Therio - Mare Breeding Management

drraythe's version from 2017-10-09 16:14


Question Answer
What are the 2 types of natural breeding?(1) Pasture breeding (not common)
(2) Assisted breeding ("Live cover")
3 types/ways to handle semen for AI?Fresh, cooled & shipped, frozen.
What is pasture breeding?Where you just let them naturally breed out in the pasture
Explain how live cover breeding is doneMare is teased daily or every other day → When she is in good heat, she is covered. She is teased again 2 days later & re-covered if she is still standing. Cont. until mare rejects the stallion
What is the only kind of breeding allowed in TBs?Live cover (the actual sex)
Why is ovulation timing critical for live cover breeding?1 cover per estrous cycle ("covering fee") therefore ovulation timing critical! (Induction of ovulation...)
Do you bring the mares to the stallions or the stallions to the mares for live cover?Mares will visit stallion at stud farm
What are some ways to insure the safety of the stud during live cover?Mare is hobbled, twitched, has non-kick boots on (horse bondage, totes normal)
*What is the insemination dose for fresh or chilled semen?500 million progressively motile, morphologically normal spermatozoa
How long is semen good for once it is extended?+/- 24hr
What is the special container in which the semen is placed & shipped after it is extended for AI?"Equitainer" or "Clipper"
When inseminating the mare during AI, what are some ways to maintain hygiene?Tail bandage/wrap, clean perineum w/ water & mild soap (not Βetadine) & rinse well. Sterile rectal glove (inside out or autoclaved)
Once you are thoroughly cleaned & you have the sterile rectal glove on, how do you AI her?Arm passed to the cervix & insemination pipette passed intrauterine & semen deposited - massage cervix - Oxytocin release. Hand w/drawn slowly to avoid getting air in vagina
Since you want to ensure that ovulation occurs ASAP after insemination ie. W/in 24-48h... you can induce ovulation w/ what 2 agents?(1) hCG – Chorulon
(2) GnRH analogues
What does hCG do, & when do you want to use this? How long till intended effect?Use to INDUCE OVULATION! Bc has LH like effect. You want to use this when follicle is >or equal to 35mm → ovulation w/in 36hrs!!
What do GnRH analogues do, how long until intended effect?Used to INDUCE OVULATION (can be ovuplant implant, or Sucromate/Fertagyl Injxn) get ovulation w/in 42h avg
*For how long is frozen & then thawed semen good for?Frozen thawed semen is fertile in the mare for a maximum of 12 hrs
*How long is the ovum good for after ovulation?After ovulation, the oocyte viable for a 6-12 h period
**Since frozen semen is only good for max 12hr, & oocyte is only good for 6-12h after ovulation...what are the goals for when you wanna inseminate the mare w/ frozen semen?The goal is to inseminate the mare in the window 12h BEFORE ovulation & 12 h AFTER ovulation
Explain how to go about insemination once you have given the hCG Injxn?Start examining the mare every 6-12h starting 12h after hCG Injxn until ovulation has occurred. Inseminate immediately AFTER Dx of ovulation by deep intrauterine insemination (on the side w/ the follicle).
Why would you wanna do foal heat breeding?In order to get mare pregnant again ASAP so that she can foal down as close to 1st January as possible (risky!)
After foaling, when is the 1st ovulation? When does uterine involution happen?1st ovulation btwn 4 & 14 days postpartum (average 10 days). Uterine involution takes >12d
How long does uterine involution take?Greater than 12d
What are the downsides of foal heat breeding?Fertility (% pregnant) is lower (-10%), Risk for early embryonic loss is higher (+10%)
What will happen if you skip the 1st ovulation of the foal heat breeding? (How long till you can breed?)Will then only be breeding +/- 20 days after foaling & may push back next yr's foaling date or lose her for the whole season
Why might you not want to inseminate during the foal heat?Uterus not involuted properly, high risk of EED
How can you postpone the 1st ovulation of the foal heat?Using progesterone (Regumate) from foaling until +/- 12 days post foaling & then inseminate when mare shows heat
If you decide to skip the 1st foal heat ovulation, how can you still shorten your wait period? (When would you breed then?)Skip 1st ovulation & give PGF2α to shorten the luteal phase - Mare is then bred +/- 14d after foaling
Examine the teasing record of the following TB mare. What Tx was given on 27th February? PGF2α
(hGC given on March 6th to induce ovulation)
What Tx is given on the 6th March? hCG
(PGF2α was given on Feb 27th)
You examine a mare due to be bred by live cover. You find the following structure on the ovary. At what stage of the cycle is this mare? This is a U/S of a CL, so she is in diestrus
Examine the following 2 images of the uterus of a mare obtained on rectal ultrasound scan on 2 successive examinations w/ an interval of 8 days. Which ultrasonogram is typically associated w/ low uterine tone? A
Examine the following 2 images of the uterus of a mare obtained on rectal ultrasound scan on 2 successive examinations w/ an interval of 8 days. Artificial insemination w/ fresh semen is more likely to be indicated on the day you observe which ultrasonogram? A