Final: Stallion Flashcards
What is included in the breeding soundness exam in a stallion that is not evaluated in the bull?
Libido and mating ability
When evaluating stallion semen, two ejaculates are collected. How far apart should these be collected? After what time period of sexual rest? What value are you looking for?
1 hour
1 week
1 billion progressively motile, morphologically normal sperm
HOLY GRAIL OF STALLION BREEDING SOUNDNESS
What is the most important infectious disease to test a stallion for?
Equine Viral Arteritis
Why is it important to test for EVA in stallions?
Stallions are chronic carriers (sex glands)and asymptomatic, causes huge abortion storms
Every ejaculate is contaminated if stallion is infected
What is the only practical way to collect semen from a stallion?
Artifical vagina
Colorado, Missouri, Roanoke, INRA
Where in an AV should the stallion ejaculate?
a. Middle
b. Far end
c. Near end
d. Anywhere
b. Far end
Middle is too warm
Why can a spayed mare be used for mounting?
The absence of progesterone rather than the presence of estrogen causes sexual behaviors, so an OVX mare is always acting receptive
T/F: Ejaculation can be induced in the unstimulated stallion by means of drugs alone.
True
Generally, the ______ nervous system controls ejaculation while the _______ nervous system controls erection.
Sympathetic
Parasympathetic
What is the minimum number of progressively motile, morphologically normal sperm in the second ejaculate?
1 billion (1x10^9)
Which drugs and via which routes are used for chemical ejaculation?
Imipramine IV (PO needs to be given for several days)
Xylazine IV
Norepinephrine IM
What is the average ejaculate volume?
50mL
20-150mL
What % motility and normal morphology is required?
>60% for both
T/F: In stallions it is acceptable for sperm to have abaxial tail implantation and thus can be normal for the sperm to swim in large circles.
True
What does the presence of several secondary spermatocytes in the ejaculate of a stallion indicate?
Testicular degeneration
If ejaculate originates from the epididymus there will be a high concentration of __________. A level of <____ U/L indicates a blockage.
Seminal plasma alkaline phosphatase
100 (<1000 =suspicious)
N=25,000 U/L
What affects daily sperm output (4 things)?
Season
Testicular size
Age
Sexual behavior
Typically the [sperm] is lower in the ______ (winter/summer).
Winter
How much does the [sperm] decrease in the second ejacualte?
Approx 50%
What is the approximate total scotal width of a sound stallion?
10cm
Stallions reach their maximal sperm production and storage at or above ___ years of age.
7
How many million/billion progressively motile sperm (for AI) should be found in:
- Fresh semen
- Cooled semen
- Frozen semen
- Fresh= 500 million
- Cooled = 1 billion
- Frozen = 800 million to 1 billion (min. 240 mil at thawing)
You are packaging semen from a stallion for cooled shipment. You should aim for an inseminating dose of:
a. 500 million PMS
b. 800 million PMS
c. 1 billion PMS
d. 5 billion PMS
c. 1 billion PMS
Where does presperm come from?
Bulbourethral grands and Urethra
Where does the sperm rich fraction of semen come from?
Epididymis and Ampullae (testes)
Where does the sperm poor fraction of semen come from?
Prostate and Vesicular glands
Where does the gel fraction of semen come from?
Vesicular glands
If the urethra tears, where does this occur?
Convex surface of the urethra at the ischial arch
What is the most common cause of urospermia?
Idiopathic
Which of the following is NOT a treatment option for urospermia?
a. Furosemide
b. Empty bladder completely before collection
c. Sildenafil
d. Lavage bladder
e. Dilute ejaculate with semen extender
f. Phenylopropanolamine or Imiprimine
c. Sildenafil
Diluting is probably the best treatment
T/F: Cryptorchidism in stallions has a strong genetic component.
True
What tool is most useful to assess testicular trauma and monitor the progression?
Ultrasound
If you want to continue breeding a stallion that has ruptured one of its testicles, what is your immediate plan of action and why?
Remove the damaged testicle
Body forms autoantibodies against testicular tissue which will affect the healthy testicle
What is the most common testicular neoplasia in young horses?
Teratoma
Esp. cryptorchidism (Dogs= sertoli)
______ cell tumors tend to look gray and hard while _____ cell tumors look yellowish tan. A ______ is whiteish and soft.
Sertoli
Intersitital
Seminoma
T/F: A testicular biopsy is more dangerous in stallions than in bulls.
False, safer in stallions
What disease do these horses have?
Herpes (EHV-3)
Note: depigmented skin
What is the term for serous fluid collecting between the visceral and parietal layers on the vaginal tunic of the testes/testicle?
Hydrocele / Vaginocele
Which of the following is not a treatment for a hydrocele?
a. Benign neglect
b. Move to cooler environment
c. Move to warmer environment
d. Exercise
e. Scerlotherapy
f. A and C
g. C and E
h. None of the above are treatments, the condition is always fatal
g. C and E
What is the term for the inability to retract the penis?
Paraphimosis
What is the term for a persistent erection without sexual arousal?
Priapism
In horses, is priapism usually caused by high-flow (arterial supply) or low-flow (venous drainage) ?
Low flow
Which of the following is NOT a treatment for priapism?
a. Benztropine mesolate IV (Parkinson’s medication)
b. Tertbutaline
c. Surgical irrigation of the urethra
d. Clenbuterol
e. Phenylephrine intra-CCP
c. Surgical irrigation of the urethra
Surgical irrigation of the CCP would be correct
What disease causes equine coital exanthemia?
EHV-3
T/F: EHV-3 does not cause longterm fertility problems.
True
Lesions are painful but resolve, no abortions
What is the most common penile neoplasm in horses?
SCC
What is ampullar spermiostasis?
Plugged ampullae
Excessive accumulation of spermatozoa that become inspissated and block the lumen
T/F: Alkaline phosphatase concentration in semen is a good test to confirm suspected unilateral ampullar spermiostasis.
False
Must be bilateral block to diagnose with alk phos
What is the causative agent if you note a mare with metritis accompanied by excessive purulent discharge?
Taylorella equigenitalis
(Contagious Equine Metritis)
T/F: Your client’s stallion is to be shipped to Europe. You find the stallion is seronegative for EVA. The next step is semen culture to confirm EVA status.
False
If positive must check to make sure he is semen negative
