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