sertoli (equivalent of granulosa cells) which secrete inhibin to stop FSH (neg feedback)
what do sertoli cells secrete?
inhibin and estrogen ("nurse cells")
LH effects which cells?
leydig cells (secrete Testosterone) (LH Leydig)
what do leydig cells secrete?
sertoli cells are the equivalent of granulosa cells. Sertoli cells secrete estrogen! Leydig cells secrete testosterone. testosterone converted to dihydrotestosterone. Then T, DHT, and E all have neg feedback on the hypothalamus (how the cycle is regulated)
Scanning electron microscope section through a seminiferous tubule looks like... (just kinda nice to look at)
repro organs pic (she breezed by this as well)
what is the orientation of the testes of the stallion?
HORIZONTAL!!!! (in bull they are vertical)
Thermoregulation in the testis--> why is it important? how is this accomplished?
6° C temperature difference between body & testes! too hot impairs spermatogenesis and causes sperm abnormalities. they are kept cool by being external to the body, and there is Countercurrent heat exchange at pampiniform plexus, there are Sweat glands on surface, the Cremaster muscle (Brings testes closer or further away from body), and Tunica dartos (Contracted & wrinkled= decrease surface area. Relaxed & smooth= increased surface area)
which accessory sex glands does the stallion have?
Prostate, Bulbourethral, Vesicular gland, Ampulla
what is unique about the equine vesicular gland?
Produce the gel fraction of the seminal plasma. Produce lots of gel in stallions
what type of penis does the stallion have?
Musculocavernous (fibroelastic is rumis and pigs)
anatomy of the penis (pic- she breezed by this)
anatomy of the prepuce and glans of penis (pic)
where is the corona glandis, Urethral sinus, glandular diverticulum, and Urethral process of the horse? (pic)
where do smegma beans like to be?
urethral sinus. these can be painful
is the tail of the epididymis at the front or the back of the balls? why do we care?
back (caudal). we care because there can be torsion of the spermatic cord so you need to know your orientation
need to take swabs from what 3 places for CEM (contagious equine metritis)
Pre-purchase, Check up before breeding season, figure out if Fertility issues
first three things to do for a BSE are...
ID!!! Then history, then General physical examination....all before you start the breeding stuff
Once you have the basic exam done, what do you do for the BSE?
Examination of the external genital organs, Evaluation of libido and breeding behavior, Exclude/identify venereal diseases (CEM, EVA, Pseudomonas, Klebsiella), Semen collection, Semen evaluation
what are some diff ways you can ID the stallion for the BSE?
passport, microchip (in the nuchal lig, L side of the neck, about half way up), DNA (TB’s)
what are some things you'd want to ask for the breeding history of the stallion?
number of mares per season, type of mares (% maiden, barren and foaling mares), per cycle pregnancy rate, etc
what are some general clinical exam things you should check which would pertain to his ability to breed?
locomotor, backproblems, eyes
3 potentially hereditary dzs one must look out for during their BSE?
Cryptorchidism, Wobbler, OCD
Palpation of testes-- normal results?
Firm & elastic!, SYMMETRICAL, Freely mobile, Correct orientation, No edema/swelling
you measure the testes because...
to determine “Daily sperm output” (Indication of how many mares he will be able to cover) (size is related to output)
how can you measure the size of the horse's testes?
calipers or U/S
how do you need to go about measuring the stallion's daily sperm output?
First you need to deplete the extragonadal reserves (EGR) which will take 5-7 days of daily sperm collection. This means that The daily sperm output becomes apparent after approximately 1 week of daily semen collections
3 factors which can influence daily sperm output?
(1) age (2) season (more in summer) (3) Frequency of collection/breeding (After depletion of reserves the weekly output is identical with 3x or 6x/week collection. Every other day collection. With natural cover, libido is often the limiting factor)
what is usually the limiting factor for natural cover situations?
before semen collection you should wash the penis- what are some reasons why?
Increases sexual stimulation, Decrease contamination of the semen sample, and allows you to check for any lesions (habronema, coital exanthema (EHV3)) (not to mention help dec post-breeding endometritis)
with what do you wash the penis?
Clean materials (stainless bucket, plastic bucket liner, disposable towels,…). Use clean warm water. Minimum amount of soap (MILD hand soap, easy to rinse, do not clean out the sheath is reserve of normal flora)
which part of the penis do you not wash out?
dont wash out the sheath, that is the reserve for the natural flora
how do you measure libido in a stallion?
time how long it takes him from laying eyes on the mare to getting an erection, mounts, and ejaculates
libido--> how long should it, from first eye contact with estrus mare, take the stallion to: get an erection, mount, ejaculate? what influences these times?
To erection (2 min), To mounting (5 min), To ejaculation (1-2 mounts/ejaculation). This can be influenced by the stallions inherent libido, Influenced by previous experience and training, and Is relevant for future potential. Might indicate a "hidden" problem
what are some different ways you can mentally/physically stim a stallion for collection?
A tease mare (either ovariectomized and given estradiol, or a mare in heat) or use a phantom/ a dummy, and Artifical vaginas
if you will be using a mare for mounting, how so you make sure she is under good control?
Twitch, Breeding Hobbles at the hocks or pastern, Sideline on front or rear leg, Protective soft boots
what two tools are used to protect the mare and the stallion during the time the mount mare is being used?
(1) Neck protection to protect mare from being bitten by stallion (2) Tail bandaging to avoid tail hair being caught over the penis during breeding – may cause cuts on penis
what are the 5 kinds of artificial vaginas?
Missouri, Colorado, Hanover, Japanese, Open-ended
how does the missouri artificial vagina work?
which AV is most popular?
missouri (leather outside one)
pros and cons of the missouri AV?
PRO: Most popular ; lightweight ; adjustable pressure ; No contact of semen with hot liner. CONS: does not hold temp as long
what is the Colorado AV like?
Hard shell, heavy, long, semen can come in contact with hot liner
what is the japanese type AV like?
how does the open-ended AV work?
open ended, put liner in, not a common type
how do you keep the AV safe, and how do you make it appealing to the stallion?
SAFE: Clean and sterile AV, Use disposable liners, cups and recipients wherever possible. Appealing: Fill AV with hot water, inner temperature should be between 113-122 °F (check temp before use) Lubricate AV with a water soluble NON SPERMACIDAL lubricant (KY Jelly or Pre-seed) or with petroleum jelly (Vaseline); copious in first third of AV; avoid having lubricant mix in with the semen
Chemical ejaculation is used WHEN?
For stallions that cannot jump phantom (Musculoskeletal problems)
what chemicals are used for chemical ejaculation (how?)
Imipramine PO (antidepressant). 1-2 h later xylazine IV of detomidine IV. There will be semen loss during entry and exit of sedation