Semen extending, chilling or freezing and shipment

Question 1

Where is seminal plasma produced?

Answer 1

Epididymis
Ampulla
Seminal Vesicles
Prostate Gland
Bulbourethral glands

Question 2

List 5 important roles of seminal plasma..

Answer 2

• Media for Transport- Fluid volume to sperm - urethra
• Ideal Environment- Enhances sperm viability in mare repro tract
• Stimulates sperm motility- Biochemical stimulation – activates metabolic activity
• Delays sperm capacitation- Prevents them from events for immediate fertilisation
• Stimulates intrauterine transport of sperm- Uterine muscle contractions

Question 3

What does extender do?

Answer 3

extends the motility and viability of the spermatozoa

Question 4

How does extender work?

Answer 4

nutrients, Buffers, Antibiotics, Electrolytes, Protects against changes in temperature (purely as a physical barrier), Limits oxidative stress, Dilutes Effects of Seminal Plasma.

Question 5

In terms of temperature.. at what range is sperm most vulnerable?

Answer 5

Sensitive area between 20oC and 4oC

Question 6

What is the normal pH of ejaculate?

Answer 6

Normal pH of ejaculate is 7.3-7.5… slightly basic/alkali

Question 7

Why is there a need for buffers in extender? i.e. what causes the pH to drop, thus creating a more acidic environment?

Answer 7

Buffers such as NaHCO3 are included in semen extenders because pH is altered in the semen sample by metabolically active sperm that secrete acids, decreasing the pH

Question 8

Is xtended semen a good medium for bacterial growth??

Answer 8

Yes, very!

Question 9

The most common energy sources in extenders are simple sugars: (2 types)

Answer 9

glucose and sucrose

Question 10

Types

Answer 10

Commercial extenders- Provide a pre-mixed solution with all necessary additives
Non Fat Dry Skim Milk (NFDSM)- Glucose extender

Question 11

Why can ‘normal’ milk not be used as an extender?

Answer 11

it contains lactoferrin

Question 12

Why is it necessary to cool semen?

Answer 12

Fresh Semen stored at 36-37oC (BT) and room temperature (20-22oC) deteriorates rapidly

Question 13

At body temp spermatozoa metabolism is maximal. What effects does this have on the integrity of the sperm?

Answer 13

At body temp spermatozoa metabolism is maximal, which causes waste products such as lactic acid which can change the pH causing permanent cellular damage. (increase LA= decrease pH)

Question 14

In a quick flow chart, summarise the effects of cooling semen and how this aids in its’ longevity..

Answer 14

Decrease temp= decrease metabolic activity= lipid peroxidation = increased longevity

Question 15

‘Cold shock’ is characterised by.. (4)

Answer 15

• Abnormal swimming patterns
• Damage to sperm membrane and acrosome
• Loss of motility
• Reduced metabolism

Question 16

Reduction in temperature changes does what, to the sperm membrane?

Answer 16

Reduction in temperature, changes sperm membrane from the liquid crystalline state to the gel state

Question 17

List the three most common causes of sperm death during preparation for chilling and shipment

Answer 17

temperature shock, UV light exposure or lack of a nutrient source.

Question 18

The four criteria for a maximum fertility dose of fresh or chilled semen are:

Answer 18

• Minimum 1:3 semen to extender ratio
• 20-60mL total dose volume
• 25-50 million progressively motile sperm per mL
• Minimum 500 million progressively motile sperm per dose

Question 19

What is cryopreservation?

Answer 19

Freezing, or cryopreservation, of semen in liquid nitrogen at -196ºC

Question 20

For frozen semen, the criteria for a maximum fertility dose are:

Answer 20

• 4-8 straws (0.5mL each) per dose
• Minimum 500 million progressively motile sperm after thawing (allow for a 50% loss of progressively motile sperm during the freeze-thaw process)