Collecting boar semen
Collect boar semen in a shady, draught-free environment. Exposure to ultraviolet light and any sudden temperature changes can cause deterioration of boar semen. Therefore, a warm (34°C), dry, insulated flask is required for collection.
Once the boar has mounted the adjustable dummy sow, the person collecting the semen should grasp the spiral end of the penis with their gloved hand (polyvinyl, not latex, and clean, dry and warm) and allow the boar to thrust a few times before applying pressure. The pressure caused by the clenched hand (some boars prefer more pressure than others, which becomes obvious with experience) imitates the oestrus sow's cervix and stimulates ejaculation.
To minimise irritation to the boar and disruption to the process, the long hairs around the boar's prepuce should be clipped.
To reduce the risk of dirt entering the semen sample, it's good practice to wear 2 gloves on the manipulating hand, removing one glove when the boar's penis is grasped.
A 4-phase ejaculation process occurs once the boar's penis is 'locked' in the hand and the boar relaxes. This takes 5–10 minutes to complete. Large amounts of gel signal the end of ejaculation. The boar should be observed after collection to ensure that the penis is fully retracted.
- First phase (pre-sperm fraction) consists of clear seminal fluid, some gel, and dead sperm cells, and is heavily contaminated with bacteria. This should not be collected.
- Second phase (sperm-rich fraction) is around 50mL in volume, creamy-white in colour, and contains the greatest density of spermatozoa. Collect in the pre-warmed thermos or cup.
- Third phase is about 80ml in volume, and greyish in colour due to the lower density of spermatozoa.
- Fourth phase (post-sperm fraction) is up to 250ml. Clear seminal plasma (free of spermatozoa) and gel is secreted from the accessory glands (the gel is separated from the collection by gauze, or similar material, fastened over the collection flask).
Cap the collection thermos or cup, place in a warm receptacle and transport to the processing area.
Filtering particles of gel from the semen prevents catheter blockage during insemination. Hair, skin or dust particles from the boar or dummy must be excluded from the flask during collection.
When semen is to be collected for dilution and storage over a few days, only the second and third phases of boar ejaculate are collected.
When to collect
Collection of semen (from the same boar) should be restricted to no more than 3 times a week. This ensures high sperm concentration and semen volume. Excessive collection over a short period of time results in low semen quality and quantity and can reduce the boar's sex drive.
It's important to maintain accurate records that identify the:
- name and number of the semen donor
- volume of the samples collected
- date and time the sample was collected
- use-by-date (for diluted semen) or use-by-time (for fresh semen)
- motility and density of each sample, including reference to abnormalities.
These records are especially important for diluted semen, which can be kept for several days. Accurate records will ensure that the oldest stocks are used first and that expired samples are discarded.