Semen Collection & Freezing

Semen collection centre

RAMSEM is a registered semen collection centre.

The purpose of the centre is to collect and freeze sheep and goat semen for the owner and to make semen available to the small-stock industry.

Advantages of Frozen Semen for the stud breeder

Frozen semen is the best insurance for a ram – preservation of genetic material.
More ewes can be inseminated with semen from a single ram.
Several co-owners of one expensive ram can still make full use of the ram
Genetic progress – Semen from rams proven on merit, based on performance testing of their progeny, can be distributed throughout a country and many stud breeders can benefit from a national program
More economical to buy semen from a few top stud rams than to invest heavily in only one expensive ram.
Frozen semen can be transported nationwide –no need to transport rams, therefore there is no risk for injury of the ram
AI programs can be planned and executed properly – breeders know exactly how many doses of semen are available.
Frozen semen can be stored in liquid N2 for a very long time.

Precautionary measures for greater success with semen collection

A ram must be in good health, condition and adapted to pellets
A ram must be used to handling
4-6 weeks rest after the mating season or any form of stress
Application of Multimin + Se and Vit A, D, E / Ovi-Thrive 4-6 weeks prior to semen collection
Shear, dose and vaccinate timeously.
Observe the condition of hooves and drain abscesses beforehand

Collection of Semen by Electrical Stimulation

Electrical stimulators with a bipolar rectal electrode that gives a 10-15 Volt output. The ram is restrained in a lateral position. Straightening of the sigmoid flexure extends the penis and the glans penis is grasped and held with a piece of gauze swab. The rectal probe is lubricated and inserted into the rectum to a depth of 15-20cm, taking care to avoid injury. The rectal probe is applied towards the floor of the pelvis and short stimuli are applied with intervals. The glans penis shows congestion and with the correct stimulation semen is collected in a pre-heated and sterile tube.

Semen is very sensitive, especially to temperature
All glassware for collection and handling must be clean, sterile, dry and warm (minimum 30°C). Work in a clean, enclosed area, protected against sun, wind, dust and insects
Directly after collection the tube with semen is put in a water bath at 32°C-34°C
Each semen sample is examined for the following
Volume: This is assessed by a calibrated collecting glass. Semen volume varies from 0,3ml to 2 ml with an average of 1 ml. Variation due to individual rams, size of testes, age of ram, frequency of collection, feeding, condition and health of ram.
Density and colour: Density or consistency is an indication of the concentration of the semen

Semen Collection by Artificial Vagina

This is the first step that has to be mastered to do AI on a sustainable basis.
Both the semen collector or operator and rams need to be well trained.
The operator has to know his rams and gain their trust.
Rams must be accustomed to be being in pens and to be handled regularly.
For semen collection you need a fixed routine.
Put a teaser ewe in a neck clamp and introduce the ram for short intervals until the ram mounts
Identify temperament of each ram. Dominant rams are easier to collect. Spend more time with rams of shy and wild temperament
There are 5 stages of collection: Foreplay; Erection; Mounting; Ejaculation; Dismount and Rest
An artificial vagina (AV) is an imitation of the vagina of the ewe and provides thermal (temperature) and mechanical (pressure) stimulation to the erect penis of the male to cause ejaculation. The AV consists of an outer casing of rubber or plastic 15-20cm x 5-6cm and an inner liner made of rubber or latex. The liner is folded back and secured over the end of the casing. At one end a sterile calibrated semen collection glass is inserted. The space between the casing and liner is filled with warm water through a tap in the casing. The vagina can also be inflated through the tap to exert more pressure. The temperature on the inside of the liners should be 42°C -45°C - this is a critical aspect of successful collection. When the AV is filled with water of 50°C-55°C – this usually provides correct internal temperatures. Temperature of surroundings affects temperature of equipment and adjustments have to be made. Check with a thermometer to find the correct inside temperature and water temperature.
To prevent cold shock, the collecting tube should be warmed to 30°C-37°C before collections
When the ram mounts the sheath is gently grasped and the penis is deflected onto the open end of the A.V. A vigorous upward and forward thrush signifies that ejaculation has occurred
The A.V. is turned with the collecting glass downwards, the pressure of the liner is released and the glass with semen placed in a warm bath at 30°C-34°C

An artificial vagina (AV) is an imitation of the vagina of the ewe and provides thermal (temperature) and mechanical (pressure) stimulation to the erect penis of the male to cause ejaculation. The AV consists of an outer casing of rubber or plastic (T-piece) 15-20cm x 5-6cm and an inner liner made of rubber or latex. The liner is folded back and secured over the end of the casing. At one end a sterile calibrated semen collection glass is inserted. The space between the casing and liner is filled with warm water through a tap in the casing. The vagina can also be inflated through the tap to exert more pressure. The temperature on the inside of the liners should be 42°C -45°C – this is a critical aspect of successful collection. When the AV is filled with water of 50°C-55°C – this usually provides correct internal temperatures. Temperature of surroundings affects temperature of equipment and adjustments have to be made. Check with a thermometer to find the correct inside temperature and water temperature.

To prevent cold shock, the collecting tube should be warmed to 30°C-37°C before collections.
When the ram mounts the sheath is gently grasped and the penis is deflected onto the open end of the A.V. A vigorous upward and forward thrush signifies that ejaculation has occurred.
The A.V. is turned with the collecting glass downwards, the pressure of the liner is released and the glass with semen placed in a warm bath at 30°C-34°C.

Microscopic Examination of White Waterbuck Semen

Collection of Semen by Electrical Stimulation

Semen is very sensitive, especially to temperature.
All glassware for collection and handling must be clean, sterile, dry and warm (minimum 30°C). Work in a clean, enclosed area, protected against sun, wind, dust and insects.
Directly after collection the tube with semen is put in a water bath at 32°C-34°C.
Each semen sample is examined for the following:
- Volume: This is assessed by a calibrated collecting glass. Semen volume varies from 0,3ml to 2 ml with an average of 1 ml. Variation due to individual rams, size of testes, age of ram, frequency of collection, feeding, condition and health of ram.
Density and colour: Density or consistency is an indication of the concentration of the semen

Density Concentration (Number of spermatozoa x109 per ml.)

Thick Creamy	5,0 (4-6 x 109)
Creamy	4,0 (3,5-4,5 x 109)
Thin Creamy	3,0(2,5-3,5 x 109)
Milky	2,0 (1-2,5 x 109)
Thin Milk	0,7 (0,4-1,0 x 109)
Watery	Insignificant

Colour

Ram Semen	White to Ivory
Buck Semen	White to Yellow
Presence of Blood	Pink
Contamination or infection	Grey or Brown

Wave motion and Motility

Assessment of wave motion is the simplest test for motility of fresh undiluted semen. Good wave motion can be seen in the collection glass with the naked eye. Under a microscope a scoring system from 0-5 is assessed for each undiluted sample.

Score	Class	Description
5	Very Good	Dense, very rapidly moving waves, 90% or more of the spermatozoa are active.
4	Good	Vigorous wave movement but not as rapid as for score 5 70-85% of sperm cells are active.
3	Fair	Only small, slow moving waves 45-60% of sperm cells are active.
2	Poor	No waves are formed but some movement of sperm is visible. 20-40% of sperm cells are alive but with poor motility.
1	Very Poor	Only weak movement, Only about 10% of spermatozoa, show signs of life.
0	Dead	All sperm cells are motionless.

With a good phase contrast microscope equipped with a heated stage, a drop of diluted semen under a cover slip can be examined for progressive motility, percentage of live and dead sperm and also an assessment of the morphology of the sperm.

Further tests on semen.

Stained smears to examine for sperm morphology and presence of infection.

Freezing of Semen in straws

For one-step freezing, good quality semen is diluted at 30°C-34°C with the prepared diluent for freezing. Only the best samples are diluted according to their density.
The diluted semen is cooled in a walk-in refrigerator to 5°C over a period of 1½-2 hours.
Semen straws are identified by a straw printer by means of heat transfer.
Then semen straws are filled up by using an automated filling machine that seals the straw with ultrasound.
The straws are frozen by using a computer temperature controlled liquid nitrogen freezing chamber.

One straw from each batch is thawed the next day and a proper evaluation is done with a good phase contrast microscope equipped with a warm stage at 37°C.
Only batches of semen with a progressive motility of 35% and higher are kept for AI.
An incubation test, where thawed semen is kept for 2-4 hours in a water bath at 37°C, is useful as an additional quality test.
One straw of 0,25ml with good post thaw motility is regarded as a semen dose/ewe.
Each straw consists of at least 20 million live progressive spermatozoa.