Breeding

Question 1

are mares mono or polyestrus

Answer 1

seasonally polyestrus (summer + spring/autumn transition)

Question 2

Describe basic hormone pattern

Answer 2

hypothalamus: GnRH –>
pituitary: FSH and LH –>
ovary

Question 3

affects of FSH on ovary, hormone, hypothalamus

Answer 3

follicular growth
estrogen production
+ feedback to hypothalamus

Question 4

affects of LH on ovary, hormone, hypothalamus

Answer 4

ovulation
formation of CL
progesterone production
- feedback on hypothalamus

Question 5

how long is estrus? how long is the whole cycle?

Answer 5

3-8d
21d

Question 6

CL is lyzed by ____ released by the endometrium at d15 if no embryo

Answer 6

PGF2a

Question 7

options for estrus suppression

Answer 7

1. altrenogest (progresterone)
2. GnRH vax
3. intra-uterine devices
4. ovariectomy

Question 8

how does altrenogest (synthetic progesterone) work? how is it given?

Answer 8

inhibit secretion of LH (via - feedback)

Orally

Question 9

options for intra-uterine devices?

Answer 9

1. Marble
2. Upod (magnetic,

Question 10

how do intra-uterine devices work? how long do effects last?

Answer 10

mimics embryo, prevenets PGF2a

2-3 months (not long)

Question 11

how to advance breeding season

Answer 11

1. put under light 16h/d for 2 mo
2. blast light for 2h 9h after darkness falls

Question 12

once a mare is in transition period, option to get into season?

Answer 12

10d oral progesterone

Question 13

once in season, ____ can induce estrus within 2-5d

Answer 13

prostaglandin (causes lysis of CL)
altrenogest

Question 14

what can be given to induce ovulation within 36-48h

Answer 14

GnRH (hCG, deslorelin)

Question 15

which has better pregnancy rate: AI or natural

Answer 15

Natural

Question 16

Longevity of sperm natural vs frozen semeen

Answer 16

natural: 48-72h
frozen: 6-24

Question 17

when you arrive for AI visits, what to evaluate to know if she’s ready

Answer 17

follicle development
endometrial edema
cervical relaxation

Question 18

grading of endometrial edema

Answer 18

0 = no edema
4 = max edema +/- free fluid

Question 19

protocol for chilled semen

Answer 19

1. scan daily
2. hCG and order semen for next day
3. inseminate
4. next day: check for ovulation + no free fluid

Question 20

chilled vs frozen semen: given within __ h after ovulation

Answer 20

chilled = 24
frozen = 6

Question 21

why check for free fluid 4h after frozen semen?

Answer 21

bc more likely to develop endometritis

Question 22

pregnancy dx

Answer 22

US (day 15)
Blood test (day 45, look for eCG or estrone sulphate)

Question 23

pro of scanning c.f. BW

Answer 23

can tell if twins

Question 24

when can you find eCG vs estrone sulphate on BW

Answer 24

eCG at 45 days
estrone sulphate at 120 days