Key Points and Detailed Operating Methods of Boar Artificial Semen Collection

An ideal semen collection method should meet the following four conditions: (1) it can collect all the semen ejaculated by the boar in one ejaculation; (2) it does not affect semen quality; (3) the boar's reproductive organs and sexual function will not be damaged or affected; (4) the instruments and equipment are simple and convenient to use.

The methods of artificial semen collection include: the electrical stimulation method, the artificial vagina method, the hand-grip method and the cylinder-grip method.

1. The electrical stimulation method is to insert a probe with electrodes into the boar's rectum and stimulate the ejaculation center of the reproductive tract with low-voltage pulses to induce ejaculation; even if the penis is not fully extended, semen can still be obtained. The semen obtained by this method is thinner than that from natural mating, and the success rate is not high. This method is suitable for collecting semen from boars that cannot mount due to leg injuries but have high breeding value.

2. The artificial vagina method uses an artificial vagina that simulates the environment of the sow's vagina; when the boar mounts a sow in estrus or a dummy sow, the semen is collected. This method is relatively convenient, but it is time-consuming and labor-intensive, so it is rarely used now.

3. The hand-grip method and the cylinder-grip method. The hand-grip method of collecting boar semen is currently a widely used method. It has the advantages of simple equipment, convenient operation, and the ability to collect the sperm-rich portion of the semen, but its disadvantages are that the semen is easily contaminated and affected by cold shock.

The hand-grip method of semen collection mimics the constricting force of the sow's cervix on the boar's spiral glans penis to induce ejaculation; therefore, appropriate pressure is very important in the hand-grip method of semen collection.

The hand-grip method of semen collection must follow the following three principles: (1) the spiral glans penis should be fixed; (2) the semen should be kept from contamination as much as possible; (3) the sperm should be prevented from cold shock.

Therefore, during operation, attention should be paid to the following: the semen collector should wear sterilized gloves and squat on the left side of the dummy sow; after the boar mounts the dummy sow, wash and disinfect the area near the boar's prepuce with 0.1% potassium permanganate solution, and rinse with physiological saline; then form the hand into an empty fist, and when the boar's penis extends out, guide it into the empty fist and let it thrust and rotate for a moment; use the fingers to grip the spiral glans penis from light to heavy with an elastic rhythm so that it cannot rotate, and when the penis is fully erect, extend it forward along the movement (do not pull forcefully), adjusting the pressure with the fingers in an elastic and rhythmic manner, and the boar will then ejaculate. The other hand holds a semen collection bottle with filter gauze and insulation to collect the sperm-rich portion of the semen. When the boar stops ejaculating, pressure can be applied again in the same way, and the 2nd or 3rd-4th ejaculation can be obtained, until ejaculation is completely finished.

The cylinder-grip method is made by shortening the artificial vagina and attaching a rubber funnel. It is a combination of the artificial vagina and the hand-grip method, and has the dual advantages of the artificial vagina and the hand-grip method. During operation, the semen collector holds the funnel part with the right hand in a fist-grip shape, close to the rear of the dummy sow; when the penis extends into the artificial vagina and enters the fist-grip part of the funnel, the semen is collected in the same way as with the hand-grip method.