ET: control of the estrous cycle

Question 1

Breeding results in some degree of ___________

Answer 1

Endometritis
inflammation fo the endometrium

Question 2

Endometritis in a susceptible mare

Answer 2

Older, problem mares
May respond slowly or not at all to an inflammatory response induced breeding

Question 3

Endometritis in a resistant mare

Answer 3

Usually younger, normal, maiden mare
Can respond quickly to inflammation or contamination that’s introduced

Question 4

How do you control the mare’s cycle during vernal transition

Answer 4

Artificial light (earlier onset OV)
Exogenous progesterone
Or a combo of both

Question 5

Control of mare’s cycle using progesterone

Answer 5

Shorten duration of spring transition (diminish erratic estrus behavior and ↓ uncoordinated follicular activity)
Treat persistent follicles (lutenize and regress)
Estrus suppression (race and show mares depending on behavior)

Question 6

Progesterone routes of delivery

Answer 6

Oral: altrenogest and allyltrenbolonen
Parenteral: progest in oil (daily IM) and long acting form

Question 7

What is required to shorten transition?

Answer 7

Multiple small follicles (15-20 mm)
12-15days treatment with ReguMate then PGF on day 15
Breed on next estrus

Question 8

What happens when ovaries are still inactive when trying to shorten the cycle?

Answer 8

Treatment will cause ovarian activity to regress (the mare returns to anestrus state)

Question 9

Control mare’s cycle during diestrus (within the ovulatory period)

Answer 9

PGF effective if 5+ days post OV (between 5-17 dys with mature CL present)
After early luteal and before follicular

Question 10

PGF dose

Answer 10

Lutalyse (natural PGF, IM)
Estrumate: cloprostenol (analogue, IM)

Question 11

Control mare’s cycle during estrus (within OV period)

Answer 11

Inducing OV
Limiting use to stallion and unnecessary breeding
Avoid live cover breeding
Minimum follicle size of 35 mm

Question 12

Follicular phase of the estrous cycle

Answer 12

FSH: 10 days
LH: long t1/2 and peaks over OV
OV 1-2 days before the end of estrus

Question 13

Drugs to hasten OV

Answer 13

hCG: LH like activity (IV)
GnRH product: produces LH spike by mimicking response of hypothalamus
Injectable deslorelin acetate

Question 14

Injectable deslorelin acetate

Answer 14

IM
Sustained-release GnRH
Mare must have at least 30-40 mm follicle present

Question 15

Controling mare’s cycle during autumnal transition

Answer 15

Suppress estrus behavior in show and racehorses
ReguMate: suppress follicular activity

Question 16

Oxytocin

Answer 16

Treatment of retained fetal membranes
Facilitate mechanical drainage from uterus
Induction of parturition

Question 17

Estrogen

Answer 17

ECP: estradiol cypionate
Induce behavioral estrus in an OVX mare
Creates a jump mare to tease to stimulate stallions
Brings mare into behavioral estrus in any time of year

Question 18

Abx and antiseptics

Answer 18

Treating the uterus
Use low systemic dose 3-5 days of admin
Most infections are superficial

Question 19

With the appropriate use of ________ (to treat DUC) abx use has diminished

Answer 19

Ecbolics

Question 20

Ultrasound monitoring

Answer 20

Tool to ID early DUC

Question 21

When should you treat DUC

Answer 21

Treat before fluid accumulation ↑ or is allowed to maintain in place for a while (luminal fluid)
Longer it remains, ↑ degree of endometritis

Question 22

Endometrial fold edema

Answer 22

Persists after OV and a marker for inflammation

Question 23

Tris-EDTA

Answer 23

Reduces biofilm formation on the endometrium
(biofilm prevents abx from contacting the endometrium)

Question 24

Antiseptics

Answer 24

Stimulates an influx of activated neutrophils that help reduce the chronic cellular infiltrates in the endometrium

Question 25

When should you use artificial light

Answer 25

Begin Nov 15, latest Dec 1
Requires minimum 60 days stimulation

Question 26

Artificial/ Supplemental light

Answer 26

Watt bulb, foot candles in 12x12 stall
Minimum 16 hrs light exposure
Padlock lighting
Add supplemental light to the end of the day

Question 27

Artificial light alternatives

Answer 27

Flash lighting (2 hr exposure) and start 9 hrs after onset of darkness
Light masks (Equilume)