Applied Reproduction In The Stallion

Question 1

Stallions at stud
-usually kept….
-require…
-ensure they are not…
-not all stallions are…

Answer 1

Separate from mares
-require special facilities and experienced handlers
-fertile

Question 2

What are some breeding soundness questions you would investigate in a stallion when asking, “does a stallion have the mental and physical capability to:”

Answer 2

-deliver semen that contains viable spermatozoa
-not transfer infectious disease to the mare
-deliver semen at the correct time
-establish pregnancy in a reasonable number of mares per season

Question 3

What would a breeding soundness physical examination of the horse consist of?

Answer 3

-BCS
-musculoskeletal
-respiratory
-eyes
-mouth

Question 4

What would a breeding soundness reproductive examination consist of?

Answer 4

-scrotum
-testicular size & consistency; palpation, US, good correlation with sperm output
-penis; often require a mare in oestrus
-internal genital organs; palpation, US
-observation of libido/mating ability

Question 5

Breeding soundness evaluation of semen

Answer 5

-Gross appearance; no blood, urine or purulent material
-semen volume
-semen pH
• Spermatozoal motility
• Spermatozoal morphology
• Spermatozoal concentration
-longevity or motility

Question 6

What is the average semen volume in a stallion?

Answer 6

50ml (range 20-250ml)

Question 7

What is average semen pH in a stallion?

Answer 7

7.2-7.7

Question 8

Breeding soundness of a horse must be tested when?

Answer 8

Before breeding season

Question 9

What disease is tested via a swab in a stallion?

Answer 9

Contagious equine metritis (CEM)

Question 10

What diseases are tested via blood sample in a stallion?

Answer 10

1. Equine viral arthritis (EVA)
2. Equine infectious anaemia (EIA)

Question 11

What are some advantages of artificial insemination?

Answer 11

• One ejaculate divided into several insemination doses
– ^number of mares covered
• Mare can be bred to remote stallion
• Prevent disease transmission (especially venereal)
• Reduced uterine inflammation
• May improve fertility for some stallions
• Avoids breeding injuries
• Assess semen at collection and before insemination

Question 12

What are som disadvantages of artificial insemination?

Answer 12

• Can be expensive
• Increased skill levels required
• Not all stallion’s semen can be used
• Risk of human injury during semen collection

Question 13

How do you collect Semen in artificial insemination?

Answer 13

an artificial vagina (AV)
– a water filled cylinder with collection bottle at end
– Rubber liner
-can alter temperature (range 44-48*C)
-can alter volume of water in AV

Question 14

Describe process of collecting semen in AI

Answer 14

—Allow stallion to mount either
-mare in oestrus
-ovarioectomised mare
-phantom
—divert penis into AV & monitor for ejaculation

Question 15

Name the 2 Fractions of ejaculate

Answer 15

–gel. Fraction;
-removed by filtration
-filtration also removes other debris
-is discarded
–gel-free. Fraction
-contains majority of spermatozoa
-assessed. And usually mixed with semen extender
-extender based on Skimmed-milk or egg Yolk & includes antibiotics

Question 16

What types of semen exist

Answer 16

Liquid-
Fresh Semen; raw, use direct writhin 30 min with extender of 6-12 hours
Chillier extended semen; over 6 hours & remain motile for up to 72 hours, however motility deteriorates so ideally use in <24hours

Frozen-
Needs extender
Packaged in straws
Need several straws to inseminate mare
Thaw before use

Question 17

What are some reasons animal should be castrated?

Answer 17

Control of repro, population, sexual behaviour
Testicular neoplasia
Testicular trauma
Inguinal herniation
Spermatic cord torsion

Question 18

When is animal usually castrated
-age
-season

Answer 18

-Can be done any age (^ risk with age)
-usually as a colt ; TB at 1-2 years
-ponies 6-12 months
Season- usually spring/autumn (open scrotal incisions cause risk of myiasis (fly strike) in summer)

Question 19

How should you make a correct safe palpating of male/female sex organs?

Answer 19

Stand at withers, head up& palpate blind

Question 20

What instrument would you use to crush males testis?

Answer 20

Emasculators

Question 21

Spermatic vessels consist of…

Answer 21

testicular artery surrounded by tortuous testicular veins

Question 22

What are the 2 methods of castration?

Answer 22

Closed and open castration

Question 23

What is closed castration?
-requires what
-what age is it completed at?
-skin left sutured or unsutured?

Answer 23

-Castration completed whilst vaginal tunic not opened
-requires a ligature around spermatic cord & general anaesthesia
-any age
-Unsutured

Question 24

Open castration
-open via what
-what age is it completed at
-which normal can this not be completed on?
-requires ligature or not
-skin left sutured or unsutured?

Answer 24

-open via inguinal ring to peritoneal cavity
-max 3-4 years
-not stallions
-no ligature required
-skin left usutured

Question 25

What are some complications that can occur with a castration?

Answer 25

• Oedema/swelling
• Haemorrhage*
– Testicular artery
• Infection
• Protrusion of tissue*
• Eventration/Evisceration*
* Increased risk with open castration

Question 26

What is the term for a cryptorchid or horse that behaves like a stallion with no visible testicles

Answer 26

Rig

Question 27

Term used to describe a horse with both testicle removed but still heaves like a stallion

Answer 27

False rig

Question 28

What is smegma?

Answer 28

-A waxy secretion
-can be excessive
-can form a ‘bean’ in the urethral fossa

Question 29

Which animals tend to accumulate smegma as they drop penis less often?

Answer 29

Horse- geldings

Question 30

What is the most common malignant skin tumour in horses?

Answer 30

-squamous cell carcinoma

Question 31

What are some common sites of squamous cell carcinoma

Answer 31

– ocular/periocular tissues
– Genitalia
- penis
– nares
– mouth