L18: Small Ruminant Theriogenology Pt.1 (Pozor)

Question 1

age rams reach puberty

Answer 1

6 mo. (as early as 3 mo, depending on breed)

Question 2

age ewes reach puberty

Answer 2

5-7 mo. (as early as 3 mo, depending on breed)

Question 3

age bucks reach puberty

Answer 3

6 mo.

Question 4

age pigmy goats reach puberty

Answer 4

2-3 mo.

Question 5

age does reach puberty

Answer 5

5-7 mo.

Question 6

age of first breeding for sheep and goats

Answer 6

6-8 mo., or when 60-70% of mature BW

Question 7

length of estrous cycle in sheep

Answer 7

17 days

Question 8

length of estrous cycle in goats

Answer 8

21 days

Question 9

duration of estrus in sheep

Answer 9

24-36 hrs

Question 10

duration of estrus in goat

Answer 10

12-36hrs

Question 11

time of ovulation in sheep

Answer 11

24-30 hrs from onset of estrus

Question 12

time of ovulation in goats

Answer 12

30-36 hrs from onset of estrus

Question 13

optimal breeding time for sheep

Answer 13

towards end of estrus

Question 14

optimal breeding time for goats

Answer 14

at acceptance of buck (24 hrs) and again in 12 hrs

Question 15

sheep/goats long or short day breeders?

Answer 15

short (~sep-jan); some breeds more seasonal than others

Question 16

when is anovulatory season?

Answer 16

jan-june (after ovulatory season)

Question 17

when is transitional season?

Answer 17

june-sep (before ovulatory season)

Question 18

manipulations of the estrous cycle

Answer 18

• induction of estrus during transition or anovulatory season (goal = 3 pregnancies in 2 years)
• synchronization of estrus during ovulatory season
• increasing prolifacy (goal = homogenous crop of twins)

Question 19

How to induce estrus during transition or anovulatory season?

Answer 19

• progestagen/progesterone impregnated vaginal devices
• eCG injection
• ram effect
• melatonin (tricks animal into thinking its dark outside)
• manipulating length of daylight

Question 20

“hormone of darkness”

Answer 20

melatonin

-can advance breeding season by 4 weeks

Question 21

how do progestagen/progesterone impregnated vaginal devices work?

Answer 21

• stops estrous cycle until everyone else “catches up” then take it out and will be synchronized
• mimic CL function
• note: progestagen is a synthetic substance that has similar effects as progesterone
• 2 examples of devices: intravaginal CIDR (approved), sponges with progestagens (not approved)

Question 22

eCG

Answer 22

equine chorionic gonadotropin

• secreted by endometrial cups
• fx in fuminants: induces follicular growth**
• fx in horses: acts like LH to stimulate ovulation**
• can give an injection of it when trying to induce estrus during transition or anovulatory season

Question 23

sheep/goat breeding management protocol

Answer 23

insert CIDR or sponge device, then remove 12-14d later and give eCG injection. Follow with one or multiple AI/matings 50-60 hrs later (DNK timings)
-CIDR or sponge in for shorter period of time in goats

Question 24

What is a CIDR?

Answer 24

medicl silicone elastomer over a nylon core impregnated with natural progesterone
-approved for use in sheep

Question 25

progestagen vaginal devices effect on submission rate, fertility, prolificacy. Can use with AI?

Answer 25

Can use with AI sub. rate: +++ fertility: ++ prolificacy: +++

Question 26

ram effect on submission rate, fertility, prolificacy. Can use with AI?

Answer 26

Don't use with AI sub. rate: + fertility: + prolificacy: +

Question 27

Melatonin implant on submission rate, fertility, prolificacy. Can use with AI?

Answer 27

Don't use with AI. sub. rate: ++ fertility: ++ prolificacy: ++

Question 28

Light control protocol of induction of estrus during transition or anovulatory season

Answer 28

8-12 wks of "long days" (16hrs of light) followed by 8-12 wks of "short days" (8 hrs of light) -labor intensive - not practical!

Question 29

Dow/Ewe anatomy

Answer 29

Ewe: 7 rings, tortuous Doe: 5 rings, aligned

Question 30

natural breeding male to female ratios

Answer 30

rams/ewes: 3-5/100 with 27 days together bucks/dows: 3/100 with 32 days together (these are for normal breeding w/o manipulation

Question 31

AI methods***

Answer 31

1) Vaginal (highest + sperm) 2) Cervical 3) trans-cervical (difficult) 4) Laparoscopic 5) Intrauterine (lowest # sperm) * **decrease volume of sperm as you go deeper into the repro tract***

Question 32

where are sperm naturally deposited?

Answer 32

urethral process

Question 33

T/F: better to deposit sperm cervical than damage repro tract by trying to go through cervix

Answer 33

T

Question 34

Pregnancy Dx: indirect methods

Answer 34

- return to estrus - progesterone >1ng/ml * *both are INDIRECT methods (could have been pregnant, lost it and have retained CL which is falsely elevating progesterone)

Question 35

How many days for doe to return to estrus?

Answer 35

21d

Question 36

How many days for ewe to return to estrus?

Answer 36

17

Question 37

Pregnancy Dx: direct methods

Answer 37

US (transrectal/transabdominal around 30d) Rads (>58d) Ballotement (>100d gestation)

Question 38

when can see cotyledons on transabdominal US?

Answer 38

>30d

Question 39

when do fetuses become difficult to count with US?

Answer 39

>90d

Question 40

Biomarkers for pregnancy Dx

Answer 40

BioPRYN (>30d) Estrone sulfate (>50d) : used to check viability of fetus Placentallactogene (>60d)

Question 41

gestation length of ewes***

Answer 41

148d (CL dependent up to 60d, then depend on placenta progestagens >60d)

Question 42

induction of labor in ewes

Answer 42

>142d: glucocorticoids (dex) | -parturition occurs 36-48hrs later

Question 43

gestation length of does***

Answer 43

150d (CL dependent throughout ENTIRE pregnancy)

Question 44

induction in does

Answer 44

>140d: glucocorticoids (dex) -inconsistent timing of parturition >144d: prostaglandins (cloprostenol, dinoprost) -parturition occurs 42-72 hrs later Can use combo of dex then PGF: parturition occurs 32-36 hrs later

Question 45

most commonly used and accurate method of pregnancy dx in SR**

Answer 45

US