Wk 7 male & female clinical applications Flashcards
(31 cards)
Why does testicular circumference become bigger?
- More cells producing more sperm
- Produced in the seminiferous tubules
More cells that are produced = expanding testicles
What drives spermatogenesis?
- Hormones
So if we aren’t producing enough hormones, we won’t produce sperm
What happens if testicles are not big enough?
- Defect in spermatogenesis –> low hormones etc. Which drive it
Test for testosterone and LH –> these are sperm producing hormones
What is the pampiniform plexus?
- Counter current heat exchange
What is the role of the cremaster muscle?
- Raise/lower testicles to control temperature
Protects the testicles as well –> fight or flight response (if a bull is scared it is going to raise and protect it etc. –> if you see a bull with very low and swollen testicles, may not be fit for reproduction..)
What is DHT?
Why is it important compared to testosterone?
- Dihydrotestosterone
4 x more potent than testosterone
What happens when we have too much dihydrotestosterone?
- Can cause prostate disease
- To fix this we can reduce testosterone
- Reduce/block DHT to clear prostate disease
Finasteride drug blocks DHT to treat prostate disease
Surgical methods of male sterilisation
- Orchidectomy - remove the testicles
Vasectomy - remove part of the vas deferens
Chemical methods of male sterilisation
- GnRH agonists/antagonists
- Reduces the FSH and LH which can reduce diseases in Daschounds for example who get disc disease
- Increased FSH/LH also has an effect for cancer, bone disease, cruciate ligaments etc.
Vaccines (GnRH, Kisspeptin, Zona pellucida)
What happens when we desex an animal?
Loss of negative feedback –> increased GnRH –>Increased FSH and LH with no negative feedback
Effect of chemical method: Deslorein implant
- Suppresses GnRH –> stops LH and FSH
- Prevents testosterone from being produced
Testicles get small as not producing sperm –> sperm production = teste size
Breeding soundness examination: 7 categories of this exam
1) General physical examination
2) Reproductive physical examination
3) Measurement of scrotal circumference
4) Semen evaluation - initial evaluation on collection
5) Semen evaluation - morphology and other laboratory evaluations
6) Serving ability or capacity
Testing for specific infectious or genetic diseases may be carried out on an as-needed basis
What effect does progesterone
Blocks oestrogen and surge centre = no ovulation
What drives poor libido?
- Testosterone
Scrotal circumference
- Provides reliable estimate of testicular mass and daily sperm production
High correlation of 0.95 with paired testis weight
Is sperm concentration important? Why?
- Pregnancy rates significantly higher when more sperm is present
Higher sperm concentration = higher conception
Freezing semen - process:
- Semen prepared at room temperature then cooled at 4 degrees
- Packaged in straws/pellets
- Cooled in a step-down fashion to -196 degrees
- Stored in liquid nitrogen indefinitely
Sperm trapped in unfrozen water channels and surrounding area is frozen as well
Why do we freeze semen
- Insurance
- Genetic improvement
Convenience of shipping semen
Removing gonads and effect on HPG axis
Oestrus Seasonality with melatonin and light
- horses - long day breeders, rely onlow melatonin and warmer days
- Also with sheep -> short day breeders, high melatonin and colder days
Cats: we can use melatonin to suppress oestrous in cats instead of desexing..
Surge centre in females
- Positive feedback with oestrogen
What happens if we remove gonads? Everything in the surge centre will be unregulated
Female sterilisation methods: surgical methods
- Ovariohysterectomy
- Hysterectomy
Ovary sparing spey -> leave the ovary and take the uterus out (not correct, can have ectopic pregnancy through endometriosis)
What happens if we leave the ovaries in females?
- Ovary sparing spey -> leave the ovary and take the uterus out (not correct, can have ectopic pregnancy through endometriosis)
- Disaster if leaving ovaries in:
Female still has heat when ovaries are in = still attracted to dogs = can still mate with males –> where does the sperm go when they mate? Peroneal abdomen = vagina bursting so the sperm goes into the abdomen = immune reaction as sperm is foreign = BIG PROBLEM
- Disaster if leaving ovaries in:
Chemical methods of female sterilisation
- GnRH agonists/antagonists
Vaccines (GnRH, kisspeptin, zona pellucida)
