Small Ruminant Reproduction Management

Question 1

What does it mean when they say sheep are seasonally polyestrus?

Answer 1

They are short day breeders
-Breeding period depends on photoperiod, food, breed, presence of make, breeding system and physiologic state

Question 2

What is secreted by the pineal gland during darkness that influences the gonadotropin releasing hormone and HPG feedback loop?

Answer 2

Melatonin - increase gnrh and makes them cycle

Question 3

What factors influence SR reaching puberty?

Answer 3

Age, nutrition, season, breed, exposure to make

Question 4

When do the following go into puberty?
Rams/Buck:
Doe:
Ewe:

Answer 4

Ram: 4-6m
Doe: 6-8m (pygmy 3m)
Ewe: 6-9m

Question 5

When should we breed SR?

Answer 5

Once they reach 60-70% adult body weight

Question 6

Why are SR hard to AI breed?

Answer 6

6-7 cartilaginous rings

Question 7

What is the average estrus cycle for sheep and goats?

Answer 7

Sheep 17d
Goat 21d
(short cycle beginning and end or postpartum)

Question 8

How many follicular waves do SR have?

Answer 8

3-4 = hard to synchronize

Question 9

How long after the Lh surge does ovulation occur?

Answer 9

20-26hrs

Question 10

What are signs of estrus in SR?

Answer 10

Swollen vulva, mucous discharge turning cloudy, tail flagging, mounting/immobilization reflex

Question 11

How long does estrus last for SR?

Answer 11

Sheep: 30-36hr
Goat: 24-48hr

Question 12

Why do we manipulate the estrous cycle in SR?

Answer 12

Max milk, meat through year (cornell star)

Question 13

How do we manipulate the cycle in SR?

Answer 13

Adapted nutrition
Photoperiod manipulation (artificial light, melatonin)
Hormonal treatment - most not approved
Male effect
Combo

Question 14

What is adapted nutrition?

Answer 14

Flushing before breeding - increase energy increase ovulation and kidding rate
-best response if marginal BCS
-2 week pre-breed up to 2-3 week into breeding season

Question 15

What BCS should males have entering breeding season?

Answer 15

3-4/5
-Will lose lots breeding
-Need energy and protein supplement 4-6 week prior to breeding
-Don’t over condition or effect semen quality

Question 16

How do you manipulate the photoperiod?

Answer 16

Alter light or melatonin implants

Question 17

What hormones can be used in sheep and goats?

Answer 17

None are labeled so all extra label use

Prostaglandin - Lyse Cl
-Single or double injection 11-12 days apart, estrus 24-72hr, must be cycling

Progestin: mimic luteal phase, estrus 24-96hr after withdrawal (CIDR)

eCG/PMSG: FSH like activity - stimulate ovulation

GnRH Agonist: Act on anterior pituitary to stimulate LH/FSH activity

Question 18

What are some synch protocols?

Answer 18

Day 1: PGF
Day 8: GnRH
Day 15: PGF
Day 18: TAI and GnRH

Question 19

How do you bring a ewe in to synch when its out of season?

Answer 19

-Progestin >14d + PG600 24-48hr before progestin removal
-AI lighting - mimic long day 60d then short 60d
-Melatonin

Question 20

What is the ratio of ram to eve and buck to doe for natural breeding?

Answer 20

Ram:Ewe: 1:30-50
Buck:Doe: 1:50

Question 21

What is a teaser male? Why do we use them?

Answer 21

Help to dected female in heat - use AI

Teasing Harness
Vasectomized
Epididectomized

Question 22

Where is the site of semen deposit in ewes?

Answer 22

Vagina

Question 23

What type of semen should you use in SR and with what technique?

Answer 23

Fresh - AI in sheep tortuous cervix
Frozen - only Lap AI sheep

Goat AI - in vagina fine

Question 24

Where do you go for transcervical AI?

Answer 24

Through external os

Question 25

For Lap AI where is the semen being deposited?

Answer 25

Left horn uterus if can - but split between both sides

Question 26

How do you embryo flush a ewe?

Answer 26

Surgically - scrub, exteriorize, make hole and use tomcat cath to flush up and collect in dish

Question 27

What is the average gestation for sheep and goats?

Answer 27

Sheep: 145-150 days Goats: 147-155 days

Question 28

When does the embryo enter the uterus and when is MRP?

Answer 28

Enter uterus on day 4 MRP D12-13

Question 29

When does the embryo implant?

Answer 29

D16

Question 30

When does it become an aminotic vesicle?

Answer 30

D20

Question 31

How is pregnancy maintained in a sheep and goats?

Answer 31

Sheep: CL up to day 60-70 when placental progestins take over Goat: CL dependent

Question 32

Why do we do pregnancy detection?

Answer 32

Tell if breeding successful, any infertility issues, health problems, need to cull, see how many Help with nutritional management, know preg tox risk, dystocia considerations

Question 33

How and when do you preform Pregnancy diagnosis?

Answer 33

Transrectal ultrasound >20d Transabdominal ultrasound >30d(fetal sex 55-70d Radiograph >70d - very accurate for number of kids

Question 34

Where does the probe go for transabdominal ultrasound?

Answer 34

Left fold of flank

Question 35

What do you see on ultrasound based on day of pregnancy? D21 D25-35 D30-40 D40-90 >50

Answer 35

D21: Placentomes - small echongenic area D25-35: see embryo better- hyperechoic, amnion D30-40: C shaped placentomes D40-90: Placematone, umbilical cord, fetus >D50: Fetus begin to resemble lamb/kid >90 hard to count fetus - ballotment useful

Question 36

What kind of placenta do sheep have?

Answer 36

Cotylendonary synepitheliochorial

Question 37

What is the best way to fetal age?

Answer 37

Crown to rump length

Question 38

What should you ask the owner to do before ultrasounding?

Answer 38

fast 12hr food, 4hr water

Question 39

When should you ultrasound to say yes/no preg? When to gestation age or # fetus?

Answer 39

40day after ram/bock removed or last possible date of breeding 50-55d, count 90d

Question 40

How much fetal growth occurs in last 6 weeks?

Answer 40

70% -Good nutrition needed to prevent preg diseases - concentrate and best hay