Semen evaluation

Question 1

Define Daily sperm production

Answer 1

The minimum number of spermatozoa produced within a 24-hour time period is known as daily sperm production. This will vary among stallions and is strongly influenced by testicular size.

Question 2

Define Daily sperm output

Answer 2

Refers to the number of spermatozoa that can be collected per 24-hour period from a stallion and is determined by collecting the stallion daily for seven days.

Question 3

How is semen collected in the bull?

Answer 3

Via artificial vagina (Total ejaculate is 5-8ml)

Question 4

How is semen collected in the ram?

Answer 4

Via artificial vagina (Total ejaculate is 0.5-2ml)

Question 5

How is semen collected in the stallion?

Answer 5

Via artificial vagina, large condom or residual drips from the urethra after dismounting (Total ejaculate is 60ml)

Question 6

How is semen collected in the boar?

Answer 6

Via artificial vagina (Total ejaculate is 200ml)

Question 7

How is semen collected in the dog?

Answer 7

Via artificial vagina (Total ejaculate is 2ml)

Question 8

How is semen collected in the tom?

Answer 8

Via artificial vagina or electro-ejaculation (Total ejaculate is 0.75ml)

Question 9

What is the epididymal transit time for a bull?

Answer 9

14 d

Question 10

What is the epididymal transit time for a ram?

Answer 10

12 d

Question 11

What is the epididymal transit time for a stallion?

Answer 11

9 d

Question 12

What is the epididymal transit time for a boar?

Answer 12

11 d

Question 13

What factors can influence the production of sperm?

Answer 13

The production of sperm can be influenced by puberty (the epididymis matures after the testes), hormones (androgen), seasonality, age, number of Sertoli cells.

Increased ejaculation frequency can reduce passage time from tail (immature sperm are ejaculated), increased temperature speeds up sperm transport (can be bad for sperm maturation and fertility), oestrdiol speeds up transit time too.

Question 14

What effect do hormones have on sperm production?

Answer 14

The function of the epididymis is influenced by Androgen and dihydrotestosterone. Oxytocin and vasopressin increase contractility,

Question 15

What are sperm stained with and why?

Answer 15

The semen are stained with nigrosin: eosin,
Sperm with damaged membranes allow eosin to penetrate so sperm appear pink and sperm with intact membranes exclude eosin so sperm remain unstained (white).

Question 16

What is the scale for sperm motility?

Answer 16

0 - Non motile
I - Motile but not progressive
II - Small circles with slow progression
III - Large circles with moderate progression
IV - Vigorous forward progression