General Animal Reproduction

It begins with the reproductive system in the embryo

Promotes genetic diversity Sexual reproduction is a biological process by which organisms create descendants that have a combination of genetic material contributed from two different members of the species.

Estrus: the period of sexual receptivity in females. Also known as Heat’

the reproductive cycle of non-primate females that is defined by a time interval between one Heat (estrus) to another Heat (estrus)

Dogs have a rather unique reproductive cycle that differs from many other mammals - Its estrous cycles have quite long periods of inactivity. The variation is dependent on breed. - Puberty usually correlates to the time dogs reach adult weight and height: - Small breed dogs: 6-10 months ◼ Large breed dogs:18-24 month

This is breed dependent

• Anestrus • proestrous • estrus • diestrus (or metestrus)

Period of reproductive rest. Time between whelping (diestrus) and the next proestrus phase

Time: Last 6-11 days (average 9 days) Time interval prior to estrus and characterized by increased ovarian follicular activity - LH and FSH increases estrogen levels - The estrogen increases growth of the uterus and vagina mucosa and increased vascularization Change in behaviour: restlessness, increased urination, more playful with the male

Restlessness, increased urination, more playful with males

Period of sexual receptivity - First day the female will allow the male to mount (standing heat) - End of estrus: Female will not stand for male Estrogen rise 1-2 days prior to estrus and as estrogen levels decrease pregesterone level invrease LH surge leads to ovulation During estrus: vaginal secrestion progress from blood tinged to staw coloured

Lasts usually 2 months long Corpus luteum produces progestrone - Maintains pregnant and non-pregnant uterus Non-pregnant uterus: diestrus ends as corpus lutea regresses (day 60-80) Diestrus begins: female refuses to stand for male

Pregnant uterus: diestrus terminates at whelping (day 56-58) Non-pregnant uterus: diestrus ends as corpus lutea regresses (day 60-80

Female refuses to stand for male

Day 20-30: feel ‘walnut size’ growths in uterus. Day 30-50: uterus is large (diffuse) but difficult to palpate individual fetuses Greater than Day 50: individual fetus can be distinguished from intestines

Can diagnose pregnancy at Day 25 gestation

Enlarged uterus at Day 20: - Day 45: radiograph can identify individual fetuses (calcified skeleton)

• Abdomen • Ultrasound • Radiographs • Blood or Urine Hormoe Testing (NOT HUMAN PREGNACY TEST) • Blood test • Can measure relaxin levels in the dogs at day 24-30

• split heats: first proestrus/estrus: no ovulation, but second proestrus/estrus there is ovulation and normal fertility • ovulation failure: seen in bitches with short inter-estrus periods (<4 months) • Prolonged proestrus/estrus: (this period last longer than 21 days) Causes: ovarian cysts

• incorrect time of mating • stress: too much stress with the bitch and will lead to infertility • infertile males • Uterine problems: infection, endometriosis

first proestrus/estrus: no ovulation, but second proestrus/estrus there is ovulation and normal fertility

Difficult birthing (parturition) Common in bulldogs → You need to do a c-section for them

• uterine weakness; electrolyte imbalance, fatigue (long delivery, too many puppies) • narrow pelvic canal (i.e. pug, bulldog) • fetus is too large or malposition • obstruction of vagina (scarring, tumors)

Infection of uterus Most common in older dogs (8-10 years) and dogs with multiple births - ‘looser’ cervix allows more pathogens iside - If the cervix does not open during parturition - Uterus may burst • Prolonged progesterone; makes the uterus a great place to grow bacteria • Treatment: surgery or if breeding animal prostaglandins (open cervix only and antibiotics)