Beths Repro Class Ft. Lewis 2-11-04.Reproduction

8/16/2019 Beths Repro Class Ft. Lewis 2-11-04.Reproduction

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Female Reproduction

Anatomy and Physiology

Ryon Walker

PhD Grad Student,

CSU – Dept. of Animal Sciences


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Cow’s Reproductive CycleCow’s Reproductive Cycle

Reproductive

Tract

Follicles and

New CorpusLuteum

Mature Corpus

Luteum


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OvaryFemale Gonad (sex

gland)

Site of Action for LH,

FSH, PGF2alpha

Transient Organs

– Follicle

– Corpus Luteum


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OvaryOvary

GraffianGraffian Follicle (dominant follicle)Follicle (dominant follicle)

-- Fluid filled sacFluid filled sac – – oocyteoocyte developsdevelops-- OocyteOocyte suroundedsurounded by theca and by theca and granulosagranulosa cellscells

-- OvulationOvulation

CorpusCorpus LuteumLuteum (yellow body)(yellow body)

-- Develops at site of ovulationDevelops at site of ovulation

-- LutealLuteal cells develop from theca andcells develop from theca and granulosagranulosa

cellscells

-- Remains if female is pregnantRemains if female is pregnant


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Ovarian Structures


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Hormones

Hypothalamus

– Gonadtropin Releasing Hormone (GnRH)

Posterior Pituitary – Luteinizing Hormone (LH)

– Follicle Stimulating Hormone (FSH)

Ovary – Estrogen

– Progesterone

Uterus

– Prostaglandin F2α (PG)


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Estrous CycleEstrous Cycle

Alternating domination ofAlternating domination of either either ::

-- estrogen from follicleestrogen from follicle

-- Progesterone from corpusProgesterone from corpus luteumluteum


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Follicle ProductionFollicle Production

Pituitary gland releases:Pituitary gland releases:

-- FSH for initiating growth of folliclesFSH for initiating growth of follicles-- LH for steroid hormone production fromLH for steroid hormone production from

folliclefollicle GraffianGraffian follicle produces Estrogenfollicle produces Estrogen

CorpusCorpus LuteumLuteum produces Progesterone produces Progesterone


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Estrous CycleEstrous Cycle LutealLuteal Phase (d 1Phase (d 1--18)18)

Follicular Phase (d 18Follicular Phase (d 18--21)21)


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Estrous CycleEstrous Cycle

Estrus (d 0)Estrus (d 0)

Ovulation (d 1)Ovulation (d 1)

MetestrusMetestrus (d 1(d 1--5)5)

DiestrusDiestrus (d 5(d 5--17)17)

ProestrusProestrus (d 17(d 17--21)21)

Estrus (d 0)…….Estrus (d 0)…….

Follicular

Luteal

Follicular


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Estrus (day 0) Estrus (day 0)

Follicle maturesFollicle matures

Estrogen increases as follicle maturesEstrogen increases as follicle matures

Increase estrogen = increaseIncrease estrogen = increase GnRHGnRH

IncreaseIncrease GnRHGnRH = increase LH= increase LH

LH surgeLH surge

Estrus (standing heat)Estrus (standing heat)

OvulationOvulation


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Ovulation (day 1)Ovulation (day 1)

Oocyte (egg) release

Induced by LH surge

28 hours after first heat


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Metestrus Metestrus (day 1(day 1 – – 5)5)

Corpus luteum formation

Growth and development of follicular wave

Increase in progesterone production

– Non responsive to PG – Prepares uterus to accept fertilized egg

– Maintains pregnancy and prevents heat

– Presence of fetus keeps CL alive


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Diestrus Diestrus (day 5(day 5 – – 17)17)

Mature Corpus Luteum

Maximal progesterone production

GnRH inhibited by progesterone

Maternal recognition of pregnancy

Unfertilized cow: – PG kills CL and stops producing progesterone

around day 16 - 18


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Proestrus Proestrus (day 17(day 17 – – 21)21)

Prostaglandin production by uterus

Luteolysis

– Decreased progesterone production

– CL regresses

GnRH no longer inhibited

Final maturation of dominant follicle

Increased estrogen

..Estrus (d 0) … Ovulation (d 1)....Estrus (d 0) … Ovulation (d 1)..


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Estrous Cycle

0 2 4 6 8 10 12 14 16 18 20 1

H o r m

o n e L e v e l

Progesterone (P4)

Estradiol (E2)

Day of Estrous Cycle

New CL

Forming

Mature CL Present Fol. Size

& CL Size


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Sperm ActivitySperm Activity

Sperm travels and waits in oviduct (Sperm travels and waits in oviduct (ampullaampulla))

-- Sperm life span in female tract (24 hrs.)Sperm life span in female tract (24 hrs.)-- Need sperm in tract hours before egg Need sperm in tract hours before egg

releasedreleased-- Egg life span in female tract after releaseEgg life span in female tract after release

(8(8 -- 12 hrs.)12 hrs.)

-- Ovulation occurs 28 hours after heatOvulation occurs 28 hours after heat


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Approximately 6% of beef cattle

(cows) in Colorado are artificiallyinseminated.

About 18% of heifers in the US areartificially inseminated.

Why?

– According to a national survey the #1reason for not using synchronization or

AI “Time and Labor.”


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Obstacles

- Lack of producer

education.

- Economics of

time and labor.

- Inadequate Facilities

- Cost

- Relative poor conception rates.

- Lack of information


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Benefits of Synchronization

Tighter breeding and calving season

Decreased time needed for estrousdetection

Improved calf uniformity.

Increased time for post partum recovery

Inducement of estrous cycles, anestrous

cows

Increased calf performance.


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Classes of Synchronization

Drugs

1) Prostaglandins

2)Progestins

3) GnRH


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Prostaglandins

PGF2α

Causes regression of the corpus luteum

Stops progesterone block on estrogen and

LH release so follicle can mature andovulate.


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Prostaglandins

Cattle with a functional CL at time of PG

injection will exhibit estrus 2 to 7 days later.

Will only affect cattle in diestrus or the

luteal phase.


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Progestins

Synthetic progesterone - prevents estrusfrom occurring.

Most cows exhibit estrus 2-5 days afterremoval of progestins.

Administration: – Oral administration (MGA)

– Intravaginal insert (CIDR)

– Implant (Syncro-Mate B)


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GnRH

Causes release of LH and FSH.

LH and FSH act on the ovary to stimulate

follicular

development and

ovulation or

regression of

dominant follicle.

Manipulation of dominant follicle


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Manipulation of dominant follicle

with MGA Select Synch


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Follicle Study

Dominant Follicle Corpus Luteum


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Follicle Study

Dominant Follicle Corpus Luteum


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Red Cow Left Ovary

0

2

4

6

8

10

12

14

16

18

20

22

14 15 16 17 18 19 20 0 1 2 3 4 5 6 7 8 9 10 11 12 13

Day of Estrous

S i z e ( m m )

Follicle I

Follicle II

Follicle IIIFollicle IV

S h i ti St d


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Synchronization Study

SJBRC – 2003

Objective – Synchronize heifers to increase fertility with anew progestin (CIDR)

Heifers from three locations

– San Juan Basin Research Center (CO; 39 head)

– Beef Improvement Center (WY; 125 head) – Quinn Cattle CO (SD; 211 head)

P t l


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Protocol

• Control (CON) - Give nothing at breeding

• Treatment (Trtmt) - Give GnRH at breeding

Day 0 Day 7 Day 9

CIDR Insert

CON

54 h Mass Mate

CIDR InsertGnRH

CIDR RemovalPG Trtmt


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CIDRs

“T” shaped device (insert)

Wings collapse to form

a rod and inserted into

the applicator.

Nylon backbone

Progesterone

impregnated intosilicone skin.

1.38 g progesterone

CIDR Application


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CIDR Application

CIDR is applied into the vagina with an

applicator gun and released

CIDR is removed by pulling on tail.Progesterone levels rise dramatically within 1 hour.

F lli l S d SJBRC 2003


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Follicle Study – SJBRC 2003

Objective

– Measure dominant follicles at breeding

– Determine if ovulation occurs

P R lt


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Pregnancy Results

a

52.6 %

a

55 %

a

54 %

a

56.5 %

b

40.4 %

a

54.2 %

0

10

20

30

40

50

60

70

P r e g n a n c y R a

t e T A I , %

Colorado (CO) Wyoming (WY) South Dakota (SD)

CON

TRMT

Follicle Results


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Follicle Results

Follicle Size at Breeding

0

10

20

30

40

50

60

70

80

90

100

P r e g n a n c

y R a t e , %

10 - 11.9

mm

12 - 13.9

mm

14 - 15.9

mm

16 - 18 mm

Follicle

Diameter

Follicle Results


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Follicle Results

Ovulation

0

1020

30

40

50

60

70

80

90

P r e g n a n c y R

a t e , %

Control Treatment

Ovulation, %

Pregnancy Rate, %

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Beths Repro Class Ft. Lewis 2-11-04.Reproduction