Lecture 14- Canine Breeding Management

Breeding management starting point

Identify first day of vulvar discharge = Day 1; begin progesterone testing Day 4–5; vaginal cornification ~60%; identify first day of standing estrus

LH peak timing

LH peaks 24–48 hours into estrus; caused by estrogen peak in proestrus; LH peak short duration → must assay daily

Ovulation timing

Occurs 24–48 hours after LH surge (Day 3–4 of estrus); ovulation takes ~24 hours to complete

Oocyte maturation

Bitch ovulates primary oocyte (2N); requires 2–3 days to mature to secondary oocyte (1N); secondary oocyte viable 3–4 days

Progesterone testing method

ELISA semi‑quantitative; RIA or chemiluminescence preferred; sample every other day (M‑W‑F)

Initial progesterone rise

Coincides with LH peak; begin progesterone assays Day 4–5; vaginal cornification ~60%

2‑2‑2 rule

2 ng/mL = LH surge; 2 days later ovulation; 2 days later breed; ovulation progesterone 4–10 ng/mL

Progesterone interpretation

2 ng/mL = LH peak; 5 ng/mL = ovulation starting; ovulation confirmed by ≥3 ng/mL rise in 24 hrs; failure to confirm ovulation → conception failure, small litters, inaccurate due dates

Breeding timing: natural/cooled semen

Breed 48 and 96 hrs after progesterone reaches ≥5 ng/mL; alternative: 24 and 72 hrs

Breeding timing: frozen semen

Breed 72 hrs after progesterone ≥5 ng/mL; may breed at 96 hrs with TCI; mature oocytes viable 4–5 days; can breed into diestrus if bypass cervix (TCI/surgical)

Alternate natural breeding method

Breed every 2–3 days during standing estrus; typical Day 10, 12, 14; sperm viable up to 6 days with natural cover; higher conception rates/larger litters

Target® ovulation kit ranges

C1: 0–1 ng/mL; C2: 1–2.5 ng/mL; C3: 2.5–8 ng/mL; C4: >8 ng/mL

LH assay advantages

More definitive than progesterone; gestation length defined (65 days from LH peak); spayed animals have high LH; breed 4–6 days after LH peak

Confirming numbers

Count backward from first day of cytologic diestrus → LH peak ~8 days prior

Gestation length

65 ±1 days from LH surge; 63 ±1 days from ovulation; 57 ±1 days from first day of cytologic diestrus

Fertile male requirements

200 million progressively motile, morphologically normal sperm; 300 million–2 billion per ejaculate; ≥80% normal morphology; ≥80% motility; Brucella canis negative

Natural breeding tie

Bulbus glandis engorgement; inside vs outside tie; normal physiologic occlusion of venous return

Canine BSE components

Similar to other species; prostate exam; Brucella testing; scrotal width measurement

Scrotal width equation

log(scrotal width) = 0.324(log body weight) + 1.249

Scrotal evaluation

Assess symmetry; asymmetry suggests degeneration or inflammation

Semen collection methods

Manual stimulation (most common); drug‑enhanced ejaculation; electroejaculation (rare, requires anesthesia, urine contamination risk)

Manual semen collection

Hand caudal to bulbus glandis; slide prepuce over bulbus; collect in bag/cone; 3 fractions: presperm, sperm‑rich, prostatic; estrual bitch/swabs helpful

Drug‑enhanced ejaculation

Oxytocin 5 IU SC/IM 5–10 min prior; PGF2α 0.1 mg/kg SC/IM 15 min prior; epididymal duct smooth muscle responds

Normal semen fractions

Fraction 1: 0.5–5 mL clear; Fraction 2: 1–4 mL opalescent, 4–400 million/mL, 300–2000 million total; Fraction 3: 1–80 mL clear; motility >70–80%; morphology >80%; pH 6.3–6.7

Semen concentration

4–400 million/mL; measured via Makler, hemocytometer, spectrophotometer, nucleocounter

Total sperm per ejaculate

300–2000 million; volume × concentration

Motility evaluation

Gross motility (VG, G, F, P); progressive motility >80% normal dog

Morphology evaluation

Normal, primary, secondary abnormalities; >80% morphologically normal; eosin‑nigrosin stain

Sperm longevity

Fresh: 48–72 hrs; cooled: ≥24 hrs; frozen: 8–12 hrs; longevity testing recommended before shipping

Artificial insemination

Difficult cervical placement; commercial pipettes available; no need to elevate hind end; ~2–4 mL with 200 million motile normal sperm

TCI anatomy considerations

Cervical canal ventro‑dorsal direction; dorsal vaginal fold; catheter may enter fornix; withdraw until cervical os visualized

Cooled semen handling

Avoid bladder entry; extend 1:1 to 1:4; skim milk or canine extender; may centrifuge; ship via FedEx; 3 mL small dogs, 5 mL large dogs

Semen freezing

Freeze early in career; pellets or straws; 10–12 pellets per dose; thaw in warm extender; 100 million sperm per 0.5 mL straw; dose ~150 million motile sperm

Frozen semen breeding

Must use TCI or surgical; breed Day 5–6 post LH peak; or 72 hrs post progesterone ≥5 ng/mL; surgical insemination via laparotomy; AKC requires approved freezing facility

Reasons breeding fails

Female pre‑ovulation; proestrus; vaginal anomaly (band, stricture); male arthritis; pain; prostatic pain; penile issue; behavior/psych

Vaginal stricture/band

Located vestibulo‑vaginal; prevents natural breeding; may require AI or C‑section; bands can be cut; Mullerian septum may create cul‑de‑sac; diagnose via digital exam/endoscopy/vaginogram; developmental, not heritable

Superfecundation

Two males breed same female in one estrus → multiple sires possible

Superfetation

Pregnancy followed by second estrus and second pregnancy; does NOT occur in dogs