ET: control of the estrous cycle Flashcards
Breeding results in some degree of ___________
Endometritis
inflammation fo the endometrium
Endometritis in a susceptible mare
Older, problem mares
May respond slowly or not at all to an inflammatory response induced breeding
Endometritis in a resistant mare
Usually younger, normal, maiden mare
Can respond quickly to inflammation or contamination that’s introduced
How do you control the mare’s cycle during vernal transition
Artificial light (earlier onset OV)
Exogenous progesterone
Or a combo of both
Control of mare’s cycle using progesterone
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)
Progesterone routes of delivery
Oral: altrenogest and allyltrenbolonen
Parenteral: progest in oil (daily IM) and long acting form
What is required to shorten transition?
Multiple small follicles (15-20 mm)
12-15days treatment with ReguMate then PGF on day 15
Breed on next estrus
What happens when ovaries are still inactive when trying to shorten the cycle?
Treatment will cause ovarian activity to regress (the mare returns to anestrus state)
Control mare’s cycle during diestrus (within the ovulatory period)
PGF effective if 5+ days post OV (between 5-17 dys with mature CL present)
After early luteal and before follicular
PGF dose
Lutalyse (natural PGF, IM)
Estrumate: cloprostenol (analogue, IM)
Control mare’s cycle during estrus (within OV period)
Inducing OV
Limiting use to stallion and unnecessary breeding
Avoid live cover breeding
Minimum follicle size of 35 mm
Follicular phase of the estrous cycle
FSH: 10 days
LH: long t1/2 and peaks over OV
OV 1-2 days before the end of estrus
Drugs to hasten OV
hCG: LH like activity (IV)
GnRH product: produces LH spike by mimicking response of hypothalamus
Injectable deslorelin acetate
Injectable deslorelin acetate
IM
Sustained-release GnRH
Mare must have at least 30-40 mm follicle present
Controling mare’s cycle during autumnal transition
Suppress estrus behavior in show and racehorses
ReguMate: suppress follicular activity
Oxytocin
Treatment of retained fetal membranes
Facilitate mechanical drainage from uterus
Induction of parturition
Estrogen
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
Abx and antiseptics
Treating the uterus
Use low systemic dose 3-5 days of admin
Most infections are superficial
With the appropriate use of ________ (to treat DUC) abx use has diminished
Ecbolics
Ultrasound monitoring
Tool to ID early DUC
When should you treat DUC
Treat before fluid accumulation ↑ or is allowed to maintain in place for a while (luminal fluid)
Longer it remains, ↑ degree of endometritis
Endometrial fold edema
Persists after OV and a marker for inflammation
Tris-EDTA
Reduces biofilm formation on the endometrium
(biofilm prevents abx from contacting the endometrium)
Antiseptics
Stimulates an influx of activated neutrophils that help reduce the chronic cellular infiltrates in the endometrium
When should you use artificial light
Begin Nov 15, latest Dec 1
Requires minimum 60 days stimulation
Artificial/ Supplemental light
Watt bulb, foot candles in 12x12 stall
Minimum 16 hrs light exposure
Padlock lighting
Add supplemental light to the end of the day
Artificial light alternatives
Flash lighting (2 hr exposure) and start 9 hrs after onset of darkness
Light masks (Equilume)
