Semen collection refers to the process of obtaining semen from males with the use of various methods.The methods of collection of semen have been devised from time to time. The older unsatisfactory methods have been gradually replaced by the newer modern techniques. Suitability of a particular method depends on the type and condition of a species, e.g. artificial vagina method is applicable to almost all of our domestic animals but certainly not on poultry, where the massage method is the only practical solution to get ejaculation.

Semen collection from bull by Artificial Vagina

This method is closest to the natural condition that is assumed to yield the most normal ejaculate of all methods used. Preparation of bulls and methods of collection are described below as per the MSP

1. Ideally, the floor of the collection yard shall be made of concrete layer at a depth of one foot from the ground level. Mixture of sand and limestone shall be used to fill up to ground level and pressed firmly. Alternatively, good quality rubber mat (with interlocking arrangement) or coir mat shall be put into concrete groove of the mounting area for adequate cushioning effect. After collection, the area must be thoroughly cleaned and odorless disinfectant solution (Colloidal iodine) be sprayed. A dusty floor shall be avoided to prevent dust falling on the AV and semen samples.
2. On the day of collection, before taking semen collection, the bulls shall be properly washed and cleaned. After the bulls are brought to collection arena, before taking collection, the prepuce shall be cleaned externally with a sterilized napkin soaked in normal saline to remove any sand or dust particles. For each bull a separate napkin shall be used. The person responsible to carry out preputial wash must use disposable gloves and separate sterilized nozzle for each bull to avoid transmission of IBR infection from one bull to another
3. The temperature of the artificial vagina is more important and should always be checked before making the collection. Too high a temperature may cause injury to the penis and the bull may refuse to serve in future. On the other hand at lower temperature, there may not be complete ejaculation and the whole ejaculate may be contaminated with urine.
4. At the time of collection the temperature inside the artificial vagina should be between 40⁰ to 52⁰C
5. The bulls shall be sexually prepared by giving two / three false mounts followed by two minutes restraint and the total time limit should be not more than 12 minutes. The duration of each false mount shall be for 1 to 2 minutes.
6. Sterilized bull aprons shall be used to avoid penis touching hindquarter of the dummy.
7. Preferably veterinarians shall take semen collection. If semen is collected by staff, a veterinarian shall remain present to supervise the collection process. While taking collection it shall be ensured that AV is not thrusted on penis of bull, instead penis should be guided to AV.
8. During collection AV is held at an angle of 55 degree with the horizontal plane of the cow or dummy. It is so because the penis of the bull enters the vagina of the cow at that angle. When the bull mounts, the penis is quickly guided into the artificial vagina with the operator’s hand. Care is taken not to touch the exposed part of the penis, as this stimulates the bull to ejaculate. After the bull dismounts, the aritificial vagina is taken off the penis and kept in an upright condition after releasing the pressure by draining water and air out of it. This allows the ejaculate to flow from the cone of the vial which is then detached from the cone and taken to the laboratory for examination.
9. Separate AVs shall be used for each mounting.
10. Generally mature bulls require an outer rubber casing 40 cm in length and 6.4 cm in diameter while yearling bulls and buffalo bulls require a casing 30 -35 cm in length and 5.1 -5.7 cm in diameter. In case of goat and sheep the outer tube should be about 20 cm long and 5 cm in diameter.
11. Use of lubricant shall be avoided. If it is extremely essential to use lubricant, separate sterilized glass rods shall be used for smearing K- Y Jelly on each AV.
12. The AV shall not to be shaken after ejaculation; otherwise lubricant and debris may mix with the semen samples.
13. The entryof visitors/staff/ laborers’ shall be strictly prohibited in the collection arena at the time of semen collection and inside the semen laboratory.
14. Semen must be obtained from a bull having normal libido. While taking two ejaculations the semen station shall keep a gap of 10 to 12 minutes between two ejaculates, depending upon the refractory period of the bull. (To harvest more quantity of semen, interval between two ejaculates shall be kept for 40 to 45 minutes. After taking first ejaculate, the bull shall be taken back to the shed for feeding and watering and again brought backfor taking second ejaculate.
15. Semen stations must follow the norm of two ejaculates per collection and two collections per bull per week for taking annually at least 90 collections and 180 ejaculatesfrom each adult bull.

Advantages

• Practically the whole ejaculate is collected in uncontaminated and natural stage.
• It is free from the extraneous secretions.
• Sterile conditions of the apparatus ensure disease control.
• The viability of the sperm is better.

Disadvantages

• Occasionally it is difficult to get the males to serve the artificial vagina.
• The apparatus involved is slightly costly and requires technical hands.