448 semen collection (Exam 2)

Spermatogenesis

- initiated in male testis at start of puberty

- occurs within sertoli cells

- involves mitosis, meiosis, and cell differentiation

- takes 8 weeks

Spermiogenesis

involves differentiation required by spermatids to develop into sperm cells

- elongates

- nucleus condensed

- flagella and acrosome structures develop

- cytoplasm is shed

sperm cell head

1. apical ridge - indicator of sperm viability

2. acrosome - produces enzymes that facilitate sperm in penetration of oocyte

3. plasma membrane - contains small amount of cytoplasm remaining in sperm. surrounds entire cell

4. nucleus - haploid, condensed DNA

5. post-acrosomal region - where sperm attaches head to vitelline membrane of the oocyte during fertilization

sperm cell tail

1. capitulum - attachment site to head during differentiation

2. mid piece - contain mitochondrial helix for energy production

3. inner double tubules - 9 + 2 arrangement, causes tail to bend and allows movement

4. outer coarse fibers - fibrous sheath that surrounds tail

spermatozoa

1. only cell known to perform its function separate from parent organism

2. can live independently of parent organism

3. capable of independent motility

4. mature sperm cells are non dividing

* need to mature before they are capable of fertilization

ejaculation process

1. intromission - penis into vagina

2. stimulation of the glans penis - spinal nerves - contractions in epididymis and vas deferens - semen into urethra

3. emission - movement of seminal fluids from accessory sex glands into pelvic urethra for mix with sperm cells

4. forceful muscle contractions - urethralis, ischiocavernosus and bulbospongiosus muscles contract to expel semen

semen collection ways

1. artificial vagina

2. electroejaculation

3. glove-hand method

4. condom

5. digital manipulation

Artificial Vagina (rams, bulls, boars, stallions)

advantage: representative sample achieved 

disadvantage:Training needed 

electroejaculation (bulls, rams, boars)

advantage: No training needed

disadvantage: non-representative sample

Glove-Hand Method (boars)

advantage: representative sample can be achieved

disadvantage: can take up to 10 minutes

condom

advantage: ?

disadvantage: can fall off

digital manipulation (poultry, dogs, cats)

advantage: representative sample can be achieved

disadvantage: time consuming

boar - 100-250 mL

highest total number of sperm cells per ejactulation

ram - 3.0 billion/mL

highest sperm cell concentration ejaculate in mammals

determining sperm cell concentration

1. Visual appraisal - thick, chalky, high concentration

2. spectrophotometer - calibrated using standard curve and comparing sample

3. Hemocytometer - glass slide with precision grid etched within

progressive motility

forward movement of sperm cells

good = 60% or higher

abnormal sperm cells

influenced by genetic and environmental factors

- 20b sperm cells are produced daily

- 5-15% abnormal cells is acceptable

- 20%+ may lead to low fertility

head abnormalities sperm

crater defect, tapered heads, ruffled acrosome, knobbed acrosome

tail abnormalities sperm

coiled tail, double midpiece, folded tail, detached head

1:100

dilution for stallion, boars, dogs

1:200

dilution for rams and bulls

500 million (fresh) & 1 billion (cooled and shipped)

stallion motile cells req/dose

20 million ~ .02 billion

bull motile cells req/dose

3 billion

boar motile cells req/dose

40 million ~ .04 billion

ram motile cells req/dose

150 million ~ .150 billion

dog motile cells req/dose

1. calculate motile cells/mL

cells/mL X progressive motile

2. calculate total motile cells

motile cells/mL X semen volume

3. calculate insemination doses

total motile cells / motile cells required per dose

then income

#^ X cost

steps to determine sperm cell concentration

calculate motile cells/mL

cells/mL X progressive motile

calculate total motile cells

motile cells/mL X semen volume

calculate insemination doses

total motile cells / motile cells required per dose x income