drugs

Piglet survival only after day 111 of gestation.

Lutalyse + oxytocin (promotes uterine contractions).

Mare Artificial Induction with Drugs

Only do in extreme circumstances, as gestation length and foal development are variable and unknown.

Oxytocin after day 320

calving preparation

1-24 hours

Restlessness and colic signs

Appetite loss

Contractions with tail raising

Changing often from lying to standing

Colostrum let down

delivery of calf

½ to 6 hours

Lying down

Strong abdominal contractions

Placenta and calf appearance

Calf delivery

Dystocia

Difficult Birth

Abnormal presentations.

Large calves.

Twins

placenta expulsion

If not expelled within 24 hr it may be retained for 5 - 6 day

can be deadly if retained for too long

bull semen stored…

frozen

boar/stallion semen stored…

fresh

Ovum Pick-Up

Transvaginal, ultrasound-guided, retrieval of oocytes. Can be used immediately for IVF, or frozen and saved for a later time.

Same technique in humans as cows

natural service

Ejaculation at time of mating + Ovulation

artificial insemination

Semen collection and preservation + Oocyte retrieval

in vitro fertilization

Semen collection and preservation + Oocyte retrieval

ICSI

Intracytoplasmic sperm injection

Delivers a single sperm to the oocyte via a needle

Eliminates almost all male-factor infertility

In vivo derived (IVD) embryos

made inside the cow

In vitro produced (IVP) embryos

made in a lab

Proper Milking Routine

Pre-dip teat

fore-strip teat

throughly dry teat

apply milker

remove milker

post-dip teat

Herringbone

outlet of claw should point at the head of the cow

Parallel

outlet of claw points directly between the legs

Ideal Milking Order

First lactation cows

Second and later lactation cows with low SCC

High somatic cell cows

Cows with clinical mastitis

Sub clinical mastitis

Normal milk, SCC>200,000

Clinical mastitis

Abnormal milk, SCC variable

Mild –milk only

Moderate- milk and tissue inflamed

Severe- milk, tissue, and general symptoms

Udder Tissue

Sub pelvic tendon (attached to pelvic bone)

Lateral suspensory ligament (elastic/fibrous)

Median suspensory ligament (attached to body wall)

Mammary Gland Circulatory System

The vascular network 400-500 units of blood pass through the udder for each

unit of milk synthesized

The right and left udder halves have their independent arterial supply.

Udder blood volume (lactating cow) is 7-10% of total body blood volume.

A 2 to 6-fold increase in blood flow in the mammary pre-partum occurs.

Blood flow through the capillary beds surrounding the alveoli is essential to milk

production.

Mammary blood flow and milk production are positively correlated

Udder Lymphatic System

Two supra-mammary Lymph nodes (one per rear quarter)

Scattered Lymphatic vessels

They collect the interstitial fluids that bathe the cells

Helps regulate proper fluid balance within the udder.

Help Combat infection (rich in lymphocytes)