Exam 2 - Canine Breeding Management Flashcards
What are the breeding management stepping stones?
Identify 1st d of vulval discharge & start counting = Day -18
Start 3-4 d after proestrus starts or when vaginal cornification is ≈ 50% to perform dx bw
Identify 1st d of standing estrus (Day -9)
Ovulation process in the bitch
LH peaks 24-48 h into estrus and is caused by Estrogen peak during
proestrus
LH has a very short peak duration - assayed daily to detect the peak rise
Ovulation occurs 24-48 h after LH surge (day 3-4 of estrus)
Ovulation takes about 24 h to complete
In the bitch a primary oocyte (2N) is ovulated (Prophase 1)
and must go through further meiotic division to a secondary oocyte (1N) before the oocyte is ready for fertilization
This takes 2-3 days
The secondary oocyte is then viable for 3-4 days (≈108 h) (in general) and then become atretic if not fertilized
What is the modern standard for breeding management of the bitch
Progesterone (P4) assay
Sample every other day M-W-F
Start 3-4 days after proestrus or when vaginal cornification
(superficial cells) is 50% superficial & 20% anucleated cells
What is the [P4] at time of LH surge?
2.0
day 6
What is the [P4] when ovulation starts?
5.0
day 8
When is the best time for Natural mating/Fresh semen AI?
When [P4] is > 8
days 10-13
When is it advisable to AI with cooled/chilled semen
When [P4] >14
days 14-16
At what [P4] is ovulation completed?
>15.0
day 15
When is the best [P4] to AI w/ frozen semen (surgical/TCI)?
>19.3 but <22
days 18-20
What is the principle behind progesterone evaluation
2ng/mL = LH peak
5ng/mL = Ovulation starting
Confirm ovulation (>15ng/mL)
When to breed a bitch
Breed 48-72 h after 5 ng/ml P4 (start of ovulation) for natural
Breed 72-96 h after 5ng/ml P4 with shipped semen
Breed at least 96 h with frozen semen (TCI or Surgical)
Embryos remain in oviduct for 9-10 days after ovulation, enter
uterus as late morula or early blastocyst
Canine oocytes are fertilizable 108 h post-ovulation
Could breed sometimes into diestrus with good results if by -
pass closed cervix (ie surgical insemination or trans-cervical)
What about LH assays?
used in conjunction w/ P4 assay
More definitive than Progesterone
Spayed animals will have high LH - no negative feedback
initial rise in P4 coincides to LH peak⇒ breed ≈4-6 d post LH peak
Make sure you confirm your numbers!! How?
Count backwards from first day of cytologic diestrus
LH peak on Tues, Ovulation on Thurs, Breed Sat and Mon
Breed 48 and 96 h post ovulation
Ovulation is 48 to 72 h post LH peak
LH peak = when P4 = 2 ng/ml
Ovulation starts when P4 = 5 ng/ml, & when jump of 3 ng/ml in 24h
If frozen semen, ?? (Ovulation Completed ≈ 15 ng/ml)
what do we want to have in our fertile male canine
200 x 106 progressiely motile, morphologically normal spermatozoa
80% normal morphology
80% motility
Brucella canis negative
How is a BSE of dog done?
Scrotal measurements
either by calipers or u/s (avoid including epididymis in measurement)
symmetrical
