Applied Reproduction In The Stallion Flashcards
Stallions at stud
-usually kept….
-require…
-ensure they are not…
-not all stallions are…
Separate from mares
-require special facilities and experienced handlers
-fertile
What are some breeding soundness questions you would investigate in a stallion when asking, “does a stallion have the mental and physical capability to:”
-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
What would a breeding soundness physical examination of the horse consist of?
-BCS
-musculoskeletal
-respiratory
-eyes
-mouth
What would a breeding soundness reproductive examination consist of?
-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
Breeding soundness evaluation of semen
-Gross appearance; no blood, urine or purulent material
-semen volume
-semen pH
• Spermatozoal motility
• Spermatozoal morphology
• Spermatozoal concentration
-longevity or motility
What is the average semen volume in a stallion?
50ml (range 20-250ml)
What is average semen pH in a stallion?
7.2-7.7
Breeding soundness of a horse must be tested when?
Before breeding season
What disease is tested via a swab in a stallion?
Contagious equine metritis (CEM)
What diseases are tested via blood sample in a stallion?
- Equine viral arthritis (EVA)
- Equine infectious anaemia (EIA)
What are some advantages of artificial insemination?
• 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
What are som disadvantages of artificial insemination?
• Can be expensive
• Increased skill levels required
• Not all stallion’s semen can be used
• Risk of human injury during semen collection
How do you collect Semen in artificial insemination?
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
Describe process of collecting semen in AI
—Allow stallion to mount either
-mare in oestrus
-ovarioectomised mare
-phantom
—divert penis into AV & monitor for ejaculation
Name the 2 Fractions of ejaculate
–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
What types of semen exist
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
What are some reasons animal should be castrated?
Control of repro, population, sexual behaviour
Testicular neoplasia
Testicular trauma
Inguinal herniation
Spermatic cord torsion
When is animal usually castrated
-age
-season
-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)
How should you make a correct safe palpating of male/female sex organs?
Stand at withers, head up& palpate blind
What instrument would you use to crush males testis?
Emasculators
Spermatic vessels consist of…
testicular artery surrounded by tortuous testicular veins
What are the 2 methods of castration?
Closed and open castration
What is closed castration?
-requires what
-what age is it completed at?
-skin left sutured or unsutured?
-Castration completed whilst vaginal tunic not opened
-requires a ligature around spermatic cord & general anaesthesia
-any age
-Unsutured
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?
-open via inguinal ring to peritoneal cavity
-max 3-4 years
-not stallions
-no ligature required
-skin left usutured
What are some complications that can occur with a castration?
• Oedema/swelling
• Haemorrhage*
– Testicular artery
• Infection
• Protrusion of tissue*
• Eventration/Evisceration*
* Increased risk with open castration
What is the term for a cryptorchid or horse that behaves like a stallion with no visible testicles
Rig
Term used to describe a horse with both testicle removed but still heaves like a stallion
False rig
What is smegma?
-A waxy secretion
-can be excessive
-can form a ‘bean’ in the urethral fossa
Which animals tend to accumulate smegma as they drop penis less often?
Horse- geldings
What is the most common malignant skin tumour in horses?
-squamous cell carcinoma
What are some common sites of squamous cell carcinoma
– ocular/periocular tissues
– Genitalia
- penis
– nares
– mouth
